Antibodies to blood group system antigens and their characteristics must be identified when such antibodies are detected in a potential recipient's  serum  or  plasma . [ 9 ]  The specificity of the antibody aids the  medical laboratory scientist  in determining if the antibody is clinically significant. Antibody identification is a very laborious process. [ 1 ]


Characteristics of clinically significant antibodies include: reactive at body temperature (37°C),  immunoglobulin (Ig) class G ,  IgM  that reacts at body temperature, ability to cross the  placenta , ability to cause red blood cell destruction, and/or antibodies directed against commonly known clinically significant red cell antigens. [ 10 ]  For example, if an individual is exposed to a red cell antigen (via blood transfusion, pregnancy, stem-cell transplant) that they do not inherently possess, they may form a clinically significant antibody directed against that antigen. If a patient receives a transfusion of packed red blood cells possessing the  Kell  antigen (big K or simply K), they may form an antibody called anti-K (anti big K). Subsequent transfusions with K-positive packed red blood cells would cause an immediate  hemolytic transfusion reaction . The K antibody reacts at 37°C, is IgG, capable of crossing the placenta, and known to cause immediate red blood cell destruction.


The presence of  autoantibodies  directed against self red blood cell antigens can complicate the antibody identification process. Red blood cell autoantibodies tend to be specific for red cell antigens of high frequency within the population. An antibody elution can aid in the identification of clinically significant  alloantibodies  when autoantibodies interfere with the antibody identification process. [ 11 ]


There are several methods of antibody elution used in clinical blood banking. Some of these methods include manipulating temperature, manipulating  pH , use of organic solvents, and  chloroquine . [ 2 ]  Each of these methods have advantages and disadvantages, and the method of elution will vary depending on clinical utility. One of the more commonly used methods is an acid elution, because it is quick, cheap, and relatively easy to perform. [ 3 ] [ 12 ]


The main steps involved in an acid elution include: [ 3 ] [ 2 ]


The main method of antibody and antigen detection used in a clinical laboratory is red blood cell  agglutination . [ 1 ]  Most IgM antibodies are easier to detect because they are larger and react at room temperature (20°C). [ 13 ] [ 14 ]  This concept is what makes ABO/Rh testing so quick and easy to perform. However, most clinically significant non-ABO antibodies react at body temperature (37°C) and will not result in agglutination without the addition of multiple steps: incubation, washing, and the addition of anti-human globulin (AHG) reagent. [ 15 ]


Anti-human globulin is an antibody directed against human IgG antibodies. [ 16 ]  When the smaller IgG antibody is attached to red blood cells, the larger AHG antibodies create a cross-link between IgG sensitized RBC forming visual agglutination. When this agglutination is observed, the antiglobulin test is considered positive for the detection of the antibody and/or antigen(s) present. [ 2 ]


There are two main types of antiglobulin testing: indirect and direct. [ 17 ] [ 18 ]  Indirect antiglobulin testing is used to detect antibodies in  plasma / serum , whereas direct antiglobulin testing is used to detect antibody bound to red blood cells. When the direct antiglobulin test is positive, we must perform an antibody elution to remove the antibody for identification and to determine the antibody's clinical significance. [ 3 ]


Antifibrinolytics  are a class of  medication  that are inhibitors of  fibrinolysis . [ 1 ]  Examples include  aminocaproic acid  (ε-aminocaproic acid) and  tranexamic acid .  These  lysine -like drugs interfere with the formation of the fibrinolytic enzyme plasmin from its precursor plasminogen by plasminogen activators (primarily t-PA and u-PA) which takes place mainly in lysine rich areas on the surface of fibrin. [ citation needed ]


Another example,  aprotinin , is a naturally-occurring broad-spectrum protease inhibitor; [ 2 ]  some countries refuse to approve this medication because it supposedly has a greater mortality rate than its alternatives (tranexamic acid and aminocaproic acid) and causes damage to the kidneys and heart. It is widely agreed that systemic aprotinin use should be minimized due to these concerns. [ 3 ]


An  antihemorrhagic  ( British English :  antihaemorrhagic ) agent is a substance that promotes  hemostasis  (stops  bleeding ). [ 1 ]  It may also be known as a  hemostatic  (also spelled  haemostatic ) agent. [ 2 ]


Antihemorrhagic agents used in medicine have various mechanisms of action:


Hemostatic agents are used during surgical procedures to achieve hemostasis and are categorized as hemostats, sealants and adhesives. They vary based on their mechanism of action, composition, ease of application, adherence to tissue, immunogenicity and cost. These agents permit rapid hemostasis, better visualization of the surgical area, shorter operative times, decreased requirement for transfusions, decreased wound healing time and overall improvement in patient recovery time. [ 3 ]


There are several classes of antihemorrhagic drugs used in medicine.  These include  antifibrinolytics , blood  coagulation factors ,  fibrinogen , and  vitamin K . [ 4 ]


Topical hemostatic agents have been gaining popularity for use in  emergency bleeding control , especially in  military medicine .  They are available in three forms—as a granular powder poured on wounds, as a styptic pencil [ 5 ]  or embedded in a  dressing . [ 6 ]


Microfibrillar  collagen  hemostat (MCH) is a topical agent composed of resorbable microfibrillar collagen. It attracts platelets and allows for the formation of a blood clot when it comes into contact with blood. Unlike the hemostatic clamp, no mechanical action is involved.  The surgeon presses the MCH against a bleeding site, and the collagen attracts and helps with the clotting process to eventually stop bleeding. [ 7 ]


The practical application for MCH is different from that of the hemostatic clamp. [ 8 ]


Chitosan  hemostats are topical agents composed of chitosan and its salts. Chitosan bonds with platelets and red blood cells to form a gel-like clot which seals a bleeding vessel. Unlike other hemostat technologies its action does not require the normal hemostatic pathway and therefore continues to function even when anticoagulants like heparin are present. [ 9 ]


Chitosan is used in some emergency hemostats which are designed to stop traumatic life-threatening bleeding.  Their use is well established in many military and trauma units. [ 10 ]


Kaolin  (and the  zeolite  in it) activate the coagulation cascade, and have been used as the active component of hemostatic dressings (for example, in  QuikClot ). [ 11 ]


A  styptic  (also spelled  stiptic ) is a specific type of antihemorrhagic agent that works by contracting  tissue  to seal injured  blood vessels . Styptic pencils contain  astringents . [ 12 ]


A common delivery system for this is a styptic or hemostatic pencil (not to be confused with a  caustic pencil ). This is a short stick of  medication .   Anhydrous   aluminium sulfate  is the main ingredient and acts as a vasoconstrictor in order to disable blood flow.  The stick is applied directly to the bleeding site. The high  ionic strength  promotes  flocculation  of the blood, and the astringent chemical causes local vasoconstriction.  Before  safety razors  were invented, a styptic pencil was a standard part of a shaving kit and was used to seal shaving cuts. [ 13 ]   Some people continue to use styptic pencils for minor skin wounds from safety or electric razors. [ 13 ]


Styptic powder is used in the  veterinary  trade to stop bleeding from nails that are clipped too closely.  This powder is generally used on animals, such as   cats ,  dogs , and  rabbits , whose vein is found in the center of the nail. [ 14 ]


NM_004925 NM_001318144


NP_001305073 NP_004916


Aquaporin 3  ( AQP-3 ) is the protein product of the human  AQP3  gene. [ 5 ]  It is found in the basolateral cell membrane of principal  collecting duct  cells and provides a pathway for water to exit these cells. [ 6 ]  Aquaporin-3 is also permeable to   glycerol ,  ammonia ,  urea , and  hydrogen peroxide . It is expressed in various tissues including the skin, respiratory tract, and kidneys as well as various types of cancers. [ 7 ]  In the kidney, aquaproin-3 is unresponsive to the antidiuretic hormone  vasopressin , unlike  aquaporin-2 . [ 8 ]  This protein is also a determinant for the GIL blood group system. [ 9 ]


Suberoylanilide hydroxamic acid  (SAHA) (a  HDAC inhibitor ) increases expression of aquaporin-3 in normal skin cells ( keratinocytes ). [ 10 ]


Aquaporin 3 levels are often lower in  psoriasis  than in healthy skin. [ 10 ]


Aquaporin 3 is expressed more in  atopic eczema . [ 11 ]


Recent studies indicate that aquaporin 3 is overexpressed in many types of malignancies such as  melanoma [ 7 ]  and  primary effusion lymphomas [ 12 ]  as well as cancers of the lung, colon, stomach, esophagus, mouth, liver, and pancreatic duct. [ 5 ] [ 12 ]  Based on these as well as  cell culture  studies, it is suggested that this overexpression contributes to the growth and spread of at least some of these cancers and therefore may be a therapeutic target for the treatment of these cancers. [ 5 ] [ 7 ] [ 12 ]


Auberger's blood group  is a type of  human blood group [ 1 ]  in which the Aua  antigen  is expressed. It is found in 82% of  caucasians . It may be related to the  Lutheran antigen system . [ citation needed ]


The blood group was named after patient Auberger, who was a 59-year-old  French  woman with  oesophageal varices . [ citation needed ]


Auberger's blood group  at  Who Named It?


The  Augustine blood group system  is a  human blood group system . It includes four  red blood cell  surface  glycoprotein   antigens  which are encoded by  alleles  of the gene  SLC29A1 . [ 1 ]


The protein which acts as the Augustine antigens is  equilibrative nucleoside transporter 1 , a transmembrane  glycoprotein  that mediates cellular uptake of  nucleosides . [ 2 ]  This protein is abundant in  erythroid progenitor cells  and in mature red blood cells. [ 3 ]  There are four known variants of the antigen: AUG1, AUG2, AUG3, and AUG4. [ 1 ]  One person may express multiple variants; AUG:1,2,4 (expressing AUG1, AUG2, and AUG4) is the common  phenotype . [ 3 ]


Antibodies  against Augustine system antigens can be stimulated by pregnancy or  blood transfusion  and have the potential to cause severe  hemolytic disease of the fetus and newborn  and  acute hemolytic transfusion reactions . [ 1 ] [ 3 ]


In red blood cells, the Augustine antigen protein seems to play a role in  adenosine  transport in  cell differentiation , when immature cells become red blood cells. [ 3 ]  Individuals with the null phenotype, lacking any form of the transporter protein, have  mineralization  around the joints,  ectopic calcification , and abnormal red blood cells. [ 3 ] [ 4 ]


AUG2 was first identified as At a  in 1967 as a common human antigen. [ 3 ]  The SLC29A1 gene was identified in 1997 and found to encode AUG1 and AUG2 in 2015. [ 3 ]  In response to the 2015 discovery, the  International Society of Blood Transfusion  established the Augustine blood system as the 36th human blood group system. [ 3 ]  AUG3 and AUG4 were identified in 2018. [ 1 ]


The blood group system was named Augustine after the surname of the individual with the first identified anti-At a  antibody, a woman of African ancestry whose third child had a positive  direct antiglobulin test  at birth. [ 4 ]


Autoimmune hemolytic anemia  ( AIHA ) is an  autoimmune disorder  which occurs when  antibodies  directed against the person's own  red blood cells  (RBCs) cause them to burst ( lyse ), leading to an insufficient number of oxygen-carrying red blood cells in circulation ( anemia ). The lifetime of the RBCs is reduced from the normal 100–120 days to just a few days in serious cases. [ 1 ] [ 2 ]  The intracellular components of the RBCs are released into the circulating blood and into tissues, leading to some of the characteristic symptoms of this condition. The antibodies are usually directed against high-incidence  antigens , therefore they also commonly act on allogenic RBCs (RBCs originating from outside the person themselves, e.g. in the case of a  blood transfusion ). [ 3 ]  AIHA is a relatively rare condition, with an incidence of 5–10 cases per 1 million persons per year in the warm-antibody type and 0.45 to 1.9 cases per 1 million persons per year in the  cold-antibody  type. [ 4 ]  Autoimmune hemolysis might be a precursor of later onset  systemic lupus erythematosus . [ 5 ]


The terminology used in this disease is somewhat ambiguous. Although  MeSH  uses the term "autoimmune hemolytic anemia", [ 6 ]  some sources prefer the term " immunohemolytic anemia " so drug reactions can be included in this category. [ 7 ] [ 8 ]  The  National Cancer Institute  considers " immunohemolytic anemia ", " autoimmune hemolytic anemia ", and " immune complex hemolytic anemia " to all be synonyms. [ 9 ]


Symptoms of AIHA may be due to the underlying anemia; including shortness of breath or  dyspnea , fatigue, headache, muscle weakness and  pallor . [ 10 ]  In  cold agglutinin disease  (cold antibody type), agglutination and impaired passage of red blood cells through capillaries in the extremities causes  acrocyanosis  and  Raynaud phenomenon  with a rare complication of  gangrene [ 4 ]


Spherocytes  are found in immunologically mediated  hemolytic anemias . [ 11 ]  Signs of hemolysis that are present in AIHA include low  hemoglobin  (blood count), alterations in levels of cell markers of hemolysis; including elevated  lactate dehydrogenase (LDH) , decreased  haptoglobin  and elevated  unconjugated bilirubin . [ 4 ]  Reticulocytosis, or an increase in circulating immature red blood cells, may be seen. [ 4 ]


The causes of AIHA are poorly understood. The disease may be primary, or secondary to another underlying illness. The primary illness is  idiopathic  (the two terms used synonymously). Primary AIHA accounts for more than 60% of unselected  cases. [ 12 ]


Secondary AIHA can result from many other illnesses. Warm and cold type AIHA each have their own more common secondary causes. The most common causes of secondary warm-type AIHA include lymphoproliferative disorders (e.g.,  chronic lymphocytic leukemia ,  lymphoma ) and other autoimmune disorders (e.g.,  systemic lupus erythematosus ,  rheumatoid arthritis ,  scleroderma ,  Crohn's disease ,  ulcerative colitis ). Less common causes of warm-type AIHA include neoplasms other than lymphoid, and infection. Secondary warm type AIHA has been observed in cases of  Covid-19 . [ 4 ]  Secondary cold type AIHA is also caused primarily by lymphoproliferative disorders but is also commonly caused by infection, especially by mycoplasma, viral pneumonia, infectious mononucleosis, and other respiratory infections. Less commonly, it can be caused by concomitant autoimmune disorders. [ 13 ]


Drug-induced AIHA , though rare, can be caused by a number of drugs, including  α-methyldopa  and  penicillin . This is a  type II immune response  in which the drug binds to  macromolecules  on the surface of the RBCs and acts as an antigen. Antibodies are produced against the RBCs, which leads to complement activation. Complement fragments, such as C3a, C4a and C5a, activate granular leukocytes (e.g., neutrophils), while other components of the system (C6, C7, C8, C9) either can form the membrane attack complex (MAC) or can bind the antibody, aiding phagocytosis by  macrophages  (C3b). This is one type of "penicillin allergy". [ citation needed ]


In about half of cases, the cause of autoimmune hemolytic anemia cannot be determined (idiopathic or primary). This condition can also be caused by or occur with another disorder (secondary) or rarely, occur following the use of certain drugs (such as  penicillin ) or after a person has a blood and marrow  stem cell transplant . [ 14 ]


Secondary causes of autoimmune hemolytic anemia include: [ 14 ]


AIHA can be caused by a number of different classes of antibody, with  IgG  and  IgM  antibodies being the main causative classes. Depending on which is involved, the  pathology  will differ. IgG is not very effective at activating  complement  and effectively binds the  Fc receptor  (FcR) of  phagocytic cells , [ 15 ]  AIHA involving IgG is generally characterized by phagocytosis of RBCs. IgM is a potent activator of the  classical complement pathway , thus, AIHA involving IgM is characterized by complement-mediated opsonization and phagocytosis of RBCs as the amount of C3b deposited is sublytic. IgM also leads to phagocytosis of RBCs however, because phagocytic cells have receptors for the bound complement (rather than FcRs as in IgG AIHA). In general, IgG AIHA takes place in the  spleen , whereas IgM AIHA takes place in  Kupffer cells  – phagocytic cells of the  liver . Phagocytic AIHA is termed extravascular, whereas complement-mediated lysis of RBCs is termed intravascular AIHA. In order for intravascular AIHA to be recognizable, it requires overwhelming complement activation, therefore most AIHA is extravascular – be it IgG- or IgM-mediated. [ 3 ]


AIHA cannot be attributed to any single autoantibody. To determine the autoantibody or autoantibodies present in a patient, the  Coombs test , also known as the antiglobulin test, is performed. There are two types of Coombs tests, direct and indirect; more commonly, the direct antiglobulin test (DAT) is used. Classification of the antibodies is based on their activity at different temperatures and their etiology. Antibodies with high activity at physiological temperature (approximately 37 °C) are termed warm autoantibodies. Cold autoantibodies act best at temperatures of 0–4 °C. Patients with cold-type AIHA, therefore, have higher disease activity when body temperature falls into a hypothermic state. Usually, the antibody becomes active when it reaches the limbs, at which point it opsonizes RBCs. When these RBCs return to central regions, they are damaged by complement. Patients may present with one or both types of autoantibodies; if both are present, the disease is termed "mixed-type" AIHA. [ citation needed ]


When DAT is performed, the typical presentations of AIHA are as follows. Warm-type AIHA shows a positive reaction with  antisera  to IgG antibodies with or without complement activation. Cases may also arise with complement alone or with  IgA , IgM or a combination of these three antibody classes and complement. Cold-type AIHA usually reacts with antisera to complement and occasionally to the above antibodies. This is the case in both cold agglutinin disease and cold paroxysmal hematuria. In general, mixed warm and cold AIHA shows a positive reaction to IgG and complement, sometimes IgG alone, and sometimes complement alone. Mixed-type can, like the others, present unusually with positive reactions to other antisera. [ 13 ]


Diagnosis is made by first ruling out other causes of hemolytic anemia, such as  G6PD ,  thalassemia ,  sickle-cell disease . Clinical history is also important to elucidate any underlying illness or medications that may have led to the disease. [ citation needed ]


Laboratory investigations are carried out to determine the etiology of the disease. Following confirmation of hemolysis (seen with laboratory markers of low hemoglobin, elevated LDH, decreased haptoglobin, and elevated unconjugated bilirubin), a  direct antiglobulin test  (DAT)(also known as a Coomb's test) is done to show auto-immune pathogenesis with antibodies, complement or both on the erythrocyte surface. [ 4 ]  This is followed by a monospecific DAT that identifies the specific antibody and complement types on the erythrocyte surface. [ 4 ]  In cold agglutinin disease, the monospecific DAT is by definition positive for the complement molecule C3d but IgM may be negative as the molecule may detach at the time of testing. [ 4 ]  The diagnosis of cold agglutinin disease is confirmed with an elevated cold agglutinin titer. [ 4 ]


A  bone marrow biopsy  is used in AIHA to identify a possible underlying lymphoproliferative disorder. [ 4 ]


AIHA can be classified as  warm autoimmune hemolytic anemia   or  cold autoimmune hemolytic anemia , which includes  cold agglutinin disease  and  paroxysmal cold hemoglobinuria . These classifications are based on the characteristics of the autoantibodies involved in the pathogenesis of the disease. Each has a different underlying cause, management, and prognosis, making classification important when treating a patient with AIHA. [ 16 ]


The following findings may be present: [ 20 ] [ 21 ] [ full citation needed ]


Steroids are the first line treatment in warm AIHA; with oral prednisone achieving an 80% initial response rate, with a 30-40% sustained remission rate at 1 year. [ 4 ]  Steroids may be decreased at 3 weeks and tapered at 3–6 months depending on the response. [ 4 ]   Rituximab  may be added to initial management to increase the response rate, or it may be used in cases of severe disease such as IgA mediated warm AIHA, mixed AIHA,  Evans syndrome  or in cases of high hemolysis levels). [ 4 ]  If a response cannot be achieved with steroids or rituximab,  splenectomy  can be done. [ 4 ]  Other third line options, that are less studied, include  azathioprine ,  cyclophosphamide ,  cyclosporine ,  mycophenolate mofetil  and  bortezomib . [ 4 ]  The treatments for secondary warm AIHA are generally the same as primary warm AIHA, but with the addition of treating the underlying disease if possible. [ 4 ]


Steroids are not indicated in the treatment of cold agglutinin disease due to low response rates. [ 4 ]  Cases of cold agglutinin disease with mild anemia with limited and compensated hemolysis can be monitored with adjunct supportive care (such as avoidance of cold exposure or thermal protection to prevent against hemolysis). [ 4 ]  Rituximab is used to treat pathogenic B-cell clones in cold agglutinin disease with response rates of 45-60%. [ 4 ]  Relapses are common upon discontinuation of rituximab, but the medication can be restarted to achieve subsequent remission. [ 4 ]  Rituximab can be combined with  bendamustine  to achieve a 71% overall and 40% complete response rate with an increased response seen with prolonged therapy (with a time to best response at a median of 30 months) due to the drugs' effect on  long lived plasma cells . [ 4 ]  Splenectomy is less efficacious in cold agglutinin disease. [ 22 ]


Special considerations are required when treating people with AIHA using  blood transfusion . In cold agglutinin disease; the patient and the extremity should be kept warm during transfusion to prevent agglutination and hemolysis of the donor and patient red blood cells. [ 4 ]  In warm AIHA; cross-matching of blood will show incompatibility so it is recommended to perform a bedside in vivo compatibility test prior to infusion. [ 4 ]   Erythropoietin  (EPO) has been shown to increase hemoglobin levels in cold and warm AIHA. [ 4 ]


"Blood-induced icterus" produced by the release of massive amounts of a coloring material from blood cells followed by the formation of bile was recognized and described by Vanlair and Voltaire Masius' in 1871. About 20 years later, Hayem distinguished between congenital hemolytic anemia and an acquired type of infectious icterus associated with chronic splenomegaly. In 1904, Donath and Landsteiner suggested a serum factor was responsible for hemolysis in paroxysmal cold hemoglobinuria. French investigators led by Chauffard stressed the importance of red-cell  autoagglutination  in patients with acquired hemolytic anemia. In 1930, Lederer and Brill described cases of acute  hemolysis  with rapid onset of anemia and rapid recovery after transfusion therapy. These hemolytic episodes were thought to be due to infectious agents. A clear distinction between congenital and acquired hemolytic anemia was not drawn, however, until Dameshek and Schwartz in 1938, and, in 1940, they demonstrated the presence of abnormal hemolysins in the sera of patients with acquired  hemolytic anemia  and postulated an  immune mechanism . [ citation needed ]


During the past three decades, studies defining red-cell blood groups and serum antibodies have produced diagnostic methods that have laid the basis for immunologic concepts relevant to many of the acquired hemolytic states. Of these developments, the antiglobulin test described by Coombs, Mourant, and Race in 1945 has proved to be one of the more important, useful tools now available for the detection of immune hemolytic states. This technique demonstrated that a rabbit antibody against human globulin would induce agglutination of human red cells "coated with an incomplete variety of rhesus antibodies".   C. Moreschlit  had used the same method in 1908 in a goat antirabbit-red-cell system. The test was premature and was forgotten. In 1946, Boorman, Dodd, and Loutit applied the direct antiglobulin test to a variety of hemolytic anemias, and laid the foundation for the clear distinction of autoimmune from congenital hemolytic anemia. [ citation needed ]


A hemolytic state exists whenever the red cell survival time is shortened from the normal average of 120 days. Hemolytic anemia is the hemolytic state in which anemia is present, and bone marrow function is inferentially unable to compensate for the shortened lifespan of the red cell. Immune hemolytic states are those, both anemic and nonanemic, which involve immune mechanisms consisting of antigen-antibody reactions. These reactions may result from unrelated antigen-antibody complexes that fix to an innocent-bystander erythrocyte, or from related antigen-antibody combinations in which the host red cell or some part of its structure is or has become antigenic. The latter type of antigen-antibody reaction may be termed "autoimmune", and hemolytic anemias so produced are autoimmune hemolytic anemias. [ 2 ]


In general, AIHA in children has a good prognosis and is self-limiting. However, if it presents within the first two years of life or in the teenage years, the disease often follows a more  chronic course , requiring long-term  immunosuppression , with serious developmental consequences. The aim of therapy may sometimes be to lower the use of steroids in the control of the disease. In this case,  splenectomy  may be considered, as well as other immunosuppressive drugs. Infection is a serious concern in patients on long-term immunosuppressant therapy, especially in very young children (less than two years). [ 23 ]


Autologous blood therapy , also known as  autologous blood injection  or  autohemotherapy , comprises certain types of  hemotherapy  using a person's own  blood  ( auto-  +  hemo-  +  therapy ). There are several kinds, the original belonging only to  traditional medicine ,  alternative medicine , and some newer kind of medicine under investigation. The original, unscientific form is "the immediate  intramuscular  or  subcutaneous  reinjection of freshly drawn  autologous  blood". It was used in the early 20th century, when some  physicians  believed that it had  efficacy  and a logical  mechanism of action ; it was abandoned as advancing  science  made clear that it lacked those.  [ 1 ]


The other forms involve some change to the blood before it is reinjected, typically  oxygenation ,  ozonation  (ozonated autohemotherapy), [ 2 ] [ 3 ]   ultraviolet light  exposure, or  centrifugation . Forms include  platelet-rich plasma  (PRP), and  autologous conditioned serum  (ACS). [ 4 ]


It is possible that ozonated or UV autohemotherapy may have real  efficacy  and  effectiveness  in  autoimmune diseases , if they are  immunomodulatory  in some way (such as by interfering with the deranged  autoantibodies ), [ 2 ]  but this mechanism of action, if it exists, is not yet well understood; [ 2 ]  it is also logical that whatever molecular changes the ozone and UV bring about are unlikely to act  specifically  on just the desired target molecules, meaning that risks are involved.


Although  autologous blood donation  and  plasmapheresis  are conceptually analogous, they are differentiated from autologous blood therapy in the autohemotherapy sense of that term, having thoroughly scientific bases.


Autohemotherapy use in  dermatology  was popular in the early 1900s but was abandoned by conventional dermatologists due to a lack of supporting evidence of efficacy. A resurgence of interest in the 2000s [ 1 ]  has led to several investigations evaluating the use of autohemotherapy as a treatment for specific dermatological conditions such as  hives (urticaria)  and  eczema . [ 1 ]  A review of these studies concludes that, though safe, autohemotherapy is only somewhat more effective than injection of  saline solution . [ 1 ]


In 2022, autohemotherapy was studied for its effect on ME/CFS, in which 220 patients were treated with oxygen-ozone autohemotherapy for X weeks, at least two 30min long sessions per week. Significant improvements in ME/CFS were noted at statistically significant p-value < 0.0001. When treated with O2-O3-AHT fatigue symptoms within the first one-two weeks ameliorated from a score value of 7 (meaning the worst) to 1 (meaning the best, i.e., completely absent symptoms) in almost half of the oxygen-ozone treated patients (43.5%). However, researchers did not determine the mechanism of action resulting in patient improvement.  [1]  The study did not include a control group, [2]  making it impossible to know if the treatment had any effect greater than a placebo. No  randomized control trial , considered the standard for medical research, has shown ozone autohemotherapy to be effective.


One fringe  dermatologic  application of autohemotherapy, colloquially called a "vampire facial", came to public attention in 2013 when an Instagram posting by celebrity  Kim Kardashian West  portrayed her "blood-soaked face" during the administration of the procedure. [ 5 ]  Kardashian West later stated that she regretted undergoing the painful procedure. [ 6 ]  A vampire facial procedure involves a combination of  microneedling [ 6 ]  followed by topical application of  platelet-rich plasma  derived from the  centrifugation  of the subject's own blood into various autologous  blood products . [ 6 ]  Proponents claim that autologous  platelet-rich plasma  delivered subcutaneously to the skin of the face can improve its health by stimulating skin cell growth and  collagen [ 5 ]  though the treatment is considered to lie outside of mainstream medicine because claimed benefits are unsupported by scientific evidence from clinical studies. [ 6 ]  Side effects of the treatment may include redness, swelling, bruising, tenderness, tingling, numbness, lumpiness, and/or a feeling of pressure or fullness at the injection sites [ 6 ]  which, providers claim, people recover from within two days with outlying reports from patients whose recovery took a week or more with scabbing and other problems. [ 6 ]


More serious safety concerns have been cited for these treatments when performed in non-medical settings by people untrained in  infection control . [ 5 ] [ 7 ]  The New Mexico Department of Health issued a statement that at least one such business offering vampire facials "could potentially spread blood-borne infections such as HIV, hepatitis B and hepatitis C to clients.” [ 5 ]  This was subsequently confirmed by the CDC following a number of HIV infections first reported in 2024. [ 8 ]


In contrast, so-called "vampire filler" is autologous platelets used as dermal filler in the  platelet-rich fibrin matrix method  of cosmetic surgery; [ 9 ]  it is generally not described as autohemotherapy and the FDA-approved machines for it are approved for use by only licensed surgeons. [ citation needed ]


Autotransfusion  is a process wherein a person receives their own  blood  for a  transfusion , instead of  banked  allogenic (separate- donor ) blood. There are two main kinds of autotransfusion: Blood can be  autologously  "pre-donated" (termed so despite "donation" not typically referring to giving to one's self) before a  surgery , or alternatively, it can be collected during and after the surgery using an  intraoperative blood salvage  device (such as a Cell Saver, HemoClear or CATS). The latter form of autotransfusion is utilized in surgeries where there is expected a large volume blood loss – e.g. aneurysm, total joint replacement, and spinal surgeries. The effectiveness, safety, and cost-savings of intraoperative cell salvage in people who are undergoing thoracic or abdominal surgery following trauma is not known. [ 1 ]


The first documented use of "self-donated" blood was in 1818, and interest in the practice continued until the  Second World War , at which point blood supply became less of an issue due to the increased number of blood donors.  Later, interest in the procedure returned with concerns about allogenic (separate-donor) transfusions.  Autotransfusion is used in a number of  orthopedic ,  trauma , and  cardiac  cases, amongst others. Where appropriate, it carries certain advantages, including the reduction of infection risk, and the provision of more functional cells not subjected to the significant storage durations common among banked allogenic (separate-donor) blood products. [ citation needed ]


Autotransfusion also refers to the natural process, where (during fetal delivery) the uterus naturally contracts, shunting blood back into the maternal circulation. [ 2 ]  This is important in pregnancy, because the uterus (at the later stages of fetal development) can hold as much as 16% of the mother's blood supply. [ 2 ]


Autotransfusion is intended for use in situations characterized by the loss of one or more units of blood and may be particularly advantageous for use in cases involving rare  blood groups , risk of infectious disease transmission, restricted  homologous  blood supply or other medical situations for which the use of homologous blood is contraindicated. Autotransfusion is commonly used intraoperatively and postoperatively. Intraoperative autotransfusion refers to recovery of blood lost during surgery or the concentration of fluid in an extracorporeal circuit. Postoperative autotransfusion refers to the recovery of blood in the  extracorporeal  circuit at the end of surgery or from aspirated drainage. [ 3 ]  Further clinical research in the form of randomized controlled trials is required to determine the effectiveness and safety of this procedure due abdominal or thoracic trauma surgery. [ 1 ]  For elective surgeries, cell salvage techniques may not be linked to more negative outcomes or adverse effects and there is weak evidence indicating that this approach may reduce the chances that the person needs an allogenic transfusion. [ 4 ]


The disadvantage of autotransfusion is the depletion of  plasma  and  platelets . The washed autotransfusion system removes the plasma and platelets to eliminate activated  clotting factors  and activated platelets which would cause  coagulopathy  if they were reinfused to the patient, generating a  packed red blood cell  (PRBC) product. This disadvantage is only evident when very large blood losses occur. The  autotransfusionist  monitors blood loss and will recommend the transfusion of  fresh frozen plasma  (FFP) and platelets when the blood loss and return of autotransfusion blood increase. Typically the patient will require FFP and platelets as the estimated blood loss exceeds half of the patient's blood volume. When possible diagnostic tests should be performed to determine the need for any blood products (i.e. PRBC, FFP and platelets). [ citation needed ]


The use of blood recovered from the operative field is contraindicated in the presence of  bacterial  contamination or  malignancy . The use of autotransfusion in the presence of such contamination may result in the dissemination of pathologic microorganisms or malignant cells. The following statements reflect current clinical concerns involving autotransfusion contraindications. [ 3 ]


Any abdominal procedure poses the risk of enteric contamination of shed blood. The surgical team must be diligent in observing for signs of  bowel  contamination of the blood. If there is a question of possible contamination the blood may be held until the surgeon determines whether or not bowel contents are in the  surgical field . If the blood is contaminated the entire contents should be discarded. If the patient's life depends upon this blood supply it may be reinfused with the surgeon's consent. While washing with large amounts of a  sodium chloride  solution will reduce the bacterial contamination of the blood, it will not be totally eliminated. [ citation needed ]


There is a possibility of the reinfusion of  cancer  cells from the surgical site. [ 6 ]  There are possible exceptions to this contraindication:


The use of leukocyte reduction filters is recommended. [ citation needed ]


Autotransfusion is not normally used in  Caesarean sections , because the possibility of an  amniotic fluid   embolism  exists. Emerging literature suggests that amniotic fluid is being cleared during the wash cycle. It is possible that the utilization of autotransfusion in obstetrics may increase as more research is completed. However, if a patient is at risk for blood loss and is a Jehovah's witness, for example, the cell saver can be used with strict guidelines of irrigating profusely to remove amniotic fluid and then suctioning the blood that is being lost. [ citation needed ]


In life saving situations with the consent of the surgeon, autotransfusion can be utilized in the presence of the previous stated contraindications i.e.  sepsis , bowel contamination and malignancy. [ citation needed ]


Utilizing a special double lumen suction tubing, fluid is aspirated from the operative field and is mixed with an anticoagulant solution. Collected fluid is filtered in a sterile  cardiotomy  reservoir. The reservoir contains filter and has a capacity of between two and three liters of fluid. When a volume adequate to fill the wash bowl has been collected, processing may begin. The volume required to fill the bowl is dependent on the  hematocrit  (HCT) and size of the centrifuge wash bowl. If the patients HCT is normal, the amount needed to process a unit is roughly two times the bowl volume. [ 7 ]


When aspirating the blood it is important to utilize the following technique whenever possible: [ citation needed ]


Following these techniques will help reduce  hemolysis  of the red cells and will help increase the amount of red cells that will be salvaged.


Antibiotics that are plasma bound can be removed during the autotransfusion wash cycle, however, topical antibiotics which are typically not plasma bound may not be washed out during autotransfusion, and may actually become concentrated to the point of being  nephrotoxic . [ citation needed ]


When Avitene, Hemopad, Instat, or collagen type products are used, autotransfusion should be interrupted and a waste or wall suction source must be used. Autotransfusion can be resumed once these products are flushed from the surgical site. If Gelfoam, Surgicel, Thrombogen or Thrombostat are used, autotransfusion can continue, however, direct suctioning of these products should be avoided. [ citation needed ]


Cement  is often used or encountered during primary or revision total  joint replacement surgery . Cement in the liquid or soft state should not be introduced into the autotransfusion system. When cement is being applied a waste or wall suction source must be used, however when the cement hardens autotransfusion may be resumed. The use of ultrasonic equipment during revision of total joints changes the cement to a liquid or soft state, which precludes the use of autotransfusion during the use of such equipment. Autotransfusion can only continue when the cement has hardened. [ citation needed ]


In the prime phase, the  centrifuge  begins rotation and accelerates to the speed selected on the centrifuge speed control, typically 5,600 rpm. Simultaneously, the pump begins counterclockwise rotation, enabling the transfer of the reservoir contents to the wash bowl. The application of centrifugal force separates the components of the fluid according to their weight. The wash bowl filling continues until the  buffy coat  reaches the shoulder of the wash bowl. Some autotransfusion devices have automatic features including a buffy coat sensor, which is calibrated to detect a full bowl and advance the process to the wash phase automatically. [ citation needed ]


The wash phase begins when the wash bowl is appropriately filled with red cells. The pump continues a counterclockwise rotation and clamps adjust, enabling the transfer of wash solution to the wash bowl. The washing phase removes cellular stromata, plasma free hemoglobin, anticoagulant solution, activated clotting factors, any plasma bound antibiotics, intracellular enzymes, plasma, platelets, and white cells. The unwanted fluid passes out of the wash bowl and into a waste reservoir bag. Washing continues until the reinfuse button is depressed (or the program ends, in the case of an automatic device) and the appropriate amount of wash solution has been delivered to the wash bowl. The wash phase is terminated when one to two liters of wash solution has been transferred, or the fluid transferred to the waste bag appears transparent (or both).


When the empty phase is initiated, the centrifuge begins braking. The clamps change positions, enabling the transfer of the wash bowl contents to the reinfusion bag. The centrifuge bowl must come to a complete stop before the pump begins a clockwise rotation to empty the bowl. Once the bowl is emptied, the cycle is ended and a new cycle can be begun. The reinfusion bag attached to the autotransfusion wash set should not be used for high pressure infusion back to the patient. The reinfusion bag contains a significant amount of air, careful monitoring should take place during reinfusion to avoid the potential of air embolism. Therefore, it is recommended to use a separate blood bag attached to the reinfusion bag. This second bag can then be disconnected, air purged from it, and then tied off before giving to anesthesia for reinfusion. Thus reducing the chances of an air embolism. In accordance with Guidelines set by the  American Association of Blood Banks  the blood should be reinfused within 4 hours from washing. [ citation needed ]


Postoperative autotransfusion is performed by connecting the double lumen autotransfusion suction line directly to the drain line placed at the conclusion of surgery. Postoperative autotransfusion begins in the operating room when the drain line is placed and the surgical site is closed. Typical postoperative cases are total  knee  and  hip  replacements. Autotransfusion is continued and is effective while the patient actively bleeds during the immediate postoperative phase of recovery. Autotransfusion is ended when bleeding is stopped or is significantly slow, and is discontinued by connecting an ordinary self draining device to the drain lines. Available for postoperative autotransfusion are universal bifurcated connectors which can accommodate two drain lines of any size, these connectors can be attached to the standard ten foot double lumen suction line for postoperative use. [ citation needed ]


In some institutions to maximize the effectiveness of autotransfusion and provide the best conservation and return of red cells the soaking of sponges is employed. During the surgical procedure the blood soaked sponges are collected and placed in a sterile basin by the surgical team, sterile  heparinized   saline  is added to the basin to prevent clotting and facilitate the release of red cells. The sponges are periodically wrung out and removed from the basin, the remaining solution can be suctioned into the autotransfusion reservoir so that the red cells can be recovered. The usual ratio of heparinized saline is 5,000 units of heparin per 1,000 ml of 0.9% sodium chloride. The heparin is removed during the autotransfusion process. [ 8 ] [ 9 ]


There is some evidence that in 1785 Philip Physic of Philadelphia transfused a  post-partum  patient. [ 10 ]  However the first documented use of autologous blood transfusion was in 1818 when an Englishman, Rey Paul Blundell, salvaged vaginal blood from patients with postpartum  hemorrhage . By swabbing the blood from the bleeding site and rinsing the swabs with saline, he found that he could re-infuse the result of the washings. This unsophisticated method resulted in a 75% mortality rate, but it marked the start of autologous blood transfusion. [ 11 ]


During the  American Civil War  Union Army physicians are said to have administered four transfusions. In 1886, J. Duncan used autotransfusion during the  amputation  of limbs by removing blood from the amputated limb and returning it to the patient by femoral injection. This method was apparently fairly successful. [ 12 ]  A German, M. J. Theis, reported the first successful use of intraoperative autotransfusion in 1914, with a ruptured  ectopic pregnancy . [ 13 ]  The earliest report in the American literature on the use of autotransfusion was by Lockwood in 1917 who used the technique during a  splenectomy  for Banti syndrome. [ 14 ]  Interest in the unrefined technique of autotransfusion continued through to the early 1940s, and was applied to various procedures including treatment of ectopic pregnancy, [ 15 ] [ 16 ]  hemothorax, [ 17 ]  ruptured spleen, [ 18 ] [ 19 ]  perforating abdominal injuries, [ 20 ]  and neurosurgical procedures. [ 21 ]


The interest in autotransfusion dwindled during  World War II , when there was a large pool of donors. After the war, blood testing, typing, and crossmatching techniques were improved making  blood banks  the answer to the increased demand for blood. In the 1960s, interest in autotransfusion revived. With the advances in all fields of surgery, new companies developed autotransfusion devices. Problems still arose, however, with air embolism,  coagulopathy , and hemolysis. [ 22 ]  The devices used during the Korean and Vietnam War collected and provided gross filtration of blood before it was reinfused. [ 23 ]  With the introduction of  cardiopulmonary bypass  in 1952, autotransfusion became an area of study. Klebanoff began a new era of autotransfusion by developing the first commercially available autotransfusion unit in 1968. [ 24 ]  His system, the Bentley Autotransfusion System aspirated, collected, filtered and reinfused autologous whole blood shed from the operative field. The problems with the Bentley system included the requirement of systemic anticoagulation of the patient, introduction of air embolism, and  renal  failure resulting from unfiltered particulate in the reinfused blood.


As the Bentley system lost favor  Wilson and associates proposed the use of a discontinuous flow centrifuge process for autotransfusion which would wash the red cells with normal saline solution. [ 25 ]  In 1976, this system was introduced by  Haemonetics Corp.  and is known commonly as "Cell Saver". [ 26 ]  More recently in 1995  Fresenius  introduced a continuous autotransfusion system. [ 27 ]


There are three types of systems: un-washed filtered blood; discontinuous flow centrifugal; and continuous flow centrifugal. The unwashed systems are popular because of their perceived inexpense and simplicity. However unwashed systems can cause increase potential for clinical complications. The washed system requires a properly trained and clinically skilled operator. It returns only red blood cells suspended in saline and is rarely associated with any clinical complications. Discontinuous autotransfusion can practically eliminate the need for exposure to homologous blood in elective surgical patients and can greatly reduce the risk of exposure to emergency surgical patients. [ citation needed ]


Individuals of the  Jehovah's Witness  religion in particular refuse to accept homologous and autologous pre-donated blood. However some individual members may accept the use of autotransfusion by means of the Cell Saver. The process of autotransfusion using the Cell Saver is modified to maintain a continuous circuit of blood that maintains continuous contact with the body. This process when carefully explained to the patient may be acceptable when a patient otherwise refuses based on religious beliefs. [ citation needed ]


Many of the newest autotransfusion machines are programmable to provide separation of blood into three groups; red cells, platelet poor plasma, and platelet rich plasma. Blood can be drawn from the patient just prior to surgery and then separated. The separated blood components which have been sequestered can be stored during the surgical procedure. The red cells and platelet poor plasma can be given back to the patient through  intravenous  transfusion during or after surgery. The platelet rich plasma can be mixed with  calcium  and  thrombin  to create a product known as  autologous platelet gel . This is an autologous product that can be used for a variety of techniques including use as a hemostatic aid, a dural sealant, and an aid to fusion of bone.


An  autotransfusionist , also known as a  perioperative blood management technologist ,  is a specialized allied  health professional  who operates the cell saver machine during surgeries that expect significant blood loss.


The autotransfusionist is responsible for collecting shed blood from the patient during the operation, scrubs or cleans the blood of impurities, then makes it available to be reinfused into the patient. The process is commonly known as "cell-saver" and is considered far superior to the use of blood from a donor, because it reduces the possibility of infection and provides more functional cells back to the patient. [ 1 ]  Because the blood is recirculated, there is no limit to the amount of blood that can be given back to the patient. [ 2 ]


Autotransfusion  can be achieved in the operating room,  intensive care unit , and  emergency department  and require varying degrees of expertise depending on the procedure. [ 3 ]


In order to become a  Certified Perioperative Blood Management Technologist  ( CPBMT ), one must: [ 4 ]


Autotransplantation  is the  transplantation  of  organs ,  tissues , or even particular  proteins  from one part of the body to another in the same person ( auto-  meaning "self" in  Greek [ 1 ] ).


The  autologous  tissue (also called  autogenous ,  autogeneic , or  autogenic  tissue) transplanted by such a procedure is called an  autograft  or  autotransplant . [ 2 ]


It is contrasted with  allotransplantation  (from other individual of the same species),  syngeneic  transplantation (grafts transplanted between two genetically identical individuals of the same species) and  xenotransplantation  (from other species).


A common example is the removal of a piece of bone (usually from the hip) and its being ground into a paste for the reconstruction of another portion of bone.


Autotransplantation, although most common with blood, bone,  hematopoietic stem cells , or skin, can be used for a wide variety of organs. One of the rare examples is autotransplantation of a kidney from one side of the body to the other. Kidney autotransplantation is used as a treatment for  nutcracker syndrome . [ 3 ]


In  blood banking  terminology, autologous  blood donation  refers to a blood donation marked for use by the donor, typically for a scheduled surgery. (Generally, the notion of "donation" does not refer to giving to oneself, though in this context it has become somewhat acceptably idiomatic.) They are commonly called "autos" by blood bank personnel, and it is one major form of the more general concept of  autotransfusion  (the other being  intraoperative blood salvage ).


Some advantages of autologous blood donation are:


The disadvantages are:


Autologous blood is not routinely tested for infectious diseases markers such as  HIV  antibodies. In the United States, autologous blood is tested only if it is collected in one place and shipped to another.


There is also a risk that, in an emergency or if more blood is required than has been set aside in advance, the patient could still be exposed to donor blood instead of autologous blood. Autologous donation is also not suitable for patients who are medically unable to or advised not to give blood, such as  cardiac  patients or small  children  and infants. [ 5 ]


In  orthopaedic medicine , a  bone graft  can be sourced from a patient's own bone in order to fill space and produce an osteogenic response in a bone defect. However, due to the donor-site morbidity associated with autograft, other methods such as bone  allograft  and  bone morphogenetic proteins  and synthetic graft materials are often used as alternatives.  Autografts have long been considered the "Gold Standard" in oral surgery and implant dentistry because it offered the best regeneration results.  Lately, the introduction of morphogen-enhanced bone graft substitutes have shown similar success rates and quality of regeneration; however, their price is still very high. [ medical citation needed ]


Autotransplantation of selected organs is often preceded by  ex vivo  (also  bench ,  back-table , or  extracorporeal ) surgery. [ 6 ]  For example,  ex vivo  liver resection and autotransplantation is used in the treatment of selected cases of conventionally unresectable hepatic tumors. [ 7 ]  It can also be implemented in rare scenarios of a blunt abdominal trauma. [ 8 ]  Kidney autotransplantation is a method of a nephron-sparing renal tumor excision or complex renal artery aneurysm management. [ 9 ] [ 10 ]  The uses of  ex vivo  surgery followed by autotransplantation were reported also for heart, lungs and intestines, including  multivisceral  approaches. [ 6 ]


Induced pluripotent stem cells  (iPSCs), capable of differentiating into any cell type,  have potential for solving the problem of donor organ shortage. Reprogramming technology would be used to obtain a personalized, patient-specific, cell product without problems related to histocompatibility of the transplanted tissues and organs. However, the ability to generate such tissues and organs will depend on successful strategies to overcome immunogenicity of the manipulated product. [ 11 ]


Autologous stem-cell transplantation  involves harvesting peripheral blood mononuclear cells (PBMCs) by  apheresis  collection following mobilization of stem cells from the bone marrow into the peripheral blood.  This is typically used for treatment of  multiple myeloma  or aggressive  lymphoma .  Stem cells are  cryopreserved  after collection for infusion after the patient undergoes high-dose  chemotherapy .  Stem cell rescue permits the use of higher doses of chemotherapy than would be tolerated otherwise. [ 12 ]


1BH7 ,  1BNX ,  1BTQ ,  1BTR ,  1BTS ,  1BTT ,  1BZK ,  1HYN ,  3BTB ,  2BTA ,  2BTB ,  4KY9 ,  4YZF


Band 3 anion transport protein , also known as  anion exchanger 1  ( AE1 ) or  band 3   or  solute carrier family 4 member 1  (SLC4A1), is a  protein  that is encoded by the  SLC4A1   gene  in humans.


Band 3 anion transport protein is a  phylogenetically -preserved  transport protein  responsible for mediating the  exchange  of  chloride  (Cl − ) with  bicarbonate  (HCO 3 − ) across  plasma membranes . Functionally similar members of the AE clade are  AE2  and  AE3 . [ 5 ]


Band 3 is present in the basolateral face of the  α-intercalated cells  of the collecting ducts of the  nephron , which are the main acid-secreting cells of the kidney. They generate  hydrogen  ions and bicarbonate ions from carbon dioxide and water – a reaction catalysed by  carbonic anhydrase . The hydrogen ions are pumped into the collecting duct tubule by  vacuolar H +  ATPase , the apical  proton pump , which thus excretes acid into the  urine . kAE1, the kidney isoform of AE1, exchanges bicarbonate for chloride on the basolateral surface, essentially returning bicarbonate to the blood. Here it performs two functions: [ citation needed ]


It is ubiquitous throughout the  vertebrates . In  mammals , it is present in two specific sites: [ citation needed ]


The erythrocyte and kidney forms are different  isoforms  of the same  protein . [ 6 ]


The erythrocyte isoform of AE1, known as eAE1, is composed of 911 amino acids. eAE1 is an important structural component of the erythrocyte cell membrane, making up to 25% of the cell membrane surface. Each red cell contains approximately one million copies of eAE1. [ citation needed ]


The kidney isoform of AE1, known as kAE1 (which is 65 amino acids shorter than erythroid AE1) is found in the  basolateral  membrane of alpha-intercalated cells in the  cortical collecting duct  of the kidney. [ citation needed ]


Mutations of kidney AE1 cause distal (type 1)  renal tubular acidosis , which is an inability to acidify the urine, even if the blood is too  acidic . These mutations are disease causing as they cause mistargetting of the mutant band 3 proteins so that they are retained within the cell or occasionally addressed to the wrong (i.e. apical) surface. [ citation needed ]


Mutations of erythroid AE1 affecting the extracellular domains of the molecule may cause alterations in the individual's blood group, as band 3 determines the  Diego antigen system  ( blood group ). [ citation needed ]


More importantly erythroid AE1 mutations cause 15–25% of cases of  hereditary spherocytosis  (a disorder associated with progressive red cell membrane loss), and also cause the hereditary conditions of  hereditary stomatocytosis [ 7 ]  and Southeast Asian  ovalocytosis . [ 8 ]


Band 3 has been shown to  interact  with  CA2 [ 9 ] [ 10 ] [ 11 ] [ 12 ]  and  CA4 . [ 13 ]


AE1 was discovered following  SDS-PAGE  (sodium dodecyl sulfate polyacrylamide gel electrophoresis) of erythrocyte  cell membrane . The large 'third' band on the electrophoresis gel represented AE1, which was thus initially termed 'Band 3'. [ 14 ]


Bleeding ,  hemorrhage ,  haemorrhage  or  blood loss  is  blood  escaping from the  circulatory system  from damaged  blood vessels . [ 1 ]  Bleeding can occur  internally , or externally either through a natural opening such as the  mouth ,  nose ,  ear ,  urethra ,  vagina  or  anus , or through a puncture in the  skin .
 Hypovolemia  is a massive decrease in blood volume, and death by excessive loss of blood is referred to as  exsanguination . [ 2 ]  Typically, a healthy person can endure a loss of 10–15% of the total blood volume without serious  medical difficulties  (by comparison,  blood donation  typically takes 8–10% of the donor's blood volume). [ 3 ]  The stopping or controlling of bleeding is called  hemostasis  and is an important part of both  first aid  and  surgery .


Bleeding arises due to either traumatic injury, underlying medical condition, or a combination.


Traumatic bleeding is caused by some type of injury. There are different types of  wounds  which may cause traumatic bleeding. These include:


The pattern of injury, evaluation and treatment will vary with the mechanism of the injury. Blunt trauma causes injury via a shock effect; delivering energy over an area. Wounds are often not straight and unbroken skin may hide significant injury. Penetrating trauma follows the course of the injurious device. As the energy is applied in a more focused fashion, it requires less energy to cause significant injury. Any body organ, including bone and brain, can be injured and bleed. Bleeding may not be readily apparent; internal organs such as the liver, kidney and spleen may bleed into the abdominal cavity. The only apparent signs may come with blood loss. Bleeding from a bodily orifice, such as the rectum, nose, or ears may signal internal bleeding, but cannot be relied upon. Bleeding from a  medical procedure  also falls into this category. [ citation needed ]


"Medical bleeding" denotes hemorrhage as a result of an underlying medical condition (i.e. causes of bleeding that are not directly due to trauma). Blood can escape from  blood vessels  as a result of 3 basic patterns of injury: [ citation needed ]


The underlying scientific basis for blood clotting and hemostasis is discussed in detail in the articles,  coagulation ,  hemostasis  and related articles. The discussion here is limited to the common practical aspects of blood clot formation which manifest as bleeding.


Some medical conditions can also make patients susceptible to bleeding. These are conditions that affect the normal hemostatic (bleeding-control) functions of the body. Such conditions either are, or cause,  bleeding diatheses .  Hemostasis  involves several components. The main components of the hemostatic system include  platelets  and the  coagulation  system.


Platelets  are small blood components that form a plug in the blood vessel wall that stops bleeding. Platelets also produce a variety of substances that stimulate the production of a blood clot. One of the most common causes of increased bleeding risk is exposure to  nonsteroidal anti-inflammatory drugs  (NSAIDs). The prototype for these drugs is aspirin, which inhibits the production of thromboxane. NSAIDs (for example Ibuprofen) inhibit the activation of  platelets , and thereby increase the risk of bleeding. The effect of aspirin is irreversible; therefore, the inhibitory effect of aspirin is present until the platelets have been replaced (about ten days). Other NSAIDs, such as "ibuprofen" (Motrin) and related drugs, are reversible and therefore, the effect on platelets is not as long-lived. [ citation needed ]


There are several named coagulation factors that interact in a complex way to form blood clots, as discussed in the article on  coagulation . Deficiencies of coagulation factors are associated with clinical bleeding. For instance, deficiency of Factor VIII causes classic  hemophilia A  while deficiencies of Factor IX cause "Christmas disease"( hemophilia B ). Antibodies to Factor VIII can also inactivate the Factor VII and precipitate bleeding that is very difficult to control. This is a rare condition that is most likely to occur in older patients and in those with  autoimmune  diseases. Another common bleeding disorder is  Von Willebrand disease . It is caused by a deficiency or abnormal function of the "Von Willebrand" factor, which is involved in platelet activation. Deficiencies in other factors, such as factor XIII or factor VII are occasionally seen, but may not be associated with severe bleeding and are not as commonly diagnosed.


In addition to NSAID-related bleeding, another common cause of bleeding is that related to the medication,  warfarin  ("Coumadin" and others). This medication needs to be closely monitored as the bleeding risk can be markedly increased by interactions with other medications. Warfarin acts by inhibiting the production of  Vitamin K  in the gut. Vitamin K is required for the production of the clotting factors, II, VII, IX, and X in the liver. One of the most common causes of warfarin-related bleeding is taking antibiotics. The gut bacteria make vitamin K and are killed by antibiotics. This decreases vitamin K levels and therefore the production of these clotting factors.


Deficiencies of platelet function may require platelet transfusion while deficiencies of clotting factors may require transfusion of either  fresh frozen plasma  or specific clotting factors, such as  Factor VIII  for patients with hemophilia.


Infectious diseases such as  Ebola ,  Marburg virus disease  and  yellow fever  can cause bleeding. [ 6 ]


Dioxaborolane  chemistry enables radioactive  fluoride  ( 18 F ) labeling of  red blood cells , which allows for  positron emission tomography  (PET) imaging of intracerebral hemorrhages. [ 7 ]


Hemorrhaging is broken down into four classes by the American College of Surgeons'  advanced trauma life support  (ATLS). [ 8 ]


This system is basically the same as used in the staging of  hypovolemic shock .


Individuals in excellent physical and  cardiovascular  shape may have more effective compensatory mechanisms before experiencing cardiovascular collapse. These patients may look deceptively stable, with minimal derangements in vital signs, while having poor peripheral perfusion. Elderly patients or those with chronic medical conditions may have less tolerance to blood loss, less ability to compensate, and may take medications such as betablockers that can potentially blunt the cardiovascular response. Care must be taken in the assessment. [ citation needed ]


Although there is no universally accepted definition of massive hemorrhage, the following can be used to identify the condition: "(i) blood loss exceeding circulating blood volume within a 24-hour period, (ii) blood loss of 50% of circulating blood volume within a 3-hour period, (iii) blood loss exceeding 150 ml/min, or (iv) blood loss that necessitates plasma and platelet transfusion." [ 9 ]


The  World Health Organization  made a standardized grading scale to measure the severity of bleeding. [ 10 ]


Acute bleeding from an injury to the skin is often treated by the application of direct pressure. [ 11 ]  For severely injured patients,  tourniquets  are helpful in preventing complications of  shock . [ 12 ]   Anticoagulant  medications may need to be discontinued and possibly reversed in patients with clinically significant bleeding. [ 13 ]  Patients that have lost excessive amounts of blood may require a  blood transfusion . [ 14 ]


The use of  cyanoacrylate glue  to prevent bleeding and seal battle wounds was designed and first used in the  Vietnam War . [ 15 ]   Skin glue, a medical version of "super glue", is sometimes used instead of using traditional stitches used for small wounds that need to be closed at the skin level. [ 16 ]


The word "Haemorrhage" (or  hæmorrhage ; using the  æ ligature ) comes from Latin haemorrhagia, from Ancient Greek αἱμορραγία ( haimorrhagía , "a violent bleeding"), from αἱμορραγής ( haimorrhagḗs , "bleeding violently"), from αἷμα ( haîma , "blood") + -ραγία ( -ragía ), from ῥηγνύναι ( rhēgnúnai , "to break, burst"). [ 17 ]


A  blood product  is any therapeutic substance prepared from human  blood . [ 1 ]  This includes  whole blood ; blood components; and plasma derivatives. Blood components include:  red blood cell concentrates  or suspensions;  platelets  produced from whole blood or via apheresis;  Granulocyte ,  plasma ; and  cryoprecipitate . Some products for topical use, such as serum eye drops, have also been recently classified as blood components. [ 2 ]  Plasma derivatives are plasma proteins prepared under pharmaceutical manufacturing conditions, including: albumin; coagulation factor concentrates; and  immunoglobulins .


Blood products may also be called  blood-based products or blood-derived products.  to differentiate them from  blood substitutes , which generally refer to artificially produced products. Although many blood products have the effect of volume expansion, the group is usually distinguished from  volume expanders , which generally refers to artificially produced substances and are thereby within the scope of  blood substitutes .


A  blood substitute  (also called  artificial blood  or  blood surrogate ) is a substance used to mimic and fulfill some functions of  biological   blood . It aims to provide an alternative to  blood transfusion , which is transferring blood or  blood-based products  from one person into another. Thus far, there are no well-accepted  oxygen-carrying  blood substitutes, which is the typical objective of a  red blood cell  transfusion; however, there are widely available non-blood  volume expanders  for cases where only volume restoration is required. These are helping doctors and surgeons avoid the risks of disease transmission and immune suppression, address the chronic blood donor shortage, and address the concerns of  Jehovah's Witnesses  and others who have religious objections to receiving transfused blood. [ citation needed ]


The main categories of "oxygen-carrying" blood substitutes being pursued are hemoglobin-based oxygen carriers (HBOC) [ 1 ]  and  perfluorocarbon emulsions . [ 2 ]  Oxygen therapeutics are in clinical trials in the  U.S.  and  European Union , and  Hemopure  is available in  South Africa .


After  William Harvey  discovered blood pathways in 1616, many people tried to use fluids such as beer, urine, milk, and non-human animal blood as blood substitute. [ 3 ]   Sir Christopher Wren  suggested wine and opium as blood substitute. [ 4 ]


At the beginning of the 20th century, the development of modern transfusion medicine initiated through the work of Landsteiner and co-authors opened the possibility to understanding the general principle of  blood group  serology. [ 5 ]   Simultaneously, significant progress was made in the fields of heart and circulation physiology as well as in the understanding of the mechanism of oxygen transport and tissue oxygenation. [ 6 ] [ 7 ]


Restrictions in applied transfusion medicine, especially in disaster situations such as World War II, laid the grounds for accelerated research in the field of blood substitutes. [ 8 ]  Early attempts and optimism in developing blood substitutes were very quickly confronted with significant side effects, which could not be promptly eliminated due to the level of knowledge and technology available at that time. The  emergence of HIV  in the 1980s renewed impetus for development of infection-safe blood substitutes. [ 4 ]  Public concern about the safety of the blood supply was raised further by  mad cow disease . [ 4 ] [ 9 ]  The continuous decline of blood donation combined with the increased demand for blood transfusion (increased ageing of population, increased incidence of invasive diagnostic, chemotherapy and extensive surgical interventions, terror attacks, international military conflicts) and positive estimation of investors in biotechnology branch made for a positive environment for further development of blood substitutes. [ 9 ]


Efforts to develop blood substitutes have been driven by a desire to replace  blood transfusion  in emergency situations, in places where infectious disease is endemic and the risk of  contaminated blood products  is high, where refrigeration to preserve blood may be lacking, and where it might not be possible or convenient to find  blood type  matches. [ 10 ]


In 2023,  DARPA  announced funding twelve universities and labs for synthetic blood research. Human trials would be expected to happen between 2028-2030. [ 11 ]


Efforts have focused on molecules that can carry  oxygen , and most work has focused on recombinant  hemoglobin , which normally carries oxygen, and  perfluorocarbons  (PFC), chemical compounds which can carry and release oxygen. [ 10 ] [ 12 ]


The first approved oxygen-carrying blood substitute was a per fluorocarbon -based product called  Fluosol -DA-20, manufactured by  Green Cross  of Japan. It was approved by the  Food and Drug Administration  (FDA) in 1989. Because of limited success, complexity of use and side effects, it was withdrawn in 1994. However, Fluosol-DA remains the only oxygen therapeutic ever fully approved by the FDA.  As of 2017 no hemoglobin-based product had been approved. [ 10 ]


Perfluorochemicals are not  water soluble  and will not mix with blood, therefore  emulsions  must be made by dispersing small drops of PFC in  water . This liquid is then mixed with  antibiotics ,  vitamins ,  nutrients  and  salts , producing a mixture that contains about 80 different components, and performs many of the vital functions of natural blood. PFC particles are about   1 / 40   the size of the diameter of a  red blood cell  (RBC). This small size can enable PFC particles to traverse  capillaries  through which no RBCs are flowing. In theory this can benefit damaged, blood-starved  tissue , which conventional red cells cannot reach. PFC solutions can carry oxygen so well that  mammals , including  humans , can survive breathing liquid PFC solution, called  liquid breathing . [ citation needed ]


Perfluorocarbon-based blood substitutes are completely man-made; this provides advantages over blood substitutes that rely on modified hemoglobin, such as unlimited manufacturing capabilities, ability to be heat-sterilized, and PFCs' efficient oxygen delivery and carbon dioxide removal. PFCs in solution act as an intravascular oxygen carrier to temporarily augment oxygen delivery to tissues. PFCs are removed from the bloodstream within 48 hours by the body's normal clearance procedure for particles in the blood – exhalation. PFC particles in solution can carry several times more oxygen per cubic centimeter (cc) than blood, while being 40 to 50 times smaller than hemoglobin. [ citation needed ]


Fluosol was made mostly of  perfluorodecalin  or  perfluorotributylamine  suspended in an  albumin  emulsion. It was developed in  Japan  and first tested in the  United States  in November 1979. [ 13 ]  In order to "load" sufficient amounts of oxygen into it, people who had been given it had to breathe pure oxygen by mask or in a  hyperbaric chamber . [ 14 ]  It was approved by the FDA in 1989, [ 15 ]  and was approved in eight other countries. [ citation needed ]  Its use was associated with a reduction in ischemic complications and with an increase in pulmonary edema and congestive heart failure. [ 16 ]   Due to difficulty with the emulsion storage of Fluosol use (frozen storage and rewarming), its popularity declined and its production ended in 1994. [ 10 ]


Oxygent was a second-generation,  lecithin -stabilized  emulsion  of a PFC that was under development by Alliance Pharmaceuticals. [ 21 ] [ 1 ] [ 22 ]    In 2002 a Phase III study was halted early due an increase in incidences of strokes in the study arm. [ 23 ]


Haemoglobin  is the main component of red blood cells, comprising about 33% of the cell mass. Haemoglobin-based products are called haemoglobin-based oxygen carriers (HBOCs). [ 1 ]


Unmodified cell-free haemoglobin is not useful as a blood substitute because its oxygen affinity is too high for effective tissue oxygenation, the half-life within the intravascular space that is too short to be clinically useful, it has a tendency to undergo dissociation in dimers with resultant kidney damage and toxicity, and because free haemoglobin tends to take up nitric oxide, causing vasoconstriction. [ 4 ] [ 24 ] [ 25 ] [ 26 ]


Efforts to overcome this toxicity have included making  genetically engineered  versions,  cross-linking ,  polymerization , and encapsulation. [ 10 ]


HemAssist, a diaspirin cross-linked haemoglobin (DCLHb) was developed by  Baxter Healthcare ; it was the most widely studied of the haemoglobin-based blood substitutes, used in more than a dozen animal and clinical studies. [ 8 ]    It reached Phase III clinical trials, in which it failed due to increased mortality in the trial arm, mostly due to severe vasoconstriction complications. [ 10 ] [ 8 ]    The results were published in 1999. [ 27 ]


Hemolink (Hemosol Inc., Mississauga, Canada) was a haemoglobin solution that contained cross-linked an o-rafinose polymerised human haemoglobin. [ 10 ]  Hemosol struggled after Phase II trials were halted in 2003 on safety concerns [ 28 ]  and declared bankruptcy in 2005. [ 29 ]


Hemopure was developed by Biopure Corp and was a chemically stabilized, cross-linked bovine (cow) haemoglobin in a salt solution intended for human use; the company developed the same product under the trade name Oxyglobin for veterinary use in dogs.  Oxyglobin was approved in the US and Europe and was introduced to veterinary clinics and hospitals in March 1998. Hemopure was approved in South Africa and Russia. Biopure filed for bankruptcy protection in 2009. [ 30 ]  Its assets were subsequently purchased by HbO2 Therapeutics in 2014. [ citation needed ]


PolyHeme was developed over 20 years by  Northfield Laboratories  and began as a military project following the Vietnam War. It is human haemoglobin, extracted from red blood cells, then polymerized, then incorporated into an electrolyte solution. In April 2009, the FDA rejected Northfield's  Biologic License Application [ 31 ]  and in June 2009, Northfield filed for bankruptcy. [ 32 ]


Dextran-Haemoglobin was developed by Dextro-Sang Corp as a veterinary product, and was a conjugate of the polymer dextran with human haemoglobin. [ citation needed ]


Hemotech was developed by HemoBiotech and was a chemically modified haemoglobin.


Somatogen developed a genetically engineered and crosslinked tetramer it called Optro. It failed in a phase II trial and development was halted. [ 10 ]


A pyridoxylated Hb conjugated with  polyoxyethylene  was created by scientists at Ajinomoto and eventually developed by Apex Biosciences, a subsidiary of Curacyte AG; it was called "PHP" and failed in a Phase III trial published in 2014, due to increased mortality in the control arm, [ 10 ] [ 33 ]  which led to Curacyte shutting down. [ 34 ]


Similarly, Hemospan was developed by Sangart, and was a  pegylated  haemoglobin provided in a powdered form. While early trials were promising Sangart ran out of funding and closed down. [ 10 ]


Stem cells  offer a possible means of producing transfusable blood. A study performed by Giarratana et al. [ 35 ]  describes a large-scale ex-vivo production of mature human blood cells using  hematopoietic stem cells . The cultured cells possessed the same haemoglobin content and morphology as native red blood cells. The authors contend that the cells had a near-normal lifespan, when compared to natural red blood cells. [ citation needed ]


Scientists from the experimental arm of the  United States Department of Defense  began creating artificial blood for use in remote areas and transfuse blood to wounded soldiers more quickly in 2010. [ 36 ]  The blood is made from the  hematopoietic  stem cells removed from the  umbilical cord  between human mother and newborn using a method called blood  pharming . Pharming has been used in the past on animals and plants to create medical substances in large quantities. Each cord can produce approximately 20 units of blood. The blood is being produced for the  Defense Advanced Research Projects Agency  by Arteriocyte. The  Food and Drug Administration  has examined and approved the safety of this blood from previously submitted O-negative blood. Using this particular artificial blood will reduce the costs per unit of blood from $5,000 to equal or less than $1,000. [ 36 ]  This blood will also serve as a blood donor to all common  blood types . [ 37 ]


In 1994, the  Irish Blood Transfusion Service Board  (BTSB) informed the Minister for Health that a blood product they had distributed in 1977 for the treatment of pregnant mothers had been contaminated with the  hepatitis C  virus.
Following a report by an expert group, it was discovered that the BTSB had produced and distributed a second infected batch in 1991.
The Government established a  Tribunal of Inquiry [ 1 ]  to establish the facts of the case and also agreed to establish a tribunal for the compensation of victims but seemed to frustrate and delay the applications of these, in some cases terminally, ill women.


This controversy also sparked an examination of the BTSB's lax procedures for screening blood products for the treatment of  haemophilia  and exposed the infection of many haemophiliacs with  HIV ,  hepatitis B  and hepatitis C.


The Blood Transfusion Service Board (BTSB) has responsibility for the production and supply of human blood products used for the treatment of various blood-related conditions. In 1970, it began production of  anti-D  human immunoglobulin for the treatment of  rhesus  negative (blood type) mothers who, having previously given birth to rhesus positive babies, could have anti-bodies that would cause  haemolytic disease  (HDFN) in the foetus of future pregnancies. [ citation needed ]
If, following a neo-natal blood test, the rhesus (Rh) factor of the infant is found to be incompatible with that of the mother, an anti-D injection can be given to the mother to protect her future pregnancies. If the mother were to develop her own rhesus anti-bodies, she would be required to undergo a course of  plasma exchange transfusion  throughout her pregnancy to reduce the level of rhesus antibodies in her blood. [ 2 ]


In 1970 the BTSB began manufacturing anti-D human immunoglobulin for intravenous application at its Dublin laboratory using a process developed in 1967 by Professor Hans-Hermann Hoppe of Hamburg's Central Institute for Transfusionmedicine, one of the founders of the German transfusion service,  StKB . The process involved the use of ion-exchange chromatography together with an ethanol precipitation, which was thought at the time to inactivate viruses that might be present in donated blood, thereby removing them from the plasma eventually fractionated in the process. In 1972 Professor Hoppe notified the BTSB that he had refined his process to include a plasma quarantine period and  ultrafiltration  (instead of ethanol precipitation) but the BTSB continued to use his 1967 process. [ 3 ]  By 1975 it was known that hepatitis was a blood-born disease and that multiple types of hepatitis virus were in circulation. Tests were available to identify the hepatitis A and hepatitis B viruses and although it was suspected that another strain of the virus was responsible for Jaundice in patients whose blood did not test positive for either type, there was no diagnostic test for hepatitis C until 1990. [ citation needed ]


In 1976 a pregnant woman (referred to as "Patient X" in the report of the  Finlay Tribunal [ 1 ] ) was a patient of Dr. McGuinness, assistant master of the  Coombe Maternity Hospital .
Having had several pregnancies severely affected by haemolytic disease, Patient X was prescribed a therapeutic course of plasma exchange over a 25-week period, to reduce the antibodies that would damage her foetus. The obstetric consultant suggested to one of the BTSB staff that they could off-set the cost of Patient X's treatment by using the plasma extracted from her (which had high concentrations of anti-D) to manufacture anti-D immunoglobulin. Patient X was never asked to consent to her plasma being used in this way. [ 4 ]


Her treatment began in September 1976 and plasma from her first two treatments was mixed with that from other donors in 5 batches of anti-D produced by the BTSB and distributed between January and April 1977. On 4 November 1976, Patient X had a reaction to her plasma exchange and her treatment was suspended temporarily. On 17 November the Coombe Hospital notified the BTSB that Patient X had become jaundiced and was diagnosed as having hepatitis. [ citation needed ]


Dr. McGuinness requested that a sample of her blood be tested for hepatitis B and sent a second sample to the  Middlesex Hospital  in  London . These tests reported negative for hepatitis B (hepatitis C was not recognized not to mention testable at this time.)
As Patient X's plasma exchange treatments continued, regular blood samples were sent to the BTSB to monitor the level of rhesus anti-bodies in her blood, each sample labelled "infective hepatitis". Despite all senior medical staff at the BTSB being aware of this infection, they continued to take plasma donations from Patient X throughout January 1977 and include these in the pools used to make 16 batches of anti-D which were distributed to maternity hospitals for administration. The number of doses in each batch could vary from 250 to 400 injections. [ citation needed ]


In July 1977, the BTSB received a report from the  Rotunda Hospital  that 3 mothers who had received injections from anti-D batch 238 had subsequently developed hepatitis. On 25 July, the chief biochemist of the BTSB laboratory was instructed to exclude Patient X's plasma from all pools used to manufacture anti-D. She did precisely this but did not, however, consider disposal or recall of existing batches in which Patient X's plasma had already been used and continued to distribute these to hospitals. [ 4 ]


Samples from the 16 batches of anti-D that included Patient X's plasma and samples from the 3 Rotunda patients were sent to the Middlesex Hospital for testing, which again were inconclusive as no test for hepatitis C existed. The Scientific Committee of the BTSB began to compile a list of the destinations to which doses from anti-D batch 238 had been sent. It is unclear however, if this was completed or used in any recall operation. Between August and December 1977, the BTSB received notifications of similar cases from the maternity hospitals at the  Coombe  and  Holles Street  in Dublin indicating contamination amongst two other batches of anti-D. Despite continued notifications of hepatitis cases in 1977 and 1978, the BTSB issued no national recall of its anti-D product. [ citation needed ]


By 1990 scientists had developed multiple diagnostic test mechanisms for hepatitis C: [ citation needed ]


HCV RNA can be detected by PCR typically one to two weeks after infection, while antibodies can take substantially longer to form and be detected. Screening a population usually relies on a combination of all three test types. [ citation needed ]


With the development of a diagnostic test for hepatitis C in 1990, Dr Jeremy Garson of the Middlesex Hospital conducted retrospective testing on the many non-A, non-B hepatitis (NANBH) samples it had retained over many years. On 16 December 1991, the Middlesex Hospital FAXed a letter to the BTSB in Dublin to inform them that retained samples from Patient X and the 1977 batches of anti-D had tested positive for hepatitis C. Attached to his letter, Dr. Garson provided a list of questions that would need to be answered to determine the causes and extent of infection caused in 1977. The BTSB replied to this letter suggesting the questions be discussed at a meeting in London.  The meeting never happened and the BTSB seems to have taken no further action in respect of this letter. [ citation needed ]


When check-back of the Patient X's case commenced in 1992, 8 of the 16 batches made from the BTSB's plasma pools in from January to July 1977 were shown to be contaminated with hepatitis C. These included batch 250 from which  Brigid McCole  received her anti-D injection on 5 November 1977.


In August 1989 a pregnant woman (referred to as "Donor Y" in the report of the Finlay Tribunal [ 1 ] ) began a course of plasma exchange transfusions at  St. James's Hospital  in Dublin. In the first month of her treatment 10 donations of plasma were taken from her, all of which were clear of hepatitis C when subsequently tested in 1992. [ citation needed ]


On 13 September 1989 "Donor Y" received a unit of plasma from the BTSB which was almost certainly contaminated with hepatitis C. (Check back tests of her plasma donations after this date tested positive for hepatitis C, a sub-type different from the one that infected Patient X.) With the emergence of HIV in the 1980s and the BTSB's previous difficulties with hepatitis contamination, the BTSB now had a precautionary protocol surrounding plasma donations by mothers undergoing exchange transfusions: Plasma donations from such women could not be included in the production of blood products until they had given birth and had a blood test showing they were clear of HIV, hepatitis B and hepatitis C. [ citation needed ]


All of the plasma donated by Donor Y, therefore was frozen and stored subject to clearance for anti-D production. In September and 12 October more donations of plasma were taken from Donor Y and placed in storage. Throughout 1990, the laboratory staff of the BTSB requested the blood test clearance of Donor Y from the BTSB medical staff responsible for her case. [ citation needed ]


Despite receiving no test results, in January 1991 the BTSB lab began to include Donor Y's plasma in the plasma pools used to manufacture 46 batches of anti-D. [ 5 ] [ 6 ]


In November 1991, Donor Y was tested for HIV, hepatitis B and hepatitis C (for which a new test was available) and was found negative for all three. (It is assumed that by this point she had "sero converted" for hepatitis C, having produced sufficient antibodies to eliminate it from her blood stream.) The 4 batches of anti-D suspected of infecting women at the various Dublin maternity hospitals (and which included plasma taken from Donor Y in 1989) tested positive for hepatitis C. [ citation needed ]


It was not clearly established whether or not the BTSB laboratory chief was notified of these tests but she continued to manufacture and distribute 21 batches using Donor Y's plasma. Upon subsequent check-back of all 46 anti-D batches produced from the pools containing Donor Y's plasma, 20 batches were found to be positive for Hep-C, 3 were negative and in the remaining 23 "infectivity could not be ruled out".


After the hepatitis C virus (HCV) was identified in 1988 and a diagnostic test developed in 1990, in 1991 the BTSB added this test to its screening of all blood donors (along with HIV and hepatitis B). The BTSB's regional director for Munster set up a survey of all donors in the region who tested positive for HCV, with a view to tracing the source of infection. [ citation needed ]


She began to notice very soon that almost all positive cases were females and fell across a relatively narrow age range.
As a result of this survey, by 1994 she had identified a possible link between infected donors and the anti-D injections they had received many years previously. She made an interim report in this survey at a meeting of the BTSB Medical Consultants Group on 19 January 1994. It was decided to perform a similar study of HCV infection outside the Munster region. [ citation needed ]


Samples from the Munster donors who had tested positive for HCV were sent to the Middlesex Hospital and compared with samples from Patient X. The results suggested "a strong causative relationship" between them and the 1977 hepatitis infections. It was decided to send samples of the BTSB's current stocks of anti-D to Middlesex for testing. These still contained some batches in which Donor Y's plasma had been used. The results indicated some contamination with HCV but of a different sub-type from that found in 1977 samples.


Throughout February 1994, the board of the BTSB held several crisis meetings and on 17 February 1994, the informed the Minister for Health,  Brendan Howlin  T.D. of the discovery. The BTSB and met with  Department of Health  officials to discuss a plan of action. Following meetings between the BTSB and officials at the Department of Health the following measures were agreed:


On the advice of Department of Health officials the BTSB press release on 21 February made no mention of the second contamination of anti-D in 1991. [ 7 ]


On 22 February 1994, the Minister for Health made a Statement in  Dáil Éireann  about the issue, which had already been reported in the press. He commended the BTSB for their thorough research, assured the public that only virally inactive anti-D would now be distributed and announced some aspects of the National Screening Programme. [ citation needed ]


The BTSB's protocol for recall of its products consisted of the sending of a notification letter to each maternity hospital or GP that had been supplied with anti-D and a follow up phone call two weeks later. As the BTSB records were not up-to-date and letters were addressed to named individuals some of whom were no longer working, some of the hospitals did not receive notification and continued to dispense their stock of infected anti-D in 1994. [ citation needed ]


In order to have an immediate replacement stock of anti-D following the recall of its own product, the BTSB quickly sourced  WinRho SDF  from the  Winnipeg Rh Institute   Manitoba ,  Canada  without first getting the product approved by the  National Drug Advisory Board  (NDAB).


The BTSB launched its HCV National Screening Programme and set about trying to identify and contact all women who had received anti-D injections since it had begun issuing it in 1970. It did so by checking its own records and contacting Hospitals and GPs to whom infected doses has been sent and by publishing adverts in the national media appealing for women to come forward. By February 1997, 62,667 women had been tested for evidence of HCV infection. Almost 1,200 tested positive for HCV antibodies. [ citation needed ]


Of the samples from women who had received anti-D manufactured in 1977, 704 showed signs of current or past infection. Another 53 showed a RIBA reaction but in which antibodies could not be confirmed and a further 74 showed no signs of infection or antibodies but had recovered from an episode of hepatitis in the past. [ citation needed ]


Of the samples from women who had received anti-D manufactured in 1991, 72 showed signs of current or past infection. Another 26 showed a RIBA reaction but antibodies could not be confirmed. The BTSB noted that the number of women that came forward for testing from the cohort that received anti-D in 1991 was 30% lower than expected.


Because HCV is a blood-borne virus it is relatively difficult to transmit. However, the  risk of transmission  is greater where exposure to or exchange of blood is a factor. The risk to sexual partners is much lower.
The screening programme identified 11 individuals who had been infected with HCV through their contact with/treatment of anti-D recipients. [ citation needed ]


The greatest risk of secondary infection to the population as a whole would be from infected people donating blood to the BTSB.
Because the rhesus negative factor is relatively rare, people with that factor are encouraged to donate blood. Of the infected anti-D recipients, 103 went on to donate blood to the BTSB following their infection. These donors made total of 504 donations which resulted in an estimated 606 potentially infectious labile blood components (Another donor was identified who had been indirectly infected by an anti-D recipient and whose donations went into 8 labile blood components.) As many blood products are administered to patients with critical health issues, the level of mortality amongst all blood product recipients is relatively high. Upon tracing the recipients of the blood products potentially infected by anti-D recipients, the BTSB found that many were deceased but of 61 living recipients, 30 tested positive for on-going infection with HCV. [ citation needed ]


The development of ultra-sensitive HCV tests since the 1990s has made it possible to detect markers for the disease in people who seem to be fully recovered from hepatitis. It is accepted, however, that there may still be a level of  "occult infection"  in otherwise healthy populations.


The screening programme also examined the partners and children of anti-D recipients. As of 17 January 1995, the BTSB reported that 1,265 children and 363 partners have been screened for hepatitis C. Up to that date, ten children had tested positive for hepatitis C antibodies and two of these children have tested positive for the virus. Three partners have tested positive for hepatitis C antibodies. Further investigations were underway in these cases. [ 8 ]


Many of the women who tested positive for HCV experienced relief as the seemingly  inexplicable symptoms  they had suffered over many years could now be explained. However, they suddenly came to feel stigmatized and discriminated against by various members of society. There was a general confusion between HCV and HIV which were often mentioned together in communications about intravenous drug use. For a long time it was unclear whether women could infect their husbands with HCV through sexual intercourse or whether they might have infected their children in utero, which led to stress and tensions in families. Many of the women were refused treatment by dentists, had their employment terminated and were refused insurance. [ 9 ]


The state's largest health insurance company, the  Voluntary Health Insurance  (VHI) refused cover to several women on the grounds that they had acquired a "sexually transmitted disease". Some began to feel a deep sense of betrayal as they had contracted this virus and disease through no fault their own but through an agency of the state. Chronic hepatitis C infection when left untreated not only results in  cirrhosis  of the liver but can trigger other diseases not directly associated with the liver (cancers,  hypertension ,  Heart arrhythmia  ) and auto-immune conditions ( rheumatoid arthritis ), which may not be easily attributed to the HCV infection. [ citation needed ]


The Department of Health established Hepatology Units in  Beaumont ,  the Mater ,  St. James's  and  St.Vincent's  Hospitals in Dublin,  Cork University Hospital ,  University Hospital Galway  and later in  St. Luke's Hospital Kilkenny  and  Crumlin Children's Hospital , where those infected were referred for medical supervision and treatment. A counseling service was also provided for the infected women although this soon proved unsatisfactory as it was under the auspices of the BTSB. This was augmented with the provision of counselling by  Well Woman centres  in Dublin and Cork and was subsequently extended to private psychologists in other regions. [ 10 ]


In July 2017 the  European Association for the Study of the Liver  (EASL) published the report [ 11 ]  of a study conducted jointly by the  Health Service Executive -Health Protection Surveillance Centre, Dublin, Ireland, the  European Programme for Intervention Epidemiology Training  ( EPIET ) and the  European Centre for Disease Prevention and Control  ( EDCD ), Stockholm, Sweden into the disease outcomes for the women infected by the anti-D contamination. Of the 682 women included in the study 72 (19%) developed cirrhosis and 18 had died from liver-related causes (5%) after 36 years of infection. Disease progression accelerated in the last five years of follow-up, particularly in women with diabetes mellitus and high alcohol consumption. [ citation needed ]