Published on September 26, 2018
1. Blood Banking and Transfusion Medicine Abdul-Kader Souid9/26/2018 1 • A transfusion is given to improve blood oxygen-carrying capacity and restore blood volume. It is typically given if symptoms of anemia or blood loss are severe. Selected indications include severe bleeding, severe anemia, complications of sickle cell anemia (splenic sequestration, severe acute chest syndrome), G6PD deficiency hemolysis, thalassemia major, aplastic anemia, and autoimmune hemolytic anemia. • Blood is screened for human immunodeficiency viruses (HIV), human T-lymphotropic viruses (HTLV), hepatitis B/C viruses, West Nile virus, Trypanosoma cruzi (the parasite that causes Chagas disease), and Treponema pallidum (the spirochaete bacterium that causes syphilis). Viral transmission may occur in the “window period” between exposure and positive testing. Agents such as Babesia microti (a red cell parasite; it has arisen as an important cause of transfusion transmitted infection), dengue virus, and Creutzfeldt–Jakob disease are emerging threats for which there is currently no intervention. • Blood is donated by healthy volunteers under strict regulations. Donor interview provides the first protection from transfusion-transmitted infection. Many donors are deferred from donation at the interview stage. This approach resulted in a 10-fold lower prevalences of HIV and hepatitis among donors.
2. PRBC Transfusion • The following tests are performed whenever PRBC are requested: ABO/Rh group – The ABO group is determined because anti-A and anti-B (IgM) alloantibodies (isohemagglutinins) in recipient’s serum produce rapid hemolysis of donor’s red cells (as in acute hemolytic reaction). – The Rh group is determined because the D-antigen (major determinant of the Rh system) produces anti-D antibodies in Rh-negative recipients. An Rh-negative woman who is immunized to D-antigen by transfusion is at risk of delivering a newborn with severe hemolysis (“hemolytic disease of the newborn”). Antibody screening − It detects alloantibodies (isohemagglutinins) against non-ABO blood group antigens in recipient’s serum. It is performed using recipient’s serum against a commercial panel of red cells of known antigen composition. It is also called indirect anti-globulin test (IAT) or indirect Coombs test. • Direct anti-globulin test (DAT, also called direct Coombs test) detects antibodies or complements on the surface of red cells. Crossmatch − A crossmatch of ABO-compatible and Rh-compatible unit of blood determines whether the recipient’s serum contains antibodies to donor’s red cells. 9/26/2018 2
3. Packed Red Blood Cells (PRBC) • PRBC are prepared from whole blood by removing most of the plasma, producing a hemoglobin concentration of ~230 g/L (a hematocrit of ~70%). – Removing plasma reduces volume load and isohemagglutinin (anti-A, anti-B) titer. – Each unit contains 200 mL PRBC + 70 mL plasma + 100 mL additive nutrients (adenine- dextrose-NaCl-mannitol [ADSOL]). • Units of PRBC are stored at 4-6oC (refrigerated) for up to 42 days. • A transfusion is usually given over 2-4 h; once a unit is entered for transfusion, the transfusion must be completed within 4 h or discarded. • In children, transfusing 10-15 mL/kg of PRBC increases hemoglobin by 20-30 g/L. • In adults, transfusing 1 unit of PRBC increases hemoglobin by 10 g/L. • Leukocyte-reduced PRBC is prepared by passing the unit through a filter, which removes ≥85% of the white cells. – It produces fewer febrile reactions, allo-immunization, and viral transmission (e.g., cytomegalovirus). – It is indicated for patients who need repetitive transfusions (e.g., chemotherapy, hemoglobinopathies). • Irradiated PRBC is prepared by exposing the unit to 2,500 cGy (centigray) of radiation. – The treatment inactivates donor’s T-cells, which reduces risk of graft-versus-host (GvH) in the recipient. – It is recommended for immune-compromised patients (e.g., chemotherapy).
4. Transfusion-Transmitted Bacterial Infections • Transmitted diseases include bacteria, viruses, protozoa, and prions (a protein triggers proteins in the brain to fold abnormally). For products stored at 2-6°C (in a refrigerator), bacterial growth is slow and limited to psychrophiles or cryophiles (e.g., the genus Pseudomonas). • Bacterial contamination of blood products is the second most common cause of death from transfusion (after clerical errors of blood group determination). Risks of bacterial contamination is greater than that of viral transmission. • Contamination of platelet products is attributable to gram-positive bacteria (e.g., Staphylococcus species) and of red cell products to gram-negative bacteria (e.g., Yersinia enterocolitica, Pseudomonas, Serratia). – Yersinia enterocolitica is responsible for ~50% of the reported cases of red cell-associated, causing asymptomatic bacteremia in the donor and clinical sepsis in the recipient. On retrospective questioning, in most Yersinia cases, donors report diarrhea in the days before or after blood donation (CDC data). 9/26/2018 4
5. PRBC Transfusion in Sickle Cell Disease (SCD) - Alloimmunization • The antigens that are most commonly implicated in alloimmunization in SCD are in the Rh and Kell blood groups, followed by Kidd, Duffy, Lewis, and MNS blood group systems. – Antigen matching for these highly immunogenic and clinically significant Rh (D, C, E, c, e) and Kell antigens has significantly reduced alloimmunization in SCD. – Some centers also match for Kidd, Fya, Lewis, and MNS system antigens. • Recent studies have shown that there is a mismatch between serological Rh phenotype and RHD (MIM#111680) / RHCE (MIM#111700) genotype due to allelic diversity (the presence of different alleles at a gene locus). Thus, it may be necessary to do RH genotyping in addition to serological typing for patients with multiple antibody formation. • It is recommended that all the patients with SCD receive C, E, c, e, and Kell matched blood in addition to regular ABO and Rh (D) typing. – If a patient has developed an alloantibody, the blood should be matched for that antigen, making sure the donor cells do not express that antigen. – Genotype-matched blood for RH antigens is reserved for those who developed an antibody to an antigen that they seem to express on their RBC (such as anti-D in a D+ patient). These patients may have variant alleles (allelic diversity) that lead to development of the antibody. If this partial antigen is confirmed by genotyping, they should receive antigen negative blood. Transfusional iron (mg iron per kg) = Total volume of transfused PRBC x 0.6 (the average hematocrit in PRBC) x 0.8–1.0 mg (the amount of iron per mL PRBC) ÷ patient weight (kg). Liver iron (mg iron per g dry weight liver) = Transfusional iron (mg/kg) ÷ 10.6.
6. Other Complications • Hemolytic transfusion reactions are caused by a clerical error that results in incompatible red cells being administered. The anti-A and/or anti-B IgM alloantibodies in the recipient’s plasma produce intravascular hemolysis of donor's red cells. • Non-hemolytic (febrile) reactions: Febrile reactions are caused by cytokines (produced by donor’s leukocytes) accumulated in stored blood. Treatment includes stopping the transfusion and excluding hemolytic transfusion reaction. Pre-medication with acetaminophen is usually helpful. Pre- storage ‘leukocyte-reduced PRBC‘ lowers the risk of this complication. • Allergic reactions: Urticaria, flushing, and angioedema may result from recipient’s exposure to donor’s plasma proteins and other substances. It can be ameliorated by diphenhydramine (antihistamine) and methylprednisolone. A severe form occurs with IgA deficiency. • Transfusion-related acute lung injury (TRALI): (see Acute Transfusion Reaction – III) • Volume overload (pulmonary edema), Hyperkalemia (RBC hemolysis), Iron overload. • Viral transmission: (e.g., HIV, hepatitis A, B, C) • Alloimmunization (see PRBC Transfusion in sickle cell disease) • Graft-versus-host (GvH) reaction (in immune compromised patients; donors’ lymphocyte attack the recipient; ‘irradiated PRBC lowers the risk of this complication’). 6
7. Platelet Transfusion • Bleeding is common when the platelet count is ≤20 x109/L. • Platelets are prepared from whole blood by centrifugation or from single-donor apheresis, and stored at 22-24oC (room temperature) for up to 72 h with gentle agitation. • Platelet transfusion is not recommended for patients with: • Hemolytic-uremic syndrome (HUS) • Thrombotic thrombocytopenic purpura (TTP) • Immune thrombocytopenic purpura (ITP) • ABO compatible, single-donor apheresis, leukocyte-depleted, and irradiated platelets are less likely to produce alloimmunization and graft-versus-host reaction in the recipient. These products are recommended for patients requiring repetitive transfusion (chemotherapy, aplastic anemia). • A frequent cause of refractoriness to platelet transfusion is human leukocyte antigen (HLA)- alloimmunization (~10% of patients who receive chronic transfusion); transfusion of HLA-matched platelets is the best approach. Removal of leukocytes prior to transfusion (leuko-reduction at collection site) ↓alloimmune platelet refractoriness to ≤5%. Management of platelet refractoriness caused by HLA antibodies relies upon HLA-matching of transfused platelets. Use of HLA-matched donors is costly and requires a large pool of HLA-typed people. [Rebulla P. A mini-review on platelet refractoriness. Haematologica 2005;90:247-253].
8. Fresh Frozen Plasma (FFP) • This non-concentrated source of clotting factors is prepared from whole blood within 8 h of collection. It is stored at -18oC (freezer) for up to 1 year. • It is used for coagulopathy (e.g., disseminated intravascular coagulation), reversal of warfarin, congenital factor deficiency (factor II, X, XI and XIII), thrombotic thrombocytopenic purpura (TTP), and hemolytic uremic syndrome (HUS). 9/26/2018 8 • Cryoprecipitate is prepared from by thawing the FFP at 4oC. The precipitate (rich in fibrinogen, factor VIII, von Willebrand factor, and factor XIII) is then suspended in 15 mL plasma and refrozen. – It is mainly used to treat bleeding due to low fibrinogen (e.g., severe liver disease, disseminated intravascular coagulation). • ABO-compatibility is less relevant in the transfusion of platelets or plasma than that in ABO- incompatible red cells. Acute hemolytic transfusion reaction may follow ABO-incompatible platelet or plasma transfusion; e.g., blood group O single-donor platelets are given to a blood group A recipient. Direct antiglobulin test (DAT) is positive in the recipient and a high titer of isohemagglutinin (anti-A) would be found in the donor. This risk is higher in infants due to their relatively low blood volume. About 25% of platelet transfusions are ABO-incompatible; a survey by the College of American Pathologists found that most laboratories have a policy to minimize or avoid incompatible platelet/plasma exposures.
9. Acute Transfusion Reaction - I A 12-year-old girl with b-thalassemia major becomes anxious and reports back pain a few minutes after starting a packed red blood cell transfusion. The transfusion is immediately stopped. A normal saline infusion is started, and vital signs are monitored. She is febrile and tachycardic, but normotensive with normal respiratory rate. She does not report any respiratory symptoms. Her urine is dark orange. Which one of the following is the most likely cause of her condition? A. Acute hemolytic transfusion reaction B. Febrile non-hemolytic transfusion reaction C. Sepsis to due Yersinia enterocolitica D. Sepsis to due Staphylococcus species E. Transfusion-related acute lung injury (TRALI) 9/26/2018 9
10. Acute Transfusion Reaction - II A 5-year-old girl with sickle cell anemia and history of abnormal transcranial Doppler (TCD) velocities is on chronic transfusion therapy for primary stroke prophylaxis. She has completed an PRBC transfusion through a central venous access. At the completion of the procedure, she started feeling unwell, became febrile, was tachycardic, and her blood pressure dropped to 60/30 mmHg. A blood culture was drawn and she was started on broad- spectrum antibiotics. Cultures were also sent from the red blood cell unit used for and one of them is growing bacteria in 3 hours. What is the most likely pathogen leading to her sepsis? A. Salmonella species B. Staphylococcus aureus C. Streptococcus species D. Yersinia enterocolitica E. Serratia species 9/26/2018 10
11. Comments to the Questions • Transfusion reactions occur in 1 in 100 transfusions and are more frequent in children. • Acute hemolytic transfusion reactions: Symptoms occur within minutes of the transfusion, which can be fatal with the risk for disseminated intravascular coagulation (DIC) and acute renal failure. Fever is the most common sign, but many patients also report back or flank pain, dark urine and anxiety. Laboratory evaluation shows positive DAT (direct anti-globulin test) and markers of hemolysis (hemoglobinuria). The blood bag and a blood sample from the recipient should be returned to blood bank for retyping. • Febrile non-hemolytic transfusion reactions occur secondary to anti-leukocyte, anti-platelet, or anti-HLA antibodies, particularly in frequently transfused patients. Patients are otherwise asymptomatic and do not have evidence of hemolysis. Leukocyte reduction of the transfused product minimizes the risk for febrile non-hemolytic transfusion reactions. • Sepsis from a transfused product, most often platelets because they are stored at room temperature, can present with fever associated with rigors, hypotension, and inflammation but is not associated with hemolysis. Symptoms occur within 4 h of the transfusion. Yersinia enterocolitica is the most common gram-negative bacteria associated with PRBC sepsis. – If a septic transfusion reaction is suspected, the transfusion should be stopped immediately. Blood culture should be sent from the recipient, as well as from the infusing unit. The recipient should be started on broad spectrum antibiotics (e.g., aminoglycosides, trimethoprim- sulfamethoxazole (TMP-SMZ), piperacillin, ciprofloxacin, or a third-generation cephalosporin). If the cultures from the unit and from the recipient confirm the diagnosis of transfusion-transmitted sepsis, this should be reported to the blood bank, as well as to the blood supplier, to prevent the distribution of other units from the same donation. A donor investigation should be performed. • Transfusion-related acute lung injury (TRALI) occurs within 6 h of the transfusion with fever, hypotension, respiratory distress, and infiltrate on CXR. TRALI is life-threatening and requires aggressive supportive care.
12. Acute Transfusion Reaction - III A 16-year-old boy is admitted after a motor vehicle accident and received fresh frozen plasma in the emergency department. He developed respiratory distress and bilateral pulmonary infiltrates 4 hours after the transfusion. Which of the following is the plasma most likely to reduce the risk of transfusion-related acute lung injury TRALI)? A. Type AB positive plasma B. Type Rh positive plasma C. Cytomegalovirus-negative plasma D. Irradiated plasma E. Male donor plasma TRALI is the leading cause of transfusion- related mortality. It is due to the presence of antibodies in the donor’s plasma, which target the recipient human leukocyte antigen (HLA) or human neutrophil antigens (HNA). These antibodies most commonly occur in multiparous females after being exposed to the fetus’ antigens. Each pregnancy increases the risk of antibody development. Several countries have now implemented policies that restrict plasma donation to male donors only, which has significantly decreased the incidence of TRALI. Non-antibody-mediated TRALI occur because of accumulated pro-inflammatory mediators, such as bioactive lipids and soluble CD40 ligand (sCD40L) during storage of the transfused unit or because of aging of RBC/ platelets.
13. Key Points • A transfusion should be recommended only after its risks and benefits are carefully considered. • Most transfusion fatalities occur as a result of ABO incompatibility due to errors in identifying the patient or the unit of blood. • Leukocyte-depleted blood components are recommended for patients requiring chronic transfusion. • Irradiated blood components are recommended for immune compromised patients. 9/26/2018 13 Complications of chronic transfusion include iron overload, alloimmunization, and viral infections. Accumulation of iron in the endocrine organs results in diabetes and hypopituitarism. Cardiac iron overload leading to cardiomyopathy and arrhythmias is a leading cause of death in chronically transfused patients with thalassemia. Transmission of viral infections, especially HIV, hepatitis B, and hepatitis C remain important complications.
14. References • Klein HG. Red blood cell transfusion in clinical practice. Lancet 2007;370(9585):415-426. DOI: 10.1016/S0140- 6736(07)61197-0. • Guinet F. Transfusion-transmitted Yersinia enterocolitica sepsis. Clin Infect Dis. 2011;53(6):583-591. DOI: 10.1093/cid/cir452. • Trimble SR, et al. Assessing emerging threats to blood safety for the blood disorders community. Am J Prev Med. 2010;38(4 suppl):S468-S474. DOI: 10.1016/j.amepre.2009.12.019. • Haesebaert J. Septic shock during platelet transfusion in a patient with acute myeloid leukaemia. BMJ Case Rep. 2013;30. doi: http://dx.doi.org/10.1136/bcr-2013-010412. • Hong H. Detection of septic transfusion reactions to platelet transfusions by active and passive surveillance. Blood 2016;127:496-502. doi: http://dx.doi.org/10.1182/blood-2015-07-655944. • Klausen SS. Bacterial contamination of blood components: Norwegian strategies in identifying donors with higher risk of inducing septic transfusion reactions in recipients.Transfus Apher Sci. 2014;51:97-102. doi: http://dx.doi.org/10.1016/j.transci.2014.08.007. • US FDA. Fatalities reported following blood collection and transfusion: annual summary for fiscal year 2014. http://www.fda.gov/downloads/biologicsbloodvaccines/safetyavailability/reportaproblem/transfusiondonationfataliti es/ucm459461.pdf • Lieberman L, Petraszko T, Yi QL, Hannach B, Skeate R. Transfusion-related lung injury in children: a case series and review of the literature. Transfusion. 2014;54(1):57-64. doi: http://dx.doi.org/10.1111/trf.12249. • Peters AL, Van Stein D, Vlaar AP. Antibody-mediated transfusion-related acute lung injury; from discovery to prevention. Br J Haematol. 2015;170:597-614. doi: http://dx.doi.org/10.1111/bjh.13459. • Vlaar AP, Juffermans NP. Transfusion-related acute lung injury: a clinical review. Lancet. 2013;382:984-994. doi: http://dx.doi.org/10.1016/S0140-6736(12)62197-7. 9/26/2018 14