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  • 4immunohematologylab

    1. 1. Immunohematology Antonio Rivas PA-C 2008
    2. 2. <ul><li>A 28-year-old woman receiving her first blood transfusion begins to complain of flushing, tightness in her chest, and difficulty breathing within minutes of the start of the infusion. Her blood pressure drops rapidly and the transfusion is immediately discontinued. Epinephrine is administered with good effect. Specimens sent to the lab show no evidence of hemolysis. </li></ul><ul><li>What is the most likely cause of such a reaction? </li></ul>
    3. 3. <ul><li>A. An ABO incompatibility </li></ul><ul><li>B. Recipient antibodies against donor red cell antigens not detected on cross match C. Recipient antibodies against donor white cell or platelet antigens </li></ul><ul><li>D. Recipient antibodies against donor IgA </li></ul><ul><li>E. Donor antibodies against recipient white blood cells </li></ul>
    4. 4. Answer <ul><li>D. Recipient antibodies against donor IgA </li></ul><ul><li>Anaphylactic reactions may occur in rare patients who are IgA-deficient and have developed anti-IgA antibodies. Reactions occur in response to IgA, which is normally present in donor blood. Symptoms develop rapidly (seconds to minutes after starting the transfusion) and may include bronchospasm, nausea, vomiting, flushing, urticaria, and hypotension. Immediate treatment including epinephrine and possible intubation is required. Subsequent transfusions must consist of red cells, which are washed to remove IgA and plasma from IgA-deficient donors. </li></ul>
    5. 5. <ul><li>A 47-year-old woman presents to your office after developing a low-grade fever and mild jaundice over the past several days. Her recent history is significant for a total abdominal hysterectomy performed 12 days ago, at which time she received 2 units of packed red blood cells without incident. Although there is no evidence of bleeding at present, her hemoglobin level is only 10.2 g/dl. You believe this may be a delayed transfusion reaction. What would be the most likely cause of such a reaction? </li></ul><ul><li>A. An ABO incompatibility </li></ul><ul><li>B. Recipient antibodies against donor red cell antigens not detected on cross match </li></ul><ul><li>C. Recipient antibodies against donor white cell or platelet antigens </li></ul><ul><li>D. Recipient antibodies against donor IgA E. Donor antibodies against recipient white blood cells </li></ul>
    6. 6. Answer <ul><li>Recipient antibodies against donor red cell antigens not detected on cross match </li></ul>
    7. 7. <ul><li>Delayed hemolytic reactions occur in patients previously sensitized (through transfusion or pregnancy) to red blood cell antigens other than ABO. Levels of these antibodies are not detectable by routine laboratory tests but quickly rise when the patient is challenged with donor cells displaying the appropriate antigen (an anamnestic response). These reactions are extra vascular in nature (hemolysis occurs mainly in the spleen). Clinical symptoms appear days to weeks after the transfusion, and may include fever and mild jaundice, along with an unexpected fall in hemoglobin. While rarely life threatening, these reactions are important to recognize because of the potential for more severe reactions with subsequent transfusions. </li></ul>
    8. 8. Immunohematology <ul><li>Study of the human blood groups </li></ul><ul><li>Evaluation of blood donors </li></ul><ul><li>Collection and processing of donor blood </li></ul><ul><li>Testing for blood group antigens </li></ul><ul><li>Matching patient with compatible blood before transfusion </li></ul><ul><li>Antiglobulin tests </li></ul><ul><li>IAT / DAT </li></ul>
    9. 9. Terminology <ul><li>Antibody : serum protein that is induced by, and reacts specifically with a foreign substance (Ag) </li></ul><ul><li>Antigen : foreign substance that induces an immune response by causing production of antibodies and or sensitized lymphocytes that react specifically with that substance </li></ul>
    10. 10. Terminology <ul><li>Primary Ab response: immune response occurring after the first exposure to the Ag </li></ul><ul><li>First Ab detected is IgM, 3-4 days after exposure </li></ul><ul><li>Peaks and drops in a few weeks </li></ul><ul><li>IgG detectable after 1-2 weeks, peaks within weeks and return to normal within few months </li></ul>
    11. 11. Terminology <ul><li>IgM increases reflects recent exposure </li></ul><ul><li>Changes in IgG titters within 2-3 weeks also means recent exposure </li></ul><ul><li>Seroconversion: when an antibody becomes detectable in serum/plasma of a patient who was previously tested as negative for the same Ab </li></ul>
    12. 12. Terminology <ul><li>Secondary Ab response (anamnestic response): seen after reexposure to an Ag </li></ul><ul><li>Immune cells remember the Ag response is fast </li></ul><ul><li>IgM and IgG increase quickly within 2-3 days </li></ul><ul><li>Higher levels that stay for months to years </li></ul><ul><li>booster vaccination </li></ul>
    13. 13. Immunoglobulins
    14. 14. Immunohematology <ul><li>Earliest recorded Blood transfusion in 1628 </li></ul><ul><li>Transfusing blood from animals to human </li></ul><ul><ul><li>Disastrous results </li></ul></ul><ul><li>Prohibition of transfusion in the late 1600s </li></ul><ul><li>1900 discovered ABO blood group </li></ul><ul><ul><li>Patient blood mixed with donor blood before transfusion to look for reactions </li></ul></ul><ul><li>Discover anticoagulants </li></ul><ul><li>First Blood bank in US in 1937 in Chicago </li></ul>
    15. 15. Immunohematology <ul><li>1940 US government established a nationwide blood collection program </li></ul><ul><li>Continued improvement next three decades </li></ul><ul><li>In 1980 transfusion medicine became a medical specialty </li></ul><ul><li>1984 the cause of AIDS was proven to be the HIV-transmissible by blood </li></ul><ul><li>Changes in blood donor screening </li></ul><ul><li>Development of more sensitive tests to detect HIV and other infectious agents </li></ul>
    16. 16. General health requirements for blood donors <ul><li>Age > 16 yo </li></ul><ul><li>Weight 110 pounds </li></ul><ul><li>Temperature < 99.5 F </li></ul><ul><li>Blood pressure < 180/<100 mm Hg </li></ul><ul><li>Hemoglobin >11 g/dl </li></ul>
    17. 17. Tests for infectious diseases performed on donated blood <ul><li>Antibody tests </li></ul><ul><li>Anti-HBc </li></ul><ul><li>Anti-HCV </li></ul><ul><li>Anti-HIV 1 and 2 </li></ul><ul><li>Anti HTLV I and II </li></ul><ul><li>Syphilis test </li></ul>Antigen tests • HBsAg • HIV-1 • Hepatitis C virus • West Nile virus
    18. 18. Blood components <ul><li>Collected as whole blood(RBC/WBC/Plts suspended in Plasma) </li></ul><ul><li>Separated into </li></ul><ul><ul><li>Red blood cells </li></ul></ul><ul><ul><li>Platelets </li></ul></ul><ul><ul><li>Plasma (FFP) </li></ul></ul><ul><li>Packed RBCs can be stored refrigerated up to 42 hrs </li></ul><ul><li>Other components: factor VIII, IX concentrate </li></ul>
    19. 19. Pretransfusion testing <ul><li>ABO forward testing </li></ul><ul><li>Rh testing </li></ul><ul><li>ABO reverse testing </li></ul><ul><li>Antibody screen </li></ul><ul><li>Crossmatch </li></ul>
    20. 20. Procedures performed in the Blood Bank <ul><li>ABO grouping </li></ul><ul><li>Rh typing </li></ul><ul><li>Compatibility testing before transfusion </li></ul><ul><li>Typing of donor blood </li></ul><ul><li>Unusual blood group antibody testing </li></ul>
    21. 21. Blood group system <ul><li>Major blood group system is the ABO system </li></ul><ul><li>Four major blood types A, B, AB, or O </li></ul><ul><li>ABO grouping tests based on principle of agglutination </li></ul><ul><li>45 % of the population of the US is group O, 40% is group A, 11% is B and 4 % is AB </li></ul><ul><li>Differs according to racial and ethnic group </li></ul>
    22. 22. Blood group antigens <ul><li>Presence or absence of group A or B antigens in RBCs, leukocytes and Plts. </li></ul><ul><li>Inherited One allele from each parent </li></ul><ul><li>A and B are codominant with respect to each other </li></ul><ul><li>Group A person has A ag in blood cells </li></ul><ul><li>Group B person has B ag in blood cells </li></ul><ul><li>Group AB person has A and B antigen on blood cells </li></ul><ul><li>Group O person has neither A or B antigens on blood cells </li></ul>
    23. 23. Testing Blood group Antigens <ul><li>Patients RBCs are combined with known antiserum (antibodies) commercially available, observing for agglutination </li></ul><ul><li>If the Ag present on the cells correspond to the antibody in the reagent, Ab will bind to the Ag and cause clumping of the cells (agglutination) </li></ul><ul><li>Forward grouping </li></ul>
    24. 24. Forward grouping
    25. 27. ABO antibodies (Ab) <ul><ul><li>Naturally occurring </li></ul></ul><ul><ul><li>IgM </li></ul></ul><ul><ul><li>Ab is present if Ag is missing </li></ul></ul><ul><ul><li>Not well developed in newborns </li></ul></ul><ul><ul><li>Detected by reverse grouping </li></ul></ul>
    26. 28. ABO antibodies (Ab) <ul><li>Reverse grouping </li></ul><ul><ul><li>Detects Abs present in patients serum, by reacting the serum/plasma with suspension of commercially available A or B cells suspension and looking for agglutination </li></ul></ul>
    27. 31. Importance of ABO grouping <ul><li>Must be done before blood transfusion </li></ul><ul><li>Patient should be transfused with blood of the same ABO group </li></ul><ul><li>Severe blood transfusion reaction if not properly matched blood is transfused </li></ul><ul><li>“ avoid giving the patient an Ag he does not already have” </li></ul><ul><li>In emergency O packed RBcells given-universal donor </li></ul>
    28. 32. Tissue transplants <ul><li>Kidney, liver, cornea, skin, pancreas, BM, heart, lung, intestine and bone </li></ul><ul><li>Autologous//autografts: from the same individual </li></ul><ul><li>Homologous //allografts : from the same species </li></ul><ul><li>ABO and Rh matched </li></ul><ul><li>Histocompatibility testing </li></ul>
    29. 33. Exercise
    30. 34. Rh blood group <ul><li>Second most important blood group system(name from the Rhesus monkey) </li></ul><ul><li>Composed of many Ags </li></ul><ul><li>Most important D Ag-most antigenic </li></ul><ul><li>Only test for D Ag </li></ul><ul><li>Product of inherited genes </li></ul><ul><li>Only present in RBCs </li></ul>
    31. 35. Rh blood group <ul><li>Antibodies to Rh system do not occur naturally </li></ul><ul><li>RBCs that posses the D antigen are called: Rh –positive or D-positive </li></ul><ul><li>Weak D antigen is possible needs xtra. Testing in order to detect </li></ul><ul><li>RBCs are incubated with commercially available anti-D </li></ul>
    32. 36. Rh antibodies <ul><li>Produced by a D negative person who has been sensitized or immunized to the D Ag </li></ul><ul><li>Can occur during pregnancy or after blood transfusion </li></ul><ul><li>Anti-D is an IgG </li></ul>
    33. 37. Hemolytic Disease of the newborn <ul><li>Abs from the mother enters the fetal circulation and destroys fetal red blood cells </li></ul><ul><li>Caused primarily by maternal Anti-D recognizing D Ag in fetal RBCs </li></ul><ul><li>D-negative mother becomes pregnant with a D-positive fetus </li></ul><ul><li>During pregnancy or at birth (feto-maternal hemorrhage), mother becomes exposed to fetal RBCs and develops Anti-D </li></ul>
    34. 38. Hemolytic Disease of the newborn (HDN) <ul><li>Anti-D is a monomer can cross the placenta </li></ul><ul><li>Usually affects subsequent pregnancies </li></ul><ul><li>First pregnancy is not affected </li></ul><ul><li>Prenatal screening for ABO/Rh and possible antibodies already present in their first trimester </li></ul><ul><li>Father typing for Rh group </li></ul>
    35. 39. Hemolytic Disease of the newborn (HDN) <ul><li>Mild cases :mild anemia, jaundice, or breathing problems detected at birth </li></ul><ul><li>Severe cases : heart failure, brain damage, stillbirth or miscarriage </li></ul><ul><li>Prevention with Rh immune globulin (RhIG) given to the Rh negative mothers </li></ul>
    36. 40. RhIG (ROGHAM) <ul><li>Concentrated solution of anti-D from human plasma </li></ul><ul><li>Given to D negative mothers at 28 Wks and 72hrs after delivery of a D-positive baby </li></ul><ul><li>Also given after miscarriage, abortion or amniocentesis </li></ul><ul><li>Repeated every pregnancy </li></ul>
    37. 41. Other immunological tests <ul><li>Antihuman globulin test (Coomb’s test) </li></ul><ul><li>Uses a commercial antibody against human globulin (AHG) to detect globulin coated RBCs </li></ul><ul><li>Also used for Hemolytic conditions </li></ul>
    38. 42. Hemolytic transfusion reactions <ul><li>Most severe with ABO mismatches </li></ul><ul><li>Rapid intravascular hemolysis </li></ul><ul><li>Free Hgb is released to the plasma </li></ul><ul><li>Severity also related to the amount of RBCs given </li></ul><ul><li>Acute or delayed </li></ul>
    39. 43. Hemolytic transfusion reactions <ul><li>Major HTR </li></ul><ul><ul><li>Fever </li></ul></ul><ul><ul><li>Chills </li></ul></ul><ul><ul><li>Backache </li></ul></ul><ul><ul><li>Headaches </li></ul></ul><ul><ul><li>Apprehension </li></ul></ul><ul><ul><li>Dyspnea </li></ul></ul><ul><ul><li>Hypotension </li></ul></ul><ul><ul><li>Vascular collapse </li></ul></ul>
    40. 44. Hemolytic transfusion reactions <ul><li>In very severe cases </li></ul><ul><ul><li>DIC </li></ul></ul><ul><ul><li>Acute renal failure – from tubular necrosis </li></ul></ul><ul><li>Patient under general anesthesia will not voice symptoms, first findings may be oliguria, generalized bleeding </li></ul><ul><li>Treatment : if suspected stop transfusion, draw sample of blood and look for Hemoglobenimia(pink plasma) </li></ul><ul><li>Vigorously hydrate the patient </li></ul><ul><li>Force diuresis with Manitol may help prevent renal damage </li></ul>
    41. 45. Other transfusion reactions <ul><li>Leukoagglutinin rx: to Ags in WBCs sensitized by previous pregnancy or transfusions </li></ul><ul><li>Non hemolytic, Htc increases as expected </li></ul><ul><li>Fever and chills within 12 hrs of transfusion </li></ul><ul><li>Cough, dyspnea, and lung infiltrates may develop </li></ul><ul><li>Treated with: Tylenol, Benadryl, and steroids </li></ul><ul><li>Leukopoor filters are used to prevent </li></ul>
    42. 46. Other transfusion reactions <ul><li>Anaphylactic Reactions </li></ul><ul><li>Urticaria or bronchospasm </li></ul><ul><li>Due to plasma proteins most of the time </li></ul><ul><li>IgA deficient patients , may have anti-IgA and develop reactions to the IgA dissolved in the plasma(transfusion) </li></ul>
    43. 47. Other transfusion reactions <ul><li>Contaminated blood </li></ul><ul><li>With gram negative bacteria </li></ul><ul><li>Rare </li></ul><ul><li>Septicemia and shock from endotoxins </li></ul><ul><li>If suspected, culture the blood unit and treat patient with antibiotics </li></ul>
    44. 48. Blood Products <ul><li>Whole Blood </li></ul><ul><li>Packed cells </li></ul><ul><li>Platelets concentrates </li></ul><ul><li>Plateletaphoresis </li></ul><ul><li>Granulocytes </li></ul><ul><li>Fresh Frozen plasma </li></ul><ul><li>Cryoprecitate </li></ul><ul><li>Clotting factors concentrates </li></ul>
    45. 49. <ul><li>A 55-year-old man complains of chills, and is noted to have a rise in temperature from 98.9 to 101.7° F, within 15 minutes of starting a transfusion of packed red blood cells. The transfusion is stopped and antipyretics are administered, lowering his temperature. Specimens sent to the blood bank show no evidence of hemolysis, and there are no clerical discrepancies. What is the most likely cause of his reaction? </li></ul><ul><li>A. An ABO incompatibility B. Recipient antibodies against donor red cell antigens not detected on cross match </li></ul><ul><li>C. Recipient antibodies against donor white cell or platelet antigens </li></ul><ul><li>D. Recipient antibodies against donor IgA </li></ul><ul><li>E. Donor antibodies against recipient white blood cells </li></ul>
    46. 50. Answer <ul><li>C. Recipient antibodies against donor white cell or platelet antigens </li></ul>
    47. 65. <ul><ul><ul><ul><li>The end </li></ul></ul></ul></ul>