MT313 Lec ABO Blood Group System PDF

MT313 LEC Immunohematology and Blood Banking ABO Blood Group System Prepared by | Nhoelyn E. Burcao, RMT  OBJECTIVES At the end of the lesson the students must be able to: 1. Describe the structure of red cell membrane with the occurrence of blood group antigens. 2. D...

MT313 LEC Immunohematology and Blood Banking ABO Blood Group System Prepared by | Nhoelyn E. Burcao, RMT  OBJECTIVES At the end of the lesson the students must be able to: 1. Describe the structure of red cell membrane with the occurrence of blood group antigens. 2. Describe the reciprocal relationships between ABO antigens and antibodies for blood types O, A, B, and AB. 3. Explain the effects of disease on the expression of ABH antigens and antibodies Prepared by | Nhoelyn E. Burcao, RMT  ABO BLOOD GROUP SYSTEM Most important of all blood groups in transfusion practice. Naturally occurring antibodies The only blood group systems in which individuals predictably have antibodies in their serum to antigens that are not present from their red cells. Prepared by | Nhoelyn E. Burcao, RMT  LANDSTEINER’S LAW ✓Antigens on the RBC determines the blood group ✓Corresponding antibody is never found in the individual’s serum ✓Opposite antibody is always present in the individual’s serum Prepared by | Nhoelyn E. Burcao, RMT LANDSTEINER’S LAW Prepared by | Nhoelyn E. Burcao, RMT BERNSTEIN’S THEORY OF INHERITANCE ✓Genes are inherited from each parent ✓Each gene occupies a specific location on the chromosome known as locus. ✓At each locus there are several different forms of genes called alleles ✓The gene that codes for A, B, O is at the long arm of chromosome 9 Prepared by | Nhoelyn E. Burcao, RMT BERNSTEIN’S THEORY OF INHERITANCE ✓Single genetic locus have 3 possible alleles: A, B or O ✓O represents the absence of either A or B and is a silent allele ✓A and B genes are codominant Prepared by | Nhoelyn E. Burcao, RMT ABO GENOTYPE AND PHENOTYPE Genotype Phenotype AA A AO A BB B BO B AB AB OO O Prepared by | Nhoelyn E. Burcao, RMT Major ABO Genotypes and Phenotypes Phenotypes Possible Genotypes A1 A 1 A 1 ; A 1 A 2 ; A1 O A2 A2A2; A2O A1B A1B A2B A2B B BB; BO O OO Prepared by | Nhoelyn E. Burcao, RMT  ABO Antigens and Antibodies A. ABO Antigens ✓Based on the combinations of 3 genes on chromosome 9 ✓Demonstrated as early as 2nd month of fetal life ✓A and B antigens develop from precursor H substance ✓Persist through life unaltered ✓May be found in: saliva, pancreatic secretions, gastric secretions, bacteria and other species Prepared by | Nhoelyn E. Burcao, RMT  How are ABO antigens formed? The antigens arise from the action of specific glycosyltransferases that add individual sugars sequentially to sites on short chains of sugars (oligosaccharides) on common precursor substances. Interactions of the ABO, Hh, Sese, and Lele gene products affect the expression of the ABO, H, and Lewis antigens. Prepared by | Nhoelyn E. Burcao, RMT  Precursor Oligosaccharide Chains Type 1 Type 2 Linkage Beta 1, 3 Beta 1, 4 Origin Plasma Erythrocytic precursors Controlling H, A, B, H, A, B Genes Secretor genes and Lewis genes Prepared by | Nhoelyn E. Burcao, RMT  Formation of ABO Antigens GEN GLUCOSYLTRANSFE IMMUNODOMINAN ACCEPTO ANTIGE E RASE T SUGAR R N H -2-L- L-fucose Precursor H fucosyltransferase substance Antigen Prepared by | Nhoelyn E. Burcao, RMT H Antigen Prepared by | Nhoelyn E. Burcao, RMT  Formation of ABO Antigens GEN GLUCOSYLTRANSF IMMUNODOMINA ACCEPT ANTIG E ERASE NT SUGAR OR EN A -3-N- N-acetyl-D- H Antigen A acetylgalactosaminyltr galactosamine Antigen ansferase Prepared by | Nhoelyn E. Burcao, RMT A Antigen Prepared by | Nhoelyn E. Burcao, RMT  Formation of ABO Antigens GEN GLUCOSYLTRANSF IMMUNODOMINA ACCEPT ANTIG E ERASE NT SUGAR OR EN B -3-D- D-galactose H Antigen B galactosyltransferase Antigen Prepared by | Nhoelyn E. Burcao, RMT B Antigen Prepared by | Nhoelyn E. Burcao, RMT  Formation of ABO Antigens GEN GLUCOSYLTRANSF IMMUNODOMIN ACCEPT ANTIGEN E ERASE ANT SUGAR OR AB -3-N- N-acetyl-D- H Antigen AB acetylgalactosaminyltr galactosamine Antigen ansferase D-galactose -3-D- galactosyltransferase O None none none H Antigen Prepared by | Nhoelyn E. Burcao, RMT, MSMT© (unchang Prepared by | Nhoelyn E. Burcao, RMT ed)  Comparison of ABH Antigens on RBCs and in Secretions ABH Antigens on RBCs A, B and H Soluble Substances RBC antigens can be: Secreted substances are glycolipids glycoprotein glycoproteins or glycosphingolipids RBC antigens are only Secreted substances are primarily synthesized on type 2 precursor synthesized on type 1 precursor chains chain Prepared by | Nhoelyn E. Burcao, RMT, MSMT© Enzyme: Enzyme: H enzyme H enzyme  ABO Antigens and Antibodies B. ABO Antibodies ✓Naturally occurring in the serum ✓Predominantly IgM ✓Activates the complement ✓Optimum temperature: 21˚C or colder ✓Strong agglutination reaction with specific antigen Prepared by | Nhoelyn E. Burcao, RMT  ABO Antigens and Antibodies B. ABO Antibodies ✓Production initiated at birth ✓Detectable titers: 3-6 months of age ✓Peaks at 5-10 years Prepared by | Nhoelyn E. Burcao, RMT Blood Group Antibody Produced Characteristics A Anti- B IgM in nature B Anti- A Naturally occurring Reactive at room temperature AB No antibody O Anti- A and Anti- B IgM in nature Naturally occurring Anti- AB IgG in nature Immune antibody Prepared by | Nhoelyn E. Burcao, RMT  ABO Typing Technique 1. Forward Grouping/ Direct Typing Use of know sources of reagent antisera to detect antigens on an individuals’ RBCs Blood Antigen Reaction with Interpretation Group Anti- A Anti- B Anti- AB A A + - - Blood type “A” B B - + - Blood type “B” AB AB + + + Blood type “AB” Blood type “O” Prepared by | Nhoelyn E. Burcao, RMT, MSMT© O none - - - Procedure for Forward Typing Prepared by | Nhoelyn E. Burcao, RMT Interpretation of Results Group B Group A Group AB Group O Prepared by | Nhoelyn E. Burcao, RMT Characteristics of Routine Reagents used for ABO Testing: Forward Grouping Anti-A Reagent Anti-B Reagent Monoclonal antibody Monoclonal antibody Highly specific Highly specific IgM IgM Clear blue colored Clear yellow colored reagent reagent Prepared by | Nhoelyn E. Burcao, RMT  ABO Typing Technique B. Reverse Grouping/ Indirect Typing/ Backward Typing Use of reagent cells with known A1 and B antigens to detect which ABO antibodies are present in the patients’ serum Blood Antibody Reaction with Interpretation Group A Cells B Cells A Anti-B - + Blood type “A” B Anti-A + - Blood type “B” AB None - - Blood type “AB” O Anti-A and + + Blood type “O” Anti-B Procedure for Reverse Typing Prepared by | Nhoelyn E. Burcao, RMT Interpretation of Results Group A Group B Group O Group AB Prepared by | Nhoelyn E. Burcao, RMT  Characteristics of Routine Reagents used for ABO Testing: Reverse Grouping Reagent A1 and B Cells Human source 4%-5% red cell suspension Prepared by | Nhoelyn E. Burcao, RMT Red Cell Antigen- Antibody Reactions Serologic Grading (Macroscopic Evaluation) Grading Description 4+ One solid aggregate, clear background 3+ Several large aggregates, clear background 2+ Medium- sized agglutinates, clear background 1+ Small agglutinates, turbid background W+ Tiny agglutinates, turbid background 0 No agglutination or hemolysis Prepared by | Nhoelyn E. Burcao, RMT  Lectins useful in Blood Banking Lectin Activity Inhibited by Serologic Specificity Ulex europaeus L-fucose Anti- H N-acetyl-D-glucosamine Lotus tetragonolobus L-fucose Anti- H Vicia graminea ß-D-galactose Anti- N Arachis hypogaea ß-D-galactose Anti- Tk; Anti- T Dolichos biflorus α-N-acetyl-D-galactosamine Anti- A; Anti- Tn; Anti- Cad Salvia sclarea α-N-acetyl-D-galactosamine Anti- Tn Prepared by | Nhoelyn E. Burcao, RMT  Lectins useful in Blood Banking Lectin Activity Inhibited by Serologic Specificity Salvia horminum α-N-acetyl-D-galactosamine Anti- Tn; Anti- Cad Griffonia simplicifolia α-D-galactose (BS I) Anti- B N-acetyl-D-glucosamine (BS II) Anti-Tk Helix pomatia α-or ß- N-acetyl-D- Anti- A; Anti- Tn; Anti- galactosamine Cad Glycine soja N-acetyl-D-galactosamine Anti- T; Anti- Tn; Anti- Cad Prepared by | Nhoelyn E. Burcao, RMT  ABO Subgroups Subgroups of A Phenotype Population Reaction with Frequency Anti-A Anti-A1 A1 80% Blood type A + + A2 20% of Blood type A + - Prepared by | Nhoelyn E. Burcao, RMT  Other Subgroups of A Phenotypes Description A3 Mixed field agglutination with anti-A and/ or with anti- A,B Ax Weak agglutination with anti-A,B only Aend ≤10% red cells show very weak mf agglutination Am No agglutination with anti-A and anti-A,B Secretors demonstrate quantities of A substance in saliva Ay No agglutination with anti-A and anti-A,B Secretors contain small amount of A substance in saliva Ael No agglutination with anti-A and anti-A,B Secretors contain only H substance and no B substance in saliva  Subgroups of B Phenotypes Description B3 Mixed fields agglutination with anti-B and/or anti-A,B Bx Agglutination with anti-A,B (weak/0 with anti-B ) Bm No agglutination with anti-B and anti-A,B Secretors demonstrate quantities of B substance in saliva Bel No agglutination with anti-B and Anti-A,B Secretors contain only H substance and no B substance in saliva Prepared by | Nhoelyn E. Burcao, RMT  Bombay Phenotype General Characteristics: ✓hh genotype ✓Phenotypes as blood group O ✓A,B,H nonsecretor Anti-A, anti-B, anti-A,B and anti-H present in serum ✓Absence on α-2-L-fucosyltransferase (H enzyme) in serum and H antigen in RBCs ✓RBCs of the Bombay phenotype will not react with the anti-H lectin (Ulex europaeus) Prepared by | Nhoelyn E. Burcao, RMT  Bombay Phenotype General Characteristics: ✓Presence of A or B enzymes in serum (depending on ABO genotype) ✓Recessive mode of inheritance ✓Can only be transfused with blood from another Bombay (Oh) Prepared by | Nhoelyn E. Burcao, RMT  ABO Discrepancies 1. Group I Discrepancies: Weakly reacting or missing antibodies 2. Group II Discrepancies: Weakly reacting or missing antigens 3. Group III Discrepancies: Protein or plasma abnormalities resulting to rouleaux formation 4. Group IV Discrepancies: Miscellaneous Prepared by | Nhoelyn E. Burcao, RMT Group I Discrepancies: Weakly reacting or missing antibodies a. Newborns b. Elderly patients c. Patients with leukemia demonstrating hypogammaglobulinemia d. Patients with lymphomas demonstrating hypogammaglobulinemia Prepared by | Nhoelyn E. Burcao, RMT Group I Discrepancies: Weakly reacting or missing antibodies e. Patients using immunosuppressive drugs that yield hypogammaglobulinemia f. Patients with congenital agammaglobulinemia g. Patients with immunodeficiency diseases h. Patients with bone marrow transplantation Prepared by | Nhoelyn E. Burcao, RMT Group II Discrepancies: Weakly reacting or missing antigens a. Subgroups of A and/or B b. Leukemia c. Hodgkin’s disease d. Excess amounts of blood group-specific soluble substances (BGSS) present in the plasma in association with certain diseases e. Acquired B phenomenon f. Antibodies to low incidence antigens Prepared by | Nhoelyn E. Burcao, RMT  Group III Discrepancies: Protein or Plasma abnormalities resulting to rouleaux formation a. Elevated levels of globin from certain disease states b. Elevated levels of fibrinogen c. Presence of plasma expanders d. Wharton’s jelly Prepared by | Nhoelyn E. Burcao, RMT Rouleaux Formation Prepared by | Nhoelyn E. Burcao, RMT Group IV Discrepancies: Miscellaneous a. Polyagglutination Refers to the agglutination of altered RBCs by a large proportion of ABO- compatible adult human sera Categories: Acquired Inherited Prepared by | Nhoelyn E. Burcao, RMT Group IV Discrepancies: Miscellaneous b. Cold reactive antibodies c. Unexpected ABO isoagglutinins d. Antibodies other than anti-A and anti-B may react to form antigen-antibody complexes that may then adsorb into patient’s red cells e. RBCs with the cis “AB phenotype” cis-AB refers to the inheritance of both AB genes from one parent carried on one chromosome and an O gene inherited from the other parent Prepared by | Nhoelyn E. Burcao, RMT  Reference/s: Harmening, D. M. (2018). Modern blood banking & transfusion practices (6th ed.). F.A. Davis. Prepared by | Nhoelyn E. Burcao, RMT