WEEK 4-5.pdf

4 5 - (001) ABO BLOOD GROUP ABO BLOOD GROUP SYSTEM (001) Most important of all blood groups in transfusion practice The three genes that code for A, B, are located at the long arm of chromosome 9 HISTOBLOOD GROUP: antigens found in blood and tissues ABO H Le i p 3 allele theory by Bernstein Phenotyp...

4 5 - (001) ABO BLOOD GROUP ABO BLOOD GROUP SYSTEM (001) Most important of all blood groups in transfusion practice The three genes that code for A, B, are located at the long arm of chromosome 9 HISTOBLOOD GROUP: antigens found in blood and tissues ABO H Le i p 3 allele theory by Bernstein Phenotype A B AB O Possible Genotypes 4 allele theory by Thompson Phenotype Possible Genotypes A1 a1a1 a1O A1a2 A2 a2a2 a2O A1B a1b A2B a2b B bb, bo O oo Frequency (%) of ABO Phenotypes Phenotype WHITES BLACKS NATIVE AMERICANS ASIANS A 28 B 26 AB 5 O 41 Landsteiner's Laws The antigen on the RBC determines the blood group serum The corresponding antibody is never found in the individual's The opposite antibody is always present in the individual's serum red cell type a b ab none antigens antibodies o none ABO ANTIGENS Found on RBCs, lymphocytes, platelets, tissue cells, bone marrow AND OTHER ORGANS Can be secreted by tissue cells if the appropriate genes are present Developed in utero at 5-6 weeks of gestation; full expression occurs between 2-4 years of age Precursor Oligosaccharide Chains: Type 1 Type 2 Linkage beta-1,3 beta-1,4 Origin Plasma Seen on erythrocytic precursors Controlling genes H, A, B, Se, and Lewis H, A, and B Precursor Substance (PS) CERAMIDE GALACTOSE GALACTOSE RBC GLUCOSE N-ACETYLGLUCOSAMINE GALACTOSE GALACTOSE PROTEIN GLUCOSE N-ACETYLGLUCOSAMINE Precursor Substance (PS) ABO ANTIGEN ABO ANTIGEN H-ANTIGEN H-ANTIGEN PRECURSOR PRECURSOR RBC PROTEIN FORMATION OF H ANTIGEN H GENE HH, Hh PRECURSOR A GENE A Ag B GENE B Ag AB GENE AB Ag O GENE O Ag H Ag FORMATION OF H ANTIGEN CERAMIDE GALACTOSE GALACTOSE RBC GLUCOSE N-ACETYLGLUCOSAMINE l-fucose Formation of ABO Antigens: Gene Glucosvitransferase Immunodominant Sugar Acceptor Antigen H a-2-L-fucosyltransferase L-fucose precursor h A a-3-N-acetylgalactosaminyl transferase N-acetyl-D-galactosamine h a B a-3-D-galactosyltransferase D-galactose H B H AB NONE unchanged H Ag AB o a-3-N-acetylgalactosaminyltransferase N-acetyl-D-galactosamine a-3-D-galactosyltransferase D-galactose FORMATION OF A,b,ab ANTIGEN CERAMIDE GALACTOSE GALACTOSE RBC GLUCOSE N-ACETYLGLUCOSAMINE l-fucose amount of h-antigen o > a2 > b > a2b > a1 >a1b ABH Antigens on Red Cells A, B, and H Soluble Substances Glycolipids, Glycoproteins, or Glycosphingolipids Glycoprotein Type 2 precursor chain Type 1 precursor chain h enzyme Se enzyme Secretor: SeSe, Sese (78%) NonSecretor: sese (22%) Landsteiner's Laws The antigen on the RBC determines the blood group serum The corresponding antibody is never found in the individual's The opposite antibody is always present in the individual's serum red cell type a b ab none antigens antibodies o none ABO ANTIBODIES Naturally occurring; predominantly IgM Production initiated at birth Detectable titers: 3-6 months; peaks at 5-10 years Blood Group ANTIBODY PRODUCED A anti-b B anti-a AB none O Anti-A Anti-B Anti-AB CHARACTERISTICS IgM Naturally occurring antibodies React at room temperature Cannot cross the placenta MOSTLY IGM (SOME ARE IGG) Anti-ab Predominantly IgG Immune antibodies react at 37C Can cross the placenta ABO TYPING TECHNIQUES Principle: Hemagglutination 1. Forward Grouping Using known sources of reagent antisera (anti-A, anti-8) to detect antigens on an individual's red cells BLOOD GROUP ANTIGEN ANTI-A ANTI-B ANTI-A,B A B AB O Anti-A,B Checks the reaction of anti-A and anti-B reagents Detects weak subgroups of A and B INTERPRETATION Hemagglutination inhibition Test for the determination of secretor status detects soluble haptens A A A A AG IN BODY FLUID + = A A + = A A A RGT AB AB NEUTRALIZED RGT CELLS (+) NO AGGLUTINATION X AG IN BODY FLUID + + = RGT AB AB NEUTRALIZED = RGT CELLS (-) AGGLUTINATION Characteristics of Routine Reagents Used for ABO Testing: Forward Grouping 1. Anti-A Reagent Monoclonal antibody Highly specific IgM Clear blue colored reagent Blue dye: Bromphenol blue Thymol blue Patent blue 2. Anti-B Reagent Monoclonal antibody Highly specific IgM Clear yellow colored reagent Yellow dye: Acriflavin Tartrazine yellow Note: Sodium azide (0.1%) - chemical preservative ANTI-A ANTI-B ANTI-AB AHG BLUE YELLOW COLORLESS GREEN Lectins Proteins present in plants (usually seeds), which bind specifically to carbohydrate determinants and aGGlutinate erYthrocYtes through their cell surface of oligosaccharide determinants. For ABO antigens Ulex europaeus Anti-H Lotus tetragonolobus Anti-H Dolichos biflorus Anti-A, Anti-Tn, Anti-Cad Helix pomatia Anti-A, Anti-Tn, Anti-Cad Griffonia simplicifolia (Bandeiraea simplicifolia) Anti-B. Anti-Tk For antigens causing polyagglutination Arachis hypogaea Anti-T, Anti-Tk Glycine soja (Glycine max) Anti-T, Anti-Tn, Anti-Cad Salvia sclarea Anti-Tn Salvia horminum Anti-Tn, Anti-Cad (separable) For other blood group antigens Iberis amara Anti-M Vicia graminea and Bauhinia species Anti-N REVERSE GROUPING Using reagent cells with known A; and B antigens and testing the serum of the patient for ABO group antibodies Blood Group A B AB O Antibody A1 Cells B Cells Interpretation PATIENT FORWARD TYPING REVERSE TYPING ANTI-A ANTI-B A CELLS B CELLS 1 + 0 0 + 2 0 + + 0 3 + + 0 0 4 0 0 + + ABO TYPE Red Cell Antigen-Antibody Reactions Serologic Grading - Macroscopic Evaluation 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 MF numerous small clumps of cells exist amid a sea of free cells 0 MIXED-FIELD Bombay Phenotype (HnulL) hh genotype No H antigens formed; therefore, no A nor B antigens formed Phenotypes as blood group O Anti-A, anti -B, anti-A,B and anti-H present in the serum Can only be transfused with blood from another Bombay (O%) H GENE HH, Hh H Ag PRECURSOR A GENE A Ag B GENE B Ag AB GENE AB Ag O GENE O Ag hh BOMBAY: hh sese PARABOMBAY: hh Sese PRECURSOR BOMBAY PHENOTYPE Precursor Substance (PS) ABO ANTIGEN ABO ANTIGEN H-ANTIGEN PRECURSOR PRECURSOR RBC RBC Phenotype Forward Typing REVERSE TYPING ANTI-A ANTI-B ANTI-H A CELLS B CELLS O CELLS O 0 0 + + + 0 OH 0 0 0 + + + subgroups of a Phenotype Antigens present Population Frequency A1 A1 A2 a2 a2 note: 1-8% of a2 25% of a2b Reaction with Anti-A (from B sera) Anti-A1 lectin Dolichos biflorus 80% + + 20% + - --> can form anti-a1 subgroups of a forward typing reverse typing control anti-a anti-b anti-a,b a1 cells b cells autocontrol o cells 3+ 0 4+ 0 3+ 0 0 w+ 0 2+ 0 3+ 0 0 w+ 0 2+ 1+ 3+ 0 0 A3 AX Mixed field agglutination with anti-A and/or anti-A,B Weak agglutination with anti-A,B only Aend Acquired A resistance to P falciparum confirmation: Agglutination with most adult sera no agglutination with cord sera panagglutination Patient's RBCs are agglutinated by ALL including OWN serum Confirmation of Polyagglutination: If RBCS show (1) agglutination with and (2) NO agglutination with Panel of Lectins: Lectin tn cad t tk Arachis hypogaea - - + + Salvia sclarea + - - - Salvia horminum + + - - Glycine soja + + + - b. 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 RBC RBC C. others Cold reactive antibodies Unexpected ABO isoagglutinins Antibodies other than anti-A and anti-B may react to form antigenantibody complexes that may then adsorb into patient's red cells resolution: RBC (sample) Wash with saline at 37°C retype 0.01 M Dithiothreitol (DTT) disperse IgM Serum (sample) Warmed at 37°C read results at 37°C Pre-warmed technique