Immunohematology - The ABO blood group system

• Karl Landsteiner


  Who discovered the ABO blood group system?
• ABO blood group system


  What is the concept of individual's uniqueness defined by the RBC antigens present on the RBC membrane?
• Forward and reverse grouping


  Karl Landsteiner is the first person to perform ___ and ___ blood grouping.
• Forward grouping (front type)


  It is defined as using known sources of commercial antisera (anti-A, anti-B) to detect antigens on an individual's RBCs.
• Reverse grouping (back type)


  It is defined as detecting ABO antibodies in the patient's serum by using known reagent RBCs, namely A1 and B.
• All donors and patients


  Both ABO forward and reverse grouping tests must be performed on all ___ and ___ patients.
• Inverse/reciprocal relationship


  What is the relationship of forward and reverse blood typing?
• Naturally occurring antibodies

  To what type of antibody does ABO antibodies are classified?
• IgM


  What immunoglobin class is predominant in ABO antibodies?
• Agglutination


  What is a positive reaction in ABO testing?
• 3-6 months


  Titers of ABO antibodies of the infants are generally low for detection until infants are ___ months old.
• 5-10 years


  ABO antibody production peaks during ___ years old and declines later in life.
• Intravascular hemolysis


  What type of hemolysis occurs due to incompatible ABO blood transfusion?
• IgG


  What is the usual immunoglobin nature of Anti-A,B antibody?
• ≥ 20-24˚C


  Both immunoglobin (IgM and IgG) classes of ABO antibodies react preferentially at what temperature?
• 37˚C


  ABO antibodies efficiently activate complement at what temperature?
• Monoclonal antisera


  What is the type of antisera used in ABO blood typing to detect weak A and B antigens?
• Mendelian genetics


  What genetic concept is used as the basis for ABO genes inheritance?
• Chromosome 9


  What chromosome carries the ABO genes?
• Amorph


  What is the term used to a gene that has no ability to produce antigen?
• O gene


  What ABO gene is amorph?
• Codominant


  What is the law of genetic inheritance seen in ABO blood system?
• Autosomal recessive trait


  What type of trait is expressed by all blood type O individuals?
• ABO, Hh, and Se genes


  The formation of ABH antigens/substances results from the interaction of what genes?
• Glycosyltransferase


  What is enzyme responsible for the addition of sugars to the basic precursor substance to produce ABH antigens?
• Paragloboside or glycan or ceramide


  What is the basic precursor material from which A, B, and H antigens all originate?
• Type 2


  When the terminal galactose on the precursor substance is attached on the N-acetylglucosamine in a beta 1 → 4 linkage, the precursor substance on RBCs is referred to as what type?
• Type 1


  When the terminal galactose on the precursor substance is attached on the N-acetylglucosamine in a beta 1 → 3 linkage, the precursor substance on RBCs is referred to as type ___
• H antigen


  What is the precursor antigen on which A and B antigens are made?
• FUT 1 (H) and FUT 2 (Se)


  What are the genes located on chromosome 19 that are essential for the expression of ABH antigens/substances?
• 2-4 years


  The A and B antigens on the RBCs of an individual is fully developed by what year?
• α-2-L-fucosyltransferase


  What enzyme is responsible for the transfer of sugar L-fucose to an oligosaccharide chain on the terminal galactose of type 2 chain; encoded by H gene?
• Immunodominant sugars


  These are sugars occupying the terminal positions of this precursor chain and conferring blood group specificity.
• L-fucose


  What is the immunodominant sugar of H antigen?
• O blood group


  What blood group has the highest concentration of H antigen?
• Bombay


  What phenotype has inherited hh genotype, which lacks normal expression of the ABH antigens?
• α-3-N-acetylgalactosaminyltransferase


  What enzyme is responsible for the transfer of N-acetyl-D-galactosamine (GalNac) sugar to the H substance?
• N-acetyl-D-galactosamine (GalNac)


  What is the immunodominant sugar of A antigen?
• α-3-D-galactosyltransferase


  What enzyme is responsible for the transfer of D-galactose (Gal) sugar to the H substance?
• D-galactose (Gal)


  What is the immunodominant sugar of B antigen?