ABO Flashcards
He discovered the first human blood group system→Types A, B, O.
Karl Landsteiner
Discovered Type AB
Von Decastello, Sturli
described the first theory of inheritance of ABO, follows the simple Mendelian genetics.
Bernstein
discovery of A1 and A2 subgroups
Thompson
Landsteiner Rule on Ags and Ab
-Blood group antigens found on the RBC membrane identifies the blood type.
-Antibodies in plasma (serum) are reciprocal to the antigens.
The most important of all blood group systems in transfusion practice.
ABO BLOOD GROUP SYSTEM
The only system where antibodies are predictably (expected) found in plasma/ serum and reciprocal to antigens on RBCs.
Abo blood group system
Transfusion due to incompatible antibodies can result to
immediate lysis of red cells→serious fatal transfusion reaction.
It is the foundation on which all other pretransfusion testing is based.
Abo incompatibility between donor and patient
Blood types can be determined by?
Forward and Reverse Typing
ABO antigens are found on tissue cells→important in
Tissue/ Organ transplant
ABO and H antigens are secreted into body fluids by
Secretors
Chromosome of ABO genes
Chromosomes 9
A and B genes are
Autosomal codominant
O genes is
Amorph and recessive
What are the other genes that interact with ABO genes locus at chromosome # 9:
H, Le, Se, I, and P
The ABO genes do not code directly for the antigens, but instead, they code for the production of enzymes
Glycosyltransferases
which are involved in the formation of respective antigenic determinants (epitopes of antigens).
Glycosyltransferases
Not able to bring out the production of active enzyme
Gene O
What gene present in more than 99.99% of random population.
H gene
What is the immunodominant sugar of A gene
N-acetylgalactosamine
What is the immunodominant sugar of H
L-fucose
What is the immunodominant sugar of B
Galactose
What enzymes are coded for H gene
Fucosyl transferase
What enzymes are coded for A gene
N-acetylgalactosaminyl transferase
What enzymes are coded for B gene
Galactosyl transferase
The precursor of A and B antigens
H antigen
It does not elicit the production of catalytically active polypeptide.
O gene
What blood group has the highest amount of H antigens on the red cells.
O blood group
H antigen in decreasing amount
O>A2>B>A2B>A1>A1B
ABH antigens begin to develop in the
5-6th weeks of fetal life
ABH antigens are not well developed at birth(T/F)
True
The presence of H substance in body secretions is controlled by the
Se genes
How many percent of the population have secretor genes
80%
attachment of galactose to terminal galactose of H substance.
B subtances
attachment of fucose to terminal galactose of precursor substance.
H subtance
attachment of N-acetylgalactosamine to terminal galactose of H substance.
A substance
Group O secretor = has what substances in secretion
H substance
Group A secretor = has what substances in secretion
A and H substance
Group B secretor = has what substances in secretion
B and H subtances
Individuals who are homozygous sese (do not have the Se gene) are
Nonsecretors
Starts to develop shortly after baby is born
Abo antibodies
Not able to develop the H antigen from the precursor antigen.
Bombay phenotype
they are not able to develop, as well, the A and B antigens
Bombay phenotype
Bombay phenotype discovered by
Bhende in Bombay, now in Mumbai India
H antigens weakly expressed on RBC
Parabombay phenotype
H antigens may be present in secretions but none on the
red cells
Parabombay phenotypes
Reported to occur in Type O or Type B
Acquired A antigen
Associated with aseptic infection with Proteus mirabilis
Acquired A antigen
A rare phenomenon, associated with polyagglutination of
red cells.
Acquired A antigen
patients with bacterial infections and often cancer of the colon or rectum
Acquired B antigen
Weakly reacting or missing antibodies
Group 1
weakly reacting or missing antigens
Group 2
caused by protein or plasma abnormalities→ rouleaux formation of cells
Group III
