ABOH and Se Flashcards
Most important blood group system
ABO
What is the inheritance pattern for A B and O antigens
A and B are co-dominant over O (recessive)
Which chromosome are ABO alleles on
Chromosome 19
Which substrate are ABO antigen built on
H
Precursor for H
Type 2 precursor chain
Name for the H gene
FUT1 gene (built on type 2 precursor chain)
Transferase that the H gene codes for
L-fucosyl transferace (L-fucose)
Chromosome location for ABO vs H
ABO- chromosome 9
H- chromosome 19
What type of gene is O
Amorph recessive
What transferase does A code for
N-Acetylgalactosaminyltransferase
(N-Acetylgalactosamine sugar, also called N-Acetyl-D-galactosamine)
What transferase does B code for
D Galactosyl transferase (D-galactose sugar)
If you inherit both A and B, which one will have more antigens? (AB type)
B is more competitive and there will be more B than A antigens
At what age do ABO antigens develop
5-6 weeks gestation
At what age do ABO antigens fully develop
2-4 years
ABO frequencies for Whites
O 45%
A 40%
B 11%
AB 4%
ABO frequencies for Blacks
O 50%
A 26%
B 20%
AB 4%
ABO frequencies for Hispanics
O 56%
A 31%
B 10%
AB 3%
ABO frequencies for Asians
O 40%
A 28%
B 25%
AB 7%
When do ABO antibodies start to develop
As early as 3 months after birth, usually 4-6 months
They are naturally occurring
What antibody class are ABO antibodies
Predominantly IgM for group A and B people (IgM is the general answer)
Predominantly IgG for group O people
What type would ABO antibodies detected at birth be?
IgG because IgM cannot cross placenta. Any antibodies seen are moms, so moms IgG ABO antibodies are the ones observed on baby
Antibodies present in group O people
Anti-A, anti-B, and anti-A,B
What type are reagent cells A1 and B
A1 are type A1 Rh negative
B are type B Rh negative
Why is a saline control needed when typing AB people
To rule out possibility of panreactivity or autoagglutination
Precursor substance for Se
Precursor substance 1 or type 1 chain
Name for Se gene
FUT2
Precursor substances
On RBC (H) type 2
On secretions (Se) type 1
FUT genes
FUT1 H
FUT2 Se
What transferase does Se produce
L-fucosyl transferase (same as H, which is why there is a H-like antigen in secretions)
Percentage of population that are secretors
80%
Bombay inherited alleles
hh/sese
Parabombay inherited alleles
hh/Sese
Difference between Bombay and Parabombay
Bombay don’t have H at all, parabombay have Se gene so they have H and can have A/B in their secretions, just not on rbc
What would a Bombays ABO and screen look like
aBO would look normal like a type O. Screen would be reactive with all cells at all phases except for the autocontrol
How to identify a bombay
Test with anti-H should be negative (ulex europaeus). Need RESt adsorptions to remove anti-H (cold)
A1 vs A2
A1 people have A and A1 antigens
A2 people only have A
80% of A people are A1
How to test for A1 vs A2
A1 will react with anti-A1 lectin
A2 will not
A2 people can make anti-A1
Which A subgroups can make anti-A1
A2, A3, Ax are the main ones (not always and not naturally occurring for A2)
Ax and Ael usually make anti-A1 due to very weak A expression
Which A subgroups would show MF reactions when typing
A3 and Aend
Which A subgroup will react with anti-A1
A1 only
Name for A1 lectin
Dolichos Bifloris
Name for H lectin
Ulex europaeus
Which B subgroup shows MF
B3
Weakest subgroups of A and B
Ael and Bel
Type as O, need adsorption elution
Greatest to leas amount of H on ABOs
O>A2>B>A2B>A1>A1B
Name for B lectin
Bandeiraea simplicifolia
