(P) ABO BGS Flashcards
The detection of ABO incompatibility between the donor and the recipient is the basis or foundation of _________________________
.
Pre-transfusion testing
The transfusion of ABO-incompatible blood will result to ____________ of donor RBC which would lead to very severe transfusion reaction and could be fatal and lead to death.
lysis
What is the leading cause of death due to transfusion
TRALI (transfusion related acute lung injury)
- 1st person to perform both the forward and reverse method of blood typing
- discovered ABO in 1901
Karl Landsteiner
- most important blood group systems in terms of blood transfusion
- 1st and simplest human BGS known
*
ABO BGS
The only blood group system in which the reciprocal antibodies are consistently and predictably present in the sera of normal people whose RBCs lack the corresponding antigen(s)
ABO BGS
This is the rule wherein the reciprocal antibodies are consistently and predictably present in the sera of normal people whose RBCs lack the corresponding antigen(s)
Landsteiner’s rule
what is the only BGS that have the Landsteiner’s rule
ABO
ABO genes are located on ?
chromosome 9
in what manner are ABO genes inherited?
codominant
Which ABO gene is considered an amorph / recessive gene
O
a silent gene wherein no detectable Ag is produced in response to the inheritance of this gene.
amorph gene
O gene can only be detected when performing ______________
genotyping
when we do blood typing in the laboratory, we are doing _____________
a. genotyping
b. phenotyping
b. phenotyping
- the A/B/O gene inherited codes for the production of ____________
- this adds immunodominant sugars to a basic precursor substance (paragloboside) to be added the the Red cell
Glycosyltransferases
Which type of paragloboside?
- β 1→3 linkage: #1C of D-galactose connects to #3 C of Nacetylglucosamine
Type 1 Precursor chain
Which type of paragloboside?
β 1→4 linkage: #1 C of D-galactose connects to #4 C of Nacetylglucosamine
Type 2 precursor chain
Development of A and B antigens
- detected on embryonic red cells as early as _______
- A and B antigens are detectable in the red cells as early as _______ week of fetal life.
- Expression is fully developed by __________
- five weeks after conception
- 37th week of fetal life
- 2 to 4 years of age
What is the pre requisite for the production of glucosyltransferases to add immunodominant sugars to a basic precursor substance
H gene must first attach to its own immunodominant sugar to the paragloboside
matching type
a. H gene
b. A gene
c. B gene
- α-3-Nacetylgalactosaminyl transferase
- α-2-Lfucosyltransferase
- α-3-D’Galactosyltransferase
- B
- A
- C
Matching type
a. H gene
b. A gene
c. B gene
- D’Galactosyltransferase
2.L-fucose - N-acetyl-D’Galactosamine
- C
- A
- B
These are the 0.01 of individuals that do not have the H gene
- they are unable to express their own antigens on the red cells
- they can transmit normal A and B gene to their offspring
Bombay blood group
Explain how H gene influences A and B antigenic expression
- H gene codes for fucosyl transferase production -> catalyzes the addition of L-fucose attached on to Type 2 precursor chain
- A and B specified products can act to add sugars to the chains that carry H
which ABO gene elicits a higher concentration of transferase?
- can effectively convert H gene to its own antigen
A gene
which ABO gene competes more efficiently for the H substance?
B gene
which ABO gene does not produce an active form of transferase
O gene
Which ABO group has the greatest amount of H antigen on the red cells
O gene
O > A2 > B > A2B > A1 > A1B
Which has the least amount of H antigen
A1B
Hello just please review the genotypes and phenotypes as well as the punnet square
me thinks alam niyo naman na ‘yan
What are the 2 genes that make up the H gene
dominant H and h (silent genus)
serves as the precursor molecule on which A and B antigens are built/ can attach their own sugars
H antigen (L-fucoseimmunodominant sugar)
- the reagent used to detect H antigen
ULEX EUROPAEUS (Anti-H lectin)
Why are groups A. AB, and B that produce anti-H clinically insignificant ?
(i hope this made sense my brain is fried)
they react at room temperature
Therefore tethers are higher chances for blood transfusion reactions to take place
Which is more significant?
a. IgM
b. IgG
b
- IgM - optimum reactivity is RT so it is clinically insignificant
*IgG - more significant because they react at body temperature and can produce transfusion reactions when transfused
Para-Bombay phenotypes: Ah, Bh, ABh) virtually always reacts at room temperature
IgM
________________________ have no A, B, or H antigen, forms a potent clinically significant anti-H which reacts well over a wide thermal range and with all RBCs, except those of the same Oh people.
Rare Oh (hh) phenotype
T or F
Bombay phenotype has all antibodies, it can agglutinate all the red cells
T
Why is the Oh phenotype called “BOMBAY”
it was first discovered in Bombay, India in 1952
This phenotype occurs when an individual inherits two (2) silent state hh genes in a homozygous state.
They lack the H gene necessary for H antigen production
- these cannot attach their own sugars as they don’t have the H antigen
Bombay phenotype
T or F
people with the Bombay phenotype have potent A, B, AB, and H antigens
F (potent anti-A, anti-B, anti-A B and Anti-H which is most clinically significant)
CONFIRMATORY TESTING FOR Oh
what is the expected result of a patient with Anti-H?
no agglutination = positive result for Bombay
CONFIRMATORY TESTING FOR Oh
Patient’s serum (will / will not) agglutinate Oh cells
will NOT