TRANSFUSION MEDICINE Flashcards
The most important in transfusion and transplantation from age of 6 months: posses clinically significant anti-A and/or anti-B antibodies in serum.
ABO system
Is the precursor to the ABO blood group antigens
H-antigen
H-antigen deficiency is known an __ that do not express H antigen on their RBCs.
Bombay phenotype
Results from mutations in ABO that causes a lot of glycosyl transferase activity
Group O phenotype
Genes of the 33 blood group systems are:
- autosomal (except XG and XK which are X-borne)
- MIC2 (present on both X and Y chromosomes)
As H-antigen acts as precursor, its absence means the
absence of
Antigen A and B
second most important blood group system after ABO. Consists of 50 defined blood group antigens out of which only five are important.
Rhesus system
The status of Rhesus system is indicated as either
Rh-positive (D-antigen present) or Rh-negative (D-antigen absent).
normally not present in the blood of individuals with D-negative RBCs, unless the circulatory system of these individuals has been exposed to D-positive RBCs.
anti-Rh antibodies
is given against Rh immunization using anti-D lg for pregnant Rh- negative mothers who have given birth to Rh-positive child.
Prophylaxis
- first described by Landsteiner and Levine in 1927 is based on two genes: Glycophorin A and Glycophorin B.
- It is under control of an autosomal locus on chromosome 4 and also under control of a pair of co-dominant alleles LM and LN.
MNS antigen system
are usually IgM types and rarely, associated with transfusion reactions.
Anti-M and anti-N
Comprised of four pairs of allelic antigens representing single amino acid substitution in the Lutheran glycoprotein at chromosome 19. Antibodies against this blood group are rare and generally not considered clinically significant.
Lutheran system
- the third most potent immunogenic antigen after ABO and Rh system, and are defined by an immune antibody, anti-K.
- It was first noticed in the serum of Mrs. Kellacher. She reacted to the erythrocytes of her newborn infant resulting in hemolytic reactions. Since then 25 Kell antigens have been discovered.
Kell system
causes severe hemolytic disease of the fetus and newborn (HDFN) and haemolytic transfusion reactions (HTR).
Anti-K antibody
= first isolated in a patient called Duffy who had haemophilia.
= also known as Fy glycoprotein and is present in the surface of RBCs.
= It is a nonspecific receptor for several chemokines and acts as a receptor for human malarial parasite, Plamodium vivax.
Duffy system
antibodies on the Duffy glycoprotein can result in four possible phenotypes, namely Fy(a+b-—), Fy(a+b+), Fy(a—b+), and Fy(a—b-). The antibodies are IgG subtypes and can cause HTR.
Antigens Fya and Fyb
- known as Jk antigen, it is a glycoprotein, present on the membrane of RBCs and acts as a urea transporter in RBCs and renal endothelial cells.
- Kidd antibodies are rare but can Cause severe transfusion reactions.
- These antigens are defined by reactions to an antibody designated as anti-Jk?, discovered in the serum of Mrs. Kidd who delivered a baby with HDFN.
- Jk was the first antigen to be discovered by Kidd blood group system, subsequently, two other antigens Jk® and Jk3 were found.
Kidd system
In minor blood groups, the most commonly appearing phenotypes were ___ for Lewis, ___ for Duffy, ___ for Kidd, and ___ for MNS system.
- Le (a—b-)
- Fy(a+b+)
- Jk(a+b+)
- M+N+
Blood group system antigen that are carbohydrate in structure.
- ABO,
- H,
- P1Pk,
- I,
- GLOB
Blood group system antigen that are obtained from plasma
- LE
- CH/RG
Five major protein sequence of the RBC membrane protein.-
- DI
- Rh
- RhAG
- MNS
- GE
- CO
shows no immune system abnormalities when compared with mice except for a blunted neutrophil response on exposure to bacterial lipopolysaccharide.
null phenotype of any system (nonfunctional copy of a gene caused by a genetic mutation)
is prepared from plasma and contains fibrinogen, von Willebrand factor, factor VIII, factor XIII and fibronectin.
= the only adequate fibrinogen concentrate available for intravenous use.
=available in pre-pooled concentrates of five units
Cryoprecipitate
