blood groups and red cell disorders Flashcards
how meny blood groups
45 different blood groups ISBT , ABO and RH are the most most tested for
which ones are clinicaly significat
ABO = clinically significant = blood transfusion,
how is a Haemolytic transfusion reaction cuased
caused by blood mismatch
Carbohydrate based blood system ?
ABO gene will code for an enzyme which will allow a carbohydrate to attch to the RBC molecule,
Phenotype = A
results from this genotype = A/A or A/O
phenotype B
B/B or B/O
phenotype AB
A/B
Phenotype O
O/O
red blood cell type = A
anti-B antibodies , A antigen
red blood cell type =B
anti-A antibodies , B antigen
red blood cell type = AB
no antibodies , A and B antigens
red blood cell type = O
anti-A and anti-B antibodies and no antigens
universal donar
O type
universal acceptor
AB
A and B are ?
aligosaccharides synethsied by glycotransferases
} Glycosyltransferases
transfer monosaccharides to H antigen
Blood groups A and B are made from the H antigen, blood group A = A-tranferase
Blodd group B = B-tranferase is added
Rh blood group system
Rh protien = membrane multi-protien complx floats around on lipid fats
RHD negative gene
caucasian not have , African do
Weak D alleles
single neocleotide change in the gene
Parital D phenotype
hybirid versions of the gene gene changes on the external site of the RBC
Change is antigen site density , more d antigen present as you get closer to partial D from weak D
imcombaitible preganacy
mum and baby have different Rh antigen which leads to a memory cells 1st preganacy is not effected but 2nd preganacy (mum RHD + baby RHD - ) there immune system will be reawakened from memory cells from the last baby , prevention with anti D antibodies (rhogam)
Prophylactic anti-d =
inhibiting any activzation of the B cells, it minimises the death due to anti-D haemoytic disease of the fetus
- ffDNA
4th week of gestation Used for fetal sex determination, fetal RhD status and monogenic diseases e.g. cystic fibrosis
