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Glossary of Bld Grps

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Blood groups
are heritable polymorphisms of RBC surface ag's
Clinical assay
agglutination rxn w/ certain ab's
ag-ab rxn=>agglutination
Bld grp systems
> 20 each deined by the polymorphic surface ag
importance:
-paternity testing
-maternal/fetal incompatibility
-transfusions
ABO system
chemistry:
oligosacharides on
-glycolipids & glycoproteins (imp for self recog in the imm. system)
-they make gene products of glycotransferases in the ER and Golgi
Genetics of the ABO system
-4 phenotypes (AB,A,B,O)
-determined by 3 alleles on 1 locus
Alleles and corresponding enzymes
A->N-acetylgalactosamine transferase

B-> galactose transferase

O-> no enzyme
Bld grp frequenciees
O common in:europe and africa
A: more common in europe and asia
B: higer prev in asia
AB: higher prevalance in asia
ABO disease associations
cholera and duodenal ulcer risk susceptibility in O
Transfusion rxn's
A can only recieve A & O
B:B&O
AB:all
O: only O
Paternity testing and ABO
mom is O baby A then dad A
mom=AB,baby=B,dad=B
mom=B,baby=O,dad=O
mom=O,baby=AB,dad=AB
Secretor types
O,A,&B are secreted in saliva & other secretions
-23% of europeans are non-sec (AR)
-80% caucasians are secretors
Rhesus system
-polymorphisms in 3 RBC membrane proteins (C,D,E)
-D most important
- RH neg is AR
-RH neg is 15% in europe less elsewhere
Rhesus incompatibility
RH neg mom forms an IgG ab to her babys'RH pos ag
ab crosses into fetal bld and coats the RBC's of fetus=hemolysis of fetus
erythroblastosis fetalis b4 birth
kernicterus from hypobilirubinemia after birth
prevented by RhoGAM (anti-rhesus anti serum)fo Rh neg mom w/ Rh pos baby at time of birth

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