Blood groups Flashcards
What type of molecules are antigens?
Glycoproteins
What blood group systems are used to describe a persons blood group?
ABO and presence or absence of Rhesus
What enzyme does the O genotype activate and what does this cause?
Does not activate glycosytransferase so the glycoprotein H is unmodified
What enzyme does the A genotype activate and what does this cause?
Activates A glycosytransferase so glycoprotein H is modified by antigen A
What enzyme does the B genotype activate and what does this cause?
Activates B glycosytransferase so glycoprotein H is modified with antigen B
Describe the dominance pattern of ABO
A is dominant over O
B is dominant over O
A and B are codominant
Which blood group is the universal donor and why?
O because there are no modified antigens on the surface so no agglutination will occur with any other antigen
Which blood group os the universal receivers and why?
AB - contain both of the types of modified antigen, so no immune response will be mounted as neither A B nor O will be regarded as foreign
When does agglutination occur?
When blood from incompatible blood groups are mixed e.g. A and B
Which Rhesus antigen is the most antigenic?
D
What percentage of Caucasians are Rh+ve?
85%
When does heamolytic disease of new borns occur?
During the second pregnancy of a mother that is Rh-ve having a child that is Rh+ve
If a mother is Rh-ve why is it likely that the child may get haemolytic disease?
Majority of Caucasians are Rh+ve so likelihood is the child will be
Describe how haemolytic disease of a new born manifests?
Mother (Rh-ve) carries a child (Rh+ve)
Mother will mount an immune response against the childs antibodies.
In the first pregnancy this is not harmful (primary response)
Second pregnancy = secondary immune response = haemolytic disease
Why is haemolytic disease not a concern in first pregnancies?
Only a primary immune response will be mounted
