RBC antigens and antibodies
[Ref: PK1:p241]
Red cell antigens
- Over 400 RBC antigens have been described
- Most are inherited in a simple Mendelian fashion
RBC antigens are important because
- Individuals lacking in a particular antigen may produce antibodies reacting with that antigen
- Most important RBC antigens are ABO and Rhesus
- Others are less important because
* Weak antigen
* Antibodies develop only after multiple exposures
* e.g. Kell, P, Lewis, MNS, Kidd, Lutheran system
Red cell antibodies
- Most important naturally occuring RBC antibodies
= Anti-A and anti-B antibodies
* Mostly IgM
* Does not cross placenta
- Most important RBC antibodies that occurs after exposure
= Rhesus
* Mostly IgG
* Crosses placenta
Other notes
Kell system
Kell system is the 3rd most important system after ABO and Rh systems
K antigen is present on RBC, leukocytes, and platelets
Low frequency
--> Only cause iso-immunization in patients who have had multiple blood transfusion
