C antigen

The C antigen belongs to the Rh antigen system and is highly immunogenic. Antibodies to the C antigen are usually formed in response to exposure to antigen-positive blood during transfusion or pregnancy. Anti-C antibodies are clinically significant and may result in acute or delayed hemolytic transfusion reactions or hemolytic disease of the fetus and newborn (HDFN) if the patient is challenged with antigen positive blood.