The name<unk> esus factor <unk>  goes back to the use of erythrocytes extracted from the blood of<unk> esus monkeys for obtaining the first blood serum. The<unk>  is a human blood group system. It contains proteins on the surface of red blood cells. After the ABO blood group system, it is the most likely to be involved in transfusion reactions. The<unk>  consists of 49 defined blood group antigens, among which the five antigens D, C, c, E, and e are the most important. There is no d antigen.<unk> (D) status of an individual is normally described with a positive (+) or negative (−) suffix after the ABO type (e.g., someone who is A+ has the A antigen and<unk> (D) antigen, whereas someone who is A− has the A antigen but lacks the<unk> (D) antigen). The terms<unk>  factor,<unk>  positive, and<unk>  negative refer to the<unk> (D) antigen only. Antibodies to<unk>  antigens can be involved in hemolytic transfusion reactions and antibodies to the<unk> (D) and<unk>  antigens confer significant risk of hemolytic disease of the fetus and newborn.
Rh blood group system
Junior blood group system
Vel blood group
Hh blood group
Sid blood group system
Augustine blood group system
Lan blood group system
Indian blood group system