The<unk>  is a human blood group that has been implicated in hemolytic transfusion reactions. The blood group consists of a single antigen, the high-frequency<unk>  antigen, which is expressed on the surface of red blood cells. Individuals are typed as<unk> -positive or<unk> -negative depending on the presence of this antigen. The expression of the antigen in<unk> -positive individuals is highly variable and can range from strong to weak. Individuals with the rare<unk> -negative blood type develop anti-Vel antibodies when exposed to<unk> -positive blood, which can cause transfusion reactions on subsequent exposures.
Vel blood group
Indian blood group system
Hh blood group
Junior blood group system
P1PK blood group system
Rh blood group system
Sid blood group system
Augustine blood group system