K

Twenty-five antigens have been described within the Kell (KEL) blood group system. The most important of these are the K (Kell) and k (Cellano)

antigens

, regulated by the

K

and

k

genes. There are four other sets of antithetical antigens: Kpa/Kpb/Kpc, Jsa/Jsb, K11/ K17, and K14/K24. The Jsa antigen is found on the red cells of about 20% of black donors, but is very rare in white donors. Some phenotypes and genotypes are listed in Table 89.