KEL codes for the Kell glycoprotein, which binds to XK membrane protein, affecting the Kell blood group. Kel alleles, K1 and K2 the most common, lead to the Kell types: K, k, or Kp. Numerous alleles interact to form 35 known Kell antigens. .
Kell status affects transfusion compatibility and hemolytic anemia of the newborn.