Kell System
The Kell antigen is a glycoprotein encoded by the KEL gene on chromosome 7. The main Kell antigens are the less common K antigen and the higher frequency k antigen. K is present in 9% of the Caucasian population of individuals but only 2% of individuals of Black ethnicity and is considered to be highly immunogenic.
Antibodies targeted against the K antigen have been implicated in hemolytic reactions, and in a developing fetus can cause significant anemia even at low titres due to suppression of erythropoiesis. For this reason, many centres match women of child-bearing age for the K antigen as well as RhD.
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