Kell typing by allele-specific PCR (ASP)

The Kell blood group system is important in transfusion medicine, and the Kell antigen (K1) is probably second in importance to Rh D as an immunogen in alloimmunized pregnancies which cause haemolytic disease of the newborn. The K/k (K1/K2) blood group polymorphism has been recently defined. A point mutation changes Thr(193) (k) to Met(193) (K) in the Kell glycoprotein. The mutation which creates K destroys a consensus N-glycan addition site. We describe a simple PCR test for K blood group typing. The test is based on the use of an allele-specific K-primer. We have shown the test to give results in complete concordance with serologically defined Kell blood group status using 65 genomic DNA samples derived from both amniocytes and peripheral blood lymphocytes. The test is suitable for the prenatal determination of Kell type.