Yuka, a new platelet antigen involved in two cases of neonatal alloimmune thrombocytopenia.

We report a new platelet antigen (Yuka) defined by the sera of 2 mothers whose babies developed alloimmune thrombocytopenia. These antiplatelet antibodies were IgG detected by Mixed Passive Hemagglutination (MPHA). In the study of two families, the Yuka antigen was found to be inherited as an autosomal dominant trait. The frequency of the Yuka phenotype in the Japanese population was estimated to be 1.7% (5/300).