A new HLA-DP (SB) specificity (Cp63) defined in Japanese and Caucasian cell populations by cloned PLT cells.

Cp61, Cp62, and Cp63 are HLA-DP (SB) specificities detected by PLT testing using cloned PLT cells derived from Japanese cell donors. It was confirmed, using Japanese and Caucasian cell panels, that Cp61 is identical to DPw5 and Cp62 is identical to DPw4. Cp63, however, was found not to correlate with any known HLA-DP specificities. The gene frequency of Cp63 was found to be 3.6% in Japanese (N = 42) and 1.9% in Caucasian (N = 52) cell panels of limited size. No triplet assignment of DPw specificity including Cp63 was found in the Japanese and Caucasian cell populations. The relationship between the Cp63 and the HLA antigens demonstrated no significant correlation with HLA-A,B,C,DR, or MT antigens in this study. Linkage between Cp63 and HLA was confirmed from family segregation studies. This is the first report of a new DP specificity termed Cp63.