HLA antigens and susceptibility to psoriasis vulgaris in a non-Caucasian population.

Fifty-four unrelated Japanese patients with psoriasis vulgaris were tissue typed using the Sixth International Histocompatibility Workshop antisera. Two control groups were included in this study: Thirty-one pustulosis palmaris et plantaris and 17 seborrheic dermatitis as a disease control and 66 normal, healthy, unrelated Japanses as a reference. HLA-Al (P = 0.0065) from the A locus and HLA-BW37 (P = 0.0164) from the B locus were found to occur with increased frequency in patients with psoriasis vulgaris. No significant difference in antigen frequencies in pustulosis palmaris et plantaris was found, however, HLA-AW30 and/or AW31 and HLA-B12 occurred with increased frequency in seborrheic dermatitis. No linkage between psoriasis and HLA was observed in eight families. Therefore our findings in Japanese do not confirm the previous observation made in Caucasians of an association between psoriasis vulgaris and HLA-B13 or BW17.