The frequency of the major histocompatibility antigen, HLA-A10, was significantly increased (corrected P < .025) in 43 unrelated patients with pemphigus vulgaris (41.9%) and in 25 patients with pemphigus follaceus (48.0%), when compared with 60 unrelated healthy controls (16.7%). No significant correlations with other HLA or differences between pemphigus vulgaris and pemphigus foliaceus were observed. Both forms of pemphigus were considered to link with the HLA-A10.