We investigated antigen profiles of the sera from 2 cases of pemphigus vulgaris (PV) who subsequently developed pemphigus foliaceus (PF). Immunoblotting was carried out using normal human epidermal extracts as the antigen source. The sera during PV reacted exclusively with the 130-kD PV antigen and the sera during PF exclusively with the 150-kD antigen. Therefore, dermatologic, histologic and immunohistologic findings before and after this transition were clearly shown related to changes in serum reactivity with pemphigus antigens.