Epidermolysis bullosa acquisita. Incidence in patients with basement membrane zone antibodies.

We examined the incidence of epidermolysis bullosa acquisita in patients with circulating basement membrane zone antibodies. Serum samples from 100 sequential patients with basement membrane zone antibodies were tested by indirect immunofluorescence against 1 mol/L sodium chloride split skin and by Western immunoblot against epidermal and dermal extracts of skin. Ninety-two (92%) serum samples stained only the epidermal side of split skin, 5 (5%) stained only the dermal side, and 3 (3%) stained both sides. Four of the 5 serum samples with dermal staining but none of the serum samples with epidermal or combined staining reacted with the 290-kd epidermolysis bullosa acquisita antigen by Western immunoblot. These results indicate that approximately 5% of unselected patients with basement membrane zone antibodies have epidermolysis bullosa acquisita or bullous lupus erythematosus rather than bullous pemphigoid.