Childhood bullous pemphigoid: immunohistochemical, immunoelectron microscopic, and western blot analysis.

The most reliable diagnostic criteria of childhood bullous pemphigoid (BP) have been the linear deposition of IgG and C3 at the basement membrane zone (BMZ) and the frequent presence of circulating IgG BMZ antibodies. To characterize further the immunologic features of childhood BP, we performed direct and indirect immunoelectron microscopy (IEM) and Western immunoblotting on specimens from a 3-month-old boy with BP who had immunofluorescence evidence of linear BMZ IgG and C3 deposition and circulating IgG BMZ antibody. By direct IEM, autoantibody deposits were seen in the upper portion of the lamina lucida and on the undersurface of basal keratinocytes. Indirect IEM showed that the binding sites of BP antibody were closely related to the intracellular attachment plaques of hemidesmosomes. By Western blotting, the patient's serum recognized 180 kd epidermal protein.