Childhood bullous pemphigoid: report of a case with characterization of the targeted antigens.

The clinical and immunopathologic features of children with acquired subepidermal blistering disorders show considerable overlap, and their classification frequently requires characterization of the targeted antigens. A 8-month-old boy developed a generalized subepidermal blistering disorder with striking palmoplantar involvement. The patient's serum contained antibodies reacting against the epidermal side of 1 M sodium chloride separated normal human skin. Immunoblotting analysis demonstrated circulating IgG autoantibodies that reacted against a eukaryotic recombinant form of human bullous pemphigoid antigen 180 (BP180). In addition, the patient had circulating IgG autoantibodies that bound a protein of 120 kDa in skin basement membrane zone extracts, that might correspond to the linear IgA bullous disease (LABD) antigen. This study illustrates that a child with clinical and immunopathologic features considered characteristic of childhood bullous pemphigoid (BP) had circulating IgG antibodies that bound to an eukaryotic recombinant form of human BP180, and hence, fulfilled the diagnostic criteria of BP. Review of the literature disclosed only 10 cases of childhood BP, that were characterized on the basis of the targeted antigens. The concomitant presence of circulating IgG autoantibodies against BP180 and a 120 kDa protein may signify either coexistence of autoantibodies with distinct specificities or reflect antigenic cross-reactivity between BP180 and the 120/97 LABD antigen.