A CHILD WITH ANTIBODIES TARGETING BOTH LINEAR IGA BULLOUS DERMATOSIS AND BULLOUS PEMPHIGOID ANTIGENS

Background: Some patients with subepidermal blistering diseases show c linical, histologic, and immunopathologic features of both linear IgA bullous dermatosis and bullous pemphigoid. Such patients can be furthe r characterized by defining the target of their circulating autoantibo dies. We present the first case report of a child with linear deposits of IgA and IgG with circulating autoantibodies characteristic of both linear IgA bullous dermatosis and bullous pemphigoid. Observations: W idely distributed subepidermal vesicles showing neutrophils in the der mal papillae developed in a 3-year-old boy. Direct immunofluorescence microscopy of perilesional skin revealed linear deposits of IgA, IgG, and C3 in the epidermal basement membrane. The patient responded to th erapy with dapsone, and after 6 months, it was possible to discontinue treatment. Circulating IgA antibodies from this child bound the epide rmal side of 1-mol/L saline-split skin and immunoblotted the 97-kd lin ear IgA bullous dermatosis antigen. Circulating IgG antibodies bound t he epidermal and, at low titer, dermal sides of split skin. These IgG antibodies immunoblotted and immunoprecipitated bullous pemphigoid ant igens 1 and 2. Conclusions: Linear deposits of IgA and IgG in the epid ermal basement membrane of patients with subepidermal bullous lesions may signify the coexistence of circulating autoantibodies directed aga inst linear IgA bullous dermatosis and bullous pemphigoid antigens.