A case of bullous pemphigoid with antibodies against intercellular 130 KD antigen

Pemphigus and bullous pemphigoid are two typical autoimmune bullous diseases that involve circulating autoantibodies directed against the epidermal cell surface and the epidermal basement membrane zone, respectively. The coexistence of pemphigus and bullous pemphigoid is rare. We describe a case of a 79-year-old man who had tense bullae and erythematous, erosive lesions on his trunk and four extremities. Histopathology revealed subepidermal blister formation without any evidence of intraepidermal acantholytic changes. Direct immunofluorescence study demonstrated deposition of IgG on the epidermal intercellular spaces, as well as along the basement membrane zone; C₃ was detected only on the latter. Indirect immunofluorescence study using monkey esophagus as a substrate demonstrated the presence of circulating antibodies against both junctional and intercellular antigens. In order to analyze the precise nature of this patient's antibodies, indirect immunofluorescence study using cultured human keratinocytes and immunoblot analyses were performed. Pemphigus vulgaris sera showed smooth and uniform staining on intercellular spaces. The patient's serum showed a granular and uneven staining pattern. Immunoblot analysis showed that the patient's serum reacted with the typical 230 kd (bullous pemphigoid) antigen and 130 kd antigen, which is close to the pemphigus vulgaris antigen.