A Case of Anti-p200 Pemphigoid with Autoantibodies against both a Novel 200-kD Dermal Antigen and the 290-kD Epidermolysis bullosa acquisita Antigen

BACKGROUND: Anti-p200 pemphigoid with autoantibodies against the 200-kD dermal antigen has recently been identified. OBJECTIVES: Our patient showed small and tense blisters on her face and trunk. METHODS: Immunoblotting (IB), using extracts of normal human epidermis and dermal skin, and immunoelectron microscopy (IEM), using normal human skin, were performed using the patient's serum. RESULTS: IB analysis showed that the patient's serum did not react with 180-kD bullous pemphigoid (BP180) or BP230 antigens; however, IgG autoantibodies in the patient's serum reacted with a 200-kD dermal antigen as well as the 290-kD epidermolysis bullosa acquisita (EBA) antigen. IEM showed that IgG antibodies in the patient's serum bound to the lamina lucida, as well as both the lamina densa and sublamina densa. After the treatment with prednisolone, the 290-kD protein reactivity decreased rapidly; however, the 200-kD protein band was still observed. CONCLUSION: We describe a rare case with immunoreactive autoantibodies against both a novel dermal 200-kD autoantigen and the 290-kD EBA antigen.