[Lichen planus pemphigoides--report of a case and binding sites of circulating anti-basement membrane zone antibodies].

In this paper, we initially report a case which had clinical, histological and immuno-histochemical features consistent with the diagnosis of lichen planus pemphigoides (LPP). We then examined in vitro binding sites of circulating anti-basement membrane zone (BMZ) antibodies (Ab) from the patient using skin substrate separated through the lamina lucida by incubation in 1.0 M NaCl in order to study the localization of the LPP antigen. In indirect immunofluorescence examination, binding of anti-BMZ Ab from this patient was observed along the epidermal side of the separated skin in a linear pattern. When an indirect immunoelectron microscopy was performed on the separated skin, immune-reaction products were localized at basal cells from cytomembrane to hemidesmosomes in a massive and discontinuous fashion. These findings suggest that the binding sites of anti-BMZ Ab in LPP (localization of LPP antigen) are quite different from those of epidermolysis bullosa acquisita Ab, and show an intracellular association with hemidesmosomes in a fashion similar to those of bullous pemphigoid Ab.