In vitro organ culture model for mucous membrane pemphigoid.

Mucous membrane pemphigoid (MMP), also known as cicatricial pemphigoid, is a rare vesiculobullous disease of mucosal tissues, which involves the oral, ocular, and other mucous membranes. We have studied a group of patients with histologically and immunopathologically proven pemphigoid disease involving predominantly the conjunctiva and oral mucosa in addition to other mucosae. The purpose of our study was to (i) demonstrate the specific binding of autoantibodies present in the sera of patients with MMP to normal human oral mucosa by indirect immunofluorescence (IIF) and (ii) to study the role of these autoantibodies in the pathogenesis of subepithelial blister formation using normal human buccal mucosa in organ culture. Serum and IgG fractions from MMP patients showed homogeneous smooth linear binding along the basement membrane zone (BMZ) of the normal buccal mucosa on IIF. Serum from pemphigus vulgaris patients showed intercellular or keratinocyte cell surface staining. BMZ separation developed at 48 h after incubation of normal human buccal mucosa in organ culture, with serum or IgG from patients with MMP but not after addition of normal human serum. Addition of pemphigus vulgaris serum to the in vitro culture of normal human buccal mucosa showed acantholysis. This preliminary report suggests that circulating autoantibodies may have an important role in the pathogenesis of MMP. This in vitro organ culture model will facilitate enhancing our understanding of various molecular events during the process of blister formation in MMP and in the study of other mucosal diseases.