A spontaneous canine model of mucous membrane (cicatricial) pemphigoid, anautoimmune blistering disease affecting mucosae and mucocutaneous junctions

Mucous membrane pemphigoid (MMP) is a rare autoimmune blistering dermatosis of humans that was previously known as cicatricial pemphigoid. It is chara cterized by vesicles, ulcers and scarring that affect predominantly mucosae and mucocutaneous junctions. Circulating autoantibodies recognize epitopes on basement membrane proteins such as collagen XVII or laminin-5/6. Herein , we describe the clinico-pathological and immunological characteristics of 17 dogs afflicted with a dermatosis homologous to MMP of humans. Patients exhibited vesicles and erosions predominantly on mucous membranes or mucocu taneous junctions of the mouth, nose, eyes, genitalia or anus. Histopatholo gy revealed subepithelial vesicles with variable dermal inflammation. Direc t immunofluorescence demonstrated IgG or complement at the dermoepithelial junction. Indirect immunofluorescence using salt-split epithelia permitted the detection of circulating basement membrane-specific IgG autoantibodies in 15 cases. In 11 patients, autoantibodies recognized the NC16A segment of collagen XVII, as determined by salt-split indirect immunofluorescence, im munoblotting using canine keratinocytes and ELISA with synthetic canine pep tides. In one dog, autoantiodies bound to the dermal side of salt-split epi thelia and recognized epitopes within the 30 kDa carboxyterminal segment of human collagen XVII. Canine MMP, Like its human counterpart, exhibits dist inctive clinical signs and histopathological lesions, yet circulating autoa ntibodies target different antigenic epitopes. This spontaneous canine mode l of MMP could prove useful for studies on the pathogenesis or therapy of t his human disease. (C) 2001 Academic Press.