IgM pemphigoid.

Pemphigoid diseases are a heterogeneous group of autoimmune blistering disorders characterized by predominant deposition of IgG and/or IgA autoantibodies against structural proteins of the dermal-epidermal junction (DEJ). Sole linear IgM deposits at the DEJ in pemphigoid diseases have been observed; however, IgM-specific target antigens have not been identified yet.Characterization of IgM pemphigoid patients.Skin biopsies and sera from IgM-positive patients were assessed using histopathology, direct and indirect immunofluorescence microscopy, enzyme-linked immunosorbent assays, immunoblotting, cryosection assay, complement fixation test and internalization assay.Tissue-bound linear IgM deposits along the DEJ and circulating IgM autoantibodies against type XVII collagen (Col17) were detected. These circulating IgM autoantibodies showed no complement activating or blister inducing capacity, but the ability of Col17 internalization ex vivo.Limited number of patients.This study provides further evidence for the role of IgM autoantibodies in pemphigoid disease and highlights Col17 as a target antigen in IgM pemphigoid.

View the full article @ Journal of the American Academy of Dermatology

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