CANINE EPIDERMOLYSIS-BULLOSA ACQUISITA - CIRCULATING AUTOANTIBODIES TARGET THE AMINOTERMINAL NONCOLLAGENOUS (NC1) DOMAIN OF COLLAGEN-VII INANCHORING FIBRILS

The classification of autoimmune blistering skin diseases is based on the skin antigen(s) targeted by pathogenic autoantibodies. In humans a nd dogs, there is increasing evidence that autoimmune subepidermal bul lous diseases represent different nosological entities. This study est ablishes the existence of the canine equivalent of epidermolysis bullo sa acquisita (EBA) in humans. Canine EBA, like the inflammatory varian t of its human counterpart, is characterized by spontaneous vesicles a rising from an inflammatory eruption. Dermo-epidermal separation occur s in association with neutrophilic infiltration in the superficial der mis. Tissue-fixed and circulating IgA and IgG autoantibodies specific for the lower basement membrane zone can be detected by immunofluoresc ence methods. Using immunoelectron microscopy? autoantibodies are show n to target the distal end of anchoring fibrils in the sublamina densa . ELISA and immunoblotting utilizing eukaryotically expressed recombin ant collagen VII subdomains confirm that the circulating autoantibodie s are specific for the aminoterminal globular non-collagenous NCl doma in of type VII collagen.