Epidermolysis bullosa acquisita and bullous systemic lupus erythematosus. Diseases of autoimmunity to type VII collagen.

Autoimmunity to C7 is a genetically predisposed condition that results in the production of predominantly IgG class basement membrane autoantibodies that may cause basement membrane damage and subepidermal blisters by at least two pathogenic mechanisms. Autoimmunity to C7 cuts across traditional disease classifications (EBA versus bullous SLE), presents with heterogeneous clinical and pathologic features, mimics other diseases, and may be difficult to diagnose and treat. Autoimmunity to C7 is associated with susceptibility to SLE and perhaps inflammatory bowel disease.