Epidermolysis bullosa acquisita: a disease of autoimmunity to type VII collagen.

Epidermolysis bullosa acquisita (EBA) is one of a group of primary blistering diseases characterized by dermal/epidermal separation at the basement membrane (BM) of stratified squamous epithelium and IgG anti-BM autoantibodies (ABM). EBA ABMs can be distinguished from IgG ABMs in all other primary blistering diseases by their reactivity with the BM matrix protein, type VII collagen (C-VII). The clinical and histological features of EBA are highly variable and may be indistinguishable from those of other primary bullous diseases. The diagnosis can be confirmed by one of several methods that directly or indirectly demonstrate IgG ABMs to C-VII. IgG ABMs to C-VII are not specific for EBA. They have been described in SLE patients with and without a secondary blistering eruption, bullous eruption of SLE (BSLE). IgA ABMs to C-VII have been described in a subgroup of patients with linear IgA bullous dermatosis. Recent evidence suggests that autoimmunity to C-VII in EBA and BSLE is regulated by the same genes within the major histocompatibility complex (MHC) and contributes to the pathogenesis of acute inflammation and blisters in both disorders. The finding of ABMs to C-VII in SLE and BSLE, evidence that EBA and BSLE share an immunogenetic predisposition to C-VII autoimmunity, and an apparent association between susceptibility to SLE and EBA suggest a close relationship between SLE and autoimmunity to C-VII.