Epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is a chronic autoimmune subepidermal bullous disease with clinical features similar to the genetic form of dystrophic epidermolysis bullosa. EBA is characterized by the presence of autoantibodies against type VII collagen which is a major component of the anchoring fibrils at the dermal-epidermal junction. EBA can be divided into two main clinical types; mechanobullous and inflammatory EBA. Mechanobullous EBA, referred to as classic EBA, presents with skin fragility, blisters and dystrophic changes on trauma-prone areas. Inflammatory EBA resembles other autoimmune subepidermal bullous diseases. Compelling evidence from mouse models supports a pathogenic role of autoantibodies against type VII collagen in EBA. Treatment of EBA is often unsatisfactory. The most widely used systemic treatment is corticosteroids. Colchicine and dapsone have been reported to be good treatment modalities when combined with corticosteroids. Some intractable cases of EBA have successfully been treated with intravenous immunoglobulin or rituximab.

Kim JH ，Kim SC 《-》

Epidermolysis bullosa acquisita: what's new?

Ishii N ，Hamada T ，Dainichi T ，Karashima T ，Nakama T ，Yasumoto S ，Zillikens D ，Hashimoto T ... -  《-》

[Epidermolysis bullosa acquisita].

Epidermolysis bullosa acquisita (EBA) is a rare autoimmune subepidermal bullous disease with autoimmunity to the type VII collagen which is the major component of anchoring fibrils. Clinical manifestations of the classical EBA include skin fragility, blisters over the trauma-prone surfaces and milium cysts. Other presentations of EBA have been reported: mucosal predominant appearance reminiscent of cicatricial pemphigoid, bullous pemphigoid-like presentation and IgA-EBA. Making a definitive diagnosis of EBA could be difficult because specialized tests available in only some laboratories are necessary to confirm the clinical suspicion: immunoelectron microscopy demonstrating immune deposits on anchoring fibrils and immunoblotting or enzyme-linked immunosorbent assay (Elisa) detecting autoantibodies recognizing the type VII collagen. EBA frequently is associated with Crohn's disease and an inflammatory bowel disease must be ruled out in patients with EBA and abdominal manifestations. EBA potentially is serious, has usually a chronical evolution and is difficult to treat.There are no guidelines for treatment of EBA, which is adapted to clinical severity and include dapsone, cyclosporine and rituximab.

Caux F 《-》

Pathogenesis of epidermolysis bullosa acquisita, an autoimmune subepidermal bullous disease.

Autoimmune bullous diseases (ABDs) are organ-specific autoimmune diseases, in which blisters on the skin and mucous membranes develop through binding of pathogenic autoantibodies to target antigens. There are two major ABD groups: the pemphigus group, showing autoantibodies to desmosomal components; and the subepidermal ABD group, showing autoantibodies to hemidesmosomal components in the epidermal basement membrane zone. Recent immunological, biochemical and molecular biological studies revealed many new autoantigens, including desmocollins, various plakin family proteins and integrins. A revised ABD classification includes new disease entities such as paraneoplastic pemphigus, IgA pemphigus and anti-laminin γ1 pemphigoid. In addition to systemic corticosteroids and various immunosuppressive agents, various adjuvant therapies for ABDs have developed. Among them, intravenous immunoglobulin (IVIG) is a promising therapy, although the therapeutic mechanisms are still unknown. Various disease models for ABDs have developed, particularly for pemphigus vulgaris, bullous pemphigoid and epidermolysis bullosa acquisita (EBA), and these have provided insights into the pathogenesis of various ADBs that suggest possible new treatment strategies. However, the fundamental mechanisms in disruption of immune-tolerance are still unknown. EBA shows autoimmunity to type VII collagen, the major component of anchoring fibrils, and EBA pathogenesis has been studied in various disease models. Previous studies suggested that, following binding of autoantibodies to type VII collagen, activation of complement, cytokine release, neutrophil migration, Fcγ receptors (FcgRs) and metalloproteinases play important roles in induction of subepidermal blisters. In this issue of the Journal of Pathology, Kasperkiewicz and colleagues reveal important roles of activating FcgRIV and inhibitory FcgRIIB in EBA pathogenesis that were recognized by conducting elegant studies using both genetic analysis and functional animal model methods. The expression equilibrium of the activating and inhibitory FcgRs can be modulated towards the inhibitory FcgRIIB by IVIG therapy, resulting in beneficial clinical effects of IVIG in EBA and other autoimmune skin-blistering diseases.

Hashimoto T ，Ishii N ，Ohata C ，Furumura M ... -  《-》

Epidermolysis bullosa acquisita.

Epidermolysis bullosa acquisita (EBA) is a rare, acquired, chronic subepidermal bullous disease of the skin and mucosa characterized by autoantibodies to type VII collagen (C7) structures, a major component of anchoring fibrils, which attach the epidermis to the dermis. EBA patients have tissue-bound and circulating antitype C7 autoantibodies that attack type C7 and result in a reduction or perturbation of normally functioning anchoring fibrils. Patients with EBA have skin fragility, blisters, erosions, scars, milia, and nail loss, all features reminiscent of genetic dystrophic epidermolysis bullosa. These immunoglobulin G antitype C7 antibodies are pathogenic, because when they are injected into mice, the mice develop an EBA-like blistering disease. In addition to the classical mechanobullous presentation, EBA also has several other distinct clinical syndromes similar to bullous pemphigoid, Brunsting-Perry pemphigoid, or cicatricial pemphigoid. Although treatment for EBA is often unsatisfactory, some therapeutic success has been achieved with colchicine, dapsone, plasmapheresis, photopheresis, infliximab, and intravenous immunoglobulin.

Gupta R ，Woodley DT ，Chen M 《-》