Pemphigoïde anti-p200 : rémission sous mycophénolate mofétil (Cellcept®)

Abstract

Anti-p200 pemphigoid is a recently described autoimmune subepidermal bullous dermatosis characterized by its target antigen and the associated anatomoclinical picture. The treatment is not as yet well defined. A 73-year-old man consulted for a pruritic bullous eruption with buccal involvement. Direct immunofluorescence revealed linear deposits of IgG and C3 at the dermal-epidermal junction. Elisa screening for circulating anti-BP180 and anti-BP230 antibodies was negative. A diagnosis of bullous pemphigoid was suspected. After an unfavourable clinical outcome under clobetasol and then prednisolone and methotrexate, other immunological tests were performed. Indirect immunofluorescence on NaCl-cleaved skin revealed a deposit of IgG4 antibodies on the dermal side. Immunoblotting showed antibodies directed against a 200-kDa antigen on a dermal extract. A diagnosis of anti-p200 pemphigoid was made. The patient was treated with dapsone combined with prednisolone. Seventy-two hours later, treatment was stopped due to hepatic cytolysis related to immunoallergic hepatitis. Treatment with mycophenolate mofetil was then initiated and resulted in complete remission, which persisted at seven months. The diagnosis of anti-p200 pemphigoid was made on the basis of a set of clinical and immunological factors. Anti-p200 pemphigoid differs from standard bullous pemphigoid in terms of more frequent cephalic, acral and mucous membrane involvement, as well as a greater degree of miliary scarring. There was no eosinophilia. Elisa screening for anti-BP180 and anti-BP230 antibodies was negative. Immunoblotting showed antibodies directed against a 200kDa protein on dermal extract. The treatment is not well defined, even if dapsone appears to be the most effective therapy. To our knowledge, our patient is the first to be successfully treated with mycophenolate mofetil. Treatment of anti-p200 pemphigoid is difficult. In our case, treatment by mycophenolate mofetil was effective and could offer an alternative to dapsone.