Rituximab in refractory autoimmune bullous diseases

Treatment of autoimmune blistering diseases consists of systemic glucocorticosteroids usually in combination with additional immunosuppressants such as azathioprine and mycophenolate mofetil or immunomodulators such as dapsone, antibiotics, intravenous immunoglobulins, and immunoadsorption. In some patients, these treatment regimens are not sufficient to control disease activity and/or lead to intolerable adverse events. Rituximab, originally developed for the treatment of non-Hodgkin's lymphoma, is an anti-CD20 humanized monoclonal antibody leading to transitory B-cell depletion. For this indication, rituximab is widely employed, and severe side-effects rarely observed. Subsequently, the B-cell-depleting effect of rituximab has been exploited successfully in various autoimmune disorders, including autoimmune blistering diseases. Here, we review the effect of rituximab in such diseases. To date, application of rituximab has been reported in 26 treatment-resistant patients with the vulgaris, foliaceus, and paraneoplastic variants of pemphigus as well as in bullous pemphigoid and epidermolysis bullosa acquisita. All but a single patient showed clinical improvement with reduction of lesion formation. In about a third, a clinical remission requiring further immunsuppressive medication was achieved, and in about a quarter, complete remission was induced. In addition, the mode of action and adverse events of rituximab as well as adjuvant immunosuppressive treatments, and the effect on levels of circulating autoantibodies in these patients are discussed.