Rituximab in treatment-resistant autoimmune blistering skin disorders.

Autoimmune blistering diseases are associated with autoantibodies to desmosomal (pemphigus group) or hemidesmosomal proteins (autoimmune subepidermal blistering disorders) that are essential for the structural integrity of the epidermis and dermoepidermal junction. Treatment is usually based on systemic glucocorticosteroids, which are often combined with additional immunosuppressants such as azathioprine and mycophenolate mofetil or immunomodulators including dapsone, antibiotics, and intravenous immunoglobulins. These interventions are sometimes not sufficient to induce remission and/or may be associated with intolerable adverse events. In such situations, the anti-CD20 antibody rituximab has been successfully applied in recent years. Rituximab transitorily depletes CD20-positive B lymphocytes from the circulation. It has been employed in more than 1 million patients with CD20-positive non-Hodgkin's lymphoma and severe side effects were only rarely observed. Subsequently, the B cell-modulating effect of rituximab has encouraged its use in a variety of autoimmune diseases, including more than 40 patients with pemphigus. In addition, a few patients with bullous pemphigoid, mucous membrane pemphigoid, and epidermolysis bullosa acquisita have received rituximab. In the majority of these patients, clinical remission was induced; however, serious adverse events were considerable higher compared to both patients with non-Hodgkin's lymphoma or nonbullous autoimmune disorders like lupus erythematosus, dermatomyositis, and rheumatoid arthritis.