[Rituximab in systemic lupus erythematosus. Part I. Theoretical basis].

Rituximab is a chimeric human-mouse monoclonal antibody, which binds to the CD20 antigen on B lymphocytes and causes depletion of CD20+ cells in the mechanism of complement-dependent and independent cytolysis, cell cytotoxicity and antibody-dependent mechanism and apoptosis. Rituximab is currently registered for the treatment of non-Hodgkin's lymphoma, chronic lymphocytic leukemia and rheumatoid arthritis. Rituximab also demonstrated efficacy in a number of other autoimmune diseases, including systemic lupus erythematosus. In patients with systemic lupus erythematosus rituximab decreases the number of autoreactive VH4.34 B cells, what contributes to sustaining B cell homeostasis and immune tolerance. A decrease in levels of circulating anti-dsDNA antibodies and an increase of C3 concentration is observed parallel to clinical improvement. Diagnostic procedures performed before initiation of rituximab therapy and during treatment include basic laboratory tests as well as exclusion of heart insufficiency and infections.