Translational Mini-Review Series on B Cell-Directed Therapies: B cell-directed therapy for autoimmune diseases.

B cells play an important role in the pathogenesis of both systemic and organ-specific autoimmune diseases. Autoreactive B cells not only produce autoantibodies, but are also specialized to present specific autoantigens efficiently to T cells. Furthermore, these B cells can secrete proinflammatory cytokines and can amplify the vicious cycle of self-destruction. Thus, B cell-directed therapies are potentially an important approach for treating autoimmune diseases. On the other hand, like T cells, there are subsets of B cells that produce anti-inflammatory cytokines and are immunosuppressive. These regulatory B cell subsets can protect against and ameliorate autoimmune diseases. Thus targeting B cells therapeutically will require this balance to be considered. Here we summarize the roles of pathogenic and regulatory B cells and current applications of B cell-directed therapy in autoimmune diseases. Considerations for future development of B cell-directed therapy for autoimmune diseases have also been discussed.