B-cell directed therapies in antiphospholipid antibody syndrome--new directions based on murine and human data.

The increased awareness of the role of humoral immunophysiology in antiphospholipid syndrome (APS) has aroused interest in B cells as therapeutic targets in this disease. This paper reviews the literature on B cell directed therapies in human and experimental APS. The clinical data is limited to B cell depletion with rituximab and comprises case reports and case series. Murine studies include use of modulators of B cell function such as belimumab and abatacept. In both human and murine studies, B cell directed therapies appeared to have clinical and serologic beneficial effects including a decrease in the antiphospholipid antibody titers after treatment. Randomized controlled clinical trials are needed to determine whether B cell depletors and/or B cell modulators can be effective agents for treating patients with APS.