INTERLEUKIN-10 PRODUCING- B CELLS AND THEIR ASSOCIATION WITH RESPONSIVENESS TO RITUXIMAB IN MYASTHENIA GRAVIS

Introduction: A subset of regulatory B cells in humans and mice has been defined functionally by their ability to produce interleukin (IL)-10. We characterized IL-10-producing B (B10) cells in myasthenia gravis (MG) patients and correlated them with disease activity and responsiveness to rituximab therapy. Methods: Frequencies of B10 cells from MG patients and healthy controls were monitored by fluorescence-activated cell sorting (FACS). Results: MG patients had fewer B10 cells than controls, which was associated with more severe disease status. Moreover, patients who responded well to rituximab therapy exhibited rapid repopulation of B10 cells, whereas in patients who did not respond well to rituximab, B10 cell repopulation was delayed. The kinetics of B10 cells were related to the responsiveness to rituximab in MG. Conclusions: We have characterized a specific subset of B10 cells in MG patients which may serve as a marker for disease activity and responsiveness to immune therapy. Muscle Nerve 49:487-494, 2014