Impaired regulatory B cells in myasthenia gravis

- The frequency and number of CD19+ CD1dhiCD5+ and CD19+ CD24hiCD38hi Bregs were decreased in MG.
- IL-10+ B cells within Bregs were decreased in MG compared to Ctrl.
- Functional defects in MG could reflect decreased Breg2 number / function or resistance of CD4+ T cells to suppression.

Regulatory B cells (Bregs) attenuate the severity of experimental autoimmune myasthenia gravis (EAMG) in an interleukin-10 (IL-10)-dependent manner. The goal of this study was to investigate the role of human Bregs in MG focusing on CD19+ CD1dhi CD5+ and CD19+ CD24hiCD38hi subsets. We found that MG patients exhibited a decrease in the frequency of both Breg subsets and IL-10 producing B cells within each subset, which correlated with disease severity. In addition, there was impaired suppression of Th1 polarization in MG. These findings, taken together with EAMG data, indicate that Bregs play an important role in regulating the severity of MG.

129