Blood B Cell and Regulatory Subset Content in Multiple Sclerosis Patients

OBJECTIVE: B cell targeted therapies have been effective in slowing multiple sclerosis (MS) disease progression suggesting a direct causal link for this lymphoid subset. A small subset of B cells with regulative properties (Bregs) exists in peripheral blood, and induction of Bregs ameliorates experimental autoimmune encephalomyelitis (EAE), the murine model for MS. Therefore the frequency of B cell subsets and regulatory B cells in particular in peripheral blood of MS patients is of interest. METHODS: The phenotype and frequency of B cell subsets in peripheral blood from 32 MS patients and 34 healthy controls (HC) were examined using flow cytometry. RESULTS: We found that there is an increase in CD19(+) cell number in MS 1347 ± 159 cells/μL, (average ± SEM) compared to HC, 935 ± 129 cells/μL and no apparent deficiency in B-cells with a regulatory phenotype. In addition, we observed a loss of correlation between CD19(+) B cells and total lymphocyte count in MS. CONCLUSION: These findings suggest altered blood B-cell homeostasis in MS patients.