Comparison of follicular T helper cells, monocytes, and T cells priming between newly diagnosed and rituximab-treated MS patients and healthy controls

Background and purpose: The use of anti-CD20 monoclonal antibodies like rituximab (RTX) to deplete B cells has practical therapeutic implications in multiple sclerosis (MS) patients. However, the therapy s impact on other immune cells is also important. Therefore, in this study, we assessed the effects of RTX therapy on Tfh cells, T cells, T cells priming, and monocytes in MS patients compared to newly-diagnosed MS patients and healthy subjects. Experimental approach: Thirty newly-diagnosed and RTX-treated MS patients and healthy control were included. Peripheral blood mononuclear cells were isolated from whole blood for assessment of Tfh cells, CD4+, CD8+, CD4+CD45RA+, CD3+HLA-DR+, and CD3+CD4+CD25+ T cells by flow cytometry. Whole blood was lysed by lysis solution to assess CD45+CD14+ monocytes by flow cytometry. Also, the serum level of interleukin 21 was measured by the ELISA method. Findings / Results: We showed that RTX treatment led to a decrease in Tfh cells and their predominant cytokine, interleukin 21. Also, we found a statistically significant reduction in CD3+HLA-DR+ and CD3+CD4+CD25+ T cells in RTX-treated patients compared to new cases and healthy control. Moreover, we found a decrease in the CD45+ CD14+ monocyte population in the RTX-treated group compared to the healthy control. Conclusion and implications: Our data suggest that following treatment with RTX, Tfh cells, monocytes, and T cells priming declined happened, and fewer T cells were activated. Also, due to the interaction between B cells and Tfh cells, Tfh targeting could be assessed as a therapeutic strategy in MS.