Conclusions
While our study has some limitations, including a small sample size, absence of treatment naïve patients, and the lack of confirmative studies using animal model, we found an impressive interaction between the increased frequency of cTfh cells, particularly cTfh17.1 cells and the enhanced production of IL-21 in MS patients. Contrarily, cTfreg cells and their signature cytokine IL-10 were remarkably impaired in MS patients. Taken together, our study demonstrates an alteration of cTfh and cTfreg cells, which is reflected in the dysregulated cytokine production in MS. An additional study with a larger cohort is warranted to validate our observations regarding the role of Tfh cells and their subsets as well as Tfreg cells in MS. Functional analysis throughin vitro co-culture of purified cTfh, B and cTfreg cells may provide a better understanding of MS and other autoimmune diseases that could potentially guide us to new therapeutic interventions.