Intriguingly, our results indicated significantly increased numbers of CCR7+ and CCR7+ICOS+, but not CCR7-PD-1+, memory Tfh cells in MS patients and the numbers of CCR7+ICOS+ memory Tfh cells were positively correlated with the EDSS scores, the levels of plasma and CSF IL-21, the levels of CSF MBP-Ab and MOG-Ab in MS patients. This evidence concerns the gene IL21 and myeloid sarcoma.