A potential association between early repopulation of CD20+ T cells and MS relapse was suggested by Schuh et al., reporting that three out of eight MS patients treated with RTX relapsed 4–8 months after the last infusion, at a time when more CD20+ T cells than B cells were present, as they seem to repopulate earlier than B cells in the blood [5]. This evidence concerns the gene MS4A1 and myeloid sarcoma.