In this regard, lower frequencies in NKG2D+CD3−CD56+ NKs were found in clinically isolated syndrome (CIS, i.e., MS patients at their first relapse that can derive or not in a clinically defined MS) and untreated RRMS patients than in IFN-β-treated RRMS patients, which was linked to a negative correlation between NKG2D expression and EDSS values in MS patients, treated and untreated [72]. This evidence concerns the gene KLRK1 and myeloid sarcoma.