KLRK1 and myeloid sarcoma: The number of peripheral CD3−CD56+ NK cells was higher IFN-β-treated RR-MS patients compared to untreated patients although NKG2D+CD3−CD56+ NK cell count and endogenous IL-22 level in CD3−CD56+ NK cells were lower in untreated RR-MS and CIS patients than in treated RR-MS patients, indicating that NK cells have a therapeutic role in MS while IFN-β treatment may direct them toward a proinflammatory phenotype (40).