IL15 and B-cell chronic lymphocytic leukemia: Additionally, there is evidence showing that CLL-derived NK cells retain intrinsic functionality, given that it can be restored by adequate activating signaling, including cytokines such as IL-2, IL-15, IL-21 and IL-27 [36,37,38,39,40,41,153], and anti-CD20 mAbs that induce ADCC [34,37,39,40,153,154].