In this regard, we observed a significant up-regulation of the activating receptor KIR2S2 [64] in NK cells from CLL subjects, without significant changes in the expression of other activating molecules CD335, CD336, CD337, NKG2D and NKG2C [27,28,29,30,77]. The gene discussed is KLRK1; the disease is B-cell chronic lymphocytic leukemia.