The increased magnitude of the CMV-related NKG2C+ NK cell subset is in line with what has been found for CMV-specific CD4+ and CD8+ T cells, which also expand in CLL.25,26 Although expansion of NKG2C+ NK cells and CMV-specific T cells could be explain by increased subclinical reactivations of CMV, this has not been elucidated yet. This evidence concerns the gene KLRC2 and B-cell chronic lymphocytic leukemia.