In concordance to the previous observation after umbilical cord blood (UCB) and 1 HLA-matched sibling transplantation [10], we observed that CMV reactivation induced expansion of the NKG2C+ memory-like NK cells in patients after haplo-HSCT, which in turn produced IFNγ to control of CMV infection. The gene discussed is KLRC2; the disease is cytomegalovirus infection.