KLRC2 and cytomegalovirus infection: Moreover, the expansion of NKG2C+CD57+ memory NK cells in leukemic patients that reactivated CMV following allo-hematopoietic stem cell transplant (HSCT) is associated with a significantly reduced rate of relapse [44], suggesting that the recognition of HLA-E+ leukemic blasts by memory NKG2C+ NK cells expanded in response to HCMV infection may have beneficial effect through the eradication of minimal residual disease.