As HCMV infection promotes expansion of CD57+ NK cell subsets at the expense of CD57− subsets (28, 32–34), we reasoned that vaccine-induced generation of memory-like NK cells could differ between HCMV-infected (HCMV+) and HCMV-uninfected (HCMV−) subjects. The gene discussed is B3GAT1; the disease is cytomegalovirus infection.