KIR3DL1 and cytomegalovirus infection: The high diversity of NK cell phenotypic repertoire may depend on different factors including KIR gene content, allelic polymorphism, transcriptional regulation, copy number variation, self HLA class I polymorphism, and cytomegalovirus (CMV) infection.36, 52, 53, 54, 55, 56, 57, 58, 59