Previous studies showed that NK cells are important in immune protection against Chlamydia infections through the production of IFNγ (Jiao et al, 2011; Tseng and Rank, 1998), subsequent promotion of protective Th1 adaptive immunity via modulation of DC function (Jiao et al, 2011), and killing of Chlamydia-infected cells (Hook et al, 2004; Ibana et al, 2012). This evidence concerns the gene IFNG and chlamydia infectious disease.