This is similar to the GWI related illness myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) for which herpesviruses have been implicated as possible etiological pathogens [81, 82], and for which there is evidence of reduced NK cell function [83–88] and IL-15 levels [48] correlating with increased illness severity [89–91], highlighting the similarity between these illnesses. This evidence concerns the gene IL15 and myalgic encephalomeyelitis/chronic fatigue syndrome.