IFNG and diabetes mellitus: The most common co-morbid conditions seen in hospitalized MERS patients were obesity, diabetes, hypertension, cardiovascular diseases, or end-stage renal disease, and these chronic diseases are thought to attenuate innate immunity response by down-regulating production of pro-inflammatory cytokines such as interferon-gamma (IFN-g) and interleukins (ILs) (76, 77, 84).