IFNG and Recurrent upper respiratory tract infections: The largest study was from two military outbreaks in China and included 65 patients with upper respiratory tract infection and 95 patients with AdV CAP and reported a positive correlation of serum levels of CXCL10, IL-2, and TNF-α with disease severity, and reduced levels of IFN-γ and IL-10 in non-severe CAP patients [30].