TNF and post-traumatic stress disorder: Although not confirmed in all studies, low-grade inflammation has been shown to be associated with PTSD and physiological stress responses, as indicated by elevated serum C-reactive protein (CRP), IL-1β, IL-6, IL-12, interferon gamma (INFγ) and tumor necrosis factor (TNF) [[16], [17], [18], [19], [20], [21], [22], [23], [24]].