IL6 and Heat Stroke: While increased levels of plasma levels of TNF-α, IL-1α, and IL-6 were observed in heat stroke patients (Bouchama et al., 1991; Hammami et al., 1997) blockade of IL-1β action by the endogenous IL-1 receptor antagonist protein (aka IL-1ra) in animal experiments improved survival (Chiu et al., 1996), indicating an important role for IL-1 in pathogenesis of heat stroke.