TNF and serum lipopolysaccharide activity: The immune response to endotoxemia resulting from the collapse of the intestinal mucosal barrier activates the signaling cascade originating from pattern recognition receptors such as toll-like receptors in host immune cells in heatstroke.[18] Interleukin-1 and tumor necrosis factor-α, the potent inflammatory mediators, play an essential role in the initial immune response.