<prompt> Which of the following is not a pyrogenic cytokine?IL - 1TNFIFN - aIL - 18  <response>: Pyrogens are substances which cause fever. These can be either exogenous or endogenous. The endogenous pyrogens also called the pyrogenic cytokines include: IL-1 IL-6 Tumor necrosis factor TNF Ciliary neurotopic factor CNTF IFN-a alpha IL-18 which is a member of IL-1 family does not appear to be a pyrogenic cytokine. 