Interleukin responsible for pyrexia is?

Ans: All

In essence, all endogenous pyrogens are cytokines, molecules that are a part of the innate immune system.

They are produced by phagocytic cells and cause the increase in the thermoregulatory set point in the hypothalamus.
Major endogenous pyrogens are:
--Interleukin 1 (α and β),
--Interleukin 6 (IL-6) and
--Tumor necrosis factor-alpha.

Minor endogenous pyrogens include:
--Interleukin-8,
--Tumor necrosis factor-α,
--Tumor necrosis factor-β,
--Macrophage inflammatory protein-α
--Macrophage inflammatory protein-β
--Interferon-α,
--Interferon-β, and
--Interferon-γ.