endogenous pyrogen

That is why IL-1 is called endogenous pyrogen.

Activated white blood cells release interleukin 1 (formerly called endogenous pyrogen), which tells the hypothalamus to push up the setting of the body's thermostat.

The drug may interfere with heat dissipation peripherally, increase the rate of metabolism, evoke a cellular or humoral immune response, mimic endogenous pyrogen, or damage tissues.

He worked on the mechanism of recovery from pneumonia and was noted for early work on surface phagocytosis, research into the pathogenesis of fever, and endogenous pyrogen (now known as interleukin-1).

TNF, being an endogenous pyrogen, is able to induce fever, apoptotic cell death, sepsis (through IL1 & IL6 production), cachexia, inflammation and to inhibit tumorigenesis and viral replication.