The 'discovery* of IL-1b is found in the literature on the pathogenesis of fever. Although initially concerned with the pyrogenic properties of gram-negative bacterial endotoxins, pyrogenic protein of endogenous origin and free of endotoxins was described in 1948. The first studies were carried out by Paul Beeson in 1948 on the fever-producing properties of rabbit peritoneal exudate cells (Beeson, 1948). The historical events were reviewed by Atkins in 1960 (Atkins. 1960) and again more recently (Dinarello. 1999). Many people think that IL-1b was first described by Waksman and Gery (1972). but that important discovery was related to the ability of IL-1b to act as a co-activator of lymphocyte proliferation, the least durable property of IL-1 compared to its role in inflammation. The fact remains that the most potent endogenous pyrogen and inducer of the so-called 'acute phase response* in rabbits and humans is. in fact. IL-1b and this molecule was first described for its role in fever and the acute phase response (Merriman et ai, 1977).