Interleukin 6 (IL-6) is a cytokine that functions as a trophic and dif
ferentiating factor in cells of many types. Because of its wide-rangin
g expression and effects, the inappropriate expression and modulation
of IL-6 production has important physiological consequences. in this r
eview, the authors examine the role of IL-6 under physiological and pa
thophysiological conditions, and its feasibility as a drug discovery t
arget.