Interleukin-6 and rheumatic diseases.

IL-6 is a pleiotropic cytokine involved in both the initiation and the maintenance of the inflammatory and immunologic responses in certain autoimmune diseases. Blocking of these two complementary functions of IL-6 may confer additive, or even unique, benefits to the patient. The levels of both IL-6 and its soluble receptor (sIL-6Ralpha) are elevated to various degrees in many rheumatic diseases. IL-6 blockade has been shown to be beneficial both in experimental models and in human disease, and inhibition of IL-6 signaling with a molecule such as tocilizumab could prevent or reverse some of the complications typically associated with rheumatic diseases.