Pathology induced by interleukin-6.

Interleukin-6 (IL-6) is a multifunctional cytokine that plays an important role in the immune response, hemopoiesis, and host defense. Recombinant human IL-6 (rhIL-6) was administered at high doses to mice, rats, and nonhuman primates. In all species, IL-6 had an immunostimulatory and hemopoietic (especially on megakaryocytes) effect. An acute-phase response was most pronounced in nonhuman primates, which was, however, not associated with any significant histopathological liver change. Finally, no evidence of glomerular pathology was found. Neutralizing antibodies were detected within 10 days of rhIL-6 administration in all species.