Mediators produced by innate immune response cells such as macrophages can profoundly influence adaptive immunity. Recent studies have shown that IL-15 and IL-18 play an influential role in inflammatory response. Here I present recent data mainly from our own laboratories illustrating the importance of IL-15 and IL-18 in the induction and perpetuation of chronic inflammation during experimental and clinical rheumatoid synovitis. These Findings suggest that antagonists to these cytokines may have a potential therapeutic role against organ-specific autoimmune diseases. (C) 2002 Elsevier Science B.V. All rights reserved.