Interleukin 15 (IL15) and interleukin 18 (IL18) are cytokines produced principally by macrophages during innate immune response and subsequently profoundly influence adaptive immunity. Recent studies have shown that IL15 and IL18 play an influential part in inflammatory response. Here we present recent data mainly from our own laboratories illustrating the importance of IL15 and IL18 in the induction and perpetuation of chronic inflammation during experimental and clinical rheumatoid synovitis.