The capacity of synoviocytes to participate in inflammatory responses may be altered by the cytokine-enhanced expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1). To examine this possibility, the ability of selected cytokines to enhance ICAM-1 expression was examined. The data indicated that each of these cytokines (interleukin-1 beta greater than tumor necrosis factor-alpha, interferon-gamma much greater than interleukin-6) can up-regulate synoviocyte ICAM-1 expression. This can potentially increase the ability of these cells to interact with infiltrating inflammatory cells, thereby propagating immunologically mediated inflammation such as occurs in rheumatoid synovitis.