Immune mediators increase adherence of T-lymphocytes to human lung fibroblasts.

The purpose of the present study was to determine whether immunological mediators that are known to be released in the lungs of patients with active sarcoidosis might increase the adherence of human T-lymphocytes to human lung fibroblasts. The studies demonstrate that interleukin 1 (IL-1), tumor necrosis factor (TNF), gamma-interferon (IFN), and interleukin 2 (IL-2) increase the adherence of T-lymphocytes to fibroblasts in a dose- and time-dependent manner. An effect of IL-1, TNF, and IFN was observed at concentrations less than 1 ng/ml; an effect of IL-2 was not observed unless greater than or equal to 60 ng/ml of the mediator was used. The effect of the mediators was primarily on the fibroblasts; however, a significant increase in adherence was also observed when the T-lymphocytes were preincubated with the mediators. These observations suggest that there may be an intimate relationship between the immune response and the fibrotic response in the lungs of patients with pulmonary sarcoidosis or in other disorders where tissue fibrosis is mediated by immunological processes.