Immunoregulatory lymphokines in rheumatoid joints. II. Production by and responsiveness to interleukin-2 of eluted synovial tissue cells.

Since the role of interleukin-2 (IL-2) in rheumatoid synovial joints has been debated, we examined IL-2 production by, and IL-2 responsiveness of, cells eluted from synovial tissue (ST) of patients with rheumatoid arthritis (RA) and juvenile rheumatoid arthritis (JRA). IL-2 was not detected in unstimulated cell-culture supernatants from any of the four RA patients tested, but it was present in small amounts in supernatants of unstimulated cultures derived from three of seven JRA patients studied. After PHA stimulation, IL-2 was detected in corresponding supernatants from all RA and JRA patients and from normal mononuclear cells (MNC). There was no significant difference in IL-2 activity between supernatants of normal MNC and supernatants from either RA or JRA patients. The eluted cells showed a proliferative response to recombinant IL-2. Rheumatoid ST cells are thus able to produce and respond to IL-2. Since non-T cells present in the eluates might interfere with IL-2 metabolism, one cannot yet say whether T cells of rheumatoid ST themselves produce and respond to IL-2 in a normal or abnormal way.