Mitogen-induced interleukin 2 and gamma interferon production by CD4+ and CD8+ cells of patients with inflammatory arthritides. A comparison between cells from synovial fluid and peripheral blood.

The purpose of this study was to investigate interleukin 2 (IL-2) and gamma interferon (IFN-gamma) production by purified CD4+ and CD8+ cells isolated from peripheral blood (PB) and synovial fluid (SF) of patients with rheumatoid arthritis (RA) and other inflammatory arthritides (non-RA). CD4+ and CD8+ cells were selected positively by immunomagnetic separation. Supernatants of unstimulated CD4+ and CD8+ cells from both compartments did not contain any detectable IL-2 or IFN-gamma, while supernatants of CD4+ and CD8+ cells stimulated with phytohaemagglutinin and irradiated Raji cells mostly contained both cytokines. In vitro stimulated SF CD4+ cells gave supernatants with significantly less IL-2 than supernatants from PB CD4+ cells, while in vitro stimulated SF CD4+-cell supernatants contained significantly more IFN-gamma. SF CD4+-cell supernatants contained significantly more IL-2 than the parallel CD8+ supernatants, while there was no significant difference with regard to IFN-gamma content. The pattern of differences between SF- and PB-derived T cells was the same for the two groups of patients, but the SF CD4+ cells from RA patients produced significantly less IL-2 than the corresponding cells from the non-RA group. The difference between SF and PB T cells with regard to lymphokine production is probably related to various degrees of in vivo pre-activation. The results do not indicate a major T-cell deficiency in relation to lymphokine production in RA.