Intracytoplasmic Th1 and Th2 cytokines in rheumatoid arthritis blood and synovial tissue

In rheumatoid arthritis (RA), T cells have been proposed either as a main a ctor or as an epiphenomenon in such a primarily synoviocyte-driven disease. A major issue remains the remarkable paradox between the T cell infiltrate and the relative failure to detect definite markers of their activity. To determine the Th1/Th2 cytokine profile in RA synovium, we used a single cel l flow cytometric assay for interleukin-2 (IL-2), interferon-gamma (IFN-gam ma), IL-4 and IL-10 in paired peripheral blood (PB) and synovial tissue (ST ) lymphocytes from RA and osteoarthritis (OA) patients and PB lymphocytes f rom healthy controls. Cytokines were undetectable in unstimulated PB and ST lymphocytes. More stimulated PB and ST CD4(+) lymphocytes produced IFN-gam ma than IL-4, for all individuals tested. RA PB CD4(+) lymphocytes showed t he same Th1 cytokine pattern as normal controls. No increase of such a Th1 profile was observed for ST lymphocytes. A specific recruitment of T CD4(+) lymphocytes in the rheumatoid inflamed synovium could not be concluded on the basis of these results. (C) 1999 Academic Press.