ANALYSIS OF CYTOKINE PROFILES IN SYNOVIAL T-CELL CLONES FROM CHLAMYDIAL REACTIVE ARTHRITIS PATIENTS - PREDOMINANCE OF THE TH1 SUBSET

Subpopulations of human T cells (Th0, Th1 and Th2) can be distinguishe d by their cytokine-secretion pattern. Evidence is increasing from oth er studies that the outcome of a human disease may depend on the subpo pulation of T cells that predominates at the site of inflammation. Rea ctive arthritis serves as a useful model of chronic inflammatory disea ses, because the triggering antigen can be identified. Using this trig gering antigen we raised 33 T cell clones reactive with Chlamydia trac homatis and 25 T cell clones that were not reactive, all from the syno vial fluid of two patients suffering from Chlamydia-induced arthritis. Their cytokine secretion patterns for interferon-gamma (IFN-gamma), I L-2 and IL-4 were analysed, as also were mRNAs for IFN-gamma and IL- 1 0 by in situ hybridization. Out of the 33 antigen-reactive clones 23 s howed a Th1 pattern with IFN-gamma but not IL-4 secretion, while the r emaining 10 exhibited a Th0 pattem. The clones that did not react with Chlamydia expressed all patterns of cytokine secretion, including a T h2 pattem, thus providing a control population that excludes bias in t he sampling procedure. CD4 and CD8 clones displayed a similar cytokine -secretion pattem. In addition this study demonstrates for the first t ime the expression of IL-10 mRNA in T cell clones derived from synovia l fluid, and this was not confined to the Th2 subset. The Th1 response that Chlamydia provoke can be regarded as appropriate for such an obl igate intracellular pathogen.