DIFFERENT CYTOKINE PRODUCTION PROFILES OF GAMMA-DELTA T-CELL CLONES -RELATION TO INFLAMMATORY ARTHRITIS

This study was performed to investigate whether gamma delta T cells co uld also be divided into subsets, identified by a cytokine profile, as described for alpha beta T helper (Th) cell subsets. Cytokine product ion was studied in 22 gamma delta T cell clones obtained from the syno vial fluid and peripheral blood of one patient with inflammatory arthr itis and compared to that of 26 alpha beta T cell clones of the same a nd different patients. Interferon-gamma (IFN-gamma) was produced by 18 (82%) and interleukin-4 (IL-4) by 17 (77%) out of 22 gamma delta T ce ll clones, respectively. In contrast, IL-10 was not produced, except a t very low level in one case. The mean levels of IL-4 were lower for c lones derived from synovial fluid. When considering the production of IFN-gamma as an indicator of Th1 and that of IL-4 as an indicator of T h2, respectively, the most common pattern was a gamma delta Th1-like p attern, with the combination of high levels of IFN-gamma and low level s of IL-4. This pattern was found in V delta 1(+) clones, all from syn ovial fluid. Additional patterns were also observed: a mixed, probably gamma delta Th0-like pattern with a more balanced production of both IFN-gamma and IL-4; a gamma delta Th1 pattern with the production of I FN-gamma alone; a gamma delta Th2 pattern with the production of IL-4 alone. These three patterns were also seen in blood gamma delta T cell s which were all V gamma 2, indicating that these patterns were indepe ndent of the V delta phenotype. gamma delta T cell clones produced low er levels of IFN-gamma (p = 0.001) and higher levels of IL-4 than alph a beta clones (p < 0.02). These differences in cytokine production bet ween alpha beta and gamma delta subsets and within these subsets may c ontribute to their respective role in chronic inflammation.