γδT cells in Juvenile Idiopathic Arthritis: Higher Percentages of Synovial Vδ1+ and Vγ9+ T Cell Subsets Are Associated with Milder Disease

Objective. To analyze gamma delta T cell subsets in peripheral blood (PB) and synovial fluid (SF) of patients with juvenile idiopathic arthritis (JIA), and to correlate gamma delta T cell subsets with clinical characteristics. Methods. gamma delta T cell subsets as percentages of CD3+ T cells in samples of PB (n = 25) and SF (n = 93) were analyzed by flow cytometry in 93 JIA patients. The percentage of V gamma 9+ gamma delta T cells after 10 days of in vitro expansion with either interleukin 2 (IL-2) or isopentenyl pyrophosphate (IPP) plus IL-2 was determined. Results. Both V delta 1+ and V gamma 9+gamma delta T cell subsets were detected in SF of all patients, but only the percentage of V delta 1+ cells was higher in SF compared to PB (p < 0.01). The distribution of gamma delta T cell subsets was similar in different JIA subgroups, whereas antinuclear antibody (ANA)-positive patients had a higher percentage of SF V delta 1+ T cells than ANA-negative patients (p < 0.01). The percentage of SF V delta 1+ T cells was inversely associated with age at onset, recurrence of synovitis, and erythrocyte sedimentation rate; and that of SF V gamma 9+ T cells was inversely correlated with age at onset and was higher in patients who recovered from disease (n = 15). IPP-induced expansion of SF V gamma 9+ T cells correlated with disease remission, whereas the expansion of SF V gamma 9+ T cells in media with IL-2 alone was significantly greater in patients with uveitis. Conclusion. The percentage of V delta 1+ and V gamma 9+ gamma delta T cells among the SF T cells and their ability to respond to IPP or IL-2 correlated with specific outcomes of MA, suggesting their role in the immunopathogenesis of this disease. (First Release March 15 2011; J Rheumatol 2011;38:1123-9; doi:10.3899/jrheum.100938)