Fig. 5

IL-9 induced differentiation of Th17 and other effector T cells. a Representative FACS plots show Th17 cell frequency in PBL (HC, OA, RA) and SF (OA and RA).b Cumulative scatter plot shows frequency of Th17 (CD4 + IL-17A+) in RA (PBL and SF, n = 26), OA (PBL and SF, n = 7), HC PBL (n = 12). c Cumulative bar graphs show IFN-γ + (p = 0.0001) and TNF-α + (p = 0.02), IL-17A+ (p = 0.04) CD4+ cells were significantly higher in the presence of rIL-9 or RA SF, blocking IL-9 abrogated the same (n = 6, one-way ANOVA analysis with Dunnett’s multiple comparison test is applied for statistical significance, *p < 0.05). HC healthy control, IL-9R interleukin 9 receptor, IFN-γ interferon gamma, OA osteoarthritis, RA rheumatoid arthritis, SF synovial fluid, Th T helper