GPI modulates the secretion of TNF-α, IL-1β, TGF-β and IL-6 in FLS isolated from RA or OA patients. RA or OA FLS were transfected with GPI expression plasmids and siRNAs or treated with GPI at 1 μg/ml for 72 hours and the supernatants were collected for the analysis of TNF-α (A and B), IL-1β (C and D), TGF-β (E and F) and IL-6 (G and H) levels using ELISA. Data were shown as mean ± SD (N = 8, R = 3). P values were determined by Wilcoxon signed-rank test. (N = number of individuals, R = number of replicates).