Interleukin (IL)-17/T helper (Th)17-induced IL-32 expression from rheumatoid arthritis (RA) patients. (A) Production of IL-32 by RA fibroblast-like synoviocytes (FLSs) in contact with CD4+ T cells. RA FLSs and CD4+ T cells from healthy donors were co-cultured. FLSs (1 × 105) were cultured with CD4+ T cells (1 × 106) with or without anti-IL-17 blocking antibody (10 μg/ml). IL-17 production was then measured by sandwich ELISA, and the IL-32 mRNA levels of RA FLSs were determined by real-time PCR. ***P < 0.001 (compared with FLS+CD4+ T cells). (B) Induction of RA FLS IL-32 production by the supernatant of Th17-polarized cell cultures. RA FLSs and the culture supernatants of Th17-polarized cells from healthy donors were co-cultured. CD4+ T cells were incubated with membrane-bound anti-CD3 antibody (2 μg/ml), IL-6 (5 ng/ml), IL1β (5 ng/ml), IL-23 (10 ng/ml), TGF-β (5 ng/ml) with or without an anti-IL-17 blocking antibody incubated for 2 h before the next incubation) for 3 days to induce Th17.polarization. FLS (1 × 105) were cultured with the culture supernatants of these Th17 polarized cells. IL-17 production was measured by sandwich ELISA and the IL-32 mRNA levels in RA FLSs were determined by real-time PCR. **P < 0.01 (compared with FLSs + culture supernatant of Th17 cells), *** P < 0.001 (compared with FLSs + culture supernatant of Th17 cells). The data are representative of three experiments with similar results.