Its expression was significantly increased only in the presence of the highest concentration of Zn (3.6 ppm) and the IL-17 and TNF-α combination in both OA and RA synoviocytes (Fig 2B, OA cells: +IL-17 and TNF-α: 1.5 ± 0.2 without Zn addition vs. 3.9 ± 0.6 with 3.6 ppm Zn addition, p<0.01; same conditions for RA cells +IL-17 and TNF-α: 2.3 ± 0.4 vs. 4.2 ± 1.1, p<0.05; S2 Table). This evidence concerns the gene IL17A and rheumatoid arthritis.