Pretreatment of RA SF mononuclear cells with IL-23 and P/I resulted in a significantly (p < 0.05) increased frequency of TH-17 cells (6.8 ± 1.93%) (Figures 1f and 2), compared with untreated RA SF (Figures 1e and 2). Here, IL23A is linked to rheumatoid arthritis.