Fig. 2

Association of baseline plasma concentrations of interleukin (IL)-19, IL-20, and IL-24 with immunoglobulin M-rheumatoid factor (IgM-RF) and anti-cyclic citrullinated peptide antibody (αCCP) positivity in early rheumatoid arthritis (RA) patients and immune complex (IC) stimulation of the three cytokines in monocytes/macrophages. a The plasma concentrations of IL-20 and IL-24 were increased in IgM-RF positive (n = 108) compared with negative (n = 44) RA patients and in anti-CCP antibody positive (n = 98) compared with negative RA patients (n = 54). Data were analyzed using the Mann–Whitney U test for unpaired data. Boxes indicate the median and interquartile range and whiskers indicate 10–90 percentiles. b Secretion of IL-19, IL-20, and IL-24 from HC PBMCs stimulated with heat -aggregated immunoglobulin immune complexes (haIg-ICs) at 0.01–1 μg/ml, lipopolysaccharide (LPS) at 100 ng/ml, or immunoglobulin (Ig) at 1 μg/ml (n = 7). Data were analyzed using the Friedman test for dose–response data and the Wilcoxon signed rank test for paired data. c Secretion of IL-19, IL-20, and IL-24 from monocyte-derived macrophages stimulated with citrullinated fibrinogen immune complexes (cFb-ICs) with and without the Toll-like receptor 4 inhibitor CLI-095 (TLR), Fcγ receptor IIa-blocking antibody (Fc), or both inhibitors (n = 2 in triplicates, supernatants pooled). Bars indicate the median and whiskers indicate interquartile range. *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001