Rheumatoid arthritis (RA) synovial fluid (SF) macrophages express increased IL-23, IL-27 and IFN-γ. mRNA was extracted from RA SF macrophages (n = 12) and control macrophages (n = 12) that were either untreated or treated with peptidoglycan for four hours. Real-time PCR was employed to identify mRNA for (a) IL-23, (b) IL-27 and (c) IFN-γ which were normalised to glyceraldehyde 3-phosphate dehydrogenase (GAPDH). The results are presented as fold increase compared with control macrophages for IL-23, IL-27 and RA SF macrophages for IFN-γ, and represent the mean ± SE. *p < 0.05, **p < 0.01, ***p < 0.005.