Following treatment with PGN, the IL-27 and IFN-γ mRNA increased in both RA SF (7.5-fold for IL-27 and 3.8-fold for IFN-γ) and control macrophages (295-fold for IL-27 and from undetectable to 1.9-fold for IFN-γ). Here, IL27 is linked to rheumatoid arthritis.