Our data provide additional unifying evidence for IFN-γ's protective function in arthritis: IFN-γ lowered IL-1β-induced MMP production by RA FLS, altered the MMP/TIMP balance in favour of cartilage protection ex vivo, modulated synovial IL-1β expression in AIA and ameliorated early cartilage injury in vivo. Here, TIMP1 is linked to rheumatoid arthritis.