MMP1 and rheumatoid arthritis: Levels of MMP-1 and MMP-3 in the serum of RA patients are correlated with disease activity.85 Alternatively, successful treatment of RA with leflunomide, MTX or anti-TNFα antibodies is associated with downregulation of MMPs in serum.86 In addition, MMP concentrations might predict functional and radiographic progression, as in early untreated RA patients baseline serum levels of MMP-1 and MMP-3 correlated with erosive disease during the first 12 months.87