MMP1 and rheumatoid arthritis: In 266 RA patients, levels of 12 biomarkers (SAA/CRP/MMP-1/MMP-3/resistin/leptin/IL-6/TNF-R1/YKL-40/EGF/VEGF/VCAM-1), in the first 2 years after diagnosis, were studied in relation to SDFR, stratified for ACPA status.