Clinical significance of MMP-3 in patients with rheumatoid arthritis: comparison with other inflammatory markers(IL-6, IL-8)

We determined serum metalloproteinase-3(MMP-3) and inflammatory cytokine(IL-6, IL-8) levels in patients with rheumatoid arthritis(RA). Sera were obtained from 307 healthy subjects(female 140, male 167), 54 RA patients, and 17 osteoarthritis (OA). The MMP-3 concentrations in healthy female and male were 43.3 +/- 15.3 ng/ml and 90.7 +/- 26.0 ng/ml, respectively. The serum MMP-3 levels in male were significantly higher than those in female (p < 0.0001). MMP-3 levels in RA patients(259.1 +/- 34.2 ng/ml) were significantly higher than OA(43.6 +/- 6.1 ng/ml) or healthy controls. There was a significant correlation between MMP-3 and CRP(r = 0.586), IL-6(r = 0.345) levels in serum. In contrast, no significant correlation was observed between MMP-3 and IL-8(r = 0.19), or CA-RF(r = 0.052) levels. However, there were some cases with high MMP-3 levels in CA-RF-negative patients definitely diagnosed as RA. These findings suggest that MMP-3 determination is useful for the early diagnosis and the follow-up during the treatment for RA patients.