PRTN3 and rheumatoid arthritis: Similarly, in RA patients with high titers of ACPA (≧ 200 U/ml), there was no correlation between serum Gal-9 and MMP-3 (r = 0.111, p = 0.519), whereas serum Gal-9 levels were significantly correlated with serum MMP-3 (r = 0.300, p = 0.007) in RA patients with low titers of ACPA (< 200 U/ml) (Fig. 4c).