CRP and rheumatoid arthritis: A significant negative correlation was seen between PERP mRNA levels in RA patients and serologic parameters of disease activity, including CRP (Figure 2(a)) (P = 0.0066), ESR (Figure 2(b)) (P = 0.0014), DAS28 (Figure 3(a)) (P = 0.0014), and RF (Figure 3(c)) (P = 0.0008).