CRP and rheumatoid arthritis: Analyzing RA and OA SFBs together, significant positive correlations were observed between the constitutive expression of TGF-β1 mRNA (but not protein) and the serum levels of C-reactive protein (r = 0.711, n = 12; p = 0.01), as well as the number of fulfilled American Rheumatism Association (now American College of Rheumatology) criteria (r = 0.726, n = 12; p = 0.007).