(A) FSTL1 mRNA expression in cryogenic tissue samples from patients with RA ( n = 14) and trauma controls (Con, n = 8). Results are expressed in relative units, and horizontal lines represent means. The P values derived using Student's t-test are indicated. (B) FSTL1 protein expression in representative tissue samples from trauma controls (N1-N4: N represents normal synovial tissues; 1-4 represents four different trauma control individuals) and RA patients (RA1-RA5, RA represents RA synovial tissues; 1-5 represents five different RA patients). FSTL1 immunoreactive band appears as a band with electrophoretic mobilities corresponding to 46 kDa. β-Actin was used as loading control. (C) FSTL1 concentrations in SF from trauma controls (n = 7) and RA patients (n = 13) and in serum from healthy individuals (n = 69) and RA patients (n = 207). Values are means ± SEM. FSTL1, follistatin-like protein 1; RA, rheumatoid arthritis; SF, synovial fluid.