Fig. 4
Bar graph depicting gene expression in synovial fluid (SF) cells of patients with psoriatic arthritis (PsA; n = 30), osteoarthritis (OA; n = 4), gout (n = 6), and rheumatoid arthritis (RA; n = 5). Error bars indicate SEM. Fold change was calculated using the comparative cycle threshold (ΔΔCt) method, and values are shown as log102−ΔCt values to better visualize the difference between groups (see Methods section of main text). a Interleukin-17A (IL-17A) gene expression was 37.5-fold greater (p = 1.5 × 10−5) in synovial fluid (SF) of patients with PsA than in those with OA and 19.8-fold greater (p = 1.7 × 10−4) than in those with gout. b Chemokine (C-X-C motif) ligand 10 (CXCL10) gene expression was tenfold greater (p = 0.007) in SF of patients with PsA than in those with OA and 36.2-fold greater (p = 2.6 × 10−6) than in those with gout. Chemokine (C-X-C motif) receptor 3 (CXCR3) gene expression was 5.3-fold greater (p = 0.011) in SF of patients with PsA than in those with OA, 32.3-fold greater (p = 1.2 × 10−6) than in those with gout, and 3.9-fold greater (p = 0.02) than in patients with RA. TBX21 expression was 5.6-fold greater (p = 0.029) in SF of patients with PsA than in those with OA and 25-fold greater (p = 0.0001) than in patients with gout. RORC gene expression was 8.1-fold greater (p = 0.002) in SF of patients with PsA than in those with OA, 19-fold greater (p = 0.0001) than in patients with gout, and 3.4-fold greater (p = 0.037) than in patients with RA. No difference between patients with PsA and patients with RA was found for CXCL10, TBX21, and IL-17A. Asterisks are used to indicate significant differences between groups, where *p < 0.05, **p < 0.01, and ***p < 0.001. GAPDH Glyceraldehyde 3-phosphate dehydrogenase