Serological markers in psoriatic arthritis: promising tools

The aim of this study was to identify specific biomarkers that could be used to screen for psoriatic arthritis (PsA), as well as to assess disease activity and treatment outcome in affected patients. Forty-three outpatients considered eligible for anti-TNF-α treatment (etanercept 50 mg/week) were enrolled. Serum samples of vascular endothelial growth factor (VEGF), metalloproteinase-3 (MMP3), pentraxin 3 (PTX3), and high-sensitive C-reactive protein (hs-CRP) were collected at baseline (t0) and after 6 (t6), 12 (t12), and 24 months (t24) of treatment. Baseline values were compared with those of a group of healthy controls matched for age and sex. Disease activity scores and functional tests (DAS28, BASDAI, PASI, BASFI, HAQ, VAS pain, and VAS patient global disease activity) after treatment were found to be significantly different from baseline values. At baseline, MMP3, hs-CRP and VEGF values in the PsA-patients were found to be significantly higher with respect to levels in the controls. There were no differences in the PTX3 values. MMP3 was significantly lower at t6 (P < 0.0001), t12 (P < 0.0001) and t24 (P < 0.0001). hs-CRP and VEGF were significantly lower, respectively, at t12 (P < 0.01; P < 0.05) and t24 (P < 0.05; P < 0.01). PTX3 was significantly higher at t24 (P < 0.05). A correlation was found between MMP3 and hs-CRP (r = 0.45, P = 0.0005). MMP3, hs-CRP, and VEGF appear to be useful for the early detection of PsA and to monitor disease progression. The rise in PTX3 did not appear to be linked to the inflammatory state of the disease but might be an expression of the atherosclerotic process frequently observed in PsA.