Pentraxin-3 as a Marker of Disease Activity in Takayasu Arteritis

Background: Because pentraxin-3 (PTX3) is produced by immune and vascular cells in response to proinflammatory signals, it may be a useful biomarker for defining disease activity in patients with Takayasu arteritis. Objective: To compare PTX3 levels in patients who have Takayasu arteritis with those in healthy and infected controls, and to compare accuracy of PTX3 levels with that of C-reactive protein (CRP) levels and erythrocyte sedimentation rate (ESR) for distinguishing active and inactive disease. Design: Cross-sectional, noninterventional study conducted between September 2005 and October 2008. Setting: Immunology and rheumatology clinic at a university hospital in Italy. Patients: 57 consecutive patients with Takayasu arteritis and known disease activity, 57 healthy blood donor controls, and 15 patients with acute infection. Measurements: Disease activity by clinical criteria; plasma PTX3 and CRP levels and ESR. Results: 27 patients had active Takayasu arteritis; 30 had inactive disease. Levels of PTX3 were higher in patients with active disease(median, >2.14 ng/mL [range, 0.57 to 48.18 ng/mL]) than in those with inactive disease (median, 0.63 ng/mL [range, 0.00 to 1.64 ng/mL]) and were higher than in healthy patients (median, 0.11 ng/mL [range, 0 to 1.20 ng/mL]) or those with acute infection (median, 0.26 ng/mL [range, 0 to 0.75 ng/mL]). A plasma PTX3 level greater than 1 ng/mL was more accurate than normal thresholds of CRP or ESR for distinguishing active from inactive disease. Limitation: The study excluded patients with unknown or equivocal disease status. Conclusion: Plasma levels of PTX3 could help distinguish active from inactive Takayasu arteritis but should not be adopted for clinical use until the findings are confirmed in a broader spectrum of patients whose disease activity is unknown or equivocal before testing.