| Περίληψη: | <h4>Background</h4> <p>Pentraxin-3 (PTX3) is an acute phase protein, involved in antibacterial resistance. Recent studies have shown PTX3 levels to be elevated in the presence of a bacterial infection and in a murine sepsis model.</p> <h4>Objective</h4> <p>We aim to investigate if sputum PTX3 can be used as a biomarker for bacterial infection in subjects with COPD.</p> <h4>Methods</h4> <p>Sputum samples from 142 COPD patients (102 men) with a mean (range) age 69 years (45 to 85) and mean (SD) post-bronchodilator percentage predicted FEV1 of 50% (19) were analysed for PTX3, using a commercial assay at stable state and during an exacerbation. Association with bacteria, from culture, quantitative real time polymerase chain reaction (qPCR) and colony forming units (CFU) was investigated.</p> <h4>Results</h4> <p>The geometric mean (95%CI) PTX3 level at stable state was 50.5ng/mL (41.4 to 61.7). PTX3 levels correlated with absolute neutrophil count in sputum (r=0.37; p<0.01); but not FEV1 or health status. There was a weak correlation between PTX3 and bacterial load (CFU r=0.29, p<0.01; 16s qPCR r=0.18, p=0.05). PTX3 was a poor predictor of bacterial colonisation (defined as >105 CFU/mL at stable state) with a receiver operator characteristic (ROC) area under the curve (AUC) of 0.59, 95% confidence interval (CI) 0.43 to 0.76, p=0.21). During an exacerbation there was a modest increase in PTX3 (fold difference 0.15, 95% of difference 0.02 to 0.29; p=0.02 and PTX3 fared better at identifying a bacteria-associated exacerbation (ROC AUC 0.65, 95%CI 0.52 to 0.78, p=0.03). </p> <h4>Conclusions</h4> <p>PTX3 is associated with bacterial infection in patients with COPD, but its utility as a biomarker for identifying a bacteria-associated exacerbation warrants further studies. </p>
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