%0 Journal Article %A Thulborn, Samantha J. %A Dilpazir, Madiha %A Haldar, Koirobi %A Mistry, Vijay %A Brightling, Christopher E. %A Barer, Michael R. %A Bafadhel, Mona %D 2017 %T Investigating the role of pentraxin 3 as a biomarker for bacterial infection in subjects with COPD %U https://figshare.le.ac.uk/articles/journal_contribution/Investigating_the_role_of_pentraxin_3_as_a_biomarker_for_bacterial_infection_in_subjects_with_COPD/10197260 %2 https://figshare.le.ac.uk/ndownloader/files/18376397 %K TNF-inducible gene 14 protein %K infection %K sputum %X BACKGROUND: 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. OBJECTIVE: We aim to investigate if sputum PTX3 can be used as a biomarker for bacterial infection in subjects with COPD. MATERIALS AND METHODS: Sputum samples from 142 COPD patients (102 men) with a mean (range) age of 69 years (45-85) and mean (SD) post-bronchodilator percentage predicted forced expiratory volume in 1 second (FEV1) of 50% (19) were analyzed 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. RESULTS: The geometric mean (95% CI) PTX3 level at stable state was 50.5 ng/mL (41.4-61.7). 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 colonization (defined as >10(5) CFU/mL at stable state) with a receiver-operating characteristic (ROC) area under the curve (AUC) of 0.59 and 95% confidence interval (CI) 0.43-0.76 (P=0.21). During an exacerbation, there was a modest increase in PTX3 (fold difference 0.15, 95% of difference 0.02-0.29; P=0.02), and PTX3 fared better at identifying a bacteria-associated exacerbation (ROC AUC 0.65, 95% CI 0.52-0.78, P=0.03). CONCLUSION: 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. %I University of Leicester