Investigating the role of pentraxin 3 as a biomarker for bacterial infection in subjects with COPD.

Abstract

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 >105 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.

• Authors: Samantha J Thulborn, Madiha Dilpazir, Koirobi Haldar, Vijay Mistry, Christopher E Brightling, Michael R Barer, Mona Bafadhel
• Journal: International journal of chronic obstructive pulmonary disease (Int J Chron Obstruct Pulmon Dis) Vol. 12 Pg. 1199-1205 ( 2017) ISSN: 1178-2005 [Electronic] New Zealand
• PMID: 28458531 (Publication Type: Journal Article)

Chemical References

• Biomarkers
• Serum Amyloid P-Component
• PTX3 protein
• C-Reactive Protein

Topics

• Aged
• Aged, 80 and over
• Area Under Curve
• Bacterial Infections (diagnosis, metabolism, microbiology, physiopathology)
• Bacterial Load
• Biomarkers (metabolism)
• C-Reactive Protein (metabolism)
• Disease Progression
• Enzyme-Linked Immunosorbent Assay
• Female
• Forced Expiratory Volume
• Humans
• Longitudinal Studies
• Lung (physiopathology)
• Male
• Middle Aged
• Predictive Value of Tests
• Prognosis
• Pulmonary Disease, Chronic Obstructive (diagnosis, metabolism, microbiology, physiopathology)
• ROC Curve
• Serum Amyloid P-Component (metabolism)
• Sputum (metabolism, microbiology)
• Time Factors
• Up-Regulation