Serum IP-10 as a Biomarker of Human Rhinovirus Infection at Exacerbation of COPD

Chest. 2010 Apr;137(4):812-22. doi: 10.1378/chest.09-1541. Epub 2009 Oct 16.

Abstract

Background: Human rhinovirus (HRV) is the most frequent virus associated with COPD exacerbations. Viral infections increase exacerbation severity and likelihood of hospitalization. As ease of sampling blood makes serum a more practical marker than sputum, we investigated whether changes in serum interferon-gamma-inducible protein 10 (IP-10) from baseline to exacerbation were higher in airway HRV-positive exacerbations and whether IP-10 levels related to HRV load.

Methods: One hundred thirty-six patients with COPD and 70 controls were included over 2 years and 72 exacerbations sampled. HRV positivity and load were determined by reverse transcriptase-polymerase chain reaction in nasopharyngeal swabs and/or sputum at baseline and exacerbation. IP-10 was measured by enzyme-linked immunosorbent assay in serum and compared with HRV load.

Results: At baseline, serum IP-10 was higher in patients with COPD than controls; medians were 149.4 pg/mL (103-215) and 111.7 pg/mL (82-178), P = .02. The presence of HRV at baseline did not increase IP-10: patients with COPD, 166.9 pg/mL (110-240) and 149.4 pg/mL (103-215), P = .30; controls, 136.4 pg/mL (77-204) and 111.7 pg/mL (82-178), P = .53. IP-10 increased significantly from baseline to exacerbation in HRV-positive exacerbations: 154.9 pg/mL (114.0-195.1) to 207.5 pg/mL (142.1-333.5), P = .009. There was no change in IP-10 between baseline and exacerbation in HRV-negative exacerbations: 168.3 pg/mL (94.3-249.8) and 175.6 pg/mL (107.2-290.4), P = .49. At exacerbation, IP-10 correlated with sputum viral load: rho = 0.48; P = .02. In receiver operating characteristics analysis, the combination of IP-10 and coryzal symptoms gave an area under the curve of 0.82 (95% CI, 0.74-0.90).

Conclusions: IP-10 increases from baseline to exacerbation in HRV-positive exacerbations and correlates with sputum HRV load. Serum IP-10 may be useful as a novel marker for these events.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Aged
  • Aged, 80 and over
  • Biomarkers / blood
  • C-Reactive Protein / metabolism
  • Case-Control Studies
  • Chemokine CXCL10 / blood*
  • Female
  • Forced Expiratory Volume / physiology
  • Humans
  • Interleukin-6 / blood
  • Male
  • Middle Aged
  • Nasopharynx / virology
  • Picornaviridae Infections / blood*
  • Picornaviridae Infections / diagnosis*
  • Picornaviridae Infections / physiopathology
  • Pulmonary Disease, Chronic Obstructive / blood*
  • Pulmonary Disease, Chronic Obstructive / physiopathology
  • Pulmonary Disease, Chronic Obstructive / virology*
  • Retrospective Studies
  • Rhinovirus* / isolation & purification
  • Sputum / virology
  • Viral Load
  • Vital Capacity / physiology

Substances

  • Biomarkers
  • CXCL10 protein, human
  • Chemokine CXCL10
  • Interleukin-6
  • C-Reactive Protein