Detection of rhinovirus in induced sputum at exacerbation of chronic obstructive pulmonary disease

Abstract

Common colds are associated with exacerbations of chronic obstructive pulmonary disease (COPD). However, the role of the common cold virus (human rhinovirus) in the production of symptoms and lower airway inflammation at COPD exacerbation is unknown.

Thirty three patients with moderate‐to‐severe COPD were seen at baseline, when the number of chest infections in the previous year was noted, and acutely at COPD exacerbation. Within 48 h after the onset of the exacerbation and at baseline, nasal aspirates and induced sputum were taken for rhinovirus reverse transcriptase polymerase chain reaction (RT‐PCR) analysis and determination of cytokine levels. Symptoms, recorded on diary cards, were noted and forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) measured.

At exacerbation, mean FEV1 and FVC fell significantly from baseline (p<0.001). Ten of 43 exacerbations were associated with rhinovirus infection, detected in induced sputum. In four of these, nasophageal samples contained no detectable rhinovirus. All baseline samples were negative for rhinovirus. The simultaneous presence of increased nasal discharge/nasal congestion (in 26 of the 43 exacerbations) and increased sputum (29 exacerbations) was strongly associated with the presence of rhinovirus (odds ratio 6.15; p=0.036). Total symptom scores were greater for rhinovirus as compared to nonrhinovirus exacerbations (p=0.039). Median baseline sputum interleukin‐6 levels rose from 90.2 to 140.3 pg·mL ^‐1 at exacerbation (p=0.005); the change was greater in the presence of rhinovirus infection (p=0.008).

Rhinovirus infection can be detected at chronic obstructive pulmonary disease exacerbation. This is associated with elevation of lower airway interleukin‐6 levels, which may mediate lower airway symptom expression during chronic obstructive pulmonary disease exacerbations.