BRONCHIAL INFLAMMATION AND THE COMMON COLD - A COMPARISON OF ATOPIC AND NONATOPIC INDIVIDUALS

Background Cold virus infections are associated with asthma attacks an d with increased bronchial responsiveness even in normal subjects. Pos sible mechanisms include epithelial damage, interaction with adhesion molecules or with T-helper cell subsets. Objective To determine whethe r colds increase lower airway inflammation, comparing atopic with non- atopic normal subjects. Methods Thirty healthy volunteers (15 atopic) took part. Baseline tests included viral serology, microbiological cul ture and polymerase chain reaction for rhinovirus infection (HRV-PCR), histamine bronchial provocation and bronchoscopy. Twenty subjects (ei ght atopic) underwent repeat tests when they developed a cold. Results Forced expiratory volume in one second (FEV(1)) was significantly low er during colds (-0.19 L [95% confidence interval -0.10, -0.29], P=0.0 004) and there was a significant increase in bronchial responsiveness (+0.62 doublings of the dose-response slope [+0.24, +1.00], P=0.003). Eight subjects (two atopic) had a diagnosed viral infection: two HRV, three coronavirus (HCV), one HRV + HCV, one parainfluenza III (PI) and one respiratory syncytial virus (RSV) (also Haemophilus influenzae). In biopsies, during colds, total eosinophils (EG1(+)) increased signif icantly (geometric mean 6.73-fold [1.12,40.46], P=0.04). Activated eos inophils (EG2(+)) only increased significantly in the subgroup without diagnosed viral infection and particularly in atopic rhinitics. T-sup pressor (CD8(+)) cells also increased significantly (median +178.3 cel ls mm(2), P=0.004). Epithelial expression of intercellular adhesion mo lecule-1 mm (ICAM-1) expression increased in four atopic rhinitics dur ing colds. Bronchial washings showed a significant increase in neutrop hils (GM 1.53-fold [1.04,2.25], P=0.02). Conclusion Lower airway infla mmation was present in atopic and non-atopic normal subjects with cold s. Atopic subjects differed in that they were less likely to have posi tive virological tests and were more likely to show activated eosinoph ilia in the lower airway, despite a similar spectrum of symptoms.