Asthma patients showed greater bronchial mucosal inflammatory response to rhinovirus infection
Rhinovirus infection induced more severe bronchial mucosal neutrophil monocyte and macrophage infiltration in patients with asthma compared with patients without asthma, according to study results.
Researchers studied 10 patients with atopic asthma (mean age, 23 years; eight women) and 15 adults without asthma (mean age, 27 years; seven women) and used immunohistochemistry to determine phenotypes of inflammatory cells infiltrating the bronchial mucosa before and after experimental rhinovirus infection.
Rhinovirus infection significantly increased the epithelial (P=.005) and subepithelial (P=.017) neutrophils in patients with asthma at day 4 compared with baseline. In the patients with asthma (P=.009) and without asthma (P=.018), rhinovirus infection significantly increased subepithelial CD68+ macrophages. When comparing cohorts, patients with asthma had more subepithelial CD68+ cells (P=.021).
There was a positive association between virus load and the number of CD45+, CD68+ and CD20+ cells, neutrophils and eosinophils at day 4.
When patients with asthma were acutely infected, “CD4+ cells correlated with chest symptom scores (r=0.69, P=.029), the fall in the 10% fall in FEV1 (PC10) correlated with neutrophils (r=–0.89, P=.029), the PC10 correlated inversely with CD4+ (r=–0.67, P=.023) and CD8+ cells (r=–0.65, P=.03),” the researchers reported. “The 20% fall in FEV1 was inversely associated with CD20+ cells (r=–0.65, P=.03) and higher epithelial CD8+ cell counts were significantly associated with a greater maximum fall in FEV1 (r=–0.72, P=.03), whereas higher subepithelial mast cell counts were significantly associated with a lower maximum percent fall in peak expiratory flow (r=0.8, P=.024),” the researchers reported.
“Airway neutrophils, eosinophils, and T and B lymphocytes during infection are related to virus load and physiologic and clinical severity, whereas mast cells are related to greater lung function,” the researchers concluded.
Disclosure: See the study for a full list of relevant financial disclosures.