Cysteinyl leukotriene receptor 1 expression identifies a subset of neutrophils during the antiviral response that contributes to postviral atopic airway disease

Viral respiratory tract infections increase the risk of development and exacerbation of atopic disease. Previously, we demonstrated the requirement for a neutrophil (PMN) subset expressing CD49d to drive development of postviral atopic airway disease in mice. We sought to determine whether human CD49d+ PMNs are present in the nasal mucosa during acute viral respiratory tract infections and further characterize this PMN subset in human subjects and mice. Sixty subjects (5-50 years old) were enrolled within 4 days of acute onset of upper respiratory symptoms. Nasal lavage for flow cytometry and nasal swabs for viral PCR were performed at enrollment and during convalescence. The Sendai virus mouse model was used to investigate the phenotype and functional relevance of CD49d+ PMNs. CD49d+ PMN frequency was significantly higher in nasal lavage fluid during acute respiratory symptoms in all subjects (2.9% vs 1.0%, n = 42, P