title: Shifting of immune responsiveness to house dust mite by influenza A infection: genomic insights.
abstract: Respiratory viral infections have been associated with an increased incidence of allergic asthma. However, the mechanisms by which respiratory infections facilitate allergic airway disease are incompletely understood. We previously showed that exposure to a low dose of house dust mite (HDM) resulted in enhanced HDM-mediated allergic airway inflammation, and, importantly, marked airway hyperreactivity only when allergen exposure occurred during an acute influenza A infection. In this study, we evaluated the impact of concurrent influenza infection and allergen exposure at the genomic level, using whole-genome microarray. Our data showed that, in contrast to exposure to a low dose of HDM, influenza A infection led to a dramatic increase in gene expression, particularly of TLRs, C-type lectin receptors, several complement components, as well as FcεR1. Additionally, we observed increased expression of a number of genes encoding chemokines and cytokines associated with the recruitment of proinflammatory cells. Moreover, HDM exposure in the context of an influenza A infection resulted in the induction of unique genes, including calgranulin A (S100a8), an endogenous damage-associated molecular pattern and TLR4 agonist. In addition, we observed significantly increased expression of serum amyloid A (Saa3) and serine protease inhibitor 3n (Serpina3n). This study showed that influenza infection markedly increased the expression of multiple gene classes capable of sensing allergens and amplifying the ensuing immune-inflammatory response. We propose that influenza A infection primes the lung environment in such a way as to lower the threshold of allergen responsiveness, thus facilitating the emergence of a clinically significant allergic phenotype.
authors.affiliation: Division of Respiratory Diseases and Allergy, Center for Gene Therapeutics, McMaster University, Hamilton, Ontario L8S 4K1, Canada.
authors.forename: Amal
authors.initials: A
authors.lastname: Al-Garawi
authors.forename: Mainul
authors.initials: M
authors.lastname: Husain
authors.forename: Dora
authors.initials: D
authors.lastname: Ilieva
authors.forename: Alison A
authors.initials: AA
authors.lastname: Humbles
authors.forename: Roland
authors.initials: R
authors.lastname: Kolbeck
authors.forename: Martin R
authors.initials: MR
authors.lastname: Stampfli
authors.forename: Paul M
authors.initials: PM
authors.lastname: O'Byrne
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Coyle
authors.forename: Manel
authors.initials: M
authors.lastname: Jordana
mesh_terms: D000485:Allergens / Q000008:administration & dosage / Q000276:immunology; D000818:Animals; D005260:Female; D015967:Gene Expression Regulation, Viral / Q000276:immunology; D016679:Genome, Viral / Q000276:immunology*; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D020411:Oligonucleotide Array Sequence Analysis; D009976:Orthomyxoviridae Infections / Q000235:genetics / Q000276:immunology / Q000473:pathology; D025341:Principal Component Analysis / Q000379:methods*; D039981:Pyroglyphidae / Q000235:genetics* / Q000276:immunology* / Q000821:virology; D012130:Respiratory Hypersensitivity / Q000276:immunology / Q000473:pathology / Q000821:virology; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D013997:Time Factors
chemical_list: D000485:Allergens