The role of IL-15 deficiency in the pathogenesis of Virus-Induced asthma exacerbations

Rhinovirus infections are the major cause of asthma exacerbations. we hypothesised that il-15,a cytokine implicated in innate and acquired antiviral immunity,may be deficient in asthma and important in the pathogenesis of asthma exacerbations. we investigated regulation of il-15 induction by rhinovirus in human macrophages in vitro,il-15 levels in bronchoalveolar lavage (bal) fluid and il-15 induction by rhinovirus in bal macrophages from asthmatic and control subjects,and related these to outcomes of infection in vivo. rhinovirus induced il-15 in macrophages was replication-,nf-κb- and α/β interferon-dependent. bal macrophage il-15 induction by rhinovirus was impaired in asthmatics and inversely related to lower respiratory symptom severity during experimental rhinovirus infection. il-15 levels in bal fluid were also decreased in asthmatics and inversely related with airway hyperresponsiveness and with virus load during in vivo rhinovirus infection. deficient il-15 production in asthma may be important in the pathogenesis of asthma exacerbations. © 2011 laza-stanca et al.