title: Immunological pathways in virus-induced COPD exacerbations: a role for IL-15.
abstract: BACKGROUND
  Chronic obstructive pulmonary disease (COPD) is characterized by high levels of antiviral type 1 cytokine interferon-γ and activated CD8(+) T cells. COPD exacerbations are the major cause of morbidity and mortality, have a prolonged and intense effect on quality of life and may result in accelerated loss of lung function. Respiratory virus infections, frequently within a state of colonization by bacteria, are the major cause of COPD exacerbations, and there is also evidence of virus latency in 'stable' disease, suggesting that latent infection might be a cause of chronic inflammation in COPD.
  
  
  METHODS
  This is an update of current literature concerning the role of interleukin-15 and major histocompatibility complex class I-related chain A and B molecules in type 1 immune responses, particularly to respiratory virus infections, which are the main cause of COPD exacerbations. We also present data from our own group suggesting a role for interleukin-15 in virus-induced COPD exacerbations.
  
  
  RESULTS
  Type 1 cytokine interleukin-15 is produced by resident airway cells (epithelial cells and macrophages) in response to virus infection and bacteria. Virus infections modulate major histocompatibility complex class I-related chain A and B molecules in respiratory epithelial cells.
  
  
  CONCLUSIONS
  Interleukin-15 could play a major role in the airway inflammation in COPD directly, via its own receptors, by amplifying the type 1 immune responses and decreasing apoptosis or indirectly, via modulating molecules associated with cytotoxic activity of natural killer and CD8(+) T cells, such as major histocompatibility complex class I-related chain A and B.
authors.affiliation: Oncology Institute Prof. Dr. Ion Chiricuta, Department of Hematology and University of Medicine and Pharmacy Cluj-Napoca, Romania. mzdrenghea@umfcluj.ro
authors.forename: Mihnea T
authors.initials: MT
authors.lastname: Zdrenghea
authors.forename: Patrick
authors.initials: P
authors.lastname: Mallia
authors.forename: Sebastian L
authors.initials: SL
authors.lastname: Johnston
mesh_terms: D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D018450:Disease Progression; D015395:Histocompatibility Antigens Class I; D006801:Humans; D019409:Interleukin-15 / Q000276:immunology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000276:immunology / Q000821:virology*; D020545:Respiratory Mucosa / Q000276:immunology*; D014777:Virus Diseases / Q000276:immunology*
chemical_list: D015395:Histocompatibility Antigens Class I; D019409:Interleukin-15; C099187:MHC class I-related chain A; C098080:MICB antigen