title: DNA methylation, bacteria and airway inflammation: latest insights.
abstract: OBJECTIVE
  DNA methylation is an epigenetic mechanism that has been implicated in the pathogenesis of chronic inflammatory diseases by regulating differentiation, proliferation, apoptosis, and activation of immune cells. Changes in the methylation status of relevant genes have been linked to the origin, perpetuation, and severity of airway diseases. The DNA methylation profile can be also modified by the action of viral and bacterial colonization. Bacteria and specially Staphylococcus aureus toxins are recognized inflammatory amplifying factors in both lower and upper airway chronic diseases. This review summarizes the existent knowledge about the role of DNA methylation changes in chronic airway diseases and the contribution of bacterial infection on this event.
  
  
  RESULTS
  It has been demonstrated that changes in DNA methylation, either intrinsic or induced by allergen or infection, may be linked to the pathogenesis of asthma and allergy. These changes in methylation may suppress the production of anti-inflammatory mediators and increase the survival and activation of pro-inflammatory cells, as well as modify the immune response in response to bacterial infection, increasing their survival and pathogenicity within the infected organism.
  
  
  CONCLUSIONS
  Understanding the intrinsic epigenetic mechanisms, as well as the effect of environment -for example, bacterial infection in the pathogenesis of airways diseases - will greatly improve the management and the diagnosis of these diseases.
authors.affiliation: Upper Airways Research Laboratory, Department of Otolaryngology, Ghent University Hospital, Ghent, Belgium.
authors.forename: Claudina A
authors.initials: CA
authors.lastname: Pérez-Novo
authors.forename: Claus
authors.initials: C
authors.lastname: Bachert
mesh_terms: D000818:Animals; D001427:Bacterial Toxins / Q000276:immunology; D019175:DNA Methylation; D044127:Epigenesis, Genetic / Q000276:immunology*; D006801:Humans; D007109:Immunity; D007249:Inflammation / Q000235:genetics; D012140:Respiratory Tract Diseases / Q000209:etiology / Q000235:genetics / Q000276:immunology*; D013203:Staphylococcal Infections / Q000150:complications / Q000235:genetics / Q000276:immunology*; D013211:Staphylococcus aureus / Q000276:immunology*
chemical_list: D001427:Bacterial Toxins