title: Impact of endobronchial allergen provocation on macrophage phenotype in asthmatics.
abstract: BACKGROUND
  The role of M2 polarized macrophages (MΦ) during the allergic airway inflammation has been discussed in various animal models. However, their presence and relevance during the chronic and acute phase of allergic airway inflammation in humans has not been fully elucidated so far. In the present study we phenotypically characterized macrophages with regard to M2 polarization in mice, a human in vitro and a human ex vivo model with primary lung cells after endobronchial provocation.
  
  
  RESULTS
  Macrophages remained polarized beyond clearance of the acute allergic airway inflammation in mice. Alveolar macrophages of asthmatics revealed increased mRNA expression of CCL13, CCL17 and CLEC10A in response to allergen challenge as well as increased surface expression of CD86. Further, mRNA expression of CCL13, CCL17, and CLEC10A was increased in asthmatics at baseline compared to healthy subjects. The mRNA expression of CCL17 and CLEC10A correlated significantly with the degree of eosinophilia (each P < .01). Furthermore, macrophages from asthmatics released significant amounts of CCL17 protein in vitro which was also found increased in BAL fluid after allergen provocation.
  
  
  CONCLUSIONS
  This study supports previous findings of M2 macrophage polarization in asthmatic subjects during the acute course of the allergic inflammation and provides evidence for their contribution to the Th2 inflammation.
authors.forename: Carla
authors.initials: C
authors.lastname: Winkler
authors.forename: Lena
authors.initials: L
authors.lastname: Witte
authors.forename: Natali
authors.initials: N
authors.lastname: Moraw
authors.forename: Conny
authors.initials: C
authors.lastname: Faulenbach
authors.forename: Meike
authors.initials: M
authors.lastname: Müller
authors.forename: Olaf
authors.initials: O
authors.lastname: Holz
authors.forename: Frank
authors.initials: F
authors.lastname: Schaumann
authors.affiliation: Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany. jens.hohlfeld@item.fraunhofer.de.
authors.forename: Jens M
authors.initials: JM
authors.lastname: Hohlfeld
mesh_terms: D000328:Adult; D000485:Allergens / Q000276:immunology; D000818:Animals; D001249:Asthma / Q000235:genetics / Q000276:immunology* / Q000378:metabolism* / Q000503:physiopathology; D015415:Biomarkers; D001985:Bronchial Provocation Tests; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D004195:Disease Models, Animal; D005260:Female; D015870:Gene Expression; D006801:Humans; D008168:Lung / Q000276:immunology / Q000503:physiopathology; D008213:Lymphocyte Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism*; D016676:Macrophages, Alveolar / Q000276:immunology / Q000378:metabolism; D008297:Male; D051379:Mice; D008875:Middle Aged
chemical_list: D000485:Allergens; D015415:Biomarkers