title: Characterization and Quantification of Innate Lymphoid Cell Subsets in Human Lung.
abstract: BACKGROUND
  Innate lymphoid cells (ILC) are a new family of innate immune cells that have emerged as important regulators of tissue homeostasis and inflammation. However, limited data are available concerning the relative abundance and characteristics of ILC in the human lung.
  
  
  METHODS
  The aim of this study was to characterize and enumerate the different ILC subsets in human lung by multi-color flow cytometry.
  
  
  RESULTS
  Within the CD45+ Lin- CD127+ pulmonary ILC population, we identified group 1 (ILC1), group 2 (ILC2) and group 3 (ILC3) innate lymphoid cells using specific surface markers (i.e. IL12Rβ2, CRTH2 and CD117 respectively) and key transcription factors (i.e. T-bet, GATA-3 and RORγT respectively). Based on the presence of NKp44, ILC3 were further subdivided in natural cytotoxicity receptor (NCR)+ and NCR- ILC3. In addition, we demonstrated the production of signature cytokines IFN-γ, IL-5, IL-17A, IL-22 and GM-CSF in the pulmonary ILC population. Interestingly, we observed a tendency to a higher frequency of NCR- ILC3 in lungs of patients with chronic obstructive pulmonary disease (COPD) compared with controls.
  
  
  CONCLUSIONS
  We show that the three main ILC subsets are present in human lung. Importantly, the relative abundance of ILC subsets tended to change in COPD patients in comparison to control individuals.
authors.affiliation: Department of Respiratory Medicine, Laboratory for Translational Research in Obstructive Pulmonary Diseases, Ghent University Hospital, Ghent, Belgium.
authors.forename: Katrien C
authors.initials: KC
authors.lastname: De Grove
authors.affiliation: Department of Respiratory Medicine, Laboratory for Translational Research in Obstructive Pulmonary Diseases, Ghent University Hospital, Ghent, Belgium.
authors.forename: Sharen
authors.initials: S
authors.lastname: Provoost
authors.affiliation: Department of Respiratory Medicine, Laboratory for Translational Research in Obstructive Pulmonary Diseases, Ghent University Hospital, Ghent, Belgium.
authors.forename: Fien M
authors.initials: FM
authors.lastname: Verhamme
authors.affiliation: Department of Respiratory Medicine, Laboratory for Translational Research in Obstructive Pulmonary Diseases, Ghent University Hospital, Ghent, Belgium.
authors.forename: Ken R
authors.initials: KR
authors.lastname: Bracke
authors.affiliation: Department of Respiratory Medicine, Laboratory for Translational Research in Obstructive Pulmonary Diseases, Ghent University Hospital, Ghent, Belgium.
authors.forename: Guy F
authors.initials: GF
authors.lastname: Joos
authors.affiliation: Department of Respiratory Medicine, Laboratory for Translational Research in Obstructive Pulmonary Diseases, Ghent University Hospital, Ghent, Belgium.
authors.forename: Tania
authors.initials: T
authors.lastname: Maes
authors.affiliation: Department of Respiratory Medicine, Laboratory for Translational Research in Obstructive Pulmonary Diseases, Ghent University Hospital, Ghent, Belgium.
authors.forename: Guy G
authors.initials: GG
authors.lastname: Brusselle
mesh_terms: D000368:Aged; D016207:Cytokines / Q000096:biosynthesis; D005260:Female; D006801:Humans; D007113:Immunity, Innate; D017493:Leukocyte Common Antigens / Q000276:immunology; D008168:Lung / Q000276:immunology*; D016131:Lymphocyte Subsets; D008297:Male; D008875:Middle Aged
chemical_list: D016207:Cytokines; D017493:Leukocyte Common Antigens