title: IFN-γ-Producing T-Helper 17.1 Cells Are Increased in Sarcoidosis and Are More Prevalent than T-Helper Type 1 Cells.
abstract: Pulmonary sarcoidosis is classically defined by T-helper (Th) cell type 1 inflammation (e.g., IFN-γ production by CD4(+) effector T cells). Recently, IL-17A-secreting cells have been found in lung lavage, invoking Th17 immunity in sarcoidosis. Studies also identified IL-17A-secreting cells that expressed IFN-γ, but their abundance as a percentage of total CD4(+) cells was either low or undetermined.
  
  
  
  Based on evidence that Th17 cells can be polarized to Th17.1 cells to produce only IFN-γ, our goal was to determine whether Th17.1 cells are a prominent source of IFN-γ in sarcoidosis.
  
  
  
  We developed a single-cell approach to define and isolate major Th-cell subsets using combinations of chemokine receptors and fluorescence-activated cell sorting. We subsequently confirmed the accuracy of subset enrichment by measuring cytokine production.
  
  
  
  Discrimination between Th17 and Th17.1 cells revealed very high percentages of Th17.1 cells in lung lavage in sarcoidosis compared with controls in two separate cohorts. No differences in Th17 or Th1 lavage cells were found compared with controls. Lung lavage Th17.1-cell percentages were also higher than Th1-cell percentages, and approximately 60% of Th17.1-enriched cells produced only IFN-γ.
  
  
  
  Combined use of surface markers and functional assays to study CD4(+) T cells in sarcoidosis revealed a marked expansion of Th17.1 cells that only produce IFN-γ. These results suggest that Th17.1 cells could be misclassified as Th1 cells and may be the predominant producer of IFN-γ in pulmonary sarcoidosis, challenging the Th1 paradigm of pathogenesis.
authors.affiliation: 1 Division of Pulmonary and Critical Care, Department of Medicine.
authors.forename: Joris
authors.initials: J
authors.lastname: Ramstein
authors.affiliation: 4 Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, California; and.
authors.forename: Caroline E
authors.initials: CE
authors.lastname: Broos
authors.affiliation: 3 Department of Microbiology and Immunology, and.|2 Department of Pulmonary Medicine, Erasmus MC, Rotterdam, the Netherlands.
authors.forename: Laura J
authors.initials: LJ
authors.lastname: Simpson
authors.affiliation: 3 Department of Microbiology and Immunology, and.|2 Department of Pulmonary Medicine, Erasmus MC, Rotterdam, the Netherlands.
authors.forename: K Mark
authors.initials: KM
authors.lastname: Ansel
authors.affiliation: 1 Division of Pulmonary and Critical Care, Department of Medicine.
authors.forename: Sara A
authors.initials: SA
authors.lastname: Sun
authors.affiliation: 1 Division of Pulmonary and Critical Care, Department of Medicine.
authors.forename: Melissa E
authors.initials: ME
authors.lastname: Ho
authors.affiliation: 1 Division of Pulmonary and Critical Care, Department of Medicine.
authors.forename: Prescott G
authors.initials: PG
authors.lastname: Woodruff
authors.affiliation: 1 Division of Pulmonary and Critical Care, Department of Medicine.
authors.forename: Nirav R
authors.initials: NR
authors.lastname: Bhakta
authors.affiliation: 3 Department of Microbiology and Immunology, and.|2 Department of Pulmonary Medicine, Erasmus MC, Rotterdam, the Netherlands.
authors.forename: Laura
authors.initials: L
authors.lastname: Christian
authors.affiliation: 1 Division of Pulmonary and Critical Care, Department of Medicine.
authors.forename: Christine P
authors.initials: CP
authors.lastname: Nguyen
authors.affiliation: 1 Division of Pulmonary and Critical Care, Department of Medicine.
authors.forename: Bobby J
authors.initials: BJ
authors.lastname: Antalek
authors.affiliation: 1 Division of Pulmonary and Critical Care, Department of Medicine.
authors.forename: Bryan S
authors.initials: BS
authors.lastname: Benn
authors.affiliation: 4 Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, California; and.
authors.forename: Rudi W
authors.initials: RW
authors.lastname: Hendriks
authors.affiliation: 4 Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, California; and.
authors.forename: Bernt
authors.initials: B
authors.lastname: van den Blink
authors.affiliation: 4 Sandler Asthma Basic Research Center, University of California, San Francisco, San Francisco, California; and.
authors.forename: Mirjam
authors.initials: M
authors.lastname: Kool
authors.affiliation: 1 Division of Pulmonary and Critical Care, Department of Medicine.
authors.forename: Laura L
authors.identifier: 0000-0001-9541-3622
authors.initials: LL
authors.lastname: Koth
mesh_terms: D000328:Adult; D000368:Aged; D001992:Bronchoalveolar Lavage Fluid / Q000276:immunology; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology* / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D017565:Sarcoidosis, Pulmonary / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology* / Q000378:metabolism; D058504:Th17 Cells / Q000276:immunology* / Q000378:metabolism
chemical_list: D007371:Interferon-gamma
keywords: chemokine receptor; inflammation; lymphocyte