title: Programmed cell death-1 expression correlates with disease severity and IL-5 in chronic rhinosinusitis with nasal polyps.
abstract: BACKGROUND
  Programmed cell death-1 (PD-1) is a negative regulator of T-cell responses. Expression of PD-1 and its ligands PD-L1 and PD-L2 in chronic rhinosinusitis with nasal polyps (CRSwNP) is poorly studied.
  
  
  METHODS
  Expression of PD-1, PD-L1, PD-L2, TGF-β, IL-5, and IL-10 mRNA was measured by real-time quantitative PCR on tissue homogenates of patients with CRSwNP (n = 21) and healthy controls (n = 21) and on primary epithelial cells. Disease severity was scored using the Lund-Mackay scores of maxillofacial computed tomography (CT) scans. Expression of PD-1 and PD-L1/L2 was evaluated at the cellular and tissue levels (n = 6) by flow cytometry and immunohistochemistry.
  
  
  RESULTS
  Programmed cell death-1 mRNA expression was increased in tissue homogenates from patients with CRSwNP compared with controls, irrespective of the atopy status. Importantly, expression of PD-1 correlated with the total CT scan scores (r = 0.5, P = 0.02). Additionally, a significant association was found between PD-1 mRNA and expression of IL-5 mRNA in control nasal tissue (r = 0.95, P < 0.0001) and in CRSwNP (r = 0.63, P = 0.002). PD-1 was expressed on different subsets of T cells and CD11b-dendritic cells. Both PD-1 and its ligands were expressed on primary epithelial cells from control nasal tissue and nasal polyp tissue.
  
  
  CONCLUSIONS
  Higher PD-1 expression was found in CRSwNP than in nasal tissue from controls. This was associated with disease severity and tissue IL-5 expression but unrelated to the patients' atopy status.
authors.affiliation: Laboratory of Clinical Immunology, Department of Microbiology & Immunology, University of Leuven, Leuven, Belgium.
authors.forename: I
authors.identifier: http://orcid.org/0000-0003-3649-1131
authors.initials: I
authors.lastname: Kortekaas Krohn
authors.affiliation: Laboratory of Clinical Immunology, Department of Microbiology & Immunology, University of Leuven, Leuven, Belgium.
authors.forename: S
authors.initials: S
authors.lastname: Bobic
authors.affiliation: Translational Immunology Laboratory, VIB, University of Leuven, Leuven, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Dooley
authors.affiliation: Upper Airway Research Laboratory, Department of Otorhinolaryngology, University Hospital Ghent, Ghent, Belgium.
authors.forename: F
authors.initials: F
authors.lastname: Lan
authors.affiliation: Upper Airway Research Laboratory, Department of Otorhinolaryngology, University Hospital Ghent, Ghent, Belgium.
authors.forename: N
authors.initials: N
authors.lastname: Zhang
authors.affiliation: Upper Airway Research Laboratory, Department of Otorhinolaryngology, University Hospital Ghent, Ghent, Belgium.
authors.forename: C
authors.identifier: http://orcid.org/0000-0003-4742-1665
authors.initials: C
authors.lastname: Bachert
authors.affiliation: Laboratory of Clinical Immunology, Department of Microbiology & Immunology, University of Leuven, Leuven, Belgium.
authors.forename: B
authors.initials: B
authors.lastname: Steelant
authors.affiliation: Pediatric Immunology, Department of Microbiology and Immunology, University of Leuven, Leuven, Belgium.|Clinical Department of Pediatrics, University Hospitals Leuven, Leuven, Belgium.
authors.forename: D M
authors.initials: DM
authors.lastname: Bullens
authors.affiliation: Translational Immunology Laboratory, VIB, University of Leuven, Leuven, Belgium.
authors.forename: A
authors.initials: A
authors.lastname: Liston
authors.affiliation: Laboratory of Clinical Immunology, Department of Microbiology & Immunology, University of Leuven, Leuven, Belgium.
authors.forename: J L
authors.initials: JL
authors.lastname: Ceuppens
authors.affiliation: Laboratory of Clinical Immunology, Department of Microbiology & Immunology, University of Leuven, Leuven, Belgium.
authors.forename: S F
authors.initials: SF
authors.lastname: Seys
authors.affiliation: Laboratory of Clinical Immunology, Department of Microbiology & Immunology, University of Leuven, Leuven, Belgium.|Clinical Division of Otorhinolaryngology, University Hospitals Leuven, Leuven, Belgium.|Clinical Division of Otorhinolaryngology, Academic Medical Centre, Amsterdam, The Netherlands.
authors.forename: P W
authors.initials: PW
authors.lastname: Hellings
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D002908:Chronic Disease; D003713:Dendritic Cells / Q000378:metabolism; D005260:Female; D006801:Humans; D015848:Interleukin-5 / Q000032:analysis* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D009298:Nasal Polyps / Q000150:complications / Q000473:pathology*; D061026:Programmed Cell Death 1 Receptor / Q000032:analysis* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis; D012220:Rhinitis; D012720:Severity of Illness Index; D012852:Sinusitis / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D013601:T-Lymphocytes / Q000378:metabolism
chemical_list: D015848:Interleukin-5; C105992:PDCD1 protein, human; D061026:Programmed Cell Death 1 Receptor; D012333:RNA, Messenger
keywords: chronic rhinosinusitis; interleukin-5; nasal polyps; programmed cell death-1; radiologic severity