title: Reduced mucosal associated invariant T-cells are associated with increased disease severity and Pseudomonas aeruginosa infection in cystic fibrosis.
abstract: BACKGROUND
  Primary defects in host immune responses have been hypothesised to contribute towards an inability of subjects with cystic fibrosis (CF) to effectively clear pulmonary infections. Innate T-lymphocytes provide rapid pathogen-specific responses prior to the development of classical MHC class I and II restricted T-cell responses and are essential to the initial control of pulmonary infection. We aimed to examine the relationship between peripheral blood lymphocyte phenotype and clinical outcomes in adults with CF.
  
  
  METHODS
  We studied 41 subjects with CF and 22, age matched, non-smoking healthy control subjects. Lymphocytes were extracted from peripheral blood samples and phenotyped by flow-cytometry. Lymphocyte phenotype was correlated with sputum microbiology and clinical parameters.
  
  
  RESULTS
  In comparison to healthy control subjects, mucosal associated invariant T (MAIT)-lymphocytes were significantly reduced in the peripheral blood of subjects with CF (1.1% versus 2.0% of T-lymphocytes, P = 0.002). MAIT cell concentration was lowest in CF subjects infected with P. aeruginosa and in subjects receiving treatment for a pulmonary exacerbation. Furthermore a reduced MAIT cell concentration correlated with severity of lung disease.
  
  
  CONCLUSIONS
  Reduced numbers of MAIT cells in subjects with CF were associated with P. aeruginosa pulmonary infection, pulmonary exacerbations and more severe lung disease. These findings provide the impetus for future studies examining the utility of MAIT cells in immunotherapies and vaccine development. Longitudinal studies of MAIT cells as biomarkers of CF pulmonary infection are awaited.
authors.affiliation: Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, Queensland, Australia; School of Medicine, University of Queensland, Brisbane, Queensland, Australia; Infection and Inflammation Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Smith
authors.affiliation: Bone Marrow Transplant Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
authors.forename: Geoffrey R
authors.initials: GR
authors.lastname: Hill
authors.affiliation: Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, Queensland, Australia; School of Medicine, University of Queensland, Brisbane, Queensland, Australia; Queensland Children's Medical Research Institute, Royal Children's Hospital, Brisbane, Queensland, Australia.
authors.forename: Scott C
authors.initials: SC
authors.lastname: Bell
authors.affiliation: Department of Thoracic Medicine, The Prince Charles Hospital, Brisbane, Queensland, Australia; School of Medicine, University of Queensland, Brisbane, Queensland, Australia; Infection and Inflammation Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Queensland, Australia.
authors.forename: David W
authors.initials: DW
authors.lastname: Reid
mesh_terms: D000293:Adolescent; D000328:Adult; D016022:Case-Control Studies; D003550:Cystic Fibrosis / Q000276:immunology* / Q000382:microbiology*; D005260:Female; D006801:Humans; D008168:Lung / Q000276:immunology / Q000382:microbiology; D008297:Male; D009092:Mucous Membrane / Q000276:immunology; D010641:Phenotype; D011550:Pseudomonas aeruginosa / Q000502:physiology*; D016176:T-Lymphocyte Subsets / Q000166:cytology / Q000276:immunology; D013601:T-Lymphocytes / Q000166:cytology* / Q000276:immunology; D055815:Young Adult