title: Expression of Toll-like receptor 9 in nose, peripheral blood and bone marrow during symptomatic allergic rhinitis.
abstract: BACKGROUND
  Allergic rhinitis is an inflammatory disease of the upper airway mucosa that also affects leukocytes in bone marrow and peripheral blood. Toll-like receptor 9 (TLR9) is a receptor for unmethylated CpG dinucleotides found in bacterial and viral DNA. The present study was designed to examine the expression of TLR9 in the nasal mucosa and in leukocytes derived from different cellular compartments during symptomatic allergic rhinitis.
  
  
  METHODS
  The study was based on 32 patients with seasonal allergic rhinitis and 18 healthy subjects, serving as controls. Nasal biopsies were obtained before and after allergen challenge. Bone marrow, peripheral blood and nasal lavage fluid were sampled outside and during pollen season. The expression of TLR9 in tissues and cells was analyzed using immunohistochemistry and flow cytometry, respectively.
  
  
  RESULTS
  TLR9 was found in several cell types in the nasal mucosa and in different leukocyte subpopulations derived from bone marrow, peripheral blood and nasal lavage fluid. The leukocyte expression was generally higher in bone marrow than in peripheral blood, and not affected by symptomatic allergic rhinitis.
  
  
  CONCLUSIONS
  The widespread expression of TLR9 in the nasal mucosa along with its rich representation in leukocytes in different compartments, demonstrate the possibility for cells involved in allergic airway inflammation to directly interact with bacterial and viral DNA.
authors.affiliation: Laboratory of Clinical and Experimental Allergy Research, Department of Oto-Rhino-Laryngology, Malmö University Hospital, Lund University, Malmö, Sweden. Mattias.Fransson@med.lu.se
authors.forename: Mattias
authors.initials: M
authors.lastname: Fransson
authors.forename: Mikael
authors.initials: M
authors.lastname: Benson
authors.forename: Jonas S
authors.initials: JS
authors.lastname: Erjefält
authors.forename: Lennart
authors.initials: L
authors.lastname: Jansson
authors.forename: Rolf
authors.initials: R
authors.lastname: Uddman
authors.forename: Sven
authors.initials: S
authors.lastname: Björnsson
authors.forename: Lars-Olaf
authors.initials: LO
authors.lastname: Cardell
authors.forename: Mikael
authors.initials: M
authors.lastname: Adner
mesh_terms: D000293:Adolescent; D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D001853:Bone Marrow / Q000378:metabolism*; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000378:metabolism*; D006255:Rhinitis, Allergic, Seasonal / Q000378:metabolism*; D051217:Toll-Like Receptor 9 / Q000378:metabolism*
chemical_list: D015415:Biomarkers; C495371:TLR9 protein, human; D051217:Toll-Like Receptor 9