title: Cysteinyl leukotriene receptors are expressed by tonsillar T cells of children with obstructive sleep apnea.
abstract: BACKGROUND
  Increased expression of cysteinyl leukotriene receptors (cysteinyl leukotriene receptor-1 [LT1-R]; cysteinyl leukotriene receptor-2 [LT2-R]) has been detected in adenotonsillar tissue from children with sleep-disordered breathing (SDB) compared to control subjects. LT1-R has been localized in myeloperoxidase-positive cells. This phenomenon possibly contributes to lymphoid tissue enlargement and may be related to systemic inflammation.
  
  
  OBJECTIVE
  To characterize cells expressing LT1-R and LT2-R in tonsillar tissue and assess serum C-reactive protein (CRP) levels in children with and without SDB.
  
  
  METHODS
  Immunohistochemistry with LT1-R and LT2-R antibodies was used to examine tonsils from children who had tonsillectomy (with or without adenoidectomy) for SDB and from control subjects operated for recurrent tonsillitis/otitis. All participants underwent preoperative polysomnography and measurement of morning serum CRP.
  
  
  RESULTS
  Fifteen children with SDB (mean age +/- SD, 6.4 +/- 2.1 years; apnea-hypopnea index, 9.6 +/- 5.6 episodes per hour) and 11 control subjects (age, 7.5 +/- 2.8 years; apnea-hypopnea index, 7 +/- 0.3/h) were examined. Immunoreactivity for LT1-R and LT2-R was detected in tonsillar extrafollicular areas of all subjects with SDB but not of control subjects. Cells expressing leukotriene receptors were CD3+ lymphocytes. Children with SDB and control subjects were similar regarding CRP levels: 0.11 +/- 0.15 mg/dL vs 0.09 +/- 0.15 mg/dL, respectively (p > 0.05).
  
  
  CONCLUSIONS
  Tonsils of children with SDB but not of control subjects have enhanced expression of cysteinyl leukotriene receptors in T lymphocytes without an associated increase in serum CRP concentration. Up-regulation of LT1-R and LT2-R could potentially promote tonsillar enlargement in children with obstructive sleep apnea.
authors.affiliation: Sleep Disorders Laboratory, University of Thessaly School of Medicine and Larissa University Hospital, Larissa, Greece. Electronic address: KADITIA@hotmail.com.
authors.forename: Athanasios G
authors.initials: AG
authors.lastname: Kaditis
authors.affiliation: Department of Pathology, University of Thessaly School of Medicine and Larissa University Hospital, Larissa, Greece.
authors.forename: Maria G
authors.initials: MG
authors.lastname: Ioannou
authors.affiliation: Sleep Disorders Laboratory, University of Thessaly School of Medicine and Larissa University Hospital, Larissa, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Chaidas
authors.affiliation: Sleep Disorders Laboratory, University of Thessaly School of Medicine and Larissa University Hospital, Larissa, Greece.
authors.forename: Emmanouel I
authors.initials: EI
authors.lastname: Alexopoulos
authors.affiliation: Department of Otorhinolaryngology, University of Thessaly School of Medicine and Larissa University Hospital, Larissa, Greece.
authors.forename: Maria
authors.initials: M
authors.lastname: Apostolidou
authors.affiliation: Department of Otorhinolaryngology, University of Thessaly School of Medicine and Larissa University Hospital, Larissa, Greece.
authors.forename: Theoharis
authors.initials: T
authors.lastname: Apostolidis
authors.affiliation: Department of Pathology, University of Thessaly School of Medicine and Larissa University Hospital, Larissa, Greece.
authors.forename: George
authors.initials: G
authors.lastname: Koukoulis
authors.affiliation: Sleep Disorders Laboratory, University of Thessaly School of Medicine and Larissa University Hospital, Larissa, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Gourgoulianis
mesh_terms: D002097:C-Reactive Protein / Q000378:metabolism; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D014066:Palatine Tonsil / Q000378:metabolism* / Q000473:pathology; D018077:Receptors, Leukotriene / Q000378:metabolism*; D020181:Sleep Apnea, Obstructive / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D013601:T-Lymphocytes / Q000502:physiology*; D014068:Tonsillectomy
chemical_list: D018077:Receptors, Leukotriene; D002097:C-Reactive Protein; C412375:cysteinyl leukotriene receptor 2; C083169:leukotriene D4 receptor