title: Lymphocyte subsets and the role of TH1/TH2 balance in stressed chronic pain patients.
abstract: BACKGROUND
  The complex regional pain syndrome (CRPS) and fibromyalgia (FM) are chronic pain syndromes occurring in highly stressed individuals. Despite the known connection between the nervous system and immune cells, information on distribution of lymphocyte subsets under stress and pain conditions is limited.
  
  
  METHODS
  We performed a comparative study in 15 patients with CRPS type I, 22 patients with FM and 37 age- and sex-matched healthy controls and investigated the influence of pain and stress on lymphocyte number, subpopulations and the Th1/Th2 cytokine ratio in T lymphocytes.
  
  
  RESULTS
  Lymphocyte numbers did not differ between groups. Quantitative analyses of lymphocyte subpopulations showed a significant reduction of cytotoxic CD8+ lymphocytes in both CRPS (p < 0.01) and FM (p < 0.05) patients as compared with healthy controls. Additionally, CRPS patients were characterized by a lower percentage of IL-2-producing T cell subpopulations reflecting a diminished Th1 response in contrast to no changes in the Th2 cytokine profile.
  
  
  CONCLUSIONS
  Future studies are warranted to answer whether such immunological changes play a pathogenetic role in CRPS and FM or merely reflect the consequences of a pain-induced neurohumoral stress response, and whether they contribute to immunosuppression in stressed chronic pain patients.
authors.affiliation: Department of Anesthesiology, Klinikum Grosshadern, Ludwig Maximilians University, Munich, Germany.
authors.forename: Ines
authors.initials: I
authors.lastname: Kaufmann
authors.forename: Christoph
authors.initials: C
authors.lastname: Eisner
authors.forename: Peter
authors.initials: P
authors.lastname: Richter
authors.forename: Volker
authors.initials: V
authors.lastname: Huge
authors.forename: Antje
authors.initials: A
authors.lastname: Beyer
authors.forename: Alexander
authors.initials: A
authors.lastname: Chouker
authors.forename: Gustav
authors.initials: G
authors.lastname: Schelling
authors.forename: Manfred
authors.initials: M
authors.lastname: Thiel
mesh_terms: D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002908:Chronic Disease / Q000523:psychology; D015536:Down-Regulation / Q000276:immunology; D005260:Female; D005356:Fibromyalgia / Q000276:immunology* / Q000503:physiopathology / Q000523:psychology; D006801:Humans; D007376:Interleukin-2 / Q000097:blood / Q000276:immunology; D018655:Lymphocyte Count; D008297:Male; D008875:Middle Aged; D015213:Neuroimmunomodulation / Q000276:immunology; D012019:Reflex Sympathetic Dystrophy / Q000276:immunology* / Q000503:physiopathology / Q000523:psychology; D013315:Stress, Psychological / Q000150:complications* / Q000276:immunology* / Q000503:physiopathology; D018417:Th1 Cells / Q000276:immunology*; D018418:Th2 Cells / Q000276:immunology*
chemical_list: D007376:Interleukin-2