title: Circulating CD4+CD25+ regulatory T cells in the pathobiology of ulcerative colitis and concurrent primary sclerosing cholangitis.
abstract: BACKGROUND
  Immunopathogenetic features of primary sclerosing cholangitis (PSC) in ulcerative colitis (UC) still remains unclear. Peripheral blood CD4+CD25+ regulatory T cells have a key role in the induction and maintenance of peripheral self-tolerance and inhibit several organ-specific autoimmune diseases. Therefore, CD4+CD25+ T cells are believed to play an essential role in autoimmune diseases. The aim of the present study is to analyze the role of CD4+CD25+ T cells in the pathogenesis of UC-associated PSC.
  
  
  METHODS
  This study evaluated the levels of CD4+CD25+ T cells in peripheral blood mononuclear cells (PBMC) of 27 UC patients with PSC and 20 UC patients as controls. CD4+CD25+ T cells were isolated from PBMC with a direct immunofluorescence technique, using mice monoclonal antibodies namely FITC-labeled anti-CD4 and PE-labeled anti-CD25. In each patient, CD4+CD25+ T cells percentage in PBMC were studied by flow cytometry, and then the number of CD4+CD25+ T cells were calculated.
  
  
  RESULTS
  Twenty-seven UC patients with PSC and 20 UC patients without PSC as controls were enrolled in the present study. The percentage of CD4+CD25+ regulatory T cells among PBMC were significantly elevated in UC + PSC patients compared with UC patients without PSC (p = 0.04).
  
  
  CONCLUSIONS
  CD4+CD25+ T cells were found to be elevated in UC patients with PSC suggesting a partial role of activated T cell response in the disease pathophysiology. Our findings imply that CD4+CD25+ regulatory T cells may play a key role in the immunopathogenesis of UC-associated PSC and may affect the therapeutic management of these diseases.
authors.affiliation: Department of Gastroenterology, Turkiye Yuksek Ihtisas Training and Research Hospital, Kızılay Sok. No: 2, 06100, Sıhhıye, Ankara, Turkey. drkekilli@gmail.com
authors.forename: Murat
authors.initials: M
authors.lastname: Kekilli
authors.forename: Bilge
authors.initials: B
authors.lastname: Tunc
authors.forename: Yavuz
authors.initials: Y
authors.lastname: Beyazit
authors.forename: Mevlut
authors.initials: M
authors.lastname: Kurt
authors.forename: Ibrahim Koral
authors.initials: IK
authors.lastname: Onal
authors.forename: Aysel
authors.initials: A
authors.lastname: Ulker
authors.forename: Ibrahim Celalettin
authors.initials: IC
authors.lastname: Haznedaroglu
mesh_terms: D000328:Adult; D018791:CD4 Lymphocyte Count; D016022:Case-Control Studies; D015209:Cholangitis, Sclerosing / Q000150:complications / Q000276:immunology*; D003093:Colitis, Ulcerative / Q000150:complications / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D050378:T-Lymphocytes, Regulatory / Q000502:physiology*; D055815:Young Adult