title: Reduced FOXP3(+) regulatory T cells in patients with primary sclerosing cholangitis are associated with IL2RA gene polymorphisms.
abstract: OBJECTIVE
  Recently, genome wide association studies in primary sclerosing cholangitis (PSC) revealed associations with gene polymorphisms that potentially could affect the function of regulatory T cells (Treg). The aim of this study was to investigate Treg in patients with PSC and to associate their numbers with relevant gene polymorphisms.
  
  
  METHODS
  Treg frequency in blood was assessed by staining for CD4(+)CD25(high)FOXP3(+)CD127(low) lymphocytes and determination of Treg-specific FOXP3 gene locus demethylation. Single nucleotide polymorphisms (SNP) in the interleukin-2 receptor alpha (IL2RA), the interleukin-2 (IL2) and interleukin-21 (IL21) gene locus were analysed. Liver biopsies taken at the time of diagnosis were stained for FOXP3 and CD3. Treg function was assessed in a CFSE-based suppression assay.
  
  
  RESULTS
  The frequency of Treg in peripheral blood of PSC patients was significantly decreased. We confirmed this finding by demonstrating a reduction of non-methylated DNA in the Treg-specific demethylated FOXP3 gene region of peripheral blood cells in PSC patients. Reduced peripheral Treg numbers were significantly associated with homozygosity for the major allele of the SNP "rs10905718" in the IL2RA gene. Intrahepatic FOXP3(+) cell numbers at the time of initial diagnosis were decreased in PSC as compared to PBC. In addition to reduced numbers, the suppressive capacity of Treg isolated from PSC patients seemed to be impaired as compared to healthy controls.
  
  
  CONCLUSIONS
  Our findings indicate that Treg impairment may play a role in the immune dysregulation observed in PSC. Reduced Treg numbers in patients with PSC are associated with polymorphisms in the IL2RA gene.
authors.affiliation: I. Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Marcial
authors.initials: M
authors.lastname: Sebode
authors.affiliation: I. Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Peiseler
authors.affiliation: I. Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Björn
authors.initials: B
authors.lastname: Franke
authors.affiliation: I. Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Dorothee
authors.initials: D
authors.lastname: Schwinge
authors.affiliation: I. Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Tanja
authors.initials: T
authors.lastname: Schoknecht
authors.affiliation: I. Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Frederike
authors.initials: F
authors.lastname: Wortmann
authors.affiliation: Department of Pathology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Quaas
authors.affiliation: Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, Kiel, Germany.
authors.forename: Britt-Sabina
authors.initials: BS
authors.lastname: Petersen
authors.affiliation: Institute of Clinical Molecular Biology, Christian-Albrechts-University of Kiel, Kiel, Germany.
authors.forename: Eva
authors.initials: E
authors.lastname: Ellinghaus
authors.affiliation: Epiontis GmbH, Berlin, Germany.
authors.forename: Udo
authors.initials: U
authors.lastname: Baron
authors.affiliation: Epiontis GmbH, Berlin, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Olek
authors.affiliation: I. Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Wiegard
authors.affiliation: I. Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Christina
authors.initials: C
authors.lastname: Weiler-Normann
authors.affiliation: I. Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Ansgar W
authors.initials: AW
authors.lastname: Lohse
authors.affiliation: I. Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Herkel
authors.affiliation: I. Department of Medicine, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany. Electronic address: cschramm@uke.de.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schramm
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018791:CD4 Lymphocyte Count; D016022:Case-Control Studies; D015209:Cholangitis, Sclerosing / Q000097:blood / Q000235:genetics* / Q000276:immunology*; D005260:Female; D051858:Forkhead Transcription Factors / Q000097:blood* / Q000235:genetics; D006720:Homozygote; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000235:genetics*; D008099:Liver / Q000276:immunology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism* / Q000473:pathology; D055815:Young Adult
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C508017:IL2RA protein, human; D053645:Interleukin-2 Receptor alpha Subunit
keywords: Cholangitis; IL2RA; Immune regulation; Primary sclerosing cholangitis; Treg