title: CD4+regulatory T cells in gastric cancer mucosa are proliferating and express high levels of IL-10 but little TGF-β.
abstract: BACKGROUND
  An increase of regulatory T cells, defined as CD25high- and/or FOXP3+-expressing CD4+T cells, within tumors has been reported in several studies. Tregs promote tumor growth by modulating the antitumor immune response, mainly through inhibition of T-cell-mediated tumor cell killing: this has been suggested to be dependent on IL-10 and/or TGF-β. In stomach cancer, the mechanisms behind the accumulation of Tregs in tumor tissue has not been fully elucidated, and neither has Treg gene expression in situ.
  
  
  METHODS
  Stomach tissue from gastric cancer patients undergoing gastric resection was analyzed using flow cytometry and cell sorting, followed by RT-PCR.
  
  
  RESULTS
  We observed that stomach CD4+FOXP3+T cells proliferated to a higher degree than CD4+FOXP3-T cells, which may contribute to Treg accumulation in the mucosa. By analyzing DNA methylation, we demonstrated that both proliferating and nonproliferating FOXP3+T cells exhibited complete demethylation of the FOXP3 gene, indicating a stable FOXP3 expression in both cell populations. Furthermore, analysis of T-cell populations isolated directly from the tumor and tumor-free mucosa demonstrated that CD4+CD25highT cells have a higher IL-10/IFN-γ gene expression ratio but express lower levels of TGF-β than CD4+CD25low/-T cells.
  
  
  CONCLUSIONS
  We demonstrate strong proliferation among regulatory CD4+FOXP3+CD25highT cells in the gastric cancer mucosa. These local Treg express a suppressive cytokine profile characterized by high IL-10 and low TGF-β and IFN-γ production.
authors.affiliation: Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Box 435, 40530, Gothenburg, Sweden.
authors.forename: Bert
authors.initials: B
authors.lastname: Kindlund
authors.affiliation: Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Box 435, 40530, Gothenburg, Sweden.
authors.forename: Åsa
authors.initials: Å
authors.lastname: Sjöling
authors.affiliation: Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Box 435, 40530, Gothenburg, Sweden.
authors.forename: Chakradhar
authors.initials: C
authors.lastname: Yakkala
authors.affiliation: Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Box 435, 40530, Gothenburg, Sweden.
authors.forename: Jenni
authors.initials: J
authors.lastname: Adamsson
authors.affiliation: Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Box 435, 40530, Gothenburg, Sweden.
authors.forename: Anders
authors.initials: A
authors.lastname: Janzon
authors.affiliation: Department of Gastro-Research, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Lars-Erik
authors.initials: LE
authors.lastname: Hansson
authors.affiliation: Department of Gastro-Research, Sahlgrenska University Hospital, Gothenburg, Sweden.
authors.forename: Michael
authors.initials: M
authors.lastname: Hermansson
authors.affiliation: Clinical Allergy Research Unit, Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Peter
authors.initials: P
authors.lastname: Janson
authors.affiliation: Clinical Allergy Research Unit, Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Ola
authors.initials: O
authors.lastname: Winqvist
authors.affiliation: Department of Microbiology and Immunology, Institute of Biomedicine, University of Gothenburg, Box 435, 40530, Gothenburg, Sweden. samuel.lundin@gu.se.
authors.forename: Samuel B
authors.identifier: http://orcid.org/0000-0002-4289-2321
authors.initials: SB
authors.lastname: Lundin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000235:genetics; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D049109:Cell Proliferation; D019175:DNA Methylation; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D051858:Forkhead Transcription Factors / Q000378:metabolism; D005753:Gastric Mucosa / Q000276:immunology*; D006801:Humans; D016753:Interleukin-10 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000097:blood / Q000235:genetics / Q000276:immunology* / Q000473:pathology*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D016212:Transforming Growth Factor beta / Q000235:genetics*; D014407:Tumor Cells, Cultured
chemical_list: D014408:Biomarkers, Tumor; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C508609:IL10 protein, human; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; D016753:Interleukin-10
keywords: Gastric cancer; Helicobacter pylori; IL-10; Proliferation; Regulatory T cell