title: Impact of chemotherapy for colorectal cancer on regulatory T-cells and tumor immunity.
abstract: BACKGROUND
  Regulatory T-cells (Tregs) actively engage in the maintenance of immunological self-tolerance and immune homeostasis. The purpose of the present study was to determine how oxaliplatin plus infusional 5-fluorouracil and leucovorin (FOLFOX) and irinotecan plus infusional 5-fluorouracil and leucovorin (FOLFIRI) affect Tregs and other immune effectors.
  
  
  METHODS
  A total of 27 patients with metastatic colorectal cancer received the FOLFOX (n=17) or FOLFIRI (n=10) chemotherapeutic regimen. Blood samples were collected from patients before and 7 days after chemotherapy. The prevalence of Tregs co-expressing CD4(+)FoxP3(+) was analyzed with flow cytometry.
  
  
  RESULTS
  The percentage and the number of CD4(+)FoxP3(+) Tregs were significantly reduced after FOLFOX and FOLFIRI in the patients who had high levels of Tregs before chemotherapy. On the other hand, the total number of lymphocytes and the population of CD4(+) T lymphocytes were unchanged.
  
  
  CONCLUSIONS
  FOLFOX and FOLFIRI may enhance antitumor immunity via suppression of Tregs.
authors.affiliation: Department of Digestive Surgery and Surgical Oncology, Yamaguchi University Graduate School of Medicine, 1-1-1 Minamikogushi, Ube city, Yamaguchi Prefecture 755-8505, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Maeda
authors.forename: Shoichi
authors.initials: S
authors.lastname: Hazama
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Tokuno
authors.forename: Shin
authors.initials: S
authors.lastname: Kan
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Maeda
authors.forename: Yusaku
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Ryoji
authors.initials: R
authors.lastname: Kamei
authors.forename: Yoshitaro
authors.initials: Y
authors.lastname: Shindo
authors.forename: Noriko
authors.initials: N
authors.lastname: Maeda
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Yoshimura
authors.forename: Shigefumi
authors.initials: S
authors.lastname: Yoshino
authors.forename: Masaaki
authors.initials: M
authors.lastname: Oka
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000276:immunology*; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D051858:Forkhead Transcription Factors / Q000096:biosynthesis; D006801:Humans; D007167:Immunotherapy / Q000379:methods; D002955:Leucovorin / Q000008:administration & dosage; D008297:Male; D008875:Middle Aged; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D000970:Antineoplastic Agents; C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; D002955:Leucovorin; D005472:Fluorouracil