title: Apoptosis-induced decrease of intrathyroidal CD4(+)CD25(+) regulatory T cells in autoimmune thyroid diseases.
abstract: BACKGROUND
  We previously showed that the proportion of CD4(+) T cells was lower and both the proportion and intensity of Fas expression on intrathyroidal CD4(+) T cells were higher in the thyroid than in the peripheral blood of patients with autoimmune thyroid disease (AITD).
  
  
  OBJECTIVE
  To clarify whether the intrathyroidal CD4(+)CD25(+) regulatory T (Treg) cells are decreased by Fas-mediated apoptosis in patients with AITD.
  
  
  METHODS
  We examined intrathyroidal and peripheral lymphocytes in 20 patients with AITD (15 patients with Gravesâ disease and five patients with Hashimotoâs disease) and peripheral lymphocytes in 10 healthy volunteers by three-color flow cytometry.
  
  
  RESULTS
  The proportion of CD4(+)CD25(+) cells was lower in the thyroid of patients with AITD than in the peripheral blood of the same patients or the peripheral blood of the healthy subjects. The proportions of CD4(+)CD25(+)CD69() cells and Forkhead box P3 (Foxp3)(+)CD4(+)CD25(+) cells, which constitute more specific Treg subsets than CD4(+)CD25(+) cells, were also lower in the thyroid than in the peripheral blood of patients with AITD. The proportion of apoptotic cells was higher among intrathyroidal CD4(+) cells than among peripheral CD4(+) cells and higher among intrathyroidal CD4(+)CD25(+) cells than among intrathyroidal CD4(+)CD25() cells.
  
  
  CONCLUSIONS
  These results indicate that intrathyroidal Treg cells are decreased in response to apoptosis in patients with AITD. This decrease in Treg cells may contribute to the incomplete regulation of autoreactive T cells in AITD.
authors.affiliation: Division of Biomedical Informatics, Course of Health Science, Osaka University Graduate School of Medicine, Suita, Osaka, Japan.
authors.forename: Aiko
authors.initials: A
authors.lastname: Nakano
authors.forename: Mikio
authors.initials: M
authors.lastname: Watanabe
authors.forename: Takao
authors.initials: T
authors.lastname: Iida
authors.forename: Shoko
authors.initials: S
authors.lastname: Kuroda
authors.forename: Fumio
authors.initials: F
authors.lastname: Matsuzuka
authors.forename: Akira
authors.initials: A
authors.lastname: Miyauchi
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Iwatani
mesh_terms: D000328:Adult; D017209:Apoptosis / Q000276:immunology*; D015704:CD4 Antigens / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D053645:Interleukin-2 Receptor alpha Subunit / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D050378:T-Lymphocytes, Regulatory / Q000166:cytology* / Q000276:immunology* / Q000378:metabolism; D013961:Thyroid Gland / Q000276:immunology / Q000473:pathology; D013967:Thyroiditis, Autoimmune / Q000276:immunology* / Q000473:pathology*
chemical_list: D015704:CD4 Antigens; D053645:Interleukin-2 Receptor alpha Subunit