title: Phenotypic and genetic analyses of T-cell-mediated immunoregulation in patients with Type 1 diabetes.
abstract: OBJECTIVE
  To investigate the contribution of regulatory T cells and co-stimulatory molecules in CD4(+) T cells to the development of Type 1 diabetes (T1D).
  
  
  METHODS
  Twelve patients with T1D, nine patients with systemic lupus erythematosus (SLE), and 12 age-matched healthy control subjects participated. We analysed the proportions of CD25(+)CD4(+) T cells and natural killer T cells (NKT cells), and the expression levels of Foxp3, CTLA-4, CD28, ICOS, PD-1 and BTLA in peripheral blood mononuclear cells and purified CD4(+) T cells.
  
  
  RESULTS
  There were no significant differences in the proportions of CD25(+) CD4(+) T cells or NKT cells among the three groups. PD-1 expression levels of peripheral CD4(+) T cells from T1D patients were significantly lower than those from healthy control subjects (P = 0.00066). In contrast, PD-1 expression levels were similar in SLE patients and healthy control subjects. The expression levels of Foxp3, CTLA-4, CD28, ICOS and BTLA were similar in the three groups.
  
  
  CONCLUSIONS
  Decreased expression of the PD-1 gene in CD4(+) T cells may contribute to the development and/or maintenance of autoimmune T1D. As the population studied was small and heterogeneous, further studies are required to confirm the findings.
authors.affiliation: Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Tsutsumi
authors.forename: X
authors.initials: X
authors.lastname: Jie
authors.forename: K
authors.initials: K
authors.lastname: Ihara
authors.forename: A
authors.initials: A
authors.lastname: Nomura
authors.forename: S
authors.initials: S
authors.lastname: Kanemitsu
authors.forename: H
authors.initials: H
authors.lastname: Takada
authors.forename: T
authors.initials: T
authors.lastname: Hara
mesh_terms: D000293:Adolescent; D000328:Adult; D015703:Antigens, CD / Q000276:immunology* / Q000378:metabolism; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000235:genetics* / Q000276:immunology*; D005260:Female; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology*; D008180:Lupus Erythematosus, Systemic / Q000235:genetics* / Q000276:immunology*; D008297:Male; D010641:Phenotype
chemical_list: D015703:Antigens, CD