title: Impaired control of effector T cells by regulatory T cells: a clue to loss of oral tolerance and autoimmunity in celiac disease?
abstract: OBJECTIVE
  Regulatory T cells (Tregs) are instrumental for tolerance to self-antigens and dietary proteins. We have previously shown that interleukin (IL)-15, a cytokine overexpressed in the intestine of patients with celiac disease (CD), does not impair the generation of functional Tregs but renders human T cells resistant to Treg suppression. Treg numbers and responses of intestinal and peripheral T lymphocytes to suppression by Tregs were therefore compared in CD patients and controls.
  
  
  METHODS
  Intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) were isolated from duodenal biopsy specimens of CD patients and controls. Concomitantly, CD4+CD25+ T lymphocytes (Tregs) were purified from blood. Responses of IELs and of LPLs, and peripheral lymphocytes (PBLs) to suppression by Tregs were tested by analyzing anti-CD3-induced proliferation and interferon (IFN)-γ production in the presence or absence of peripheral Tregs. Lamina propria and peripheral CD4+CD25+FOXP3+ T cells were assessed by flow cytometry.
  
  
  RESULTS
  Although percentages of CD4+CD25+FOXP3+ LPLs were significantly increased in patients with active CD, proliferation and IFN-γ production of intestinal T lymphocytes were significantly less inhibited by autologous or heterologous Tregs in CD patients than in controls (P < 0.01). In all tested CD patients, IEL were unable to respond to Tregs. Resistance of LPLs and PBLs to Treg suppression was observed in patients with villous atrophy who had significantly enhanced serum levels of IL-15 compared with patients without villous atrophy and controls.
  
  
  CONCLUSIONS
  Our results indicate that effector T lymphocytes from active CD become resistant to suppression by Tregs. This resistance might cause loss of tolerance to gluten, but also to self-antigens.
authors: Department of Clinical Immunology, Institut Pasteur de Tunis, Tunis, Tunisia.
authors: Nadia Belhadj
authors: NB
authors: Hmida
authors: Mélika
authors: M
authors: Ben Ahmed
authors: Amel
authors: A
authors: Moussa
authors: Majd Ben
authors: MB
authors: Rejeb
authors: Yosra
authors: Y
authors: Said
authors: Nadia
authors: N
authors: Kourda
authors: Bertrand
authors: B
authors: Meresse
authors: Maha
authors: M
authors: Abdeladhim
authors: Hechmi
authors: H
authors: Louzir
authors: Nadine
authors: N
authors: Cerf-Bensussan
mesh_terms: D000328:Adult; D015551:Autoimmunity; D001706:Biopsy; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D016022:Case-Control Studies; D002446:Celiac Disease / Q000276:immunology* / Q000378:metabolism; D004386:Duodenum / Q000166:cytology / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007108:Immune Tolerance; D007371:Interferon-gamma / Q000276:immunology / Q000378:metabolism; D019409:Interleukin-15 / Q000276:immunology* / Q000378:metabolism; D053645:Interleukin-2 Receptor alpha Subunit / Q000276:immunology / Q000378:metabolism; D007413:Intestinal Mucosa / Q000166:cytology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism
chemical_list: C418974:FOXP3 protein, human; D051858:Forkhead Transcription Factors; C508017:IL2RA protein, human; D019409:Interleukin-15; D053645:Interleukin-2 Receptor alpha Subunit; D007371:Interferon-gamma