T cells in peripheral blood after gluten challenge in coeliac disease
- 1Autoimmunity and Transplantation Division, Walter and Eliza Hall Institute, and Department of Gastroenterology, the Royal Melbourne Hospital, Parkville, Victoria, Australia
- 2Department of Gastroenterology, Hammersmith Hospital, Imperial College, London, UK
- 3Transplantation Immunology, Nuffield Department of Surgery, Churchill Hospital, University of Oxford, Oxford, UK
- 4Weatherall Institute of Molecular Medicine, Nuffield Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
- 5Department of Gastroenterology, Nuffield Department of Medicine, Gibson Building, Radcliffe Infirmary, University of Oxford, Oxford, UK
- 6Wellcome Trust Centre for Human Genetics, Nuffield Department of Medicine, Churchill Hospital, University of Oxford, Oxford, UK
- Correspondence to:
Dr R P Anderson
Autoimmunity and Transplantation Division, Walter and Eliza Hall Institute, c/o Post Office RMH, Victoria, Australia 3050;
- Accepted 24 February 2005
- Revised 23 February 2005
Background: Current understanding of T cell epitopes in coeliac disease (CD) largely derives from intestinal T cell clones in vitro. T cell clones allow identification of gluten peptides that stimulate T cells but do not quantify their contribution to the overall gluten specific T cell response in individuals with CD when exposed to gluten in vivo.
Aims: To determine the contribution of a putative dominant T cell epitope to the overall gliadin T cell response in HLA-DQ2 CD in vivo.
Patients: HLA-DQ2+ individuals with CD and healthy controls.
Methods: Subjects consumed 20 g of gluten daily for three days. Interferon γ (IFN-γ) ELISPOT was performed using peripheral blood mononuclear cells (PBMC) to enumerate and characterise peptide and gliadin specific T cells before and after gluten challenge.
Results: In 50/59 CD subjects, irrespective of homo- or heterozygosity for HLA-DQ2, IFN-γ ELISPOT responses for an optimal concentration of A-gliadin 57–73 Q-E65 were between 10 and 1500 per million PBMC, equivalent to a median 51% of the response for a “near optimal” concentration of deamidated gliadin. Whole deamidated gliadin and gliadin epitope specific T cells induced in peripheral blood expressed an intestinal homing integrin (α4β7) and were HLA-DQ2 restricted. Peripheral blood T cells specific for A-gliadin 57–73 Q-E65 are rare in untreated CD but can be predictably induced two weeks after gluten exclusion.
Conclusion: In vivo gluten challenge is a simple safe method that allows relevant T cells to be analysed and quantified in peripheral blood by ELISPOT, and should permit comprehensive high throughput mapping of gluten T cell epitopes in large numbers of individuals with CD.
- CD, coeliac disease
- IFN-γ, interferon γ
- IL, interleukin
- GFD, gluten free diet
- PBMC, peripheral blood mononuclear cells
- tTG, tissue transglutaminase
- EMA, endomysial antibodies
- PPD, purified protein derivative of Mycobacterium bovis
- SFU, spot forming units