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Jefferson Adams posted an article in Celiac Disease & Gluten Intolerance ResearchCeliac.com 06/21/2017 - Circulating gluten-specific FOXP3+CD39+ regulatory T cells have impaired suppressive function in patients with celiac disease. What does that mean? Although researchers understand the effector T-cell response in patients with celiac disease pretty well, they really don't know very much about the role played by regulatory T cells (Treg cells) in the loss of tolerance to gluten. To get a better picture, a team of researchers recently set out to define whether patients with celiac disease have a dysfunction or lack of gluten-specific forkhead box protein 3 (FOXP3)+ Treg cells. The research team included L Cook, CML Munier, N3 Seddiki, D van Bockel, N Ontiveros, MY Hardy, JK Gillies, MK Levings, HH Reid, J Petersen, J Rossjohn, RP Anderson, JJ Zaunders, JA Tye-Din, AD Kelleher. For the study, gluten-free patients with celiac disease underwent oral wheat challenge to stimulate recirculation of gluten-specific T cells. The research team collected peripheral blood before and after challenge. To effectively measure the gluten-specific CD4+ T-cell response, they combined traditional IFN-γ ELISpot with a test for antigen-specific CD4+ T cells that does not rely on tetramers, antigen-stimulated cytokine production, or proliferation, but relies instead on antigen-induced co-expression of CD25 and OX40 (CD134). During the gluten challenge, levels of circulating gluten-specific Treg cells and effector T cells both rose sharply, peaking on the sixth day. The team recounts surprise on discovering that about 80% of the ex vivo circulating gluten-specific CD4+ T cells were FOXP3+CD39+Treg cells, which reside within the pool of memory CD4+CD25+CD127lowCD45RO+ Treg cells. Even though they saw normal suppressive function in peripheral polyclonal Treg cells from celiac patients, after a short in vitro expansion, the gluten-specific FOXP3+CD39+ Treg cells showed sharply reduced suppressive function compared with polyclonal Treg cells. The team's study offers the first estimates of FOXP3+CD39+ Treg cell frequency within circulating gluten-specific CD4+ T cells after oral gluten challenge of celiac patients. FOXP3+CD39+ Treg cells made up the majority of all circulating gluten-specific CD4+ T cells, but they showed reduced suppressive function, indicating that Treg cell dysfunction might be a key factor in celiac disease development. This type of research is crucial to help document the genetic physiology of celiac disease, which will help researchers to better understand and treat the disease itself. Source: J Allergy Clin Immunol. 2017 Mar 8. pii: S0091-6749(17)30343-3. doi: 10.1016/j.jaci.2017.02.015. The researchers are variously affiliated with the Immunovirology and Pathogenesis Program, The Kirby Institute, UNSW Sydney, Sydney, Australia, St Vincent's Centre for Applied Medical Research, St Vincent's Hospital, Sydney, Australia; the Infection and Immunity Program, The Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, Australia; Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Australia; the Immunovirology and Pathogenesis Program, The Kirby Institute, UNSW Sydney, Sydney, Australia; St Vincent's Centre for Applied Medical Research, St Vincent's Hospital, Sydney, Australia, Immunology Division, Walter and Eliza Hall Institute, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia; Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada; the Institute of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff, United Kingdom; the Immunology Division, Walter and Eliza Hall Institute, Parkville, Australia; Department of Medical Biology, University of Melbourne, Parkville, Australia; ImmusanT, Cambridge, Massachusetts; and the Department of Gastroenterology, Royal Melbourne Hospital, Parkville, Australia.
Jefferson Adams posted an article in Celiac Disease & Gluten Intolerance ResearchCeliac.com 05/18/2017 - Researchers understand pretty well that celiac disease is driven in part by an accumulation of immune cells in the duodenal mucosa as a consequence of both adaptive and innate immune responses to undigested gliadin peptides. Mast cells are innate immune cells that produce a majority of co-stimulatory signals and inflammatory mediators in the intestinal mucosa. A team of researchers recently set out to evaluate the role of mast cells in the development of celiac disease. The research team included Barbara Frossi, PhD, Claudio Tripodo, MD, Carla Guarnotta, PhD, Antonio Carroccio, MD, Marco De Carli, MD, Stefano De Carli, MD, Marco Marino, MD, Antonino Calabrò, MD, and Carlo E. Pucillo, MD. They are variously affiliated with the Department of Gastroenterology and Digestive Endoscopy at the University Hospital of Udine in Udine, Italy; the Department of Medical and Biological Sciences, University of Udine, Udine, Italy; the Second Unit of Internal Medicine, University of Udine, Udine, Italy; the Department of Experimental and Clinical Biomedical Sciences “Mario Serio,” University Hospital of Florence, Florence, Italy; the Tuscany Referral Center for Adult Coeliac Disease, AOU Careggi, Florence, Italy; the Department of Health Science, University Hospital of Palermo in Palermo, Italy; and the Department of Internal Medicine and Specialist at the University Hospital of Palermo in Palermo, Italy. For their study, the research team scored intestinal biopsy results from celiac patients according to Marsh classification, and characterized those results for leukocyte infiltration and MC distribution. They also characterized mast cell reactivity to gliadin and its peptides via in vitro assays. The team found that infiltrating mast cells reflected the severity of mucosal damage, and their numbers were increased in patients with higher Marsh scores. They noted that mast cells responded directly to non-immunodominant gliadin fragments by releasing pro-inflammatory mediators. Their immunohistochemical analysis of infiltrating mast cells, along with the effects of gliadin peptides on intestinal mast cells, indicates that patients in with advanced celiac disease face an increase in pro-inflammatory mast cell function. This result was also tied to increased neutrophil accumulation, the prevalence of M1 macrophages, and the severity of tissue damage. This study clearly describes the progressive stages of celiac disease, and shows that mast cells are a prominent feature of the inflammatory process. These results show that mast cells are associated with the onset and progression of celiac disease, and that the view of celiac disease should be revised to account for the contribution of mast cells in the onset and progression of the disease; and in the development any new celiac treatments. Source: Journal of Allergy, & Clinical Immunology. DOI: http://dx.doi.org/10.1016/j.jaci.2016.08.011