A gluten-free diet is the only means to manage coeliac disease, a permanent immune intolerance to gluten. We developed a therapeutic vaccine, Nexvax2, designed to treat coeliac disease. Nexvax2 is an adjuvant-free mix of three peptides that include immunodominant epitopes for gluten-specific CD4-positive T cells. The vaccine is intended to engage and render gluten-specific CD4-positive T cells unresponsive to further antigenic stimulation. We assessed the safety and pharmacodynamics of the vaccine in patients with coeliac disease on a gluten-free diet. We did two randomised, double-blind, placebo-controlled, phase 1 studies at 12 community sites in Australia, New Zealand, and the USA, in HLA-DQ2·5-positive patients aged 18-70 years who had coeliac disease and were on a gluten-free diet. In the screening period for ascending dose cohorts, participants were randomly assigned (1:1) by central randomisation with a simple block method to a double-blind crossover, placebo-controlled oral gluten challenge. Participants with a negative interferon γ release assay to Nexvax2 peptides after the screening oral gluten challenge were discontinued before dosing. For the biopsy cohorts, the screening period included an endoscopy, and participants with duodenal histology who had a Marsh score of greater than 1 were discontinued before dosing. Participants were subsequently randomly assigned to either Nexvax2 or placebo in ascending dose cohorts (2:1) and in biopsy cohorts (1:1) by central randomisation with a simple block method. In the three-dose study, participants received either Nexvax2 60 μg, 90 μg, or 150 μg weekly, or placebo over 15 days; in a fourth biopsy cohort, patients received either Nexvax2 at the maximum tolerated dose (MTD) or placebo. In the 16-dose study, participants received Nexvax2 150 μg or 300 μg or placebo twice weekly over 53 days; in a third biopsy cohort, patients also received either Nexvax2 at the MTD or placebo. In the 4-week post-treatment period, ascending dose cohorts underwent a further double-blind crossover, placebo-controlled oral gluten challenge, which had a fixed sequence, and biopsy cohorts had a gastroscopy with duodenal biopsies and quantitative histology within 2 weeks without oral gluten challenge. Participants, investigators, and study staff were masked to the treatment assignment, except for the study pharmacist. The primary endpoint was the number and percentage of adverse events in the treatment period in an intention-to-treat analysis. Both trials were completed and closed before data analysis. Trials were registered with the Australian New Zealand Clinical Trials Registry, numbers ACTRN12612000355875 and ACTRN12613001331729. Participants were enrolled from Nov 28, 2012, to Aug 14, 2014, in the three-dose study, and from Aug 3, 2012, to Sept 10, 2013, in the 16-dose study. Overall, 62 (57%) of 108 participants were randomly assigned after oral gluten challenge and 20 (71%) of 28 participants were randomly assigned after endoscopy. In the three-dose study, nine participants were randomly allocated to Nexvax2 60 μg and three to placebo (first cohort), nine were allocated to Nexvax2 90 μg and four to placebo (second cohort), eight were allocated to Nexvax2 150 μg and four to placebo (third cohort), and three were allocated to Nexvax2 150 μg and three to placebo (biopsy cohort). In the 16-dose study, eight participants were randomly allocated to Nexvax2 150 μg and four to placebo (first cohort), ten were allocated to Nexvax2 300 μg and three to placebo (second cohort), and seven were allocated to Nexvax2 150 μg and seven to placebo (biopsy cohort). The MTD for Nexvax2 was 150 μg because of transient, acute gastrointestinal adverse events with onset 2-5 h after initial doses of the vaccine, similar to those caused by gluten ingestion. In the ascending dose cohorts in the three-dose study, six (55%) of 11 placebo recipients, five (56%) of nine who received Nexvax2 60 μg, seven (78%) of nine who received Nexvax2 90 μg, and five (63%) of eight who received Nexvax2 150 μg had at least one treatment-emergent adverse event, as did all three (100%) placebo recipients and one (33%) of three Nexvax2 150 μg recipients in the biopsy cohort. In the ascending dose cohorts of the 16-dose study, five (71%) of seven placebo-treated participants, six (75%) of eight who received Nexvax2 150 μg, and all ten (100%) who received Nexvax2 300 μg had at least one treatment-emergent adverse event, as did six (86%) of seven placebo recipients and five (71%) of seven Nexvax2 150 μg recipients in the biopsy cohort. Vomiting, nausea, and headache were the only treatment-emergent adverse events that occurred in at least 5% of participants in either study. Among participants given the MTD, eight gastrointestinal treatment-emergent adverse events occurred in four (50%) of eight participants in the third cohort and none (0%) of three participants in the biopsy cohort in the three-dose study, and five events occurred in five (63%) of eight participants in the first cohort and three events in two (29%) of seven participants in the biopsy cohort of the 16-dose study. Median villous height to crypt depth ratio in distal duodenal biopsies was not significantly different between those who received the vaccine at the MTD on either schedule and those who received placebo. Of the participants who completed the post-treatment oral gluten challenge per protocol, interferon γ release assay to Nexvax2 peptides was negative (responders to treatment) in two (22%) of nine placebo-treated participants in the three-dose study versus two (33%) of six who received Nexvax2 60 μg, five (63%) of eight who received Nexvax2 90 μg, and six (100%) of six who received Nexvax2 150 μg (p=0·007); in the 16-dose study, none (0%) of five placebo-treated participants had a negative assay versus six (75%) of eight who received...

Acute gastrointestinal symptoms induced by gluten, within 4 hours, are mediated by reactivation of antigen-specific memory T cells.

Changing perspectives on the natural history of celiac disease (CD), new serology and genetic tests, and amended histological criteria for diagnosis cast doubt on past prevalence estimates for CD. We set out to establish a more accurate prevalence estimate for CD using a novel serogenetic approach.

Summary: Background: Coeliac disease patients on a gluten‐free diet experience reactions to gluten, but these are not well characterised or understood. Systemic cytokine release was recently linked to reactivation of gluten immunity in coeliac disease.Aim: To define the nature and time‐course of symptoms and interleukin‐2 changes specific for coeliac disease patients.Methods: 25 coeliac disease patients on a gluten‐free diet and 25 healthy volunteers consumed a standardised 6 gram gluten challenge. Coeliac Disease Patient‐Reported Outcome survey and global digestive symptom assessment were completed hourly up to 6 hours after gluten. Adverse events over 48 hours were recorded. Serum interleukin‐2 was measured at baseline, and 2, 4 and 6 hours.Results: Serum interleukin‐2 was always undetectable in healthy controls, whereas it was undetectable at baseline and elevated >0.5 pg/ml at 4 hours in 92% of coeliac disease patients. All patient‐reported outcome severity scores increased significantly after gluten in coeliac disease patients (P < .001 Wilcoxon signed rank test), but not in controls. Symptoms began after 1 hour, and peaked in the third. Nausea and vomiting characterised severe reactions, but mild reactions were limited to headache and tiredness. Peak interleukin‐2 correlated with symptom severity, particularly for nausea and vomiting.Conclusions: Serum interleukin‐2 elevations correlate with timing and severity of symptoms after gluten in coeliac disease. Standardised bolus gluten food challenge and interleukin‐2 assessment could provide a valuable clinical test to monitor and diagnose coeliac disease in patients established on a gluten‐free diet.

Celiac disease is a chronic immune-mediated inflammatory disorder of the gut triggered by dietary gluten. Although the effector T-cell response in patients with celiac disease has been well characterized, the role of regulatory T (Treg) cells in the loss of tolerance to gluten remains poorly understood. We sought to define whether patients with celiac disease have a dysfunction or lack of gluten-specific forkhead box protein 3 (FOXP3)+ Treg cells. Treated patients with celiac disease underwent oral wheat challenge to stimulate recirculation of gluten-specific T cells. Peripheral blood was collected before and after challenge. To comprehensively measure the gluten-specific CD4+ T-cell response, we paired traditional IFN-γ ELISpot with an assay to detect antigen-specific CD4+ T cells that does not rely on tetramers, antigen-stimulated cytokine production, or proliferation but rather on antigen-induced coexpression of CD25 and OX40 (CD134). Numbers of circulating gluten-specific Treg cells and effector T cells both increased significantly after oral wheat challenge, peaking at day 6. Surprisingly, we found that approximately 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. Although we observed normal suppressive function in peripheral polyclonal Treg cells from patients with celiac disease, after a short in vitro expansion, the gluten-specific FOXP3+CD39+ Treg cells exhibited significantly reduced suppressive function compared with polyclonal Treg cells. This study provides the first estimation of FOXP3+CD39+ Treg cell frequency within circulating gluten-specific CD4+ T cells after oral gluten challenge of patients with celiac disease. FOXP3+CD39+ Treg cells comprised a major proportion of all circulating gluten-specific CD4+ T cells but had impaired suppressive function, indicating that Treg cell dysfunction might be a key contributor to disease pathogenesis.