Understanding celiac disease monitoring patterns and outcomes after diagnosis: A multinational, retrospective chart review study.

BACKGROUND: Long-term outcomes and monitoring patterns in real-world practice are largely unknown among patients with celiac disease. AIM: To understand patterns of follow-up and management of patients with celiac disease, and to characterize symptoms and villous atrophy after diagnosis. METHODS: A retrospective chart review study was performed using medical chart data of patients diagnosed with celiac disease. Three gastroenterology referral centers, with substantial expertise in celiac disease, participated in the United Kingdom, United States, and Norway. Demographic and clinical data were collected from medical charts. Descriptive analyses were conducted on patients with biopsy-confirmed celiac disease, diagnosed between 2008 and 2012, with at least one follow-up visit before December 31, 2017. Patient demographic and clinical characteristics, biopsy/serology tests and results, symptoms, and comorbidities were captured at diagnosis and for each clinic visit occurring within the study period (i.e., before the study end date of December 31, 2017). RESULTS: A total of 300 patients were included in this study [72% female; mean age at diagnosis: 38.9 years, standard deviation (SD) 17.2]. Patients were followed-up for a mean of 29.9 mo (SD 22.1) and there were, on average, three follow-up visits per patient during the study period. Over two-thirds (68.4%) of patients were recorded as having ongoing gastrointestinal symptoms and 11.0% had ongoing symptoms and enteropathy during follow-up. Approximately 80% of patients were referred to a dietician at least once during the follow-up period. Half (50.0%) of the patients underwent at least one follow-up duodenal biopsy and 36.6% had continued villous atrophy. Patterns of monitoring varied between sites. Biopsies were conducted more frequently in Norway and patients in the United States had a longer follow-up duration. CONCLUSION: This real-world study demonstrates variable follow-up of patients with celiac disease despite most patients continuing to have abnormal histology and symptoms after diagnosis.

Cytokine release after gluten ingestion differentiates coeliac disease from self-reported gluten sensitivity.

BACKGROUND: Diagnosing coeliac disease (CD) in patients on a gluten-free diet (GFD) is difficult. Ingesting gluten elevates circulating interleukin (IL)-2, IL-8 and IL-10 in CD patients on a GFD. OBJECTIVE: We tested whether cytokine release after gluten ingestion differentiates patients with CD from those with self-reported gluten sensitivity (SR-GS). METHODS: Australian patients with CD (n = 26) and SR-GS (n = 18) on a GFD consumed bread (estimated gluten 6 g). Serum at baseline and at 3 and 4 h was tested for IL-2, IL-8 and IL-10. Separately, Norwegian SR-GS patients (n = 49) had plasma cytokine assessment at baseline and at 2, 4 and 6 h after food bars containing gluten (5.7 g), fructan or placebo in a previous double-blind crossover study. RESULTS: Gluten significantly elevated serum IL-2, IL-8 and IL-10 at 3 and 4 h in patients with CD but not SR-GS. The highest median fold-change from baseline at 4 h was for IL-2 (8.06, IQR: 1.52-24.0; P < 0.0001, Wilcoxon test). The two SR-GS cohorts included only one (1.5%) confirmed IL-2 responder, and cytokine responses to fructan and placebo were no different to gluten. Overall, cytokine release after gluten was present in 22 (85%) CD participants, but 2 of the 4 non-responders remained clinically well after 1 y on an unrestricted diet. Hence, cytokine release occurred in 22 (92%) of 24 'verified' CD participants. CONCLUSIONS: Gluten challenge with high-sensitivity cytokine assessment differentiates CD from SR-GS in patients on a GFD and identifies patients likely to tolerate gluten reintroduction. Systemic cytokine release indicating early immune activation by gluten in CD individuals cannot be detected in SR-GS individuals.

CD38 expression on gluten-specific T cells is a robust marker of gluten re-exposure in coeliac disease.

Background: Increasing efforts are being put into new treatment options for coeliac disease (CeD), a chronic disorder of the small intestine induced by gluten. Interleukin-2 (IL-2) and gluten-specific CD4 + T cells increase in the blood after four hours and six days, respectively, following a gluten challenge in CeD patients. These responses are unique to CeD and are not seen in controls. We aimed to evaluate different markers reflecting a recall response to gluten exposure that may be used to monitor therapy. Methods: CeD patients on a gluten-free diet underwent a one- (n = 6) or three-day (n = 7) oral gluten challenges. We collected blood samples at several time points between baseline and day 8, and monitored gluten-specific CD4 + T cells for their frequency and CD38 expression using HLA-DQ:gluten tetramers. We assessed the IL-2 concentration in plasma four hours after the first gluten intake. Results: The frequency of gut-homing, tetramer-binding, CD4 + effector memory T (tetramer + ß7 + TEM) cells and the IL-2 concentration measured shortly after the first dose of gluten increased significantly after the one- and three-day gluten challenges, but large interindividual differences were exhibited. The frequency of tetramer + ß7 + TEM plateaued between days 6 and 8 and was lower after the one-day challenge. We observed a consistent increase in CD38 expression on tetramer + ß7 + TEM cells and did not find a significant difference between the one- and three-day challenges. Conclusions: The optimal time points for monitoring therapy response in CeD after a three-day oral gluten challenge is four hours for plasma IL-2 or six to eight days for the frequency of tetramer + ß7 + TEM cells, but both these parameters involved large interindividual differences. In contrast, CD38 expression on tetramer + ß7 + TEM cells increased uniformly and irrespectively of the length of gluten challenge, suggesting that this parameter is more suited for monitoring drug efficacy in clinical trials for CeD.

Disease-driving CD4+ T cell clonotypes persist for decades in celiac disease.

Little is known about the repertoire dynamics and persistence of pathogenic T cells in HLA-associated disorders. In celiac disease, a disorder with a strong association with certain HLA-DQ allotypes, presumed pathogenic T cells can be visualized and isolated with HLA-DQ:gluten tetramers, thereby enabling further characterization. Single and bulk populations of HLA-DQ:gluten tetramer-sorted CD4+ T cells were analyzed by high-throughput DNA sequencing of rearranged TCR-α and -ß genes. Blood and gut biopsy samples from 21 celiac disease patients, taken at various stages of disease and in intervals of weeks to decades apart, were examined. Persistence of the same clonotypes was seen in both compartments over decades, with up to 53% overlap between samples obtained 16 to 28 years apart. Further, we observed that the recall response following oral gluten challenge was dominated by preexisting CD4+ T cell clonotypes. Public features were frequent among gluten-specific T cells, as 10% of TCR-α, TCR-ß, or paired TCR-αß amino acid sequences of total 1813 TCRs generated from 17 patients were observed in 2 or more patients. In established celiac disease, the T cell clonotypes that recognize gluten are persistent for decades, making up fixed repertoires that prevalently exhibit public features. These T cells represent an attractive therapeutic target.

A TCRα framework-centered codon shapes a biased T cell repertoire through direct MHC and CDR3ß interactions.

Selection of biased T cell receptor (TCR) repertoires across individuals is seen in both infectious diseases and autoimmunity, but the underlying molecular basis leading to these shared repertoires remains unclear. Celiac disease (CD) occurs primarily in HLA-DQ2.5+ individuals and is characterized by a CD4+ T cell response against gluten epitopes dominated by DQ2.5-glia-α1a and DQ2.5-glia-α2. The DQ2.5-glia-α2 response recruits a highly biased TCR repertoire composed of TRAV26-1 paired with TRBV7-2 harboring a semipublic CDR3ß loop. We aimed to unravel the molecular basis for this signature. By variable gene segment exchange, directed mutagenesis, and cellular T cell activation studies, we found that TRBV7-3 can substitute for TRBV7-2, as both can contain the canonical CDR3ß loop. Furthermore, we identified a pivotal germline-encoded MHC recognition motif centered on framework residue Y40 in TRAV26-1 engaging both DQB1*02 and the canonical CDR3ß. This allowed prediction of expanded DQ2.5-glia-α2-reactive TCR repertoires, which were confirmed by single-cell sorting and TCR sequencing from CD patient samples. Our data refine our understanding of how HLA-dependent biased TCR repertoires are selected in the periphery due to germline-encoded residues.

Stereotyped antibody responses target posttranslationally modified gluten in celiac disease.

The role of B cells and posttranslational modifications in pathogenesis of organ-specific immune diseases is increasingly envisioned but remains poorly understood, particularly in human disorders. In celiac disease, transglutaminase 2-modified (TG2-modified; deamidated) gluten peptides drive disease-specific T cell and B cell responses, and antibodies to deamidated gluten peptides are excellent diagnostic markers. Here, we substantiate by high-throughput sequencing of IGHV genes that antibodies to a disease-specific, deamidated, and immunodominant B cell epitope of gluten (PLQPEQPFP) have biased and stereotyped usage of IGHV3-23 and IGHV3-15 gene segments with modest somatic mutations. X-ray crystal structures of 2 prototype IGHV3-15/IGKV4-1 and IGHV3-23/IGLV4-69 antibodies reveal peptide interaction mainly via germline-encoded residues. In-depth mutational analysis showed restricted selection and substitution patterns at positions involved in antigen binding. While the IGHV3-15/IGKV4-1 antibody interacts with Glu5 and Gln6, the IGHV3-23/IGLV4-69 antibody interacts with Gln3, Pro4, Pro7, and Phe8 - residues involved in substrate recognition by TG2. Hence, both antibodies, despite different interaction with the epitope, recognize signatures of TG2 processing that facilitates B cell presentation of deamidated gluten peptides to T cells, thereby providing a molecular framework for the generation of these clinically important antibodies. The study provides essential insight into the pathogenic mechanism of celiac disease.

Tetramer-visualized gluten-specific CD4+ T cells in blood as a potential diagnostic marker for coeliac disease without oral gluten challenge.

BACKGROUND: Diagnosing coeliac disease (CD) can be challenging, despite highly specific autoantibodies and typical mucosal changes in the small intestine. The T-cell response to gluten is a hallmark of the disease that has been hitherto unexploited in clinical work-up. OBJECTIVES: We aimed to develop a new method that directly visualizes and characterizes gluten-reactive CD4+ T cells in blood, independently of gluten challenge, and to explore its diagnostic potential. METHODS: We performed bead-enrichment of DQ2.5-glia-α1a and DQ2.5-glia-α2 tetramer+ cells in the blood of control individuals, treated (TCD) and untreated patients (UCD). We visualized these cells by flow cytometry, sorted them and cloned them. We assessed their specificity by antigen stimulation and re-staining with tetramers. RESULTS: We detected significantly more gliadin-tetramer+ CD4+ effector memory T cells (TEM) in UCD and TCD patients, compared to controls. Significantly more gliadin-tetramer+ TEM in the CD patients than in controls expressed the gut-homing marker integrin-ß7. CONCLUSION: Quantification of gut-homing, gluten-specific TEM in peripheral blood, visualized with human leukocyte antigen (HLA) -tetramers, may be used to distinguish CD patients from healthy individuals. Easy access to gluten-reactive blood T cells from diseased and healthy individuals may lead to new insights on the disease-driving CD4+ T cells in CD.

Absence of somatization in non-coeliac gluten sensitivity.

OBJECTIVE: In contrast to coeliac disease (CD), the mechanism behind non-coeliac gluten sensitivity (NCGS) is unclear. The aims of the study were to measure the presence of somatization, personality traits, anxiety, depression, and health-related quality of life in NCGS individuals compared with CD patients and healthy controls, and to compare the response to gluten challenge between NCGS and CD patients. MATERIAL AND METHODS: We examined 22 CD patients and 31 HLA-DQ2+ NCGS patients without CD, all on a gluten-free diet. All but five CD patients were challenged orally for 3 days with gluten; symptom registration was performed during challenge. A comparison group of 40 healthy controls was included. Patients and healthy controls completed questionnaires regarding anxiety, depression, neuroticism and lie, hostility and aggression, alexithymia and health locus of control, physical complaints, and health-related quality of life. RESULTS: The NCGS patients reported more abdominal (p = 0.01) and non-abdominal (p < 0.01) symptoms after gluten challenge than CD patients. There were no significant differences between CD and NCGS patients regarding personality traits, level of somatization, quality of life, anxiety, and depressive symptoms. The somatization level was low in CD and NCGS groups. Symptom increase after gluten challenge was not related to personality in NCGS patients. CONCLUSIONS: NCGS patients did not exhibit a tendency for general somatization. Personality and quality of life did not differ between NCGS and CD patients, and were mostly at the same level as in healthy controls. NCGS patients reported more symptoms than CD patients after gluten challenge.

Video capsule endoscopy in celiac disease: current clinical practice.

OBJECTIVE: A complete examination of the small intestine is possible by video capsule endoscopy (VCE). The aim of this study was to evaluate current indications for performing VCE in celiac disease. METHODS: In all 84 celiac disease patients on a gluten-free diet who had undergone VCE were enrolled at five centers in Europe. The indications, findings and clinical impact of VCE were recorded by a structured questionnaire. VCE was also carried out in 34 consecutive patients with untreated celiac disease (controls) in another center. RESULTS: Out of the 84 patients, 34 had overt symptoms and small intestinal histology compatible with refractory celiac disease. VCE was normal in 9 patients, and 7 had only proximal and one distal atrophy, 14 had intestinal ulcer and 2 an intestinal stricture. VCE was used in the adjustment of immunosuppressive treatment in 9 patients. In the remaining 50 patients, a VCE was performed because of less severe symptoms, 31 of which had an earlier histological recovery. The VCE showed proximal small bowel atrophy in 21 and distal atrophy in 3 patients, and 3 ulcers were seen. In this group the patients received mainly advice with a view to achieving better dietary compliance. Of the 34 newly detected celiac patients, 4 were normal, 27 proximal and 3 had distal small intestinal atrophy in the VCE. CONCLUSIONS: VCE has a definite impact on the management of refractory sprue. In the remaining patients with established celiac disease, the procedure plays a more limited role.