Dynamics of Serologic Change to Gluten in Celiac Disease Patients.

Serologic measures of tissue transglutaminase (tTG) immunoglobulin A (IgA) and deamidated gliadin peptide (DGP) IgA and immunoglobulin G (IgG) are hallmark tests utilized when diagnosing individuals for celiac disease (CeD) and for monitoring adherence to a gluten-free diet (GFD), currently the only available treatment for CeD. We address two issues in this study: (i) the relapse to seropositivity for CeD patients who resume a gluten containing diet and (ii) the correlation between two different tTG-IgA assays near the upper limit of normal (ULN) designated thresholds. Regarding the first issue, often a suspected CeD individual is put back on a gluten diet to return to their serologic levels. However, we show it requires a substantial amount of gluten for serology to return to a positive level. For example, in one study of 22 patients treated with placebo and taking 84 g of gluten over 6 weeks, only two converted from seronegative to seropositive for tTG-IgA. Regarding the second topic, we compare the relationship for different serologic assays, namely tTG-IgA AB (recombinant, ULN = 4 units/mL) vs. tTG-IgA (non-recombinant, ULN = 20 units). There is a strong correlation between both measurements as evidenced by a Pearson coefficient of R = 0.8584; however, we observed that the cross-correlation in terms of sensitivity and specificity improved substantially by using an ULN value of three instead of four for the tTG-IgA AB (recombinant) assay. This result suggests that assay thresholds used for initial diagnosis in patients who have not yet started a GFD may need to be adjusted for monitoring and in the setting of a diagnostic gluten challenge.

A Composite Morphometric Duodenal Biopsy Mucosal Scale for Celiac Disease Encompassing Both Morphology and Inflammation.

BACKGROUND & AIMS: Villus height to crypt depth ratio (Vh:Cd) and intraepithelial lymphocytes (IEL) are key measures of histology of the small intestine in celiac disease. Although the field of celiac disease has advanced, there remains no broadly accepted measure of mucosal injury. We assessed whether a composite Vh:Cd and IEL scale (VCIEL) can improve accuracy and statistical precision for assessing histology, compared with individual measures. METHODS: The formulation of the VCIEL composite histologic scale was based on combining the Vh:Cd and IEL measurements for individual patients with equal weighting, by converting each scale to a fraction of their standard deviation and summing the results. The VCIEL formula was applied to several clinical trials and the results for Vh:Cd and IEL were compared with those for VCIEL with regards to clinical significance (effect size) and statistical significance. RESULTS: For the ALV003-1021 trial, we observed an effect size and P value (analysis of covariance) of 1.37 and 0.038 for ΔVh:Cd, 1.17 and 0.005 for ΔIEL, and 1.86 and 0.004 for ΔVCIEL. For the similar gluten-challenge IMGX003-NCCIH-1721 trial, the corresponding results were 0.76 and 0.057 for ΔVh:Cd, 0.98 and 0.018 for ΔIEL, and 1.14 and 0.007 for ΔVCIEL. Similar improvements with the use of VCIEL over individual Vh:Cd and IEL measures were observed for other studies, including a nontherapeutic gluten challenge study. CONCLUSIONS: The composite VCIEL scale combining Vh:Cd and IEL values seems to improve accuracy and statistical precision compared with either component alone.

Latiglutenase Protects the Mucosa and Attenuates Symptom Severity in Patients With Celiac Disease Exposed to a Gluten Challenge.

BACKGROUND & AIMS: Gluten ingestion in patients with celiac disease can lead to gastrointestinal symptoms and small intestinal mucosal injury. METHODS: This gluten challenge phase 2 trial was double blind and placebo controlled, and it assessed the efficacy and safety of a 1200-mg dose of IMGX003 in patients with celiac disease exposed to 2 g of gluten per day for 6 weeks. The change in the ratio of villus height to crypt depth was the primary endpoint. Secondary endpoints included density of intraepithelial lymphocytes and symptom severity. These endpoints were evaluated by analysis of covariance. Additional endpoints included serology and gluten-immunogenic peptides in urine. RESULTS: Fifty patients were randomized, and 43 patients completed the study (IMGX003, n = 21; placebo, n = 22). The mean change in the ratio of villus height to crypt depth (primary endpoint) for IMGX003 vs placebo was -0.04 vs -0.35 (P = .057). The mean change in the density of intraepithelial lymphocytes (secondary endpoint) for IMGX003 vs placebo was 9.8 vs 24.8 cells/mm epithelium (P = .018). The mean change (worsening) in symptom severity in relative units (secondary endpoint) for IMGX003 vs placebo was 0.22 vs 1.63 (abdominal pain, P = .231), 0.96 vs 3.29 (bloating, P = .204), and 0.02 vs 3.20 (tiredness, P = .113). The 3 × 2-week trend line significance values for these symptoms, respectively, were P = .014, .030, and .002. CONCLUSIONS: IMGX003 reduced gluten-induced intestinal mucosal damage and symptom severity. (ClinicalTrials.gov, Number: NCT03585478).

Latiglutenase Treatment for Celiac Disease: Symptom and Quality of Life Improvement for Seropositive Patients on a Gluten-Free Diet.

BACKGROUND: Celiac disease (CD) is a widespread autoimmune disease triggered by dietary gluten that can lead to severe gastrointestinal symptoms. Because there is no available treatment other than a lifelong gluten-free diet, many patients continue to experience chronic symptoms. AIM: In this analysis we report on the efficacy of latiglutenase, an orally administered enzyme treatment, for improving multiple gluten-induced symptoms and consequent quality of life (QOL) due to inadvertent gluten consumption. METHODS: This analysis is based on data from the CeliAction study of symptomatic patients (ALV003-1221; NCT01917630). Patients were treated with latiglutenase or placebo for 12 weeks and instructed to respond to a symptom diary daily and to multiple QOL questionnaires at weeks 0, 6, and 12 of the treatment periods as secondary endpoints. The results were stratified by serostatus. RESULTS: 398 patients completed the 12-week CDSD study. In seropositive, but not seronegative, CD patients a statistically significant and dose-dependent improvement was seen in the severity and frequency of abdominal pain, bloating, tiredness, and constipation. In subjects receiving 900 mg latiglutenase, improvements (p-values) in the severity of these symptoms for week 12 were 58% (0.038), 44% (0.023), 21% (0.164), and 104% (0.049) respectively, relative to placebo-dosed subjects. The reduction in symptoms trended higher for more symptomatic patients. Similar results were observed for the QOL outcome measures. CONCLUSIONS: Although this study was not powered to definitively establish the benefit of latiglutenase in seropositive CD patients, such patients appear to show symptomatic and QOL benefit from using latiglutenase with meals.

Determination of gluten consumption in celiac disease patients on a gluten-free diet.

Background: Celiac disease (CD) patients adhering to a gluten-free diet (GFD) are exposed frequently to low levels of gluten that contribute to symptoms and persistent intestinal histologic damage. Objective: We analyzed prior clinical data to determine how much gluten is accidentally consumed while on a GFD. The aim was to understand the range of gluten consumption for a wide distribution of CD patients. Design: A meta-analysis was conducted on data from 2 different clinical programs: 1) measurements of gluten in stool and urine in CD and non-CD populations; and 2) analysis of data from trials for the investigational therapeutic latiglutenase. The stool and urine studies included controlled gluten challenges. A calibration factor was applied that allowed normal ingestion of gluten to be computed from the urine and stool measurements. From the latiglutenase trial data, a determination of gluten consumption was made by estimating how much gluten was eliminated from patients' diets due to a trial effect that led to improved histology even in the placebo group. Results: The average inadvertent exposure to gluten by CD individuals on a GFD was estimated to be ∼150-400 (mean) and ∼100-150 (median) mg/d using the stool test and ∼300-400 (mean) and ∼150 (median) mg/d using the urine test. The analyses of the latiglutenase data for CD individuals with moderate to severe symptoms indicate that patients ingested significantly >200 mg/d of gluten. Conclusions: These surrogate biomarkers of gluten ingestion indicate that many individuals following a GFD regularly consume sufficient gluten to trigger symptoms and perpetuate intestinal histologic damage.

Discovery of highly conserved unique peanut and tree nut peptides by LC-MS/MS for multi-allergen detection.

Proteins unique to peanuts and various tree nuts have been extracted, subjected to trypsin digestion and analysis by liquid chromatography/quadrupole time-of-flight mass spectrometry, in order to find highly conserved peptides that can be used as markers to detect peanuts and tree nuts in food. The marker peptide sequences chosen were those found to be present in both native (unroasted) and thermally processed (roasted) forms of peanuts and tree nuts. Each peptide was selected by assuring its presence in food that was processed or unprocessed, its abundance for sensitivity, sequence size, and uniqueness for peanut and each specific variety of tree nut. At least two peptides were selected to represent peanut, almond, pecan, cashew, walnut, hazelnut, pine nut, Brazil nut, macadamia nut, pistachio nut, chestnut and coconut; to determine the presence of trace levels of peanut and tree nuts in food by a novel multiplexed LC-MS method.

Evaluation of qualitative and quantitative immunoassays to detect barley contamination in gluten-free beer with confirmation using LC/MS/MS.

To meet the need for the detection and quantitation of barley gluten in beer, qualitative screening and quantitative immunoassays based on the monoclonal antigluten antibody 401/21 (Skerritt) were validated in a single laboratory. Sample replicates were tested at each stage of beer production using multiple yeast strains and methods of end-stage protein removal. Quantitation was performed using barley-specific standards based on barley flour extracts. Immunoassay results were confirmed using LC/MS/MS for barley-specific peptides. The LOD for the qualitative screening test was 5 mg/L barley gluten. Recovery for the barley-spiked worts ranged from 81 to 128% in the quantitative ELISA assay; the LOD was <1 mg/L, and the LOQ was 5 mg/L. Both screening and confirmation methods were found to be fit for the purposes of detection of low levels of barley gluten in beer.

Novel aspects of quantitation of immunogenic wheat gluten peptides by liquid chromatography-mass spectrometry/mass spectrometry.

A novel, specific and sensitive non-immunological liquid chromatography-mass spectrometry (LC-MS) based assay has been developed to detect and quantify trace levels of wheat gluten in food and consumer products. Detection and quantification of dietary gluten is important, because gluten is a principle trigger of a variety of immune diseases including food allergies and intolerances. One such disease, celiac sprue, can cause intestinal inflammation and enteropathy in patients who are exposed to dietary gluten. At present, immunochemistry is the leading analytical method for gluten detection in food. Consequently, enzyme-linked immunosorbent assays (ELISAs), such as the sandwich or competitive type assays, are the only commercially available methods to ensure that food and consumer products are accurately labeled as gluten-free. The availability of a comprehensive, fast and economic alternative to the immunological ELISA may also facilitate research towards the development of new drugs, therapies and food processing technologies to aid patients with gluten intolerances and for gluten-free labeling and certification purposes. LC-MS is an effective and efficient analytical technique for the study of cereal grain proteins and to quantify trace levels of targeted dietary gluten peptides in complex matrices. Initial efforts in this area afforded the unambiguous identification and structural characterization of six unique physiologically relevant wheat gluten peptides. This paper describes the development and optimization of an LC-MS/MS method that attempts to provide the best possible accuracy and sensitivity for the quantitative detection of trace levels of these six peptides in various food and consumer products. The overall performance of this method was evaluated using native cereal grains. Experimental results demonstrated that this method is capable of detecting and quantifying select target peptides in food over a range from 10pg/mg to 100ng/mg (corresponding to approximately 0.01-100ppm). Limits of detection (LOD) and quantification (LOQ) for the six target peptides were determined to range from 1 to 30pg/mg and 10-100pg/mg respectively. Reproducibility of the assay was demonstrated by evaluation of calibration data as well as data collected from the analysis of quality control standards over a period of four consecutive days. The average coefficient of determination (R(2)) for each peptide was consistently found to be >0.995 with residuals ranging from approximately 80% to 110%. Spike recovery data for each peptide in various matrices was evaluated at a concentration level near the approximate LOQ for each, as well as at higher concentration levels (30 and 60ng/mg). The average range of accuracy of detection for all peptides at the lower concentration level was determined to be 90% (+/-11), while accuracy at the 30 and 60ng/mg levels was 98% (+/-5%) and 98% (+/-3%), respectively. The usefulness and capabilities of this method are presented in a practical application to prospectively screen a variety of common commercially available (native and processed) gluten-containing and gluten-free foods and products.