Plasma Alkylresorcinols Reflect Gluten Intake and Distinguish between Gluten-Rich and Gluten-Poor Diets in a Population at Risk of Metabolic Syndrome.

BACKGROUND: Many patients with celiac disease experience difficulties in adherence to a gluten-free diet. Methods for testing compliance to a gluten-free diet are costly and cumbersome. Thus, a simple biomarker of gluten intake is needed in a clinical setting and will be useful for epidemiologic studies investigating wider effects of gluten intake. OBJECTIVE: The aim was to evaluate plasma total alkylresorcinol concentrations as a measure of gluten intake. METHODS: In this randomized, controlled, crossover intervention study in 52 Danish adults with features of the metabolic syndrome, we compared 8 wk of a gluten-rich and gluten-poor diet separated by a washout period of ≥6 wk. We measured fasting plasma concentrations of alkylresorcinols to determine if they reflected differences in gluten intake as a secondary outcome of the original study. In addition, we investigated in 118 Danish adults the cross-sectional association between self-reported gluten intake and plasma alkylresorcinols in the same and a similar study at baseline. We used mixed-model ANCOVA for examining treatment effects, a classification tree to determine compliance to the gluten-poor diet, and linear regression models for examining baseline correlation between plasma alkylresorcinol concentrations and gluten intake. RESULTS: Plasma total alkylresorcinols decreased more during the gluten-poor period (geometric mean: -124.8 nmol/L; 95% CI: -156.5, -93.0 nmol/L) than in the gluten-rich period (geometric mean: -31.8 nmol/L; 95% CI: -63.1, -0.4 nmol/L) (P < 0.001). On the basis of the plasma alkylresorcinol profile, we built a classification tree to objectively determine compliance and found an overall participant misclassification error of 3.9%. In the cross-sectional study we found a 5.6% (95% CI: 2.4%, 8.9%) increase in plasma total alkylresorcinols per 1-g increase in reported gluten intake (P < 0.001). CONCLUSION: We propose the use of plasma alkylresorcinols to monitor compliance to a gluten-free diet as well as to help investigations into the possible effects of gluten in the wider population. This trial was registered at www.clinicaltrials.gov as NCT017119913 and NCT01731366.

Home blood testing for celiac disease: recommendations for management.

OBJECTIVE: To provide recommendations for the management of patients who inquire about the Health Canada-approved, self-administered home blood tests for celiac disease or who present with positive test results after using the self-testing kit SOURCES OF INFORMATION: PubMed and the Cochrane Database of Systematic Reviews were searched from January 1985 to April 2008, using the subject headings diagnosis of celiac disease and management or treatment of celiac disease. Guidelines for serologic testing and confirmation of diagnosis of celiac disease by the American Gastroenterological Association and the North American Society for Pediatric Gastroenterology, Hepatology and Nutrition are used in this review. Level 1 evidence was used. MAIN MESSAGE: Although blood tests are helpful for screening purposes, the confirmatory test for celiac disease is a small intestinal biopsy. CONCLUSION: Patients whose blood tests for celiac disease provide positive results should have endoscopic small intestinal biopsies to confirm the diagnosis before starting a gluten-free diet.

Proteomic analysis of wheat flour allergens.

Wheat can cause severe IgE-mediated systematic reactions, but knowledge on relevant wheat allergens at the molecular level is scanty. The aim of the present study was to achieve a more detailed and comprehensive characterization of the wheat allergens involved in food allergy to wheat using proteomic strategies, referred to as "allergenomics". Whole flour proteins were separated by two-dimensional gel electrophoresis with isoelectric focusing and lithium dodecyl sulfate-polyacrylamide gel electrophoresis. Then, IgE-binding proteins were detected by immunoblotting with sera of patients with a food allergy to wheat. After tryptic digestion, the peptides of IgE-binding proteins were analyzed by matrix-assisted laser desorption ionization tandem time-of-flight mass spectrometry. In this study, we identified four previously reported wheat allergens or their sequentially homologous proteins [serpin, alpha-amylase inhibitor, gamma-gliadin, and low molecular weight (LMW) glutenin] by a database search. As a result of the high resolution of two-dimensional gel electrophoresis, nine subunits of LMW glutenins were identified as the most predominant IgE-binding antigens. The two-dimensional allergen map can be beneficial in many ways. It could be used, for example, for precise diagnosis of wheat-allergic patients and assessment of wheat allergens in food. Additionally, we compared allergenomics to conventional biochemical methods and evaluated the usefulness of a proteomic strategy for identifying putative allergens to wheat allergy.

Evidence of a selective epitope loss of anti-transglutaminase immunoreactivity in gluten-free diet celiac sera: a new tool to distinguish disease-specific immunoreactivities.

The aim of the present study was to evaluate the epitope specific humoral human tissue transglutaminase (tTG) immunoreactivity against 3 different human recombinant tTG constructs [(full-length tTG (a.a. 1-687), tTG (a.a. 227-687); tTG (a.a. 473-687)] before and after the introduction of a gluten-free diet (GFD). To this end, sera from 64 celiac disease (CD) subjects on a gluten-containing diet (44 f, 20 m) and after 0.6 +/- 0.3 years and 2.1 +/- 1.3 years of GFD were studied using a quantitative radioimmunoprecipitation assay. All 64 CD patients at diagnosis were full-length anti-tTG (a.a. 1-687)Ab positive. These Abs significantly decreased in frequency and titer after 6 months and 2 years of GFD. However, at low titers, 64.1% (41/64) of CD patients were still fl-tTG (a.a. 1-687)Ab positive after 2 years of GFD. At disease diagnosis, 70.3% (45/64) of the CD patients had Abs directed against fragments (227-687) and/or (473-687) of the tTG protein. This percentage, after 2 years of GFD, significantly decreased to 18.7%, whereas almost 50% of GFD patients had no tTG (227-687) and tTG (473-687) fragment reactivity, but only persistent, low-titer full-length tTG (1-687)Abs. We suggest that the selective loss of immunoreactivity against tTG (227-687) and tTG (473-687) fragments in CD patients with a GFD, could be due to quantitative decrease of autoreactivity driven by tTG-gliadin interaction underlying celiac disease pathogenesis.

The relation between the psychological functioning of children with Down syndrome and their urine peptide levels and levels of serum antibodies to food proteins.

AIMS: To investigate the relation between psychological functioning of subjects with Down syndrome, and their levels of urine peptide and serum antibodies to food proteins. METHODS: 55 children with Down syndrome in a cross-sectional study. Psychological functioning was measured by the Stanford-Binet Intelligence Scale: Fourth Edition, McCarthy Scales of Children's Abilities and Fagan's computer based test of novelty preference. RESULTS: The participants, and their siblings, were found to have significantly increased total urine peptide levels. There were no significant correlations between peptide levels and psychological functioning. Significantly increased levels of IgG activity to gliadin and gluten, and IgA activity to gliadin, gluten and casein were found. There were significant negative correlations (Spearman r = -0.13 to -0.51) between psychological functioning, and IgG and IgA activity to gliadin and gluten. CONCLUSIONS: A significant relation between antibodies to gluten and psychological functioning was documented. The mechanism and potential causal link are still unknown.

Psoriasis patients with antibodies to gliadin can be improved by a gluten-free diet.

In a previous screening study, 16% of patients with psoriasis had IgA and/or IgG antibodies to gliadin (AGA). The aim of the present study was to evaluate the effect of a gluten-free diet (GFD) in 33 AGA-positive and six AGA-negative psoriasis patients. Of the 33 AGA-positive patients, two had IgA antibodies to endomysium (EmA) and 15 an increased number of lymphocytes in the duodenal epithelium, but in some this increase was slight. Two patients had villous atrophy. A 3-month period on a GFD was followed by 3 months on the patient's ordinary diet. The severity of psoriasis was evaluated with the psoriasis area and severity index (PASI). The examining dermatologists were unaware of the EmA and duodenal biopsy results throughout the study. Thirty of the 33 patients with AGA completed the GFD period, after which they showed a highly significant decrease in mean PASI. This included a significant decrease in the 16 AGA-positive patients with normal routine histology in duodenal biopsy specimens. The AGA-negative patients were not improved. After GFD, the AGA values were lower in 82% of those who improved. There was a highly significant decrease in serum eosinophil cationic protein in patients with elevated AGA. When the ordinary diet was resumed, the psoriasis deteriorated in 18 of the 30 patients with AGA who had completed the GFD period. In conclusion, psoriasis patients with raised AGA might improve on a GFD even if they have no EmA or if the increase in duodenal intraepithelial lymphocytes is slight or seemingly absent.

Detection of gluten in human sera by an enzyme immunoassay: comparison of dermatitis herpetiformis and celiac disease patients with normal controls.

We have developed a triple sandwich enzyme immunoassay to detect circulating gluten in human sera. With human sera containing known amounts of added gluten as controls, the assay was sensitive in the range of 0.75 to 75 micrograms of gluten per ml of serum. Forty-one control subjects were compared to 21 patients with dermatitis herpetiformis and 11 patients with celiac disease. The dermatitis herpetiformis and celiac disease patients had significant elevation of serum gluten values over the control subjects. Circulating gluten antigenemia is a previously unrecognized feature which may be important in understanding the pathogenesis of dermatitis herpetiformis and celiac disease.