Our aim was to explore the diagnostic value of a newly developed synthetic peptide antibody assay addressing specific synthetic gliadin-derived deamidated peptides (AGA II) for the diagnosis of ...celiac disease (CD).
We assayed serum samples obtained prospectively at diagnosis from a population of 92 consecutive adult patients with CD and 113 non-CD controls. Patients were reevaluated after 6 months (n = 56) and 1 year (n = 20) of treatment. All patients and controls underwent intestinal biopsy and a set of CD-related serology tests. A newly developed enzyme-linked immunosorbent assay (ELISA) for detecting IgA and IgG antibodies against synthetic deamidated gliadin epitopes was used.
At diagnosis, sensitivity and specificity were 94.6% and 99.1% for AGA II IgA and 92.4% and 100% for AGA II IgG. Absolute values and the proportion of positive samples for both antibodies were significantly reduced at 6 months (P < .0000) and 1 year (P < .001) after initiation of a gluten-free diet. Compared with conventional AGA, the peptide antibodies had greater sensitivity, specificity, positive and negative predictive values, accuracy, and likelihood ratios. Compared with antitissue transglutaminase antibodies, AGA II had similar sensitivity but greater specificity and predictive values, better likelihood ratios, and an excellent agreement (kappa statistic = .92).
This study assessed the value of an ELISA assay in detecting antibodies to gliadin-related peptides. This assay appears to be a reliable tool for diagnosing CD and suggests promising accuracy that may be very useful in clinical practice.
Abstract Background Deterioration of quality of life in the long term has been suggested for celiac disease patients on a gluten-free diet. Aims To determine long-term quality of life of celiac ...disease patients and to assess the benefits of gluten-free diet compliance. Patients We prospectively evaluated 53 newly diagnosed adult celiac disease patients. Methods The Short Form 36 Health Survey, the Gastrointestinal Symptoms Rating Scale and the Beck Depression Inventory were employed at the time of diagnosis, 1 year, and beyond 4 years (median: 53 months) on treatment. Results At 1 year, a significant improvement from baseline in quality of life indicators was observed ( p < 0.001 to p < 0.0001) with comparable scores to healthy subjects. At 4 years, the Short Form 36 Health Survey scores ( p < 0.002 to p < 0.0002) and Beck Depression Inventory score ( p < 0.002) show significant deterioration compare with 1 year. Most scores remained significantly better than those at diagnosis ( p < 0.03 to p < 0.0005). No changes were detected in the Gastrointestinal Symptoms Rating Scale scores. The long-term impairment of quality of life was attributable to the deterioration of most dimensions in patients who were not strictly compliant with the gluten-free diet ( p < 0.05 to p < 0.001). Conclusions Long-term deterioration of quality of life outcomes after the first year of gluten-free diet was associated with the lack of strict compliance with the diet.
Some patients with celiac disease (CD) may be seronegative with the commonly used test for IgA anti-tissue transglutaminase (anti-tTG) antibodies. Our aim was to explore whether newer assays ...incorporating synthetic deamidated gliadin-related peptides (DGPs) or other TG isoenzymes as antigen are useful for detecting gluten sensitivity in IgA anti-tTG-seronegative patients.
We assayed serum samples obtained at diagnosis from (a) anti-tTG-seronegative patients with a CD-like enteropathy (n = 12), (b) skin biopsy-proven dermatitis herpetiformis (DH) patients (n = 26), and (c) IgA anti-tTG-positive CD patients (n = 26). All patients had typical total IgA concentrations. All patients underwent intestinal biopsy and serum testing for (a) detection of IgA and IgG isotypes of both anti-DGP and anti-tTG in a single assay (tTG/DGP Screen; INOVA Diagnostics), (b) simultaneous detection of both IgA and IgG anti-DGP antibody isotypes (DGP Dual; INOVA Diagnostics), and (c) detection of antibodies to transglutaminase 3 (TG3) or transglutaminase 6 (TG6).
All anti-tTG-seropositive patients also tested positive in anti-DGP assays. Overall, tTG/DGP Screen detected 6 (31.6%) of the 19 anti-tTG seronegatives, and anti-DGP Dual produced positive results in 5 (26.3%) of these cases. Whereas both assays detected 2 anti-tTG-negative DH patients with partial villous atrophy, they were positive in only 2 of the 5 cases with no histologically discernible mucosal damage. Testing for antibodies to TG3 and TG6 identified 7 (36.8%) of the 19 anti-tTG-negative patients, 5 of which were also positive for anti-DGP.
Detection of anti-DGP with tTG/DGP Screen or anti-DGP Dual, or detection of antibodies to other TG isoenzymes, enhances the sensitivity for detecting gluten sensitivity among non-IgA- deficient, anti-tTG-seronegative patients with CD-like enteropathy.
The efficacy of celiac disease (CD)-related antibodies in monitoring clinical outcome of patients remains unclear. Our aims were to determine dynamics of antibodies after diagnosis and to assess ...their performances in monitoring patients' long-term compliance with the gluten-free diet (GFD).
We prospectively estimated the performance of seven celiac disease-related antibody tests at diagnosis and at 1 year and more than 4 years after treatment initiation in 53 adults. The ability of antibodies to identify patients partially compliant to treatment was explored by the receiver operating characteristic curve analysis. The derived cut-off values ('compliance' cutoffs) were compared with cut-off values used for diagnosis ('diagnostic' cutoffs). The degree of compliance with the GFD was assessed using a standardized, multidisciplinary approach.
Concentrations of all antibodies decreased significantly at 1 year after diagnosis. The decline continued for more than 4 years in strictly compliant patients (P<0.05-0.001). The gap between 'compliance' and 'diagnostic' cut-offs values was wider at 1 year than at more than 4 years. The predictability of partial compliance determined by the area under receiver operating characteristic curves was relevant for most tests examined at 1 year (areas ranging: 0.64-0.72) and more than 4 years (0.58-0.78). Immunoglobulin A antibodies to deamidated gliadin peptides and tissue transglutaminase had the best performance for monitoring long-term compliance.
Decreased concentrations of antibodies were significantly associated with the degree of compliance with the GFD. Immunoglobulin A antibodies to deamidated gliadin peptides and tissue transglutaminase had the best and more consistent performances. The serial measurement of antibody levels seems to be more reliable in monitoring compliance than the positive/negative expression of results.
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