Assessment of a combination screening assay for celiac disease

"Per ELISA": Time to adopt anti-transglutaminase/deamidated gliadin peptide diagnostic combination in coeliac disease of adults?

BACKGROUND

Anti-endomysial antibodies (EMA) and anti-tissue transglutaminases (a-tTg) play a pivotal role in coeliac disease (CD) diagnosis. Deamidated anti-gliadin peptides (DGP) were added to the CD diagnostic workup.

AIMS

We aimed to compare the diagnostic accuracies of ELISA-based (a-tTg/DGP) and immunofluorescence-ELISA-based strategies (EMA/a-tTg) for CD diagnosis.

METHODS

From November 2020 to November 2022, we undertook an observational prospective study including consecutive adult patients with suspected CD. All subjects were tested for EMA, a-tTg and DGP IgA. An ROC curve was plotted to establish the best specificity cut-off of a-tTg and DGP levels, which would predict the presence of Marsh≥2 and Marsh=3. The diagnostic accuracies of a-tTg/DG and EMA/a-tTg were compared.

RESULTS

The study included 275 CD patients. Histology showed Marsh=1 in 9.9%, Marsh=2 in 4.5%, and Marsh=3 in 85.6.%. The best cut-off value of a-tTg for predicting Marsh≥2 was 42 U/mL, while the best cut-off for predicting atrophy was 68.4 U/mL. The best cut-off value of DGP for predicting Marsh≥2 was 56 U/mL, while the best cut-off for predicting atrophy was 78 U/mL. A-tTg/EMA showed 97% sensitivity and 100% specificity, whereas a-tTg/DGP showed 94% sensitivity and 100% specificity.

CONCLUSION

A-tTg/DGP is accurate for CD diagnosis and could reduce costs and operator-dependency of EMA. DGP, together with a-tTg, could replace EMA in CD diagnosis.

AGY, a Novel Egg Yolk-Derived Anti-gliadin Antibody, Is Safe for Patients with Celiac Disease

BACKGROUND

Celiac disease (CD) is a gluten-triggered autoimmune disorder of the small intestine. A lifelong gluten-free diet (GFD) is the only approved treatment; however, strict adherence is difficult and many suffer from inadvertent gluten exposure. Oral egg yolk anti-gliadin antibody (AGY) is a novel treatment to neutralize gluten and may improve the efficacy of the GFD.

AIMS

To determine the safety, tolerability, and potential efficacy of AGY in patients with CD.

METHODS

This 6-week, open-label, single-arm study was conducted in adults with biopsy-proven CD on a GFD. Safety measures included adverse events, physical examination, and clinical laboratory tests. Additional measures included a daily Celiac Symptom Index, Health-Related Quality of life, anti-tissue transglutaminase and anti-gliadin IgA/IgG, and lactulose/mannitol excretion ratio (LMER). A 2-week run-in period to assess questionnaire compliance and acceptability of baseline safety laboratory results was followed by a 4-week treatment period with two AGY capsules taken before meals.

RESULTS

Ten patients completed the study (mean age 43.4 years, nine female). All followed a GFD for at least 6 months (mean 5 years). No safety concerns were identified. Most patients had fewer celiac symptoms (especially tiredness, headache, and bloating), improved quality of life, lowered antibodies, and lowered LMER when taking AGY compared to the run-in period.

CONCLUSION

In our cohort, AGY was safe and potentially associated with improved CD-related outcome measures in patients on a GFD. A larger study powered for further safety and efficacy evaluation is planned.

Clinical and biological correlations in celiac disease in children: the prospective single experience of a romanian tertiary center: A case-control study (Strobe-Compliant study)

Celiac disease-a chronic inflammatory disease of the intestine-is triggered by gluten or associated protein consumption.The aim of our study was to assess the sensitivity, specificity of the combined anti-transglutaminase 2 (TG2)/deamidated gliadin peptide antibodies (DGP), and antiendomisium antibodies (EMA), to determine the distribution of HLA-DQ2/DQ8 for the 140 tested patients, and also to evaluate the clinical and laboratory characteristics of patients admitted with the suspicion of celiac disease (CD). Children included in the study were divided into: group 1, patients with confirmed CD; group 2, patients with "potential' CD; group 3, control group, patients without CD. We assessed the standard laboratory data, the level of TG2/DGP and EMA antibodies, as well as the distribution of HLA molecules in the selected patients. Histopathological examination was considered the criterion standard for diagnosis in most cases.The sensitivity of TG2/DGP was 85% and the specificity 92%. EMA showed a sensitivity of 82% and a specificity of 98%. The vast majority of patients diagnosed with CD were either HLA-DQ2.5 (encoded by DQA1*05 & DQB1*02) positive (87.5%) or HLA-DQ8 (encoded by DQB1*03:02) positive (12.5%). One patient showed a positivity only for HLA-DQ2.2 (encoded by DQA1*02 & B1*02).Our study showed that the genetic risk for CD was present in more than one-third of the cases without a confirmed diagnosis of CD. Therefore, the awareness of genetic susceptibility for CD is essential because of the fact that these individuals can develop the disease at any point of their lives. The sensitivity of TG2/DGP and EMA were very similar, whereas EMA presented a higher specificity as that of TG2/DGP.

Simultaneous detection of celiac disease-specific IgA antibodies and total IgA

Purpose

Celiac disease (CD) serology requires analysis of tissue transglutaminase type-2 (TG2autoAbs), deamidated gliadin (DGAbs), and as reference endomysial autoantibodies (EmA). Total IgA assessment helps to determine IgA-deficient CD patients. The novel multiplex indirect immunofluorescence (IIF) technique CytoBead was used to develop the first quantitative one-step serological CD assay comprising both simultaneous IgA autoAb and total IgA testing.

Methods

CytoBead CeliAK detecting TG2autoAb, DGAb, EmA, and simultaneously total IgA uses fluorescent microparticles for antigen and antibody immobilization along with monkey-esophagus tissue sections on glass slides. The assay was interpreted visually by classical fluorescent microscopy and digital IIF using AKLIDES^®. Overall, 380 samples (155 CD patients, 5 with IgA deficiency, 68 with cystic fibrosis, 59 with eye disease, 93 blood donors) were run for performance analysis. Data were compared with classical IgA autoAb analysis by ELISA and IIF.

Results

Comparing CD-specific IgA autoAb testing by CytoBead with classical IIF and ELISA, very good agreements for EmA, TG2autoAb, and DGAb were determined (Cohen’s κ = 0.98, 0.96, 0.85, respectively). The difference between multiplex and single testing revealed a significant difference for TG2autoAb testing only (McNemar, p = 0.0078). Four CD patients and 4 controls demonstrated TG2autoAb positivity by ELISA but were negative by CytoBead. Further, 140/155 (90.9 %) CD patients demonstrated TG2autoAb levels above ten times the upper normal and all five IgA-deficient samples IgA levels <0.2 g/L by CytoBead.

Conclusions

The novel multiplex CytoBead CeliAK enables simultaneous CD-specific autoAb and IgA deficiency analyses comparable with classical testing by single-parameter assays. Thus, comprehensive CD serology by CytoBead can alleviate the workload in routine laboratories.

Electronic supplementary material

The online version of this article (doi:10.1007/s13317-016-0073-2) contains supplementary material, which is available to authorized users.