Serologic Assay for Diagnosis of XXXX Based on a Patient-Derived Monoclonal Antigliadin Antibody.

@entity1 @entity30 @entity1593 @entity8265
BACKGROUND _ AIMS: @entity1 with @entity1593 can be identified based on the detection of serum antibodies to deamidated gliadin peptides (DGPs). Recombinant human monoclonal antibodies (hmAb) against gliadin are produced by cloning antibody genes from single IgA-producing plasma cells isolated from lesions of @entity1 with @entity1593 . We developed an assay to identify @entity1 with @entity1593 based on the ability of antibodies from their serum to inhibit the binding of a gliadin-specific hmAb (1002-1E03) to a specific peptide antigen (inhibition assay). METHODS: We selected 2 peptides (a 34-mer and a 26-mer) found in   -gliadins and low-molecular-weight glutenins that had been identified as specific targets of the hmAb 1002-1E03 from a digest of gliadin treated by @entity8265 . These peptides contained repeat sequence motifs; their interaction with hmAb 1002-1E03 was assessed in an amplified luminescent proximity homogeneous inhibition assay. We also tested peptides we created that included 3 repeated sequence motifs. Serum samples from untreated @entity1 diagnosed with @entity1593 (n  = 106) and 2 control groups (198 blood donors, 151 @entity1 with @entity30 ) were analyzed using the assay, as well as in conventional commercial assays that measure IgA against @entity8265 ( @entity8265 ) or IgG against DGP. RESULTS: In our inhibition assays, the 34-mer peptide showed the best results, and identified @entity1 with @entity1593 with 86.8% sensitivity and 98.6% specificity. Its diagnostic accuracy was comparable with that of commercial anti-DGP IgG (sensitivity, 87.9%; specificity, 98.0) and anti- @entity8265 IgA (sensitivity, 81.1%; specificity, 98.9) assays, and it detected most of the patients with anti- @entity8265 IgA-negative @entity1593 without a significant decrease in specificity. Combined use of the anti-  34 and the anti- @entity8265 assays produced specificity and sensitivity values of 95.3% and 98.0%, respectively. CONCLUSIONS: We developed an antigliadin inhibition assay that identifies @entity1 with @entity1593 with high levels of specificity and sensitivity. It may prove useful as an adjunct to the current assay for anti- @entity8265 IgA.
