B epitopes in wheat allergy were different from B epitopes of coeliac disease. Differences exist in IgE-binding epitopes between patients with food allergy to wheat. IgE from those suffering from WDEIA, anaphylaxis and urticaria detected sequential epitopes in the repetitive domain of gliadins whereas IgE from AEDS patients probably recognized conformational epitopes.

A phage displayed dodecapeptide library and synthetic octapeptides spanning the complete sequence of α‐ and γ‐type gliadin and overlapping in six amino acids (pepscan) were screened for binding to human gliadin antibodies (AGA). Phage display experiments led to four sequences recognized with significantly higher frequency by sera with raised IgA‐AGA titres than by control sera. All these peptides contained the core sequence PEQ. Pepscan experiments revealed binding of AGA to five prominent regions: (i) QXQPFP (binding to IgG and IgA, X representing P, Q, and L); (ii) IPEQ (IgG) and WQIPEQ (IgA); (iii) FFQP (IgG) and QGXFQP (IgA, X representing F and S); (iv) PQQLPQ (IgG and IgA), all in α‐type gliadin; and (v) QPQQPF (IgG and IgA) in γ‐type gliadin. In two of the sequences (QPQQPF and QQQPFP), substitution of Q by E resulting in QPEQPF and QEQPFP, respectively, increased significantly binding of AGA from sera of patients with biopsy‐proven or suspected coeliac disease (CoD), all positive for endomysium antibodies (EmA). In contrast, binding of sera with high AGA titre from EmA‐negative patients (CoD and dermatitis herpetiformis excluded) was not enhanced by this substitution. Thus, AGA directed against these modified epitopes can be regarded as specific for CoD. This is the first study demonstrating that deamidation of gliadin improves reactivity of AGA of CoD patients.

In a prospective study, we validated the TTG-IgA procedure and the TTG-DGL procedure in identification of pediatric patients with or without celiac disease, without biopsy. German Clinical Trials Registry no.: DRKS00003854.

Background: Celiac disease (CD) is induced by wheat gliadins and related cereal proteins. Anti-gliadin antibodies (AGAs) are present in the serum of CD patients, but these antibodies have lower diagnostic specificity and sensitivity than autoantibodies [anti-endomysium antibodies (AEmAs) and anti-tissue transglutaminase antibodies (AtTGAs)]. Recently, AGAs from CD patients were found to recognize deamidated gliadin peptides, probably formed by the action of tissue transglutaminase. Methods: We synthesized several gliadin peptides and their glutamine-glutamic acid-substituted counterparts on cellulose membranes and tested their recognition by IgA in sera of 52 AEmA-positive CD patients and 76 AEmA-negative controls in a luminescence assay. For comparison, we assayed IgA concentrations of AGAs, AtTGAs, and AEmAs. For measurement of AtTGAs, we used the human recombinant antigen. Results: We identified several nonapeptides that were detected with high specificity by IgA in CD patients. Diagnostic accuracy of the peptide antibody assay was highest when peptide PLQPEQPFP was used in combination with peptide PEQLPQFEE within one assay. AGAs were above the cutoff in 14 of the controls, but only 5 of the controls were positive for peptide antibod-

The conformation of LTP1 appeared to have a strong impact on the type of IgE-binding epitopes elicited by this protein in both man and mouse. The responses in mice sensitized to gliadins or LTP1 were sufficiently comparable with the human response in terms of IgE-binding epitopes to provide support for the use of the mouse model in further investigations.