Immunogenicity of two oat varieties, in relation to their safety for celiac patients.

OBJECTIVE: Most of the recent studies suggest that oats are well tolerated by celiac disease (CD) patients. However, it is still possible that different oat cultivars may display different biological properties relevant for CD pathogenesis. We aimed to investigate biological and immunological properties of two oat varieties, Avena genziana and Avena potenza, in relation to their safety for CD patients. MATERIAL AND METHODS: Phosphorylation of extracellular signal-regulated kinase (ERK) and trans-epithelial electrical resistance (TEER) were evaluated in CaCo-2 cells treated with peptic-tryptic (PT) digests from the two oats and from gliadin (PTG). With the same PT-digests, duodenal biopsies from 22 CD patients were treated in vitro for 24 h and density of CD25+ cells in lamina propria and of intraepithelial CD3+ T cells was measured, as well as crypt cell proliferation and epithelial expression of interleukin 15. Finally, interferon γ (IFN-γ) production was measured as evidence of gliadin-specific T-cell activation by PT-digests. RESULTS: In contrast to PTG, oats PT-digests were not able to induce significant increase in ERK phosphorylation and decrease in TEER in CaCo-2 cells. In the organ culture system, oats PT-digests, unlike PTG, did not induce significant increase in crypt enterocyte proliferation, increase in interleukin 15 expression or in lamina propria CD25+ cells. Nevertheless Avena potenza increased intraepithelial T-cell density, while Avena genziana-induced IFN-γ production in 3/8 CD intestinal T cell lines. CONCLUSIONS: Our data show that Avena genziana and Avena potenza do not display in vitro activities related to CD pathogenesis. Some T-cell reactivity could be below the threshold for clinical relevance.

Intestinal deposits of anti-tissue transglutaminase IgA in childhood celiac disease.

BACKGROUND: High serum levels of anti-tissue-transglutaminase-2 IgA antibodies (anti-TG2), which are produced and deposited in the intestine, characterize celiac disease. AIM: To assess the diagnostic value of intestinal deposits of anti-TG2 IgA for celiac disease in a paediatric population. METHODS: 344 children underwent duodenal biopsy for the suspicion of CD, and were divided into 3 groups: group A, 144 celiac subjects with villous atrophy (Marsh 3b-c); group B, 109 subjects with high serum levels of anti-TG2 but normal intestinal mucosa (Marsh 0-1) (potential celiac disease patients); group C, 91 subjects with normal levels of serum anti-TG2: 70 with Marsh 0-1 and 21 with Marsh 3a mucosa. All duodenal sections were evaluated for the presence of intestinal deposits of anti-TG2 IgA by double immunofluorescence. RESULTS: Deposits of anti-TG2 IgA were present in 96%, 68%, 12% of patients from groups A, B, C, respectively. Diagnostic sensitivity and specificity for celiac disease were 96% and 88% vs. 97% and 100% for serum anti-TG2, respectively. The degree of concordance with serum anti-TG2 was 85%. CONCLUSION: Detection of intestinal deposits of anti-TG2 IgA is a useful diagnostic tool. Further research is needed regarding their ability to predict evolution to villous atrophy in potential celiac disease.

Serum and intestinal celiac disease-associated antibodies in children with celiac disease younger than 2 years of age.

OBJECTIVES: In children younger than 2 years of age, a diagnosis of celiac disease (CD) is difficult to make because anti-endomysium (anti-EMA)/anti-tissue transglutaminase 2 (anti-TG2) antibodies are less sensitive than in older children. The aim of our study was to evaluate how many children younger than 2 years of age and diagnosed with CD, were negative for serum anti-TG2 antibodies and to test the hypothesis that in these patients, TG2-specific IgA deposits could instead be present at mucosal level. PATIENTS AND METHODS: A total of 104 children younger than 2 years of age and 179 children older than 2 years, all of whom had been diagnosed with CD, were investigated for serum CD-associated antibodies (anti-gliadin [AGA] IgA and IgG, EMA-IgA, anti-TG2-IgA). The presence of intestinal anti-TG2 extracellular IgA deposits was searched by using double immunofluorescence in 56 of the patients younger than 2 years of age and in 40 of those who were older than 2 years. RESULTS: In children with CD who were younger than 2 years of age, high levels of AGA-IgA were found in 93/104 (89%) and 98/104 (94%) were found of have high levels of AGA-IgG. In children older than the age of 2 years with CD, 120/179 (67%) had high levels of AGA-IgA and 151/179 (84%) had high levels of AGA-IgG. Serum EMA were present in 92/104 (88%) in the younger group and in 176/179 (98%) of the older group. Ninety-one of 104 children (87%) younger and 172/179 (96%) older than 2 years showed high serum levels of anti-TG2. Finally, 41/56 (73%) children younger than 2 years and all of the 40 children (100%) older than 2 years of age showed mucosal anti-TG2-IgA deposits. CONCLUSIONS: EMA and anti-TG2-antibody measurements show higher sensitivity for the diagnosis of CD in children older than 2 years compared with younger children. The search for mucosal deposits of anti-TG2-IgA does not improve the diagnostic performance.