Sara Quaglia

Anti-transglutaminase antibodies in non-coeliac children suffering from infectious diseases.

Anti‐transglutaminase antibodies are the diagnostic markers of coeliac disease. A role is suggested for infectious agents in the production of anti‐transglutaminase antibodies. The aim was to measure positive anti‐transglutaminase antibody levels in children with infectious diseases and to compare immunological and biological characteristics of the anti‐transglutaminase antibodies derived from these children with that from coeliac patients. Two hundred and twenty‐two children suffering from infectious diseases were enrolled prospectively along with seven biopsy‐proven coeliacs. Serum samples were tested for anti‐transglutaminase antibodies and anti‐endomysium antibodies; positive samples were tested for coeliac‐related human leucocyte antigen (HLA)‐DQ2/8 and anti‐viral antibodies. Purified anti‐transglutaminase antibodies from the two study groups were tested for urea‐dependent avidity, and their ability to induce cytoskeletal rearrangement and to modulate cell‐cycle in Caco‐2 cells, using phalloidin staining and bromodeoxyuridine incorporation assays, respectively. Nine of 222 children (4%) tested positive to anti‐transglutaminase, one of whom also tested positive for anti‐endomysium antibodies. This patient was positive for HLA‐DQ2 and was diagnosed as coeliac following intestinal biopsy. Of the eight remaining children, two were positive for HLA‐DQ8. Levels of anti‐transglutaminase returned to normal in all subjects, despite a gluten‐containing diet. Purified anti‐transglutaminase of the two study groups induced actin rearrangements and cell‐cycle progression. During an infectious disease, anti‐transglutaminase antibodies can be produced temporarily and independently of gluten. The infection‐triggered anti‐transglutaminase antibodies have the same biological properties as that of the coeliacs, with the same in‐vivo potential for damage.

Regulatory T-Cell Function Is Impaired in Celiac Disease

Celiac disease (CD) is characterized by intolerance to gluten and high risk of developing autoimmune phenomena. Possible defects in immune tolerance could have a role in the pathogenesis of the disease. As regulatory T-cells (Tregs) are the main population involved in maintaining peripheral tolerance, we investigated the number of these cells in celiac patients as compared with healthy donors. Moreover, we analyzed the suppressive function of CD4+CD25+ T-cells from celiac disease patients and controls on autologous responder T-cells (CD4+CD25−). The percentage of CD4+CD25+FOXP3+ cells was not different in celiacs and in healthy controls, and among positive cells the level of expression of the two regulatory markers was comparable. However, the suppressor activity of Tregs was significantly impaired in CD patients. These results suggest that a defect in Tregs function could play a role in the pathogenesis of CD and in CD-associated autoimmunity.

Uselessness of anti-actin antibody in celiac disease screening ☆

BACKGROUND Serum anti-actin IgA antibodies (AAA) were identified in patients with celiac disease (CD), and a close correlation emerged between the presence of AAA and mucosa damage, but test for AAA found in celiacs have a wide range of sensitivity and specificity values. AIM To compare 1) the sensitivity and specificity of untreated, calcium-chelated and heated sera from 102 celiacs, 52 sick patients and 103 healthy controls in the determination of AAA, and 2) the reliability of AAA with anti-transglutaminase antibodies (anti-tTG) in diagnosing celiac disease and in predicting intestinal damage. The intestinal derived AAA was isolated by using the phage-display library technique. RESULTS Treated sera was significantly more sensitive than untreated (p=0.0001), and showed a significant correlation between AAA and the three degrees (3a, 3b, 3c) of intestinal damage (p=0.01). Sensitivity and specificity values of anti-tTG assay were higher than the AAA assay, and anti-tTG serum-concentration was only significantly correlated with more severe (3b and 3c) intestinal damage degrees. AAA isolated by phage display showed similar results of serum AAA in immunofluorescence assay. CONCLUSIONS Notwithstanding correlation between AAA and celiac disease, AAA assay, also after treatments, has little to offer in screening for CD compared to the well-established anti-transglutaminase assay.

Prevalence of celiac disease in patients with severe food allergy

The association between food allergy and celiac disease (CD) is still to be clarified. We screened for CD 319 patients with severe food allergy (IgE > 85 kU/l against food proteins and a history of severe allergic reactions) who underwent specific food oral immunotherapy (OIT), together with 128 children with mild allergy who recovered without OIT, and compared the prevalence data with our historical data regarding healthy schoolchildren. Sixteen patients (5%) with severe allergy and one (0.8%) with mild allergy tested positive for both genetic and serological CD markers, while the prevalence among the schoolchildren was 1%. Intestinal biopsies were obtained in 13/16 patients with severe allergy and in the one with mild allergy, confirming the diagnosis of CD. Sufferers from severe food allergy seem to be at a fivefold increased risk of CD. Our findings suggest that routine screening for CD should be recommended in patients with severe food allergy.

Serum Anti-Tissue Transglutaminase Antibodies Detected during Febrile Illness May Not Be Produced by the Intestinal Mucosa

Anti-transglutaminase antibodies are the diagnostic marker of celiac disease, and are considered to be synthesized only by intestinal B-lymphocytes. During an infectious disease, these antibodies are transiently detected in serum. We show that these infection-triggered antibodies may not originate in the intestinal mucosa and are not an indication of celiac disease.

Lack of evidence of rotavirus‐dependent molecular mimicry as a trigger of coeliac disease

New data suggest the involvement of rotavirus (RV) in triggering autoimmunity in coeliac disease (CD) by molecular mimicry between the human‐transglutaminase protein and the dodecapeptide (260‐271 aa) of the RV protein VP7 (pVP7). To assess the role of RV in the onset of CD, we measured anti‐pVP7 antibodies in the sera of children with CD and of control groups. We analysed serum samples of 118 biopsy‐proven CD patients and 46 patients with potential CD; 32 children with other gastrointestinal diseases; 107 no‐CD children and 107 blood donors. Using enzyme‐linked immunosorbent assay (ELISA) assay, we measured immunoglobulin (Ig)A–IgG antibodies against the synthetic peptides pVP7, the human transglutaminase‐derived peptide (476–487 aa) which shows a homology with VP7 protein and a control peptide. The triple‐layered RV particles (TLPs) containing the VP7 protein and the double‐layered RV‐particles (DLPs) lacking the VP7 protein were also used as antigens in ELISA assay. Antibody reactivity to the RV‐TLPs was positive in 22 of 118 (18%) CD patients and in both paediatric (17 of 107, 16%) and adult (29 of 107, 27%) control groups, without showing a statistically significant difference among them (P = 0·6, P = 0·1). Biopsy‐proven CD patients as well as the adult control group demonstrated a high positive antibody reactivity against both pVP7 (34 of 118, 29% CD patients; 66 of 107, 62% adult controls) and control synthetic peptides (35 of 118, 30% CD patients; 56 of 107, 52% adult controls), suggesting a non‐specific response against RV pVP7. We show that children with CD do not have higher immune reactivity to RV, thus questioning the molecular mimicry mechanism as a triggering factor of CD.

Intestinal-mucosa anti-transglutaminase antibody assays to test for genetic gluten intolerance.

Intestinal-mucosa anti-transglutaminase antibody assays to test for genetic gluten intolerance