Characterization of the Anti-Tissue Transglutaminase Antibody Response in Nonobese Diabetic Mice

Abstract Type 1 diabetes mellitus is an autoimmune disorder characterized by destruction of insulin-producing pancreatic β cells by T lymphocytes. In nonobese diabetic (NOD) mice, a role has been hypothesized for dietary gluten proteins in the onset of diabetes, and because gluten dependence is the major feature of celiac disease, together with production of Abs to the autoantigen tissue transglutaminase (tTG), we looked for the presence of anti-tTG Abs in the serum of NOD mice and, to establish their origin, analyzed the Ab repertoire of NOD mice using phage display Ab libraries. We found significant levels of serum anti-tTG Abs and were able to isolate single-chain Ab fragments to mouse tTG mainly from the Ab libraries made from intestinal lymphocytes and to a lesser extent from splenocytes. Data from NOD mice on a gluten-free diet suggest that the anti-tTG response is not gluten-dependent. The intestinal Ab response to tTG is a feature of NOD mice, but the underlying mechanisms remain obscure

Diagnostic accuracy and applicability of intestinal auto-antibodies in the wide clinical spectrum of coeliac disease

BACKGROUND: Intestinal coeliac auto-antibodies are the marker of coeliac disease (CD). Since the determination of these antibodies is still not widely available, we used immunoassays to identify the most suitable technology for revealing intestinal auto-antibodies in the wide clinical spectrum of CD. METHODS: Intestinal auto-antibodies have been prospectively investigated in CD suspected children using two immunoassays: intestinal-deposits of IgA anti-tissue transglutaminase antibodies (anti-tTG) and biopsy-culture IgA anti-endomysium (AEA). Intestinal IgM antibodies have been determined in IgA-deficient subjects. FINDINGS: Two-hundred and twenty-one suspected CD patients were enrolled. Intestinal antibodies were tested positive for both assays in classical CD patients (n\u202f=\u202f178) with villous atrophy and positive serum-CD antibodies, potential CD patients (n\u202f=\u202f16) with normal intestinal mucosa and positive serum-CD antibodies, and pre-potential CD patients (n\u202f=\u202f14) with normal intestinal mucosa and negative serum-CD antibodies. In 13/221 with normal intestinal mucosa, negative CD-serum antibodies and negative intestinal antibodies CD has been excluded. All classical, 14/16 potential and 11/14 pre-potential CD patients on gluten-free diet (GFD) improved their symptoms. In 9/11 pre-potential patients intestinal antibodies disappeared on GFD. Both assays were negative in 69/71 control subjects. The two assays showed high diagnostic sensitivity (100%) and specificity (99%). INTERPRETATION: Intestinal CD-antibodies make prompt diagnosis in the wide clinical spectrum of CD reducing the delay in diagnosis and treatment, especially in pre-potential CD patients. The easy handling biopsy culture assay is an effective diagnostic tool which should be carried out by any gastroenterology unit to recognize all CD clinical manifestations

Intestinal production of anti-tissue transglutaminase 2 antibodies in patients with diagnosis other than celiac disease

Abstract: It has been hypothesized that gluten-dependent production of anti-tissue-transglutaminase 2 (anti-TG2) antibodies may occur only at an intestinal level. We have investigated intestinal production of anti-TG2 antibodies in 136 patients with normal serum levels of anti-TG2 antibodies and normal duodenal mucosa. Intestinal deposits of anti-TG2 antibodies were evaluated by immunofluorescence and anti-TG2 antibodies released in organ culture supernatants measured by ELISA. Intestinal antibody libraries were obtained from 10 subjects. Immunohistochemistry for CD25+, CD3+, and TCR- + was assessed in subjects with positive (n = 32) and negative (n = 31) intestinal anti-TG2 antibodies. Globally 33/136 (24%) seronegative patients produced anti-TG2 autoantibodies at an intestinal level. Antibody libraries analysis confirmed the anti-TG2 antibodies mucosal production in all (n = 8) positive subjects. Lamina propria CD25+ cell count was significantly (p < 0.05) higher in patients with intestinal anti-TG2. Moreover, 13/32 (41%) of them showed high TCR- +/CD3+ ratios. Intestinal anti-TG2 antibody production does not show absolute specificity for CD. It is seen more often in association with inflamed mucosa. Further investigations are necessary to prove the possible role of dietary gluten

Cross-sectional study of coeliac autoimmunity in a population of Vietnamese children

Objective: The prevalence of coeliac disease (CD) inVietnam is unknown. To fill this void, we assessed the prevalence of serological markers of CD autoimmunity in a population of children in Hanoi. Setting: The outpatient blood drawing laboratory of the largest paediatric hospital in North Vietnam was used for the study, which was part of an international project of collaboration between Italy and Vietnam. Participants: Children having blood drawn for any reason were included. Exclusion criteria were age younger than 2 years, acquired or congenital immune deficiency and inadequate sample. A total of 1961 children (96%) were enrolled (838 females, 1123 males, median age 5.3 years). Outcomes: Primary outcome was the prevalence of positive autoimmunity to both IgA antitransglutaminase antibodies (anti-tTG) assessed with an ELISA test and antiendomysial antibodies (EMA). Secondary outcome was the prevalence of CD predisposing human leucocyte antigens (HLA) (HLA DQ2/8) in the positive children and in a random group of samples negative for IgA anti-tTG. Results: The IgA anti-tTG test was positive in 21/1961 (1%; 95% CI 0.61% to 1.53%); however, EMA antibodies were negative in all. HLA DQ2/8 was present in 7/21 (33%; 95% CI 14.5% to 56.9%) of the anti-tTG-positive children and in 72/275 (26%; 95% CI 21% to 32%) of those who were negative. Conclusions: Coeliac autoimmunity is rare in Vietnam, although prevalence of HLA DQ2/8 is similar to that of other countries. We hypothesise that the scarce exposure to gluten could be responsible for these findings

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

A Functional Idiotype/Anti-Idiotype Network Is Active in Genetically Gluten-Intolerant Individuals Negative for Both Celiac Disease-Related Intestinal Damage and Serum Autoantibodies

An unbalance between Abs that recognize an autoantigen (idiotypes; IDs) and Igs that bind such Abs (anti-IDs) is considered a functional event in autoimmune disorders. We investigated the presence of an ID/anti-ID network in celiac disease (CD), a condition in which antitissue transglutaminase 2 (TG2) Abs are suspected to contribute to CD pathogenesis. To characterize the ID side, we reproduced by in vitro yeast display the intestine-resident Abs from CD and control patients. These TG2-specific IDs were used to identify potential anti-IDs in the serum. We observed elevated titers of anti-IDs in asymptomatic patients with predisposition to CD and demonstrated that anti-ID depletion from the serum restores a detectable humoral response against TG2. Our study provides an alternative approach to quantify CD-related autoantibodies in cases that would be defined "negative serology" with current diagnostic applications. Therefore, we suggest that developments of this technology could be designed for perspective routine tests

Celiac Disease Frequency Is Increased in IgE-Mediated Food Allergy and Could Affect Allergy Severity and Resolution

Objectives: An increased frequency of celiac disease (CeD) has been reported in severe Immunoglobulin E (IgE) -mediated food allergy (FA). This observation requires confirmation, and whether CeD affects FA severity and resolution is unknown. The study aims to estimate the prevalence of CeD in patients with FA and to investigate whether CeD affects FA severity and oral tolerance. Methods: Consecutive patients with FA referred for allergen reintroduction, either to evaluate allergy resolution or to start oral immunotherapy (OIT), were evaluated for CeD and for FA severity. The primary outcome was the prevalence of CeD. Secondary outcomes were the frequency of severe FA and the level of clinical tolerance at study entry and at last follow-up in patients with isolated FA versus patients with FA + CeD. Results: Two hundred twenty-eight patients were included. CeD was confirmed in 15 patients (6.6%) of whom, 8 patients had a previously established diagnosis of CeD and were on a gluten-free diet. Severe FA was observed in 12 patients with FA + CeD (80%) versus 88 patients with FA (42%) ( P = 0.006). At baseline, patients with FA + CeD had significantly higher median allergen-specific IgE levels [61.8 kU/L; interquartile range (IQR) 11.6-279.0] compared to patients with FA (20.3 kU/L; IQR 2.9-72.7) ( P < 0.001). Complete clinical tolerance was observed in 1 of 15 patients (7%) with FA + CeD versus 98 of 205 patients (48%) with FA ( P = 0.002). Conclusions: CeD is highly prevalent in patients with FA and could affect FA severity and response to OIT. CeD screening should be considered in patients with severe or persistent FA

Ghrelin Derangements in Idiopathic Dilated Cardiomyopathy: Impact of Myocardial Disease Duration and Left Ventricular Ejection Fraction

BACKGROUND: Ghrelin may exert positive effects on cardiac structure and function in heart failure (HF) patients. METHODS: We assessed ghrelin levels in 266 dilated cardiomyopathy (DCM) patients and in 200 age, gender and body mass index (BMI) matched controls. Further, we evaluated the expression of ghrelin and growth hormone secretagogue-receptor (GHSR) in the myocardium of 41 DCM patients and in 11 controls. RESULTS: DCM patients had significantly lower levels of total, acylated and unacylated ghrelin when compared to controls (p < 0.05 for all). In controls, we observed a negative correlation of ghrelin with age, male gender and BMI. These correlations were lost in the DCM group, except for male gender. Total ghrelin was higher in patients with more recent diagnosis when compared to patients with longer duration of the DCM (p = 0.033). Further, total ghrelin was higher in patients with lower left ventricular systolic function (<40% LVEF, vs. 40% 64 LVEF < 49% vs. LVEF 65 50%: 480.8, vs. 429.7, vs. 329.5 pg/mL, respectively, p = 0.05). Ghrelin prepropeptide was expressed more in DCM patients than in controls (p = 0.0293) while GHSR was expressed less in DCM patients (p < 0.001). Furthermore, ghrelin showed an inverse correlation with its receptor (\uf072\uf020= -0.406, p = 0.009), and this receptor showed a significant inverse correlation with Interleukin-1\uf062 (\uf072\uf020\uf020= -0.422, p = 0.0103). CONCLUSION: DCM duration and severity are accompanied by alterations in the ghrelin-GHSR system

Anti-transglutaminase 6 antibody development in children with celiac disease correlates with duration of gluten exposure

Objectives: Antibodies against transglutaminase 6 (anti-TG6) have been implicated in neurological manifestations in adult patients with genetic gluten intolerance, and it is unclear whether autoimmunity to TG6 develops following prolonged gluten exposure. We measured the anti-TG6 in children with celiac disease (CD) at the diagnosis time to establish a correlation between these autoantibodies and the duration of gluten exposure. We investigated a correlation between anti-TG6 and the presence of neurological disorders. Methods: Anti-TG6 (IgA/IgG) were measured by ELISA in sera of children with biopsy-proven CD and of children experiencing gastrointestinal disorders. CD patients positive for anti-TG6 were retested after 2 years of gluten-free diet (GFD). Results: We analyzed the sera of 274 CD children and of 121 controls. Anti-TG6 were detected in 68/274 (25%) CD patients and in 19/121 (16%) controls, with significant difference between the 2 groups (P\ubc0.04). None of the CD patients and of the controls testing positive for anti-TG6 were experiencing neurological disorders. Eleven of 18 (61%) CD patients with other autoimmune diseases were positive for anti-TG6. In CD patients, a significant correlation between the gluten exposure before the CD diagnosis and anti-TG6 concentration was found (P\ubc0.006 for IgA; P<0.0001 for IgG). After GFD anti-TG6 concentrations were significantly reduced (P<0.001). No significant correlation was observed between anti-TG6 and anti-TG2 serum concentrations. Conclusions: Anti-TG6 are more prevalent in children with untreated CD in the absence of overt neurological disorders. The synthesis of the anti-TG6 is related to a longer exposure to gluten before the CD diagnosis, and the autoimmunity against TG6 is gluten dependent and disappeared during GFD