Coeliac disease and type 1 diabetes: an affair still with much hidden behind the veil

The prevalence and risk factors for coeliac disease among children and adolescents with type 1 diabetes mellitus

AIMS

Our aim was to determine in children with T1DM the prevalence of positive antibodies against tissue transglutaminase (anti-tTG IgA) as indices of coeliac disease (CD), as well as its clinical presentation, its determinants and its association with thyroid (anti-TG, anti-TPO) and pancreatic b-cell autoimmunity (anti-GAD).

METHODS

The study included 105 children and adolescents with T1DM, aged (mean±SD) 12.44±4.76 years, with a T1DM duration of 4.41±3.70 years.

RESULTS

Fifty of our patients (47.6%) were positive for anti-GAD, 9/105 (8.6%) for anti-tTG IgA and 21/105(20%) for anti-thyroid antibodies. The anti-tTG IgA (+) children, in comparison with the rest of the study population, were of younger age (9.31 vs. 12.74 years, p=0.038), shorter diabetes duration (2.16 vs. 4.62 years, p=0.056) and had mild growth impairment (height SDS: -0.55 vs. +0.20, p=0.055). Univariate logistic regression analysis revealed that the presence of anti-tTG IgA (+) was associated with younger age and shorter T1DM duration. Only 5/9 (55.6%) children with high titres of anti-tTG IgA developed mild gastrointestinal symptoms or growth retardation and had histological findings typical of CD.

CONCLUSIONS

The prevalence of anti-tTG IgA positivity among T1DM children was 8.6% and its occurrence was associated with younger age and short diabetes duration. Since CD presents in T1DM patients asymptomatically or with non-specific symptoms, periodic autoantibody screening is necessary for its early diagnosis.

Psychological stress and coeliac disease in childhood: a cohort study

Background

Psychological stress has previously been associated with several immunological diseases, e.g. inflammatory bowel disease. Through questionnaire data from the ABIS study (All Babies In southeast Sweden) we examined the association between psychological stress in the family and biopsy-proven coeliac disease (CD) in the child.

Methods

We used serious life event, parenting stress, and parental worries as measures of psychological stress. Data were collected when the child was 1 and 2.5 years old in some 11,000 and 8,800 children, respectively. CD was confirmed through small intestinal biopsy (with villous atrophy), and the diagnosis was validated through patient chart data.

Results

Serious life event in the family in the child's first 1 or 2.5 years after childbirth was not associated with future CD in the child (Odds Ratio (OR) = 0.45; 95% Confidence Interval (CI) = 0.01-2.65; P = 0.72; and OR = 1.21; 95% CI = 0.43-3.05; P = 0.64, respectively). Neither did we see any association between CD and parenting stress at age 1 year and at 2.5 years (OR = 0.40; 95% CI = 0.01-2.38; P = 0.73 and OR = 0.74; 95% CI = 0.01-4.56; P = 1.00, respectively). Among children exposed to parental worries at 2.5 years, no child had a diagnosis of CD before end of follow-up, compared to 25/8082 (0.3%) among non-exposed children (OR = 0.00; 95% CI = 0.00-2.34; P = 0.64). There was no association between the combined measures of stress and CD.

Conclusion

This study found no association between psychological stress and later development of CD in Swedish children. However, we cannot rule out that the lack of such an association is due to limited statistical power.

Diverse foxp3 expression in children with type 1 diabetes and celiac disease

Imbalance between different types of T lymphocytes, such as T helper (Th) and regulatory T cells (Tregs), has been reported to play a part in the pathogenesis behind such autoimmune diseases as type 1 diabetes (T1D) and celiac disease (CD). Defects in Tregs are proposed to at least partly explain the imbalance of Th cells found in children with immunologic diseases. Peripheral blood mononuclear cells from 24 children with T1D and/or CD, and reference children (that is, those without any of these diseases) were stimulated with disease-associated antigens (insulin, gluten, transglutaminase [tTG]), and phytohemagglutinin (PHA). The mRNA expression of the Treg-associated marker FOXP3 was analyzed with multiplex real-time RT-PCR. Children with T1D showed both a low spontaneous (P < 0.05) and PHA-induced (P < 0.01) expression of FOXP3 mRNA compared to children with CD. Children with T1D also had a low PHA-induced FOXP3 mRNA expression compared to the group of children diagnosed with both T1D and CD (P < 0.05). Spontaneous (P < 0.05) and PHA-induced (P < 0.05) FOXP3 mRNA expression was high in children with CD compared to reference children. In contrast, stimulation with insulin tended to induce high FOXP3 mRNA expression in T1D children compared to reference children (P= 0.057). In conclusion, children with only T1D generally showed a lower FOXP3 mRNA expression than did children with CD, or with T1D in combination with CD, which suggests impaired regulation of the immune system in children with T1D.

Specificity analysis of anti-gliadin mouse monoclonal antibodies used for detection of gliadin in food for gluten-free diet

A gluten-free diet (GFD) is the sole effective long-lasting treatment of celiac disease. Four monoclonal antibodies (Abs) were prepared by immunization of animals kept on GFD with gliadin. The specificity of these Abs to decapeptides of alpha- and gamma-gliadin and omega-secalin was analyzed by the PEPSCAN technique. Repetitive sequences of alpha- and gamma-gliadin and omega-secalin containing the motifs QPFPXQ (X = Q, L, P) were recognized by all Abs tested. These Abs also frequently reacted with peptides containing the sequences QQSFPQQ, QQTFPQP, and QPFRPQ. On the basis of PEPSCAN results two Abs--8D4 and 7C6--were selected for the construction of a new ELISA kit for the detection of gliadin in food. The comparison of data obtained using the newly developed ELISA kit and commercially available ones indicated that Abs selection on the basis of their fine specificity to gliadin is useful for sensitive detection of gliadin in foods.

Putting the pieces of the puzzle together - a series of hypotheses on the etiology and pathogenesis of type 1 diabetes

This paper presents a series of 10 hypotheses on the etiology of type 1 diabetes. We begin with the hypothesis that wheat gluten is one of the elusive environmental triggers in type 1 diabetes. Habitual consumption of wheat gluten increases the intestinal synthesis of dipeptidyl peptidase IV. This enzyme helps to shape the repertoire of peptides released into the small intestine following the ingestion of wheat gluten by catalyzing the release of X-Pro dipeptides from the N-terminus of the proline-rich glutenins and gliadins in wheat gluten. The release of gluten-derived peptides causes the tight junctions of the small intestine to open through a zonulin-dependent mechanism, which allows these peptides to enter the lamina propria where they get presented as antigens by HLA-DQ, -DR and CD1d molecules. Binding of one or more gluten peptides by CD1d leads to abrogation of oral tolerance, and a marked increase in peripheral immune responses to wheat proteins. Furthermore, it is our contention, that in response to beta cell apoptosis during normal remodeling of the pancreas and CCL19/CCL21 expression within the pancreatic lymph nodes (PLNs), gluten-loaded dendritic cells migrate from the small intestine to the PLNs. These dendritic cells present gluten-derived antigens on the surface of the PLNs, which leads to migration of CD4(-)CD8(-) gammadelta and CD4(-)CD8(+) alphabeta T cells to the pancreas where they mediate Fas and perforin dependent cytotoxicity. We also hypothesize that at least one of the type 1 diabetes associated HLA-DR molecules that bind and present wheat-derived peptide(s) also bind and present an islet cell antigen(s), activating plasma cell synthesis of islet cell autoantibodies and irrevocable, complement-dependent destruction of islet cells. Our final two hypotheses state that type 1 diabetes morbidity is reduced in those areas of globe where genetically susceptible individuals get adequate amounts of vitamin D, in the diet and/or through exposure to sunlight, and in areas where people are exposed to bacterial, viral, or parasitic infections in early childhood.

Epitopes recognised by tissue transglutaminase antibodies in coeliac disease

The interaction between IgA tissue transglutaminase (tTG) antibodies (Abs) and 35S-labelled tTG produced in a transcription/translation (TnT) system with various amino acid (aa) deletions has been studied. These experiments showed that the tTG N-terminal aa 1-89 were important for tTG Ab binding in all 15 coeliac disease sera studied and the central residues (aa 401-491) were important for binding of tTG Abs in all but one sera. The contribution of C-terminal residues to tTG Ab binding varied in different coeliac sera but overall was less than the contributions of the N terminal and central regions. Mouse monoclonal antibodies (MAbs) to tTG were produced and the tTG aa sequences recognised by the MAbs determined using modified 35S-labelled tTG proteins. Analysis of the inhibiting effects of patient sera tTG Ab on binding of tTG MAbs to tTG confirmed the importance of the N-terminal and central regions of tTG in forming serum tTG Ab binding sites. Recombinant human tTG was expressed in yeast and purified to better than 95% homogeneity using MAb affinity chromatography as a final purification step. This material was highly suitable for use in an ELISA for tTGAb.

In vitro-deranged intestinal immune response to gliadin in type 1 diabetes

Dietary gluten has been associated with an increased risk of type 1 diabetes. We have evaluated inflammation and the mucosal immune response to gliadin in the jejunum of patients with type 1 diabetes. Small intestinal biopsies from 17 children with type 1 diabetes without serological markers of celiac disease and from 50 age-matched control subjects were examined by immunohistochemistry. In addition, biopsies from 12 type 1 diabetic patients and 8 control subjects were cultured with gliadin or ovalbumin peptic-tryptic digest and examined for epithelial infiltration and lamina propria T-cell activation. The density of intraepithelial CD3(+) and gammadelta(+) cells and of lamina propria CD25(+) mononuclear cells was higher in jejunal biopsies from type 1 diabetic patients versus control subjects. In the patients' biopsies cultured with peptic-tryptic gliadin, there was epithelial infiltration by CD3(+) cells, a significant increase in lamina propria CD25(+) and CD80(+) cells and enhanced expression of lamina propria CD54 and crypt HLA-DR. No such phenomena were observed in control subjects, even those with celiac disease-associated HLA haplotypes. In conclusion, signs of mucosal inflammation were present in jejunal biopsies from type 1 diabetic patients, and organ culture studies indicate a deranged mucosal immune response to gliadin.

The prevalence of coeliac disease antibodies in patients with the antiphospholipid syndrome

High prevalence of coeliac disease (CD) has been reported in various autoimmune disorders, buthas not been studied in the antiphospholipid syndrome (APS). We aimed to establish the prevalence of CD antibodies in a cohort of APS patients, and to examine whether CD may be responsible for some of the manifestations of APS. Fifty-seven patients (47 females, 10 males) with APS were studied for clinical manifestations and serological markers of the disease, as well as the presence of anti-endomysial antibodies using an ELISA assay (EMA-ELISA). Control subjects were 171 healthy individuals, age- and sex-matched (141 females). Eight patients with APS (14%, six females) were found to have EMA-ELISA antibodies, compared with 2/141 (1.1%) of controls (P = 0.0003). Antibodies against beta2-glycoprotein-I (beta2GPI) epitopes (GRTCPKPDDLP) were more prevalent in EMA-positive patients than in EMA-negative patients (P = 0.006). Vasculitic skin lesions were significantly more common in EMA-ELISA-positive compared with EMA-ELISA-negative patients(62.5 versus 16.3%, P = 0.01). Among the skin manifestations, superficial cutaneous necrosis (37.5 versus 2%, P = 0.007) was more prevalent in EMA-ELISA-positive than in EMA-ELISA-negative patients. EMA-ELISA antibodies are common in APS, and their presence is associated with high prevalence of antibodies recognizing certain beta2-glycoprotein epitopes, and with cutaneous manifestations of APS.

Advances in celiac disease

In recent years, it has become evident that CD is much more common than previously appreciated, with a prevalence of 0.5% to 1% in Western, Arabian, and Indian populations. The disease may be present without symptoms (silent CD) or may present with extraintestinal manifestations only. Increasing awareness of the many faces of CD will increase diagnosis rate. CD patients have a cure for their disease, named the gluten-free diet, but this curative measure is very hard to adhere to. With the new insights into the pathogenesis of CD, clinicians enter an era where new treatment modalities for CD may turn into reality.