Screening for coeliac disease: the meaning of low titers of anti-gliadin antibodies (AGA) in non-coeliac children

Celiac disease in children and adolescents: special considerations

Although there are many commonalities between adult and pediatric celiac disease (CD), special considerations must be taken into account when working with children and adolescents. In this patient population, there are unique aspects of the epidemiology, pathogenesis, presentation, diagnosis, and management of CD. In terms of management, early and timely recognition of CD can maximize childhood and adolescent development and prevent complications. This requires insight into the unique presentations of CD in the pediatric population. Furthermore, health care providers must use proper screening methods and continue surveillance of at-risk individuals throughout childhood. Potential interventions for primary prevention of CD in children, although not completely understood, may offer some benefit. The goals of this article are to discuss in detail these special considerations when dealing with pediatric CD.

Proof of concept of microbiome-metabolome analysis and delayed gluten exposure on celiac disease autoimmunity in genetically at-risk infants

Celiac disease (CD) is a unique autoimmune disorder in which the genetic factors (DQ2/DQ8) and the environmental trigger (gluten) are known and necessary but not sufficient for its development. Other environmental components contributing to CD are poorly understood. Studies suggest that aspects of gluten intake might influence the risk of CD occurrence and timing of its onset, i.e., the amount and quality of ingested gluten, together with the pattern of infant feeding and the age at which gluten is introduced in the diet. In this study, we hypothesize that the intestinal microbiota as a whole rather than specific infections dictates the switch from tolerance to immune response in genetically susceptible individuals. Using a sample of infants genetically at risk of CD, we characterized the longitudinal changes in the microbial communities that colonize infants from birth to 24 months and the impact of two patterns of gluten introduction (early vs. late) on the gut microbiota and metabolome, and the switch from gluten tolerance to immune response, including onset of CD autoimmunity. We show that infants genetically susceptible to CD who are exposed to gluten early mount an immune response against gluten and develop CD autoimmunity more frequently than at-risk infants in which gluten exposure is delayed until 12 months of age. The data, while derived from a relatively small number of subjects, suggest differences between the developing microbiota of infants with genetic predisposition for CD and the microbiota from infants with a non-selected genetic background, with an overall lack of bacteria of the phylum Bacteriodetes along with a high abundance of Firmicutes and microbiota that do not resemble that of adults even at 2 years of age. Furthermore, metabolomics analysis reveals potential biomarkers for the prediction of CD. This study constitutes a definite proof-of-principle that these combined genomic and metabolomic approaches will be key to deciphering the role of the gut microbiota on CD onset.

Are immunoglobulin A anti-gliadin antibodies helpful in diagnosing coeliac disease in children younger than 2 years?

The usefulness of immumoglobulin (Ig) A antibodies to gliadin (AGA-IgA) in addition to IgA anti-endomysium and tissue transglutaminase antibodies was evaluated in 4122 children younger than 2 years with a suspicion of coeliac disease (CD). Eight percent (312/4122) displayed IgA anti-endomysium and/or IgA anti-tissue transglutaminase, whereas 2.1% (85/4122) displayed only AGA-IgA. Clinical data were obtained for 62 of 85 children with isolated AGA-IgA, and 33 children underwent a duodenal biopsy. Histologically proven CD was established for 5 patients, whereas 57 children were diagnosed to experience other diseases. The systematic detection of AGA-IgA using native gliadin conferred no additional diagnostic benefit for the diagnosis of CD in children younger than 2 years of age, except for rare cases.

Persistently positive gliadin antibodies without transglutaminase antibodies in the elderly: gluten intolerance beyond coeliac disease

BACKGROUND

The specificity of the conventional gliadin antibody test is considered low.

AIMS

We explored whether gliadin antibody(AGA)-positivity without tissue transglutaminase antibodies (tTGA) is persistent in the elderly population and whether such positivity indicates overt or potential coeliac disease in genetically predisposed individuals.

METHODS

AGA and tissue transglutaminase antibody were measured in 2089 elderly individuals twice with a three-year interval. AGA-positive but tissue transglutaminase antibody-negative subjects with coeliac-type human leucocyte antigen (HLA) were examined and underwent gastroduodenal endoscopy (cases). Small-bowel mucosal villous morphology and densities of CD3+ and γδ+ intraepithelial lymphocytes and the occurrence of tissue transglutaminase-specific IgA deposits were analysed. Randomly selected persistently AGA-negative age- and sex-matched subjects served as controls.

RESULTS

AGA-positivity was persistent in 81% of those initially positive. Amongst the 49 clinically studied and 36 endoscopied cases only one (2.8%) had coeliac disease. Many (54%) showed signs of inflammation in the biopsy, without villous atrophy. Coeliac-type HLA was not over-represented in the persistently AGA-positive compared to the general population. Persistently AGA-positive coeliac-type HLA-positive subjects had more gastrointestinal symptoms than AGA-negative controls.

CONCLUSIONS

AGA-positivity is often persistent. Overt coeliac disease is seldom found behind persistent AGA-positivity, but this characteristic is associated with mucosal inflammation and gastrointestinal symptoms at least in HLA-positive individuals.

Lower expression of tight junction protein 1 gene and increased FOXP3 expression in the small bowel mucosa in coeliac disease and associated type 1 diabetes mellitus

BACKGROUND

The role of regulatory T cells expressing FOXP3 in the pathogenesis of coeliac disease (CD) and type 1 diabetes (T1D) has been reported. Recent data have placed special focus on the interplay between the intestinal barrier and immunoregulatory processes. We aimed to determine whether the expression of tight junction protein 1 (TJP1), which reflects small bowel mucosa permeability, is changed in CD and T1D.

METHODS

Transcription levels of TJP1 and FOXP3 genes were evaluated in the small bowel biopsies of 14 children with CD, 12 with CD and coexisting T1D and 40 controls using real-time PCR. Serum IgA and IgG to deamidated gliadin, bovine β-lactoglobulin, bovine α-casein and human tissue transglutaminase (tTG) were determined by ELISA.

RESULTS

The highest expression of FOXP3 mRNA was seen in patients with CD and T1D compared to patients with CD alone and controls (p = 0.02). In contrast, the lowest level of TJP1 mRNA expression was found in patients with CD and T1D (p = 0.01). The levels of IgA to deamidated gliadin and tTG were highest in patients with CD and T1D (p = 0.0001 and 0.01, respectively). The expression of FOXP3 mRNA correlated highly with the level of anti-gliadin IgA (p = 0.02) and anti-tTG IgA antibodies (p = 0.004).

CONCLUSION

The significant decline in TJP1 expression in CD patients, particularly in those with coexisting T1D, was accompanied by an increase in FOXP3 expression. This might reflect an attempt to maintain immune tolerance to counterbalance the loss of mucosal integrity in the small intestine in CD associated with T1D.

Isolated short stature as a presentation of celiac disease in Saudi children

The aim of this study is to assess the prevalence of isolated short stature as a clinical presentation of celiac disease in Saudi Arab children and whether some of the routine laboratory tests performed to determine the cause of short stature could suggest the diagnosis of celiac disease. A total of 91 children with short stature were included in the study. Extensive endocrine and biochemical assessments, including total protein, serum albumin, calcium phosphate and alkaline phosphatase assays; renal function tests; coagulation profile; anti-endomysial antibodies and anti-tissue transglutaminase antibody, growth hormone, thyroid stimulating hormone, free-thyroxin (FT4) assays; stool tests for giardiasis; bone age; and endoscopic intestinal biopsies, were done for all children. Ten of the 91 children had positive intestinal biopsies in the form of total villous atrophy, an increase in crypt height, and an increase in intra-epithelial lymphocyte (IEL) numbers up to >40 IEL/100 EC (Type 3C) according to the Oberhuber classification, confirming the diagnosis of celiac disease. Five children had mild villous atrophy according to this classification (Type 3A), and they were considered to have potential celiac disease. Seventy-six children had normal intestinal biopsies. Therefore, the prevalence of celiac disease among Saudi children with short stature was 10.9%, and 4.3% of the children were diagnosed as having potential celiac disease. After confirming the diagnosis of celiac disease, all children were kept on a gluten-free diet and all of them showed improvement in their growth rate. We concluded that celiac disease is a very important cause of short stature in children without gastrointestinal complaints in Saudi Arabia. We highly recommend anti-tissue transglutaminase and anti-endomysial antibody screening tests, and a small bowel biopsy to confirm the diagnosis of celiac disease irrespective of the results of the antibody assays, in children with short stature in Saudi Arabia. Once the diagnosis is confirmed, children should be kept on a gluten-free diet so they can catch up their growth early before they develop permanent short stature.

Childhood coeliac disease: towards an improved serological mass screening strategy

BACKGROUND

In 1997-1998, 6127 asymptomatic children aged 2-4 years were screened for coeliac disease (CD) by anti-endomysium (EmA) testing in the Netherlands. After 6 (+/-2) months, biopsies were performed in 57 seropositive children; 31(54%) had villous atrophy, but 26 (46%), all HLA-DQ2/DQ8 positive, had normal histology.

AIMS

To reduce the number of unnecessary biopsies after serological mass screening for CD in asymptomatic young children by optimizing screening procedures.

METHODS

Comparing different tests and optimizing their cut-off point: screening samples were tested for EmA, tissue-transglutaminase (tTGA), antigliadin and deamidated-gliadin-peptides (anti-DGP) antibodies. Determining serological persistence over time: persistence of EmA and tTGA was determined by testing serological samples obtained at biopsy.

RESULTS

Tissue-transglutaminase and anti-DGP correlated with EmA. Optimization of standard cut-off points not only reduced unnecessary biopsies by 50-96% but also reduced sensitivity. EmA persisted in all CD children, but in only 50% of the non-CD children. tTGA persisted in 83% of CD, but in only 15% of non-CD children.

CONCLUSIONS

Coeliac disease antibodies may be present transiently in genetically predisposed children. To avoid unnecessary biopsies, serological mass screening procedures may be improved by repeating EmA and/or tTGA in initially seropositive young children after 6 months, before proceeding to biopsy. This may reduce the number of unnecessary biopsies that are performed.

Intestinal permeability in long-term follow-up of patients with celiac disease on a gluten-free diet

Intestinal permeability is frequently abnormal in patients with celiac disease. The long-term effect of a gluten-free diet on intestinal permeability and the correlation of intestinal permeability with a gluten-free diet are not known. The objectives of this study were to determine the responses of intestinal permeability and antibody testing to gluten free diet and the degree of correlation of these measurements with gluten ingestion. In this prospective study, patients with celiac disease were divided into three groups based on length of time on a gluten-free diet: Group A, < 1 month; Group B, 1 month-1 year; Group C, > 1 year. Patients in Groups B and C were tested at baseline and at 4-12 weeks later for the following: lactulose/mannitol intestinal permeability, endomysial antibody, and 3-day food record. Permeability tests were also performed in Group A and control subjects. Intestinal permeability was elevated in newly diagnosed celiac disease and in individuals on a gluten-free diet for less than 1 year. Intestinal permeability was normal in 80% at visit 1 and 87% at visit 2 in individuals with celiac disease on a gluten-free diet for more than a year. Trace gluten ingestion was associated with increased intestinal permeability on visit 2 (P = 0.0480). The sensitivity of detecting gluten ingestion as measured by a 3-day food record was higher for permeability testing (29 and 36%) compared with endomysial antibody testing (18 and 18%) for visits 1 and 2, respectively. Intestinal permeability normalizes in the majority of individuals with celiac disease on a gluten-free diet. Gluten ingestion as measured by a 3-day food record correlates with intestinal permeability measurements. The role of permeability testing in the follow-up of patients with celiac disease warrants further investigation.

IgA anti-transglutaminase antibodies as a tool for screening atypical forms of coeliac disease in a French at-risk paediatric population

OBJECTIVE

The diagnosis of coeliac disease (CD) is often delayed because many children are free from the major symptoms characteristic of this enteropathy. The aim of the present study was to determine the efficacy of antibodies directed against tissue transglutaminase (tTG Abs) for early detection of CD in a population with few symptoms of the disease, as well as in children with an autoimmune disorder.

METHODS

This was a prospective study in a paediatric population including 638 patients with clinical symptoms frequently associated with CD, autoimmune diseases such as type 1 diabetes mellitus (DM1), autoimmune thyroiditis or hepatitis, and Turner's syndrome. Anti-endomysium, tTG Abs and antigliadin antibodies were analysed in these patients using an indirect immunofluorescence technique and enzyme-linked immunosorbent assay techniques. Intestinal biopsies were performed for some patients with positive or negative antibodies.

RESULTS

tTG Abs were detected in 2.6% of children with symptoms associated with CD, such as digestive signs and growth failure, and in 5.4% of children with DM1. No other autoimmune disease was positive for tTG Abs. Biopsies performed in the patients with positive tTG Abs showed mucosal atrophy confirming the diagnosis of CD in all cases.

CONCLUSION

Children displaying minimal symptoms frequently associated with CD and children with DM1 should be systematically screened for tTG Abs.

[Anti-endomysium, anti-reticulin and anti-gliadin antibodies, value in the diagnosis of celiac disease in the child]

Coeliac disease is associated with gluten intolerance in genetically predisposed subjects. Environmental factors, particularly of viral origin, may also play a major role. In this study, the presence of IgA class anti-endomysium antibodies (AEA-IgA), IgA class anti-reticulin antibodies (ARA-IgA) and IgA class anti-gliadin antibodies (AGA-IgA) was investigated in 120 serum samples from 120 children (60 patients with coeliac disease and 60 control subjects). The AEA were detected by indirect immunofluorescence on sections of human umbilical cord. The ARA were also investigated by the same technique in rat kidney, liver and stomach. The AGA were determined by an enzyme-linked immunosorbent assay (ELISA). In the patients with coeliac disease, the sensitivity of AEA and ARA was 86% and 76% respectively. In both cases, the specificity was 100%. In children below two years of age, the sensitivity of AEA and ARA was too low, i.e., 57% and 35% respectively. In children aged between two and 15 years, the sensitivity of AEA and ARA was 95% and 89% respectively. The sensitivity of IgA class AGA was 86%, and their specificity was 83%. In this study population, these results show that IgA class AEA are interesting markers for the diagnosis of coeliac disease in the child, and could be used in screening for coeliac disease in a high-risk population.