Impact on parents of HLA-DQ2/DQ8 genotyping in healthy children from coeliac families

More Than Three Years for Normalisation of Routine Laboratory Values after Gluten Withdrawal in Paediatric Coeliac Patients

The assessment of the nutritional and inflammatory status of paediatric patients with coeliac disease is an interesting approach to early diagnosis and functional follow-up. Most authors agree that the normalisation of symptoms takes about one year. The aim of the study was to evaluate the clinical manifestation and normalisation of routine analytics in Spanish children diagnosed with celiac disease.

METHODS

We performed a retrospective case-control study in Spanish paediatric patients, including 21 celiac patients and 20 healthy controls. The 21 patients selected in the case-control study were followed for 5 years after starting a gluten-free diet (GFD). All patients had type 3 villous atrophy according to the Marsh-Oberhuber classification. A total of 39 blood samples were taken before the start of the GFD, and 109 were taken after. Twenty control sera from healthy donors were used for comparison.

RESULTS

We found that patients had a subclinical but statistically significant increase in blood calcium, transaminases, and white blood cells, and a decrease in serum iron, at the time of diagnosis. Our study also shows that analytical values normalise within five years on a gluten-free diet.

CONCLUSIONS

The use of a combination of subclinical changes, including low iron, high calcium, elevated leukocytes, lymphocytes, and ALT levels in blood samples, together with a low growth percentile, is pertinent in detecting coeliac disease. This set of parameters could help in the diagnosis of patients without clinical symptoms. We can also show that the levels of Fe, Ca, transaminases, and leucocytes remain subclinically altered after 3 years, despite the gluten-free diet.

Screening for coeliac disease in 1624 mainly asymptomatic children with type 1 diabetes: is genotyping for coeliac-specific human leucocyte antigen the right approach?

OBJECTIVES

To investigate the frequency of coeliac disease (CD)-specific human leucocyte antigen (HLA) genotypes in paediatric patients with type 1 diabetes (T1D), who are known to have a higher prevalence of CD than the general population, and to evaluate whether HLA genotyping is a suitable first-line screening method for CD.

STUDY DESIGN

The study was a multicentre observational analysis of patients with T1D aged <20 years of whom a subgroup had undergone HLA genotyping. Patient data were retrieved from the Diabetes Prospective Follow-up database, a large diabetes follow-up registry. The present analysis included data from 439 centres throughout Germany, Austria, Switzerland and Luxembourg.

RESULTS

In March 2017, the database contained 75 202 patients with T1D (53% male, mean age (SD) 14.6 (4.1) years, mean age at diagnosis 8.8 (4.3) years and mean diabetes duration 5.8 (4.3) years). 1624 patients had undergone coeliac-specific HLA genotyping, of whom 1344 (82.8%) were positive for HLA-DQ2, HLA-DQ8 or both, while 17.2% had no coeliac-specific HLA-markers. 26.6% of at-risk patients had a clinical suspected diagnosis of CD, and 3.6% had biopsy-proven CD.

CONCLUSIONS

Genotyping for HLA-DQ2, HLA-DQ8 or both is positive in the vast majority (>80%) of patients with T1D. Therefore, screening for coeliac-specific HLA genotypes as a first-line test is not a suitable method to exclude CD in T1D. Regular screening for coeliac-specific antibodies in T1D is still recommended.

Towards an individual screening strategy for first-degree relatives of celiac patients

Celiac disease (CD) is known to be more prevalent in first-degree relatives of patients. In this retrospective cohort study of 609 relatives between 1994 and 2016, we investigated the effect of sex, HLA type, and age at time of index celiac diagnosis. Pearson's chi-square test and Kaplan-Meier survival analysis were used as statistical analyses. CD screening was carried out for 427 relatives (70%), resulting in a prevalence of 15%. HLA typing in 335 relatives showed HLA-DQ2/DQ8 positivity in 87.5%. In 63% of children and all parents, celiac disease was diagnosed at first screening. It was diagnosed significantly more often in females, HLA-DQ2 homozygosity, and children (all p < 0.05). In children aged 0-1 year at time of index diagnosis, celiac disease was diagnosed after consecutive screening in 58%, after 3.9 ± 2.5 (max 10) years (p < 0.001).Conclusion: Future screening policies for relatives of celiac patients should include retesting, especially in HLA-positive relatives younger than 10 years of age. In addition, one-time celiac-specific antibody testing alone could be sufficient to rule out the disease in adolescent siblings and parents of newly diagnosed celiac patients. What is Known: • Celiac disease is more prevalent in first-degree relatives of celiac patients (risk 3-12%). • HLA-DQ2 homozygous sisters/daughters are at highest risk (25%). What is New: • If younger than 10 years of age, repeated testing is necessary in HLA-DQ2/DQ8-positive first-degree relatives when celiac disease is diagnosed in a family. • One-time celiac-specific antibody testing alone could be sufficient to rule out the disease in adolescent siblings and parents of newly diagnosed celiac patients.

Gluten-related disorders: certainties, questions and doubts

In the last decade, the ingestion of gluten, a heterogeneous complex of proteins present in wheat, rice, barley and probably in oats, has been associated with clinical disorders, such as celiac disease, wheat allergy and recently to non-celiac gluten sensitivity or wheat intolerance syndrome. Gluten-related disorders, which are becoming epidemiologically relevant with an estimated global prevalence of about 5%, require the exclusion of gluten from the diet. For the past 5 years, an important shift in the availability of gluten-free products, together with increased consumption in the general population, has been recorded and is estimated to be about 12-25%. Many people follow a self-prescribed gluten-free diet, despite the fact that the majority have not first been previously excluded, or confirmed, as having gluten disorders. They rely on claims that a gluten-free diet improves general health. In this review, we provide an overview of the clinical disorders related to gluten or wheat ingestion, pointing out the current certainties, open questions, possible answers and several doubts in the management of these conditions. KEY MESSAGE Incidence of gluten-related disorders is increased in the last decade and self-diagnosis is frequent with inappropriate starting of a gluten-free diet. Gluten and wheat are considered as the most important triggers to coeliac disease, wheat allergy and non-celiac gluten sensitivity. Pediatricians, allergologist and gastroenterologist are involved in the management of these conditions and appropriate diagnostic protocols are required.

Limited role of HLA DQ2/8 genotyping in diagnosing coeliac disease

The European guidelines for diagnosing coeliac disease in children were revised in 2012. These recommend that in symptomatic children, a diagnosis of coeliac disease can be made without small-bowel biopsies provided their anti-tissue transglutaminase (anti-tTG) titre is >10 times of upper-limit-of-normal (>10×ULN) and anti-endomysial antibody is positive. In order to firm up the diagnosis in these children with very high anti-tTG titre, HLA-DQ2/DQ8 should be checked and be positive. Approximately 25-40% of white Caucasian population has HLA-DQ2/DQ8 haplotype. However, only 0.1-1% of the population will develop coeliac disease. Therefore, HLA-DQ2/DQ8 testing must not be done to 'screen' or 'diagnose' children with coeliac disease. Its use by paediatricians should be limited to children with anti-tTG>10×ULN, where the diagnosis of coeliac disease is being made on serology alone. A review of case referrals made to a tertiary paediatric gastroenterology centre in Southwest England demonstrated that HLA-DQ2/DQ8 testing is being requested inappropriately both in primary and secondary care suggesting a poor understanding of its role in diagnosis of coeliac disease. This article aims to clarify the role of HLA-DQ2/DQ8 testing for clinicians working in non-specialist settings.

Repeated Screening Can Be Restricted to At-Genetic-Risk Birth Cohorts

OBJECTIVES

Celiac disease (CD) is associated with tissue transglutaminase autoantibodies (tTGAs) in individuals carrying the human leukocyte antigen (HLA) risk haplotypes DQA1*05:01-DQB1*02:01 (DQ2) and/or DQA1*03:01-DQB1*03:02 (DQ8). The aim of the study was to identify CD in an HLA-genotyped birth cohort prospectively screened for CD.

METHODS

In the initial screening, 13,860 HLA-DQ-genotyped children were invited, of whom 3435/13,860 (25%) accepted participation. Of the 3435, 1620 (47%) carried DQ2 and/or DQ8, of whom 73 (4.5%) were tTGA positive assessed in radioligand-binding assays and 56 (3.5%) developed CD. At age 9 years, 13,024 children from the original cohort were re-invited to follow-up screening using the same study protocol and tTGA assays as in the first screening. Diagnosis of CD was confirmed by intestinal biopsy in children with persistent tTGA.

RESULTS

In the follow-up screening, 1910/4077 (46.8%) carried DQ2 and/or DQ8, of whom 79/1910 (4.1%) were persistently tTGA positive and 72/1907 (3.8%) developed CD. Only 1/2167 (0.05%) child without HLA risk was IgG-tTGA positive, but did not have CD. Of the 980/1910 (51%) children carrying DQ2 and/or DQ8 who were already screened at 3 years of age, 30/979 (3.1%) were diagnosed as new patients at 9 years of age, compared with 42/928 (4.5%) children who did not participate in the initial screening (P = 0.094).

CONCLUSIONS

Screening for CD can be restricted to children carrying HLA-DQ2 and/or DQ8. Repeated screening using tTGA is necessary to identify new patients by 9 years of age. These findings may be relevant when considering implementing screening of the general population.

Coeliac disease and gluten-related disorders in childhood

Gluten-related disorders such as coeliac disease, wheat allergy and noncoeliac gluten sensitivity are increasingly being diagnosed in children. Coeliac disease occurs frequently, affecting 1-3% of the Western population. The condition manifests at a very young age, more so in girls, and is related to the HLA genotype. Coeliac disease might be considered a public health problem and, as primary prevention is not possible, the debate on mass screening should be reopened. Wheat proteins, including gluten, are responsible for one of the most common food allergies in children: wheat allergy. Unlike coeliac disease and wheat allergy, noncoeliac gluten sensitivity is an unclear and controversial entity. These three gluten-related disorders are treated with a gluten-free diet. In coeliac disease, the diet should be strictly followed, whereas wheat allergy only requires wheat elimination and in noncoeliac gluten sensitivity occasional trials of gluten reintroduction can be done. A good diagnostic work-up is important for gluten-related disorders in childhood to avoid unnecessary restrictive diets in children. In this Review, we provide an overview of the pathogenesis, diagnosis and management of the most common gluten-related disorders in children.