HLA Profile of Celiac Disease among First-Degree Relatives from a Tertiary Care Center in North India

Global Prevalence and Clinical Manifestations of Celiac Disease Among First-Degree Relatives: A Systematic Review and Meta-Analysis

INTRODUCTION

First-degree relatives (FDRs) of patients with celiac disease (CeD) are at high risk for developing CeD. We conducted a systematic review and meta-analysis to estimate CeD prevalence and clinical manifestations by analyzing studies that used the anti-tissue transglutaminase antibody test for screening.

METHODS

In this systematic review with meta-analysis, studies published in PubMed, Web of Science, Embase, and Scopus were searched up to January 11, 2024, using keywords related to CeD and FDRs. Random-effects models were used, with heterogeneity assessed using the Cochran Q test and the I2 statistic performed in STATA 18.

RESULTS

Of 8,764 studies screened, 34 studies involving 10,016 FDRs of patients with CeD were included. The pooled estimates for seroprevalence and the biopsy-confirmed CeD prevalence in FDRs were 11% (95% CI: 9%-13%) and 7% (95% CI: 6%-9%), respectively. Daughters and sisters had the highest prevalence rates at 23% and 14%, compared with sons and brothers at 6% and 9%, respectively. Regional analysis revealed the highest seroprevalence estimates in Hungary (24%) and Cuba (19%), while the highest prevalence of biopsy-confirmed CeD was reported in Serbia (16%) and the United States (15%). Abdominal pain (42%), bloating (39%), and flatulence (38%) were the most common gastrointestinal symptoms, while 34% of FDRs with CeD were asymptomatic. In addition, pallor was the most frequent nongastrointestinal symptom (54%).

DISCUSSION

Approximately 1 in 14 FDRs of patients with CeD is estimated to have CeD, with 1 in 4 daughters, 1 in 7 sisters, 1 in 11 brothers, 1 in 16 sons, and 1 in 20 fathers and mothers could be affected. Routine screening for FDRs could support early detection and management of CeD.

Relevance of HLA-DQB1*02 Allele in the Genetic Predisposition of Children with Celiac Disease: Additional Cues from a Meta-Analysis

Background and Objectives: Celiac disease (CD) is a multifactorial immune-mediated disorder, triggered by the ingestion of gluten in genetically-predisposed subjects carrying MHC-DQ2 and -DQ8 heterodimers, which are encoded by four HLA-DQ allelic variants, overall. This meta-analysis aims at providing further epidemiological support to the predominant relevance of one specific allele, namely HLA-DQB1*02, in the predisposition and genetic risk of CD. Materials and Methods: We performed a search of MEDLINE/PubMed, Embase, Web of Science, and Scopus, retrieving all publications (case-control study, cross-sectional, and retrospective cohort study) on the association between HLA class II polymorphisms and first-degree relatives (FDRs) of children with CD. After a critical reading of the articles, two investigators independently performed data extraction according to the following inclusion criteria: HLA class II genes, any DQ and DR molecules, and CD diagnosed following the current clinical guidelines. A third participant was consulted for discussion to reach an agreement concerning discrepancies. Results: Our search strategy selected 14 studies as being eligible for inclusion, and those were submitted for data extraction and analysis. These studies were published between 1999 and 2016 and, collectively, enrolled 3063 FDRs. Positive and negative likelihood ratios (LR+ and LR-, respectively) for CD diagnosis, according to the presence of the HLA-DQ genotype coding a complete MHC-DQ2 and/or MHC-DQ8 molecules, were 1.449 (CI 1.279-1.642) and 0.187 (CI 0.096-0.362), respectively. If only the isolated presence of HLA-DQB1*02 allele is considered, the pooled estimation of LR+ was 1.659 (CI 1.302-2.155) and, importantly, the LR- still showed a very good discriminatory power of 0.195 (CI 0.068-0.558). Conclusions: Through our differential meta-analysis, comparing the presence of the genotype coding the full MHC-DQ2 and/or DQ8 molecules with the isolated presence of HLA-DQB1*02 allelic variant, we found that the LR- of the latter analysis maintained the same value. This observation, along with previous evidences, might be useful to consider potential cost-effective widened screening strategies for CD in children.

Pediatric Celiac Disease in Central and East Asia: Current Knowledge and Prevalence

The current prevalence of pediatric Celiac Disease (CD) is estimated to be around 1% in the general population, worldwide. However, according to the geographic area, a great variability of CD prevalence has been described. Whereas a number of studies are available from Europe, North and South America, Australia, South-West Asia, and North Africa, the knowledge and awareness of CD in large parts of the remaining world areas is definitively poor. In several countries of Central and East Asia, the consumption of wheat is consistent and/or has significantly increased in recent decades, and CD is supposed to be underdiagnosed in children. In this mini-review, we aimed to summarize the current knowledge about the prevalence of pediatric CD in Central and East Asia, paying attention to the HLA-DQ immunogenetic background as well. Indeed, CD is likely not to be as uncommon as previously or currently thought in countries like Russia, Kazakhstan, and China, in addition to India, where pediatric CD has been clearly showed to be quite prevalent. Therefore, there is an urgent need for population-based studies on the prevalence of CD in those countries, especially in children, in order to increase the awareness of this disease and to improve the diagnostic strategy in these areas.

Cross-Talk Between Gluten, Intestinal Microbiota and Intestinal Mucosa in Celiac Disease: Recent Advances and Basis of Autoimmunity

Celiac disease (CD) is an autoimmune disorder of the small intestine, caused by gluten induced inflammation in some individuals susceptible to genetic and environmental influences. To date, pathophysiology of CD in relation to intestinal microbiota is not known well. This review relies on contribution of intestinal microbiome and oral microbiome in pathogenesis of CD based on their interactions with gluten, thereby highlighting the role of upper gastrointestinal microbiota. It has been hypothesized that CD might be triggered by additive effects of immunotoxic gluten peptides and intestinal dysbiosis (microbial imbalance) in the people with or without genetic susceptibilities, where antibiotics may be deriving dysbiotic agents. In contrast to the intestinal dysbiosis, genetic factors even seem secondary in disease outcome thus suggesting the importance of interaction between microbes and dietary factors in immune regulation at intestinal mucosa. Moreover, association of imbalanced counts of some commensal microbes in intestine of CD patients suggests the scope for probiotic therapies. Lactobacilli and specific intestinal and oral bacteria are potent source of gluten degrading enzymes (glutenases) that may contribute to commercialization of a novel glutenase therapy. In this review, we shall discuss advantages and disadvantages of food based therapies along with probiotic therapies where probiotic therapies are expected to emerge as the safest biotherapies among other in-process therapies. In addition, this review emphasizes on differential targets of probiotics that make them suitable to manage CD as along with glutenase activity, they also exhibit immunomodulatory and intestinal microbiome modulatory properties.