Prevalence of allergic diseases in children with inflammatory bowel disease

No Association Between Allergic Diseases and Constipation in Japanese Ulcerative Colitis Patients: A Cross-Sectional Study

BACKGROUND

Constipation is a common gastrointestinal symptom in patients with ulcerative colitis (UC). Several studies on the general population have demonstrated a link between allergic diseases and constipation. However, evidence regarding the association between allergic diseases and constipation in UC is limited. This study aims to evaluate this issue in Japanese patients with UC.

METHODS

This cross-sectional study recruited consecutive 387 patients with UC. We used a self-administered questionnaire to estimate the prevalence of physician-diagnosed allergic diseases. The definition of constipation was based on Rome I criteria and/or medication for constipation.

RESULTS

The prevalence of constipation was 12.5%. The prevalence rates of asthma, atopic dermatitis, pollen allergy, food allergy, and drug allergy were 11.8%, 9.0%, 36.3%, 6.2%, and 8.3%, respectively. Allergic diseases were not associated with constipation (adjusted odds ratio [OR] with asthma (adjusted OR 0.98 [95% confidence interval [CI] 0.27-2.80]), atopic dermatitis (adjusted OR 0.67 [95% CI 0.10-2.56]), pollen allergy (adjusted OR 0.92 [95% CI 0.41-1.97]), food allergy (adjusted OR 0.76 [95% CI 0.11-2.95]), and drug allergy (adjusted OR 1.06 [95% CI 0.28-3.24]). Additionally, the number of allergic diseases was not associated with the prevalence of constipation.

CONCLUSIONS

In Japanese UC patients, no association between allergic diseases and constipation was found.

Risk of allergic rhinitis in patients with inflammatory bowel disease: A systematic review and meta-analysis

BACKGROUND

Numerous parallels exist between inflammatory bowel disease (IBD) and allergic rhinitis (AR), which include risk factors (such as environmental and genetic factors), pathogenesis (immune disorders, epithelial cell barriers, etc.), and treatment (immunosuppressants and immunomodulators, such as cyclosporine and steroids). However, the risk of AR in IBD patients is unknown.

OBJECTIVE

In this systematic review and meta-analysis, patients with IBD are examined for their risk of AR.

METHODS

Several databases are accessible in both Chinese and English, including PubMed, BioRXiv, WanFang, the China National Knowledge Infrastructure (CNKI), Web of Science, METSTR, and MedRxiv. Findings presented at allergy, rhinology, thoracic, and gastrointestinal conferences were analyzed. Based on the inclusion and exclusion criteria, two evaluators independently retrieved data, read the literature, and evaluated bias risk. The data analysis was conducted using RevMan 5.4. Case-control and cohort studies were eligible study designs for this research.

RESULTS

There were 10 case-control studies and 1 cohort study included in the meta-analysis. The experimental group consisted of 65,687 IBD patients, of whom 5838 had AR. A total of 345,176 participants without IBD were included in the control group, of whom 24,625 developed AR. The outcomes demonstrated that IBD patients had a higher risk of developing AR (odds ratio [OR] = 1.48, 95% confidence interval [CI] [1.12, 1.95], Z = 2.78, P = 0.005) than those without IBD.

CONCLUSION

The risk of AR is higher in IBD patients. Further investigation is required to determine the mechanism behind the association between AR and IBD.

Akkermansia muciniphila exacerbates food allergy in fibre-deprived mice

Alterations in the gut microbiome, including diet-driven changes, are linked to the rising prevalence of food allergy. However, little is known about how specific gut bacteria trigger the breakdown of oral tolerance. Here we show that depriving specific-pathogen-free mice of dietary fibre leads to a gut microbiota signature with increases in the mucin-degrading bacterium Akkermansia muciniphila. This signature is associated with intestinal barrier dysfunction, increased expression of type 1 and 2 cytokines and IgE-coated commensals in the colon, which result in an exacerbated allergic reaction to food allergens, ovalbumin and peanut. To demonstrate the causal role of A. muciniphila, we employed a tractable synthetic human gut microbiota in gnotobiotic mice. The presence of A. muciniphila within the microbiota, combined with fibre deprivation, resulted in stronger anti-commensal IgE coating and innate type-2 immune responses, which worsened symptoms of food allergy. Our study provides important insights into how gut microbes can regulate immune pathways of food allergy in a diet-dependent manner.

Causal association between atopic eczema and inflammatory bowel disease: A two-sample bidirectional Mendelian randomization study of the East Asian population

Observation studies have postulated that atopic eczema is associated with a risk of inflammatory bowel disease in the East Asian population; however, this association does not obviate the biases resulting from confounding effects and reverse causation. This study aimed to determine whether this association is causal in the East Asian population using a bidirectional two-sample Mendelian randomization design. Independent genetic variants obtained from public genome-wide association studies for atopic eczema (4296 cases, 163 807 controls) were extracted to estimate the causal effects on inflammatory bowel disease (2824 cases, 3719 controls) and its two main conditions: Crohn's disease (1690 cases, 3719 controls) and ulcerative colitis (1134 cases, 3719 controls). Atopic eczema was found to be strongly associated with inflammatory bowel disease (odds ratio [95% confidence interval]: 1.520 [1.179, 1.959]; p = 0.001), but not vice versa. Subtype analyses revealed that atopic eczema is significantly associated with Crohn's disease (1.650 [1.293, 2.106]; p = 0.000) but not with ulcerative colitis. Both Crohn's disease and ulcerative colitis were found to be causally related to atopic eczema; Crohn's disease could reduce the risk of atopic eczema (0.866 [0.807, 0.930]; p = 0.000) while ulcerative colitis could increase the risk of atopic eczema (1.112 [1.021, 1.212]; p = 0.015). In conclusion, this study revealed that statistically causal relationships are present between atopic eczema and inflammatory bowel disease in the East Asian population. These findings are significant for guiding the treatment of atopic eczema and inflammatory bowel disease in clinical practice.

Intestinal mucus barrier: a missing piece of the puzzle in food allergy

The prevalence of food allergies has reached epidemic levels but the cause remains largely unknown. We discuss the clinical relevance of the gut mucosal barrier as a site for allergic sensitization to food. In this context, we focus on an important but overlooked part of the mucosal barrier in pathogenesis, the glycoprotein-rich mucus layer, and call attention to both beneficial and detrimental aspects of mucus-gut microbiome interactions. Studying the intricate links between the mucus barrier, the associated bacteria, and the mucosal immune system may advance our understanding of the mechanisms and inform prevention and treatment strategies in food allergy.

Allergic manifestations in autoimmune gastrointestinal disorders

Allergic disorders target a young population, are increasing in both incidence and prevalence and are associated with significant disease burden. They result from the complex interplay between (epi)genetic and environmental factors, resulting in a Th2 inflammatory process targeting the epithelium of the respiratory tract (allergic rhinitis and asthma), skin (atopic dermatitis), and gastrointestinal tract (food allergy). Although the exact pathogenic mechanisms remain elusive, an altered immune system response in the gut is increasingly recognized as a relevant step. Allergic and gastrointestinal autoimmune disorders share several epidemiological, pathogenic and risk factors and several treatment modalities. Here we revise the current literature and show that allergic disorders are highly prevalent in gastrointestinal autoimmune diseases, including celiac disease, inflammatory bowel disease, autoimmune pancreatitis, and autoimmune cholangiopathies. No data are available for some autoimmune diseases, such as autoimmune gastritis and autoimmune enteropathy. To ensure the comprehensive care of patients with autoimmune gastrointestinal disorders, along with disease-specific factors, the presence of allergic disorders should be evaluated and treated when present, possibly targeting shared molecular pathways. Future studies are needed to define the exact pathogenic mechanisms underpinning the association between allergic and autoimmune diseases of the gastrointestinal tract.

Nutri-epigenetics: the effect of maternal diet and early nutrition on the pathogenesis of autoimmune diseases

Autoimmune diseases comprise a wide group of diseases involving a self-response of the immune system against the host. The etiopathogenesis is very complex involving disease-specific factors but also environmental factors, among which the diet. Maternal diet during pregnancy as well as early nutrition recently attracted the interest of the scientists as contributing to the immune programming. In this paper, we reviewed the most recent literature on the effect of maternal diet and early nutrition in modulating the immune system in a selected subset of autoimmune diseases: type 1 diabetes, celiac disease, inflammatory bowel disease, juvenile idiopathic arthritis and rheumatoid arthritis. Particularly, we focused our narrative on the role of maternal and perinatal nutrition in the epigenetic mechanisms underlying the auto-immune response. Maternal diet during pregnancy as well as breastfeeding and early nutrition play a big role in many epigenetic mechanisms. Most of the nutrients consumed by the mother and the infant are known exerting epigenetic functions, such as folate, methionine, zinc, vitamins B12 and D, fibers, casein and gliadin, and they were linked to gene expression changes in the immune pathways. Despite the common role of maternal diet, breastfeeding and early nutrition in almost all the autoimmune diseases, each disease seems to have specific diet-driver epigenetic mechanisms that require further investigations. The research in this field is opening new routes to establishing a precision nutrition approach to the auto-immune diseases.

The Bidirectional Association between Inflammatory Bowel Disease and Atopic Dermatitis: A Systematic Review and Meta-Analysis

<b><i>Background:</i></b> Previous investigations have suggested a significant association between inflammatory bowel disease (IBD) and atopic dermatitis (AD). Yet, outcomes published remain inconsistent. <b><i>Objective:</i></b> To explore the association between IBD and AD by a systematic review and meta-analysis. <b><i>Methods:</i></b> A comprehensive search of studies published from March 1, 1968, to July 26, 2019, was performed in electronic databases as follows: PubMed, Embase, Cochrane Library, and Web of Science. Methodological quality was assessed based on the Newcastle-Ottawa Scale. Data analysis was conducted using R version 3.6.1 (meta package version 4.9-7). <b><i>Results:</i></b> A total of 14 studies were eligible for exploring the association between IBD and AD. Statistically significant differences were found on the risk of AD comorbidity among patients with IBD (risk ratio [RR] 1.83, 95% CI 1.39–2.40), Crohn’s disease (CD; RR 2.06, 95% CI 1.61–2.64), and ulcerative colitis (UC; RR 1.66, 95% CI 1.23–2.24). Compared with non-AD subjects, patients with AD were 48% (<i>p</i> = 0.019), 44% (<i>p</i> = 0.002), and 38% (<i>p</i> = 0.000) more likely to exhibit IBD, CD as well as UC, respectively. <b><i>Discussion:</i></b> Our evidence supported a significant bidirectional association between IBD and AD. Future prospective studies are warranted to explore underlying mechanisms linking them.