Elimination diet and intestinal permeability in atopic eczema: a preliminary study

Clinical Characteristics, Investigations and Treatment in Children with Chronic Urticaria: An Observational Study

Background and Objectives: The guidelines for chronic urticaria in children contain recommendations that are often based on adult studies. The diagnostic pathway has not been standardized and the effectiveness of anti-H1, omalizumab, montelukast, and systemic glucocorticoids is rarely reported in the pediatric population. There is a wide variation in the rate of remission of chronic urticaria between studies. The aim of this study is to enhance our understanding of pediatric chronic urticaria. Materials and Methods: This study enrolled 37 children with chronic urticaria aged from 0 to 18 years. Demographic parameters, medical history, clinical features, laboratory data and treatment information were collected. Children were treated with the recommended dosage of second-generation H1-antihistamines, which was increased by up to twofold. Omalizumab was added for refractory anti-H1 patients. A three-day course with systemic glucocorticoids was administered for severe exacerbations. Montelukast was administered to some children. Results: Wheals without angioedema were common. Chronic urticaria was spontaneous in 32 children (86.48%), inducible in 2 (5.41%), induced by a parasite in 1 and vasculitic in 2. Treatment of the potential causes of chronic urticaria was of no benefit, except for eradication of Dientamoeba fragilis. Chronic urticaria was resolved within three years in 45.9% of cases. Allergic diseases were present in nine children (24.32%) and autoimmune diseases were present in three (8.11%). All children were treated with anti-H1 at the licensed dose or at a higher dose. A partial or complete response to anti-H1 was observed in 29 (78.38%) patients. Montelukast showed no benefit. All children treated with omalizumab responded. Systemic glucocorticoids were successfully used to treat exacerbations. Conclusions: Our findings indicate that laboratory tests should not be routinely performed in children with chronic urticaria without clinical suspicion. However, comorbidities such as thyroid autoimmune disease and coeliac disease are suggested to be monitored over the chronic urticaria course. These clinical conditions could be diagnosed from the diagnostic framework of chronic urticaria. Increasing the dosage of anti-H1 and omalizumab was effective in children resistant to standard treatment but we still need further studies to generate a standard patient-centered treatment.

The Role of Gut Microbiota and Leaky Gut in the Pathogenesis of Food Allergy

Food allergy (FA) is a growing public health concern, with an increasing prevalence in Western countries. Increasing evidence suggests that the balance of human gut microbiota and the integrity of our intestinal barrier may play roles in the development of FA. Environmental factors, including industrialization and consumption of highly processed food, can contribute to altering the gut microbiota and the intestinal barrier, increasing the susceptibility to allergic sensitization. Compositional and functional alterations to the gut microbiome have also been associated with FA. In addition, increased permeability of the gut barrier allows the translocation of allergenic molecules, triggering Th2 immune responses. Preclinical and clinical studies have highlighted the potential of probiotics, prebiotics, and postbiotics in the prevention and treatment of FA through enhancing gut barrier function and promoting the restoration of healthy gut microbiota. Finally, fecal microbiota transplantation (FMT) is now being explored as a promising therapeutic strategy to prevent FA in both experimental and clinical studies. In this review article, we aim to explore the complex interplay between intestinal permeability and gut microbiota in the development of FA, as well as depict potential therapeutic strategies.

Anti-inflammatory and biologic drugs for atopic dermatitis: a therapeutic approach in children and adolescents

Atopic dermatitis (AD) is a chronic inflammatory disease with a heterogeneous pathogenesis correlated with dysregulation of the immune system and a prevalence of the T2-mediated immune pathway. Recent understanding of the pathogenesis of AD has allowed the development of new drugs targeting different mechanisms and cytokines that have changed the treatment approach. The aim of this review is to update knowledge on the standard of care and recent advancements in the control of skin inflammation. In light of recent guidelines, we report on the clinical efficacy of novel treatments, with special attention to situations where biologics and small molecules are involved.

IgE Mediated Shellfish Allergy in Children-A Review

Shellfish is a leading cause of food allergy and anaphylaxis worldwide. Recent advances in molecular characterization have led to a better understanding of the allergen profile. High sequence homology between shellfish species and between shellfish and house dust mites leads to a high serological cross-reactivity, which does not accurately correlate with clinical cross-reactions. Clinical manifestations are immediate and the predominance of perioral symptoms is a typical feature of shellfish allergy. Diagnosis, as for other food allergies, is based on SPTs and specific IgE, while the gold standard is DBPCFC. Cross-reactivity between shellfish is common and therefore, it is mandatory to avoid all shellfish. New immunotherapeutic strategies based on hypoallergens and other innovative approaches represent the new frontiers for desensitization.

Depletion of Mcpip1 in murine myeloid cells results in intestinal dysbiosis followed by allergic inflammation

MCPIP1 (called also Regnase-1) is a negative regulator of inflammation. Knockout of the Zc3h12a gene, encoding Mcpip1 in cells of myeloid origin (Mcpip1^MKO), has a pathological effect on many organs. The aim of this study was to comprehensively analyze pathological changes in the skin caused by Mcpip1 deficiency in phagocytes with an emphasis on its molecular mechanism associated with microbiome dysbiosis. Mcpip1^MKO mice exhibited spontaneous wound formation on the skin. On a molecular level, the Th2-type immune response was predominantly characterized by an increase in Il5 and Il13 transcript levels, as well as eosinophil and mast cell infiltration. Irritation by DNFB led to a more severe skin contact allergy in Mcpip1^MKO mice. Allergic reactions on the skin were strongly influenced by gut dysbiosis and enhanced systemic dissemination of bacteria. This process was followed by activation of the C/EBP pathway in peripheral macrophages, leading to local changes in the cytokine microenvironment that promoted the Th2 response. A reduced bacterial load inhibited allergic inflammation, indicating the role of intestinal dysbiosis in the development of skin diseases. Our results clearly show that MCPIP1 in phagocytes is an essential negative regulator that controls the gut-skin axis.

New insights in pediatrics in 2021: choices in allergy and immunology, critical care, endocrinology, gastroenterology, genetics, haematology, infectious diseases, neonatology, neurology, nutrition, palliative care, respiratory tract illnesses and telemedicine

In this review, we report the developments across pediatric subspecialties that have been published in the Italian Journal of Pediatrics in 2021. We highlight advances in allergy and immunology, critical care, endocrinology, gastroenterology, genetics, hematology, infectious diseases, neonatology, neurology, nutrition, palliative care, respiratory tract illnesses and telemedicine.

The Effect of Probiotics on Intestinal Tight Junction Protein Expression in Animal Models: A Meta-Analysis

This study investigates the effect of probiotics supplementation on tight junction protein (TJP) expression in animal models by meta-analysis. We estimated the effect of probiotics administration in an animal inflammatory bowel disease model based on 47 collected articles from the databases, including Sciencedirect, Pubmed, Scopus, and Google Scholar. The effect size was analyzed with the standardized mean difference, and the heterogeneity of the effect sizes was assessed using Cochran’s Q test. To explain the heterogeneity, moderate analyses, such as meta-ANOVA and meta-regression, were performed using the mixed effects model. Finally, publication bias was assessed using Egger’s linear regression test. Among the evaluated items, zonula occluden (ZO)-1 showed the highest Q statistics value, and the effect sizes of all items were positive with high significance (p < 0.0001). The I2 value of all items reflected high heterogeneity (in excess of 80%). From the results of the meta-ANOVA, the factors of the heterogeneity found in the probiotics strains were investigated. Lactobacillus reuteri was identified as having the greatest effect on claudin and ZO-1 expression. The publication bias was detected by the Egger’s linear regression test, though it revealed that the occludin and ZO-1 had larger sample sizes than the claudin. In sum, this meta-analysis reveals that probiotics are effective at improving TJP expression in a gut environment of inflammatory bowel disease (IBD)-induced animal model. Our findings will interest IBD patients, as they suggest an area warranting future study.

Allergy-related diseases and early gut fungal and bacterial microbiota abundances in children

BACKGROUND

The early gut microbiota has been proposed as an important link between environmental exposures and development of allergy-related diseases. Beyond the widely investigated associations between the gut bacterial microbiota, we investigated the involvement of early gut mycobiota and gut permeability in the pathogenesis of asthma, allergic rhinoconjunctivitis (AR) and eczema.

METHODS

In the Probiotics in the Prevention of Allergy among Children in Trondheim trial with maternal probiotic supplementation, we collected faecal samples at four timepoints between 0 and 2 years from a cohort of 278 children. Clinical information on allergy-related diseases was collected in a paediatric examination at 2 years and questionnaires at 6 weeks and 1, 2 and 6 years. By quantitative PCR and 16S/ITS1 MiSeq rRNA gene sequencing, we analysed the gut bacterial and fungal microbiota abundance and bacterial diversity and explored associations with allergy-related diseases. We also measured gut permeability markers (lipopolysaccharide-binding protein [LBP] and fatty acid-binding protein 2 [FABP2]).

RESULTS

Children with higher fungal abundance at 2 years were more likely to develop asthma and AR by 6 years, odds ratios 1.70 (95% CI: 1.06-2.75) and 1.41 (1.03-1.93), respectively. We explored causal connections, and children with eczema at 1-2 years appeared to have more mature bacterial microbiota, as well as being depleted of Enterococcus genus. Although LBP and FABP2 did not correlate with eczema, increased bacterial abundance was associated with increased serum FABP2.

CONCLUSIONS

We observed positive associations between gut fungal abundance and allergy-related disease, but increased gut permeability does not appear to be involved in the underlying mechanisms for this association. Our findings should be confirmed in future microbiota studies.

Maternal Allergy and the Presence of Nonhuman Proteinaceous Molecules in Human Milk

Human milk contains proteins and/or protein fragments that originate from nonhuman organisms. These proteinaceous molecules, of which the secretion might be related to the mother's allergy status, could be involved in the development of the immune system of the infant. This may lead, for example, to sensitization or the induction of allergen-specific tolerance. The aim of this study was to investigate the relation between maternal allergy and the levels of nonhuman proteinaceous molecules in their milk. In this study, we analysed trypsin-digested human milk serum proteins of 10 allergic mothers and 10 nonallergic mothers. A search was carried out to identify peptide sequences originating from bovine or other allergenic proteins. Several methods were applied to confirm the identification of these sequences, and the differences between both groups were investigated. Out of the 78 identified nonhuman peptide sequences, 62 sequences matched Bos taurus proteins. Eight peptide sequences of bovine β -lactoglobulin had significantly higher levels in milk from allergic mothers than in milk from nonallergic mothers. Dietary bovine β -lactoglobulin may be absorbed through the intestinal barrier and secreted into human milk. This seems to be significantly higher in allergic mothers and might have consequences for the development of the immune system of their breastfed infant.

Probiotics Prevents Sensitization to Oral Antigen and Subsequent Increases in Intestinal Tight Junction Permeability in Juvenile-Young Adult Rats

Increased intestinal permeability is thought to underlie the pathogenesis of food allergy. We explore the mechanism responsible for changes in the morphology and function of the intestinal barrier using a rat model of food allergy, focusing on the contribution of intestinal microbiota. Juvenile–young adult rats were sensitized with ovalbumin and treated with antibiotics or probiotics (Clostridium butyricum and Lactobacillus reuteri), respectively. The serum ovalbumin-IgE levels, intestinal permeability, histopathological features, tight junction (TJ)-associated proteins, Th2 cytokines, and gut microbiota in feces were analyzed in each group. Sensitized rats showed an increase in ovalbumin-IgE levels and intestinal permeability with gut mucosal inflammation, whereas rats that received probiotics were only mildly affected. Rats given ovalbumin, but not those given probiotics, showed a reduction in both TJ-related protein expression and localization. Th2 cytokine levels were increased in the sensitized rats, but not in those given probiotics. TJs in rats treated with ovalbumin and antibiotics were disrupted, but those in rats administered probiotics were undamaged. Clostridiaceae were increased in the probiotics groups, especially Alkaliphilus, relative to the ovalbumin-sensitized group. Gut microbiota appears to play a role in regulating epithelial barrier function, and probiotics may help to prevent food sensitization through the up-regulation of TJ proteins.

MAVS deficiency induces gut dysbiotic microbiota conferring a proallergic phenotype

Prominent changes in the gut microbiota (referred to as "dysbiosis") play a key role in the development of allergic disorders, but the underlying mechanisms remain unknown. Study of the delayed-type hypersensitivity (DTH) response in mice contributed to our knowledge of the pathophysiology of human allergic contact dermatitis. Here we report a negative regulatory role of the RIG-I-like receptor adaptor mitochondrial antiviral signaling (MAVS) on DTH by modulating gut bacterial ecology. Cohousing and fecal transplantation experiments revealed that the dysbiotic microbiota of Mavs-/- mice conferred a proallergic phenotype that is communicable to wild-type mice. DTH sensitization coincided with increased intestinal permeability and bacterial translocation within lymphoid organs that enhanced DTH severity. Collectively, we unveiled an unexpected impact of RIG-I-like signaling on the gut microbiota with consequences on allergic skin disease outcome. Primarily, these data indicate that manipulating the gut microbiota may help in the development of therapeutic strategies for the treatment of human allergic skin pathologies.

Change in gut microbiota for eczema: Implications for novel therapeutic strategies

Eczema is one of the most common inflammatory diseases, often constituting a lifelong burden for afflicted individuals. The complex interaction of host genetic and multiple environmental factors contribute to its pathogenesis. A relationship between maladjustment of gut microbiota and eczema has been brought into the light of day in most previous studies. In eczema preclinical models, specific intestinal microbial species have been demonstrated to prohibit or dwindle immune responsiveness, indicating that these strains among commensal gut bacteria may exert either a morbific or phylactic function in eczema progression. As such, oral probiotics can serve as a medicinal approach for eczema therapy. Given that relative scientific work is still at the early stage, only limited data are available in the field. New sequencing techniques have been fortunately performed to gain access to an extended research on the relationship between gut bacterial flora and human diseases. In the current review, we identified the role of intestinal microbiota in the development of eczema and how specific bacterial strains adjust the immune responsiveness in the midst of disease progression. Probiotics as an applicable treatment for eczema were evaluated in other threads as well.

The Role of Elimination Diets in Atopic Dermatitis-A Comprehensive Review

BACKGROUND/OBJECTIVES

Diet is a common concern for individuals with atopic dermatitis (AD) and their families. Studies regarding the effect of dietary interventions on AD exist, but many are limited by small size and poor design. Conflicting results present a challenge to clinicians seeking to counsel patients. The aim of the current review is to examine the published literature and generate helpful conclusions for clinicians faced with dietary questions in AD.

METHODS

A PubMed search was performed focusing on dietary interventions for AD in children and adults through July 2016. The search was limited to the English language and included studies that evaluated one or more forms of dietary modification for the treatment of AD. Studies of supplementation, such as with vitamins, minerals, or probiotics, were not included, nor were studies on prevention of the development of AD. A total of 43 articles met the inclusion criteria and were included in the final analysis.

RESULTS

Trials varied in type, duration, and the AD patient populations studied. Overall, there is some level I evidence to support specific exclusion diets in preselected patients but insufficient evidence for strict elimination diets (diets that are typically limited to six to eight foods). Data supporting other interventions are mixed and based on small, poorly designed studies.

CONCLUSIONS

A comprehensive literature review reveals some promising results and several areas in need of further study. More evidence is needed to form a strong foundation for recommendations regarding the utility and role of elimination diets in AD management, but current evidence suggests that strict diet management is not effective in the treatment AD in the vast majority of patients.

Health effects of probiotics on the skin

Skin is the largest organ of the body and is constantly exposed to physical, chemical, bacterial, and fungal challenges. It is well known that probiotics are helpful for specific disorders and different clinical studies have indicated that probiotics have special effects in cutaneous apparatus directly or indirectly that can be considerable from versatile aspects. Probiotic bacteriotherapy can have great potential in preventing and treating the skin diseases including eczema, atopic dermatitis, acne, and allergic inflammation or in skin hypersensitivity, UV-induced skin damage, wound protection, and as a cosmetic product. The current paper comprehensively reviews the different health effects of probiotics on the skin.

Food IgG4 antibodies are elevated not only in children with wheat allergy but also in children with gastrointestinal diseases

BACKGROUND

Food sIgG and sIgG4 are highly individually versatile. We put a hypothesis that one of the responsible factors is the presence of gastrointestinal inflammatory diseases. The objectives were: 1. An analysis of wheat and rice sIgG and sIgG4 in healthy children, children with IgE-mediated wheat allergy (WA), coeliac disease (CD) and Helicobacter pylori infection (HP). 2. Usability of wheat sIgG and sIgG4 in the WA diagnostics.

METHODS

We compared 388 each wheat and rice sIgG and sIgG4 in a group of 200 children: 50 WA (diagnosis, diet treatment, tolerance), 50 CD (diagnosis and remission), 50 HP and 50 healthy. SIgE, sIgG, sIgG4 were determined with the FEIA method (Pharmacia CAP System).

RESULTS

In healthy children food sIgG were the lowest; no sIgG4 were found. In the CD diagnosis group wheat and rice sIgG and rice sIgG4 were the most common and their concentrations were the highest (p < .001, p < .05). Wheat sIgG4 were the highest in WA children (diagnosis and tolerance) to fall during the elimination diet (p < .05). Wheat and rice sIgG remained the same in all allergy phases. Rice sIgG also did not differ in the class G4.

CONCLUSIONS

1. Serum concentrations of wheat and rice sIgG and sIgG4 are elevated in children with CD, HP and WA. 2. Sub-clinical incidence of some gastrointestinal inflammatory diseases may be responsible for high individual versatility of food sIgG and sIgG4 concentrations in serum. 3. Wheat sIgG and sIgG4 in children do not correlate with WA clinical picture.

Food Avoidance Diets for Dermatitis

Food allergy is relatively common in both children and adults, and its prevalence is increasing. Early exposure of food allergens onto skin with an impaired epidermal barrier predisposes to sensitization and prevents the development of oral tolerance. While immediate-type food allergies are well described, less is known about delayed-type food allergies manifesting as dermatitis. This is due, in part, to limitations with current diagnostic testing for delayed-type food allergy, including atopy patch testing. We conducted a systematic review of food avoidance diets in delayed-type food allergies manifesting as dermatitis. While beneficial in some clinical circumstances, avoidance diets should be used with caution in infants and children, as growth impairment and developmental delay may result. Ultimately, dermatitis is highly multifactorial and avoidance diets may not improve symptoms of delayed-type food allergy until combined with other targeted therapies, including restoring balance in the skin microbiome and re-establishing proper skin barrier function.

Nutritional management and follow up of infants and children with food allergy: Italian Society of Pediatric Nutrition/Italian Society of Pediatric Allergy and Immunology Task Force Position Statement

Although the guidelines on the diagnosis and treatment of food allergy recognize the role of nutrition, there is few literature on the practical issues concerning the nutritional management of children with food allergies.

This Consensus Position Statement focuses on the nutritional management and follow-up of infants and children with food allergy.

It provides practical advices for the management of children on exclusion diet and it represents an evidence-based consensus on nutritional intervention and follow-up of infants and children with food allergy.

Children with food allergies have poor growth compared to non-affected subjects directly proportional to the quantity of foods excluded and the duration of the diet. Nutritional intervention, if properly planned and properly monitored, has proven to be an effective mean to substantiate a recovery in growth.

Nutritional intervention depends on the subject’s nutritional status at the time of the diagnosis.

The assessment of the nutritional status of children with food allergies should follow a diagnostic pathway that involves a series of successive steps, beginning from the collection of a detailed diet-history.

It is essential that children following an exclusion diet are followed up regularly.

The periodic re-evaluation of the child is needed to assess the nutritional needs, changing with the age, and the compliance to the diet.

The follow- up plan should be established on the basis of the age of the child and following the growth pattern.

The immunopathogenesis of cow's milk protein allergy (CMPA)

The most frequent symptoms among the manifestations of cow milk protein allergy (CMPA) are gastrointestinal. CMPA pathogenesis involves immunological mechanisms with participation of immunocompetent cells and production of immunoglobulin E (IgE). Nevertheless, recent studies have been focused on the description of other forms of CMPA, not-mediated by IgE reactions, mostly involving the T lymphocite immune system. Thus, in this field it is important to note how different kind of cells are involved in the immunopathogenesis of CMPA, such as antigen-specific T cells, T regulatory cells, cytokines secreted by the different T lymphocite subsets, B lymphocytes, antingen-presenting cells, mast cells, that together orchestrate the complex mechanism leading to the phenotipic expression of CMPA.The progress in the diagnosis of immunologic disorders allowed the recent literature to develop new models for immuno-mediate disorders, involving new cells (such as Treg cells) and thus allowing the acquisition of a new vision of the pathogenesis of atopic diseases.The aim of this review is to describe the immunopathogenetic aspects of CMPA in view of these new discoveries in the immunologic field, considering the immunologic pathway at the basis of both IgE- and not-IgE mediated CMPA.

Gluten-free sourdough wheat baked goods appear safe for young celiac patients: a pilot study

OBJECTIVES

This study was aimed at showing the safety, for young patients with celiac disease (CD), of sweet baked goods made of wheat flour, which was rendered gluten-free during sourdough fermentation.

METHODS AND RESULTS

As shown by R5 antibody-based sandwich and competitive enzyme-linked immunosorbent assay (ELISA), selected lactobacilli and fungal proteases, routinely used in bakeries, degraded gluten to <10 ppm during sourdough fermentation. The resulting flour was mainly a mixture of water-/salt-soluble low-size peptides and free amino acids. Gliadin and glutenin fractions extracted from the pepsin-trypsin (PT) digest of the fermented wheat flour induced the expression of interferon (IFN)-γ at the level comparable with the negative control. After fermentation, the wheat flour was spray dried and used for making sweet baked goods. Eight patients with CD in remission were enrolled for the clinical challenge, and they daily consumed 200 g of sweet baked goods equivalent to 10 g of native gluten. Hematology, serology (total serum IgA, IgG and IgA antigluten, endomysial and tissue transglutaminase IgA antibodies), and intestinal permeability analyses were carried out over time. One patient interrupted the trial after 15 days and another after 30 days only due to difficulties in the compliance of the daily consumption. All of the other patients showed normal values of hematology, serology, and intestinal permeability during 60 days of challenge.

CONCLUSIONS

This study showed that a wheat flour-fermented product, having gluten completely degraded, is not toxic for patients with CD. Nevertheless, these foods should not be recommended for patients with celiac disease until a formal trial has been done.

IgE antibodies to omega-5 gliadin in children with wheat-induced anaphylaxis

BACKGROUND

Wheat can cause severe immunoglobulin E (IgE)-mediated systemic reactions including anaphylaxis but knowledge on relevant wheat allergens at the molecular level is scanty.

METHODS

Seven children (aged from 6 months to 13 years) experiencing from 2 to 10 anaphylactic reactions in a year after eating food-containing wheat were examined. Purified omega-5 gliadin was used as an allergen in IgE enzyme-linked immunosorbent assay (ELISA) and in skin prick testing (SPT). Wheat CAP radioallergosorbent test (RAST) and SPT were also examined.

RESULTS

All seven anaphylactic children, but none of 15 control subjects had IgE antibodies to omega-5 gliadin in ELISA. Five of the six tested anaphylactic children showed positive SPT to omega-5 and crude gliadin, and all seven had positive wheat CAP RAST and SPT. One child was challenged with wheat, which caused anaphylaxis. After adherence to a wheat-free diet four children remained symptomless and three experienced one to two anaphylactic reactions.

CONCLUSION

The present results show that wheat omega-5 gliadin is a major sensitizing allergen in children with wheat-induced anaphylaxis. They also suggest that omega-5 gliadin IgE ELISA could be used as a diagnostic test for this severe allergy.

Effect of probiotics on gastrointestinal symptoms and small intestinal permeability in children with atopic dermatitis

OBJECTIVE

To determine whether probiotic lactobacilli may alleviate small intestinal inflammation and strengthen the intestinal barrier function in children with atopic dermatitis.

STUDY DESIGN

In a double-blinded, placebo-controlled, cross-over study, probiotic lactobacilli (Lactobacillus rhamnosus 19070-2 and L reuteri DSM 12246) were administered for 6 weeks to 41 children with moderate and severe atopic dermatitis. Gastrointestinal symptoms were registered before and during treatment and small intestinal permeability was measured by the lactulose-mannitol test.

RESULTS

During Lactobacillus supplementation, there was a significant decrease in the frequency of gastrointestinal symptoms (39% during the placebo period versus 10% during active treatment, P=.002). There was a positive association between the lactulose to mannitol ratio and the severity of the eczema (r=0.61, P=.02 after placebo and r=0.53, P=.05 after active treatment). After probiotic treatment, the lactulose to mannitol ratio was lower (0.073) than after placebo (0.110, P=.001).

CONCLUSIONS

Impairment of the intestinal mucosal barrier appears to be involved in the pathogenesis of atopic dermatitis. The study suggests that probiotic supplementation may stabilize the intestinal barrier function and decrease gastrointestinal symptoms in children with atopic dermatitis.

Intestinal barrier: an interface between health and disease

The intestine constitutes the largest interface between a person and his or her environment, and an intact intestinal barrier is thus essential in maintaining health and preventing tissue injury and several diseases. The intestinal barrier has various immunological and non-immunological components. The epithelial barrier is one of the most important non-immunological components. Hyperpermeability of this barrier is believed to contribute to the pathogenesis of several gastrointestinal disorders including inflammatory bowel disease, celiac disease and food allergy. Hence, assessing barrier integrity is of the utmost importance. One of the more quantitative gauges for this assessment is transepithelial permeability of various molecular probes, among which sugars are commonly used. Measures of intestinal permeability might also be useful as markers for assessment of prognosis and follow up in various gastrointestinal disorders. The present article is a review of the normal and abnormal functioning of the intestinal barrier, the diseases that can result from loss of barrier integrity, and some promising agents and strategies for restoring barrier normality and integrity.

Duodenal IgE-positive cells and elimination diet responsiveness in children with atopic dermatitis

BACKGROUND

Parameters for identifying eczematous children who could respond to an elimination diet are needed. In children with food allergy, duodenal IgE-containing cells are enhanced.

OBJECTIVE

To determine the presence of duodenal mucosal IgE-positive cells in atopic dermatitis and to determine whether duodenal IgE-positive cells may identify eczematous children who will benefit from an elimination diet.

METHODS

Thirty-one children with severe eczema underwent gastrointestinal endoscopy because of gastrointestinal symptoms and were treated with an elimination diet. A clinical score to skin lesions was given before and after diet. All subjects were skin-prick tested with food antigens and aeroallergens. Serum IgE levels were measured. Duodenal IgE-positive cells were investigated in 18 control subjects and in all eczematous children before diet.

RESULTS

The number of duodenal IgE-positive cells in children with atopic dermatitis was significantly increased compared with that of control group (P < 0.001). Nineteen (61%) eczematous children improved on a few food diet. Diet-responsive children had significantly higher IgE-positive cells compared with both nondiet-responsive and controls. Positive predictive accuracy of duodenal IgE-positive cells was poor, whereas negative predictive accuracy was high at the cutoff level of 50 IgE-positive cells/10 visual fields. Diagnostic accuracy both of SPT reactions with foods and of food-specific serum IgE antibodies was poor.

CONCLUSIONS

An intestinal IgE-mediated reaction occurred in children with severe atopic dermatitis who underwent intestinal endoscopy because of gastrointestinal symptoms. In these eczematous children, the number of IgE-positive cells in the duodenal mucosa might be helpful for excluding a positive response to the elimination diet.

The sensitivity of the lactulose/rhamnose gut permeability test

BACKGROUND

The lactulose/rhamnose (L/R) intestinal permeability test is widely used. However, different quantities and proportions of lactulose and rhamnose are used. The aim of this study was to determine whether a low dosage of lactulose is able to discriminate between normal and increased permeability.

MATERIALS AND METHODS

Two groups of 10 healthy subjects were studied. In group 1, three different iso-osmolar test solutions were administered on 3 days. The solutions consisted of 10 g of L with 1 g of R, 5 g of L with 0.5 g of R and 1 g of L with 0.1 g of R in 65 mL of water. Group 2 ingested these solutions 1 h after ingestion of 750 mg of chenodeoxycholeic acid (CDCA), which is known to increase permeability. The urinary L/R ratio was determined using high-performance liquid chromatography. Data are presented as medians (range).

RESULTS

In group 1, no differences were observed between the three solutions. In Group 2, there was a significant difference (P = 0.045) between the three solutions. The L/R ratios were 0.0079 (0.0024-0.0152) (1L to 0.1R), 0.0138 (0.0066-0.0192) (5L to 0.5R) and 0.0144 (0.0074-0.0374) (10L to 1R). The L/R ratio differed significantly between Groups 1 and 2 (P < 0.001) using the 5L to 0.5R and 10L to 1R solutions respectively.

CONCLUSION

If the permeability is increased, the urinary L/R ratio depends on the quantity of lactulose and rhamnose administered in equal proportion. 5L to 0.5R is sufficient to discriminate between a normal and a moderately increased permeability.

Clinical food hypersensitivity: the relevance of duodenal immunoglobulin E-positive cells

Owing to poor reliability of laboratory tests, diagnosis of food allergy is based on clinical response to double-blind placebo-controlled food challenge. The aim of the present study was to assess the value of duodenal IgE-positive cells in the diagnosis of food allergy. Thirty-one children with a history of possible food allergy underwent duodenal biopsies, skin prick tests, and measurement of serum IgE antibodies, and were put on an elimination diet followed by food challenge. Open food challenges were performed in patients under 12 mo of age, and double-blind placebo-controlled challenges were for suspected foods. On the basis of clinical food hypersensitivity, patients were divided into two groups. Group 1 consisted of 13 children with food allergy. Thirteen of 20 positive provocations elicited reactions within 12 h from the end of the challenge, seven later. Group 2 was the control group and included 18 patients with negative food challenges. The number of IgE-positive cells in biopsy specimens was significantly more elevated in group 1 with respect to group 2 (153.24 +/- 83.13 versus 18.4 +/- 18.9; p < 0.01). Total serum IgE levels were elevated compared with that of the control group (p < 0.01) and correlated with the number of IgE-positive cells (p < 0.001, r = 0.62). Enhanced IgE-containing cells were found in all delayed reactors, but about one-third had negative skin prick tests or specific serum IgE antibodies to the offending foods. Our results showed that systemic reactions to foods are associated with an IgE-mediated response in the duodenal mucosa. Larger studies would be required to assess the predictive value of an increased number of IgE-positive cells in the diagnosis of allergy to food, especially in children with delayed reactions.

Time course of changes in the intestinal permeability of food-sensitized rats after oral allergen challenge

Rats were sensitized with ovalbumin (OVA) with a molecular weight of 45 kd, challenged with OVA orally, followed by orally administered beta-lactoglobulin (BLG) as an intestinal permeability marker. BLG is a macro-molecular protein with a molecular weight of 18 kd. Blood BLG concentrations were measured (by ELISA) serially over 4 hours following BLG administration, which in turn was given 1 hour after OVA challenges. The maximum BLG concentration was at 2 hours. BLG was then administered orally 1, 3, 6, 12 and 24 hours after oral OVA challenge, and the serum BLG concentration at 2 hours after BLG administration was compared among the five groups. BLG appeared in the circulation of the animals 1, 6 and 24 hours after allergen challenge, but not after 3 and 12 hours. The serum BLG concentration was not significantly different at 1, 6 and 24 hours. Histopathological examinations of the intestines showed mast cell infiltration of the intestinal mucosa at 1 hour, remarkable edema of villi at 3 hours, eosinophil infiltration at 6 hours, an increase of goblet cells at 12 hours and villous atrophy and lymphocyte infiltration at 24 hours. The appearance in the serum of three BLG peaks of comparable heights suggested that the intestinal absorption of BLG may be related to a late and delayed phase as well as the immediate IgE-dependent phase response.

Increased intestinal permeability in bronchial asthma

T lymphocytes are a major component of bronchial inflammatory processes in asthma. Because lymphocytes have the ability to migrate from one mucosal site to another, we initiated this prospective study to demonstrate mucosal abnormalities of the digestive barrier in asthma. To establish this we studied intestinal permeability in a group of 37 patients with asthma (21 allergic and 16 nonallergic) by measuring chromium 51-labeled ethylenediaminetetraacetatic acid (CrEDTA) urinary recovery. The results were compared with those obtained in a group of 13 nonasthmatic patients with chronic obstructive pulmonary disease and 26 healthy control subjects. Urinary recovery of CrEDTA was significantly higher in patients with asthma (2.5% +/- 1.95%) than in patients with chronic obstructive pulmonary disease (1.16% +/- 0.48%) and healthy control subjects (1.36% +/- 0.14%). There was no significant difference in intestinal permeability between patients with allergic asthma (2.94% +/- 2.4%) and those with nonallergic asthma (1.92% +/- 0.9%). Intestinal permeability was not correlated with the severity of asthma as measured by FEV1. Similarly, intestinal permeability did not significantly vary according to Aas score or steroid treatment. Serum IgE values and eosinophil blood count were not correlated with intestinal permeability. Intestinal permeability was evaluated sequentially in seven patients with asthma (4 allergic and 3 nonallergic) with a mean interval of 7.6 months (range, 2 to 13 months) and did not significantly change. Our results support the hypothesis that a general defect of the whole mucosal system is present as a cause or a consequence of bronchial asthma.