Allergy and the gut

Deficiency of leukotriene B4 receptor type 1 ameliorates ovalbumin-induced allergic enteritis in mice

Leukotriene B4 receptor type 1 (BLT1), a high-affinity receptor for leukotriene B4 (LTB4), plays an important role in inflammatory responses, including allergic airway inflammation. In this study, we examined the effect of genetic BLT1 deletion (BLT1KO) on ovalbumin (OVA)-induced allergic enteritis in mice to determine the pathogenic role of LTB4/BLT1 in allergic enteritis, a gastrointestinal form of food allergy. Repeated oral OVA challenges after sensitization with OVA and aluminium potassium sulphate induced allergic enteritis, characterized by systemic allergic symptoms (scratching, immobility and swelling), diarrhoea, colonic oedema and colonic goblet cell hyperplasia, accompanied by increased colonic peroxidase activity, colonic inflammatory cytokine expression and increased serum OVA-specific IgE levels. The severity of enteritis was significantly attenuated in BLT1KO mice compared with wild-type (WT) mice, without an increase in serum OVA-specific IgE levels. The accumulation of neutrophils, eosinophils, M2-macrophages, dendritic cells, CD4+ T cells and mast cells was observed in the colonic mucosa of allergic enteritis, and such accumulation was significantly lower in BLT1KO mice than in WT mice. BLT1 expression was upregulated and colocalized mostly in neutrophils and partly in eosinophils and dendritic cells in the colonic mucosa of allergic enteritis. These findings indicate that BLT1 deficiency ameliorates OVA-induced allergic enteritis in mice and that LTB4/BLT1 contributes to neutrophil and eosinophil accumulation in the allergic colonic mucosa. Therefore, BLT1 is a promising drug target for treating food allergies.

Food allergy across the globe

The prevalence of food allergy (FA) is increasing in some areas of the globe, highlighting the need for better strategies for prevention, diagnosis, and therapy. In the last few decades, we have made great strides in understanding the causes and mechanisms underlying FAs, prompting guideline updates. Earlier guidelines recommended avoidance of common food allergens during pregnancy and lactation and delaying the introduction of allergenic foods in children aged between 1 and 3 years. Recent guidelines for allergy prevention recommend consumption of a healthy and diverse diet without eliminating or increasing the consumption of allergenic foods during pregnancy or breast-feeding. Early introduction of allergenic foods is recommended by most guidelines for allergy prevention after a period of exclusive breast-feedng (6 months [World Health Organization] or 4 months [European Academy of Allergy and Clinical Immunology]). New diagnostics for FA have been developed with varied availability of these tests in different countries. Finally, the first oral immunotherapy drug for FA was approved by the US Food and Drug Administration and European Medicines Agency in 2020. In this review, we will address the global prevalence of FA, our current understanding of the causes of FA, and the latest guidelines for preventing, diagnosing, and treating FA. We will also discuss similarities and differences between FA guidelines.

Immunogloboulin E-Mediated Food Sensitization in Children with Celiac Disease: A Single-Center Experience

PURPOSE

Celiac disease (CD) is an autoimmune disorder of the small intestine caused by an abnormal immune response to gluten proteins and is often characterized by gastrointestinal symptoms. Food allergy (FA) is an adverse immune sensitivity to ingested food proteins leading to inflammation in various organs including the gastrointestinal tract. The relationship between CD and FA remains unclear. This study aimed to assess the prevalence and clinical relevance of immunoglobulin E (IgE)-mediated food sensitization in children with CD.

METHODS

Fifty-nine children diagnosed with CD were reviewed for clinical symptoms and evidence of IgE-sensitization to food and airborne allergens using the PolyCheck method.

RESULTS

IgE-mediated sensitization has been diagnosed in 20.3% of children with CD (CD/ A). In the CD/A group, 58.3% of children were sensitized to food and 66.7% to airborne allergens. Further, 41.7% of patients with CD and allergy reported gastrointestinal tract symptoms associated with the ingestion of sensitizing foods. Analysis of the clinical status revealed that the incidence of other allergic disorders in the CD/A group was as follows: atopic dermatitis (33.3%), asthma (25.0%), and allergic rhinitis (16.7%). The percentage of eosinophils was significantly higher in the CD/A group than in the CD group (0.33±0.25 vs. 0.11±0.09; p=0.006).

CONCLUSION

The diagnosis of CD does not exclude FA. The gastrointestinal symptoms in children with CD may be the result of both CD and FA; therefore, children with CD should be evaluated for the presence of FA regardless of age.

Food Intolerance of Unknown Origin: Caused by Mucosal Inflammation? A Pilot Study

INTRODUCTION

The prevalence of patients with food intolerance (FI) has increased significantly. Immunoglobulin (Ig)E-mediated food allergies (FAs) are detected by determining IgE antibodies and skin prick test. Carbohydrate malabsorptions are clarified with breath tests. However, these diagnostic measures cannot capture all intolerances and have limitations in case of gut-mediated FI. The aims of this pilot study were to evaluate different methods to determine intestinal mucosal IgE in patients with FA and to characterize the intestinal mucosa in patients with FI of unknown origin (FH).

METHODS

Patients with FA and FH were compared with healthy controls. To determine the IgE antibodies and the cytokines tumor necrosis factor (TNF)-α and interferon (IFN)-γ of the intestinal mucosal, a lavage was performed as part of an ileocolonoscopy and samples were taken using the cytobrush and biopsy forceps. In a subgroup, mucosal samples were also taken from the duodenum.

RESULTS

Data in homogenates of intestinal mucosal samples yielded the highest sensitivity for IgE antibody titers compared with lavage and cytobrush. Patients with FA presented increased intestinal TNF-α and low IFN-γ values. This was in contrast to FH patients, who showed low intestinal IgE antibodies and TNF-α levels, but increased IFN-γ values.

DISCUSSION

The determination of IgE antibodies to diagnose intestinal IgE-mediated FA is most reliable in intestinal mucosal samples. Increased TNF-α and low IFN-γ levels in patients with FA characterize an allergic reaction. Decreased TNF-α and increased IFN-γ levels in patients with FH indicate an inflammation-related intolerance reaction (see Visual Abstract, Supplementary Digital Content 1, http://links.lww.com/CTG/A520).

Atopic Dermatitis and Celiac Disease: A Cross-Sectional Study of 116,816 Patients

BACKGROUND

Both atopic dermatitis and celiac disease are often accompanied by other immune-mediated disorders.

OBJECTIVE

The objective of this study was to evaluate the potential association between atopic dermatitis and celiac disease in a broad community-based population.

METHODS

A cross-sectional observational design was used. Demographic and clinical data were collected for patients enrolled in a large health management organization who were diagnosed with atopic dermatitis by a dermatologist in 2002-17. The presence of celiac disease/celiac disease-related morbidities was recorded for the whole group, for adults (age > 18 years), and for adults with moderate-to-severe atopic dermatitis. Findings were compared with a matched control group without atopic dermatitis.

RESULTS

The study group included 116,816 patients of whom 45,157 were adults; 1909 adult patients had moderate-to-severe atopic dermatitis. Compared to the respective control subjects, the prevalence rate of celiac disease in the whole group was 0.6% vs. 0.4%; in the adults, 0.6% vs. 0.3%; and in the adults with moderate-to-severe atopic dermatitis, 0.8% vs. 0.3% (p < 0.001 for all). On multivariate analysis, atopic dermatitis was associated with a significantly higher prevalence of celiac disease (odds ratio = 1.609, 95% confidence interval 1.42-1.82, p < 0.001) in the entire study population and each subgroup.

CONCLUSIONS

We observed a significant association between atopic dermatitis and celiac disease. This association emphasizes the need for timely screening of gastrointestinal morbidities in individuals with atopic dermatitis to prevent long-term complications.

Calcium Imaging of Nerve-Mast Cell Signaling in the Human Intestine

Introduction: It is suggested that an altered microenvironment in the gut wall alters communication along a mast cell nerve axis. We aimed to record for the first time signaling between mast cells and neurons in intact human submucous preparations. Methods: We used the Ca2+ sensitive dye Fluo-4 AM to simultaneously image changes in intracellular calcium [Ca+2]i (%ΔF/F) in neurons and mast cells. Data are presented as median with interquartile ranges (25/75%). Results: We recorded nerve responses in 29 samples upon selective activation of 223 mast cells by IgE receptor cross linking with the antibody mAb22E7. Mast cells responded to mAb22E7 with a median [Ca+2]i increase of 20% (11/39) peaking 90 s (64/144) after the application. Only very few neurons responded and the median percentage of responding neuronal area was 0% (0/5.9). Mast cell activation remained in the presence of the fast sodium channel blocker tetrodotoxin. Specific neuronal activation by transmural electrical field stimulation (EFS) in 34 samples evoked instantaneously [Ca+2]i signals in submucous neurons. This was followed by a [Ca+2]i peak response of 8%ΔF/F (4/15) in 33% of 168 mast cells in the field of view. The mast cell response was abolished by the nerve blocker tetrododoxin, reduced by the Calcitonin Gene-Related Peptide receptor 1 antagonist BIBN-4096 and the Vasoactive Intestinal Peptide receptor antagonist PG97-269, but not by blockade of the neurokinin receptors 1-3. Conclusion: The findings revealed bidirectional signaling between mast cells and submucous neurons in human gut. In our macroscopically normal preparations a nerve to mast cell signaling was very prominent whereas a mast cell to nerve signaling was rather rare.

Application of the adverse outcome pathway (AOP) concept to structure the available in vivo and in vitro mechanistic data for allergic sensitization to food proteins

BACKGROUND

The introduction of whole new foods in a population may lead to sensitization and food allergy. This constitutes a potential public health problem and a challenge to risk assessors and managers as the existing understanding of the pathophysiological processes and the currently available biological tools for prediction of the risk for food allergy development and the severity of the reaction are not sufficient. There is a substantial body of in vivo and in vitro data describing molecular and cellular events potentially involved in food sensitization. However, these events have not been organized in a sequence of related events that is plausible to result in sensitization, and useful to challenge current hypotheses. The aim of this manuscript was to collect and structure the current mechanistic understanding of sensitization induction to food proteins by applying the concept of adverse outcome pathway (AOP).

MAIN BODY

The proposed AOP for food sensitization is based on information on molecular and cellular mechanisms and pathways evidenced to be involved in sensitization by food and food proteins and uses the AOPs for chemical skin sensitization and respiratory sensitization induction as templates. Available mechanistic data on protein respiratory sensitization were included to fill out gaps in the understanding of how proteins may affect cells, cell-cell interactions and tissue homeostasis. Analysis revealed several key events (KE) and biomarkers that may have potential use in testing and assessment of proteins for their sensitizing potential.

CONCLUSION

The application of the AOP concept to structure mechanistic in vivo and in vitro knowledge has made it possible to identify a number of methods, each addressing a specific KE, that provide information about the food allergenic potential of new proteins. When applied in the context of an integrated strategy these methods may reduce, if not replace, current animal testing approaches. The proposed AOP will be shared at the www.aopwiki.org platform to expand the mechanistic data, improve the confidence in each of the proposed KE and key event relations (KERs), and allow for the identification of new, or refinement of established KE and KERs.

[Food allergy in adulthood]

Food allergies can newly arise in adulthood or persist following a food allergy occurring in childhood. The prevalence of primary food allergy is basically higher in children than in adults; however, in the routine practice food allergies in adulthood appear to be increasing and after all a prevalence in Germany of 3.7 % has been published. The clinical spectrum of manifestations of food allergies in adulthood is broad. Allergy symptoms of the immediate type can be observed as well as symptoms occurring after a delay, such as indigestion, triggering of hematogenous contact eczema or flares of atopic dermatitis. The same principles for diagnostics apply in this group as in childhood. In addition to the anamnesis, skin tests and in vitro tests, as a rule elimination diets and in particular provocation tests are employed. Molecular allergy diagnostics represent a major step forward, which allow a better assessment of the risk of systemic reactions to certain foodstuffs (e.g. peanuts) and detection of cross-reactions in cases of apparently multiple sensitivities. Current German and European guidelines from 2015 are available for the practical approach to clarification of food allergies. The most frequent food allergies in adults are nuts, fruit and vegetables, which can cross-react with pollen as well as wheat, shellfish and crustaceans. The therapy of allergies involves a consistent avoidance of the allogen. Detailed dietary plans are available with avoidance strategies and instructions for suitable food substitutes. A detailed counseling of affected patients by specially trained personnel is necessary especially in order to avoid nutritional deficiencies and to enable patients to enjoy a good quality of life.

Mast Cells and Irritable Bowel Syndrome: From the Bench to the Bedside

Irritable bowel syndrome (IBS) is traditionally defined as a functional disorder since it lacks demonstrable pathological abnormalities. However, in recent years, low grade inflammatory infiltration, often rich in mast cells, in both the small and large bowel, has been observed in some patients with IBS. The close association of mast cells with major intestinal functions, such as epithelial secretion and permeability, neuroimmune interactions, visceral sensation, and peristalsis, makes researchers and gastroenterologists to focus attention on the key roles of mast cells in the pathogenesis of IBS. Numerous studies have been carried out to identify the mechanisms in the development, infiltration, activation, and degranulation of intestinal mast cells, as well as the actions of mast cells in the processes of mucosal barrier disruption, mucosal immune dysregulation, visceral hypersensitivity, dysmotility, and local and central stress in IBS. Moreover, therapies targeting mast cells, such as mast cell stabilizers (cromoglycate and ketotifen) and antagonists of histamine and serotonin receptors, have been tried in IBS patients, and have partially exhibited considerable efficacy. This review focuses on recent advances in the role of mast cells in IBS, with particular emphasis on bridging experimental data with clinical therapeutics for IBS patients.

Food allergy in irritable bowel syndrome: The case of non-celiac wheat sensitivity

Irritable bowel syndrome (IBS) is one of the most common gastrointestinal disorders, having a prevalence of 12%-30% in the general population. Most patients with IBS attribute their symptoms to adverse food reactions. We review the role of diet in the pathogenesis of IBS and the importance of dietary factors in the management of these patients. The MEDLINE electronic database (1966 to Jan 2015) was searched using the following keywords: "food", "diet", "food allergy", "food hypersensitivity", "food intolerance", "IBS", "epidemiology", "pathogenesis", "pathophysiology", "diagnosis", "treatment". We found 153 eligible papers; 80 were excluded because: not written in English, exclusive biochemical and experimental research, case reports, reviews, and research otherwise not relevant to our specific interest. We selected 73 papers: 43 original papers, 26 reviews and 4 letters to the editor. These papers focused on IBS pathogenesis, the association between IBS and atopy, and between IBS and food allergy, the relationship between IBS and non-celiac wheat sensitivity, the role of diet in IBS. Pending further scientific evidence, a cautious approach is advisable but the concept of food allergy should be included as a possible cause of IBS, and a dietary approach may have a place in the routine clinical management of IBS.

CGRP, a neurotransmitter of enteric sensory neurons, contributes to the development of food allergy due to the augmentation of microtubule reorganization in mucosal mast cells

Neuro-immune interaction in the gut is substantially involved in the maintenance of intestinal immune homeostasis and the pathology of intestinal immune diseases. We have previously demonstrated that mucosal mast cells and nerve fibers containing CGRP, a neurotransmitter of intrinsic enteric sensory neurons, are markedly increased and exist in close proximity to each other in the colon of food allergy (FA) mice. In the present study, a CGRP-receptor antagonist BIBN4096BS significantly alleviated allergic symptoms in the murine FA model. In addition, the elevated numbers of mucosal mast cells in the proximal colon of FA mice were significantly decreased in that of BIBN4096BS-treated FA mice. Thus, we investigated the effects of CGRP on calcium-independent process in degranulation of mucosal mast cells since CGRP increases intracellular cAMP levels, but not Ca(2+) concentration. CGRP did not alter a calcium ionophore A23187-increased cytosolic Ca(2+) concentration in mucosal-type bone marrow-derived mast cells (mBMMCs), but did augment microtubule reorganization in resting and A23187-activated mBMMCs. Furthermore, CGRP alone failed to cause the degranulation of mBMMCs, but CGRP significantly enhanced the degranulation of mBMMCs induced by A23187. Together, these data indicate that CGRP- enhanced microtubule reorganization augments IgE-independent/non-antigenic stimuli-induced mucosal mast cell degranulation, thereby contributing to the development of FA.

Progress in understanding the relationship between food intolerance and functional gastrointestinal disorders

Functional gastrointestinal disorders (FGIDs) are a group of conditions characterized by the presence of chronic or recurrent gastrointestinal symptoms. Currently, the exact pathogenesis of FGIDs is still unknown, and their diagnosis relies on the exclusion of organic diseases. A number of studies have found that food intolerances can induce FGIDs and therefore has important implications for the diagnosis and treatment of FGIDs. In this paper, we review the recent progress in understanding the relationship between FGIDs and food intolerances in terms of pathogenesis, diagnosis, treatment, detection, and relationship between food intolerance and other diseases.

A combined biochemical, biophysical and immunological approach towards the identification of celiac disease-specific wheat antigens

Celiac disease (CD) is an inflammatory affliction of the small bowel caused by an immunological hypersensitivity to ingested wheat antigens affecting almost 1 % of the population. The gliadin fraction of wheat has been shown to contain the pathogenic antigens which react with antibodies and T cells. However, there is only limited knowledge regarding the precise nature of the wheat antigens recognized by IgA antibodies from CD patients and diagnostic tests based on the gliadin fraction have been demonstrated to give frequently false positive results. The aim of this study was the characterization of wheat antigens specifically recognized by IgA antibodies of CD patients. We developed a combined biochemical, biophysical, and immunological approach for the identification of celiac disease-specific wheat antigens. It is based on sub-fractionation of the wheat gliadin fraction using two ion exchange chromatography steps, the localization of CD-specific antigens by immunoblotting with IgA antibodies from CD patients, subsequent digestion followed by electro spray ionization-liquid chromatography/mass spectrometry (LC-ESI-MS/MS) and N-terminal sequencing by Edman degradation. Through the sub-fractionation procedure it was possible to separate CD-specific IgA-reactive wheat antigens from other wheat antigens which were also recognized by IgA antibodies of individuals without CD or by CD patients on gluten-free diet. Analysis by LC-ESI-MS/MS and N-terminal sequencing of the sub-fractions and the proteins specifically recognized by CD patients identified certain γ-gliadins with molecular mass of 37,000 and 45,000 as CD-specific wheat antigens. The CD-specific γ-gliadins with the molecular mass of 37,000 and 45,000 should be useful to study pathomechanisms of the disease and to improve the specificity of diagnostic tests for CD.

Chemokine CCR3 ligands-binding peptides derived from a random phage-epitope library

Eosinophils are major effectors cells implicated in a number of chronic inflammatory diseases in humans, particularly bronchial asthma and allergic rhinitis. The human chemokine receptor C-C receptor 3 (hCCR3) provides a mechanism for the recruitment of eosinophils into tissue and thus has recently become an attractive biological target for therapeutic intervention. In order to develop peptides antagonists of hCCR3-hCCL11 (human eotaxin) interactions, a random bacteriophage hexapeptide library was used to map structural features of hCCR3 by determining the epitopes of neutralizing anti-hCCR3 mAb 7B11. This mAb t is selective for hCCR3 and exhibit potent antagonist activity in receptor binding and functional assays. After three rounds of biopanning, four mAb7B11-binding peptides were identified from a 6-mer linear peptide library. The phage bearing the peptides showed specific binding to immobilized mAb 7B11 with over 94% of phages bound being competitively inhibited by free synthetic peptides. In FACScan analysis all selected phage peptides were able to strongly inhibit the binding of mAb 7B11 to hCCR3-transfected preB-300-19 murine cells. Furthermore, synthetic peptides of the corresponding phage epitopes were effective in blocking the antibody-hCCR3 interactions and to inhibit the binding of hCCL11 to hCCR3 transfectants. Chemically synthesized peptides CKGERF, FERKGK, SSMKVK and RHVSSQ, effectively competed for (125)I-hCCL11 binding to hCCR3 with IC(50) ranging from 3.5 to 9.7μM. Calcium release and chemotaxis of hCCR3 transfectants or human eosinophils were inhibited by all peptides in a dose-dependent manner. Furthermore, they showed inhibitory effects on chemotaxis of human eosinophils induced by hCCL11, hCCL5, hCCL7, hCCL8, and hCCL24. Specificities of all selected peptides were assessed with hCXCR1, hCXCR2, hCXCR3, and hCCR5 receptors. Peptides CKGERF and FERKGK showed inhibitory effects on eosinophil chemotaxis in a murine model of mCCL11-induced peritoneal eosinophilia. The development of peptides inhibiting the interactions between hCCR3 and its chemokine ligands will facilitate the development of small peptides antagonists with the hope of ameliorating chronic inflammatory diseases in humans.

Patients suffering from non-IgE-mediated cow's milk protein intolerance cannot be diagnosed based on IgG subclass or IgA responses to milk allergens

BACKGROUND

Cow's milk is one of the most common causes of food allergy. In two-thirds of patients, adverse symptoms following milk ingestion are caused by IgE-mediated allergic reactions, whereas for one-third, the mechanisms are unknown. Aim of this study was to investigate whether patients suffering from non-IgE-mediated cow's milk protein intolerance can be distinguished from persons without cow's milk protein intolerance based on serological measurement of IgG and IgA specific for purified cow's milk antigens.

METHODS

We determined IgG(1-4) subclass and IgA antibody levels to purified recombinant αS1-casein, αS2-casein, β-casein, κ-casein, α-lactalbumin, and β-lactoglobulin in four patient groups by ELISA: Patients with IgE-mediated cow's milk allergy (CMA, n=25), patients with non-IgE-mediated cow's milk protein intolerance (CMPI, n=19), patients with gastrointestinal symptoms not associated with cow's milk ingestion (GI, n=15) and control persons without gastrointestinal problems (C, n=26). Cow's milk-specific IgE levels were determined by ImmunoCAP.

RESULTS

Only CMA patients had IgE antibodies to cow's milk. Cow's milk allergic patients mounted the highest IgG(1) and IgG(4) antibody levels to αS1-casein, αS2-casein, β-casein, κ-casein, and α-lactalbumin. No elevated levels of IgG(4) , IgA, and complement-binding IgG subclasses (IgG(1) , IgG(2) , IgG(3) ) to purified cow's milk allergens were found within the CMPI patients compared to persons without cow's milk protein intolerance (GI and C groups).

CONCLUSION

Cow's milk protein intolerant patients cannot be distinguished from persons without cow's milk protein intolerance on the basis of IgG subclass or IgA reactivity to cow's milk allergens.

Eosinophilic-Crohn overlap colitis and review of the literature

Eosinophilic colitis is an idiopathic inflammation of the alimentary canal and is characterized by infiltration of the intestinal wall by eosinophils, massive submucosal edema, and peripheral eosinophilia. However, the presence of eosinophils in a colon biopsy requires thorough searching for secondary causes and eosinophilic colitis remains a diagnosis of exclusion. A 67-year-old male patient underwent a diagnostic ileocolonoscopy because of recurrent episodes of diarrhea for the last six months. Colonoscopy revealed a normal terminal ileum while in the entire colon an erythematous mucosa with very slight edema on a continuous pattern that was more pronounced in the left colon. The laboratory workup demonstrated eosinophils slightly elevated, biochemical tests were unremarkable and further clinical and laboratory workup was unremarkable. Histology showed overlapping findings of eosinophilic colitis and Crohn's colitis. Patient started on mesalazine 2.4 with very good results. A review of the literature shows that the spectrum of eosinophil involvement in inflammatory bowel disease as well as in eosinophilic colitis is largely varying, including also some exceptional cases that parallel the case described herein.

In vitro model for IgE mediated food allergy

BACKGROUND

In intestinal food allergy, the non-specificity of gastrointestinal symptoms and the limited access to the reacting organ are the reasons for the limited understanding of the pathophysiology of this disease and the difficulties in establishing an appropriate diagnosis in the individual patient.

OBJECTIVE

To develop an in vitro model reproducing pathophysiological mechanisms of IgE mediated food allergy.

METHODS

Distal duodenum biopsies of nine patients with food allergy and 10 control subjects were cultured for 3 h with medium alone and with 1 mg/ml of peptic-tryptic digest of wheat gliadin, wheat albumins, and apple proteins. Each biopsy was used for conventional histological examination and for immunohistochemical detection of IgE-positive cells. We have also analyzed the expression of tight junction proteins, occludin, claudin-1, and ZO-1 by immunoconfocal microscopy. Histamine and tryptase release were measured in the culture medium and collected at 0, 30 min, and 3 h of culture using an enzyme and radio immunoassay, respectively.

RESULTS

Exposure of small intestinal biopsy specimens of patients with food allergy to food allergens led to a significative increase of IgE-positive cells with a significative increase of histamine and tryptase release and an altered expression of tight junction proteins. No differences were found in intestinal biopsies of controls, cultured with or without food antigens.

CONCLUSIONS

Small intestinal organ culture is a functional model of food allergy and could be considered as an in vitro oral food challenge, with evident reduction of costs and risks for the patients.

Diagnosis and management of IBS

IBS is a common gastrointestinal condition characterized by chronic or recurrent abdominal pain associated with altered bowel habits. IBS is considered a functional bowel disorder (that is, not defined by structural or biochemical abnormalities) and is diagnosed using symptom-based criteria. Limited and judicious use of diagnostic testing is recommended, particularly in patients with typical symptoms of IBS without alarm signs and symptoms. Management of IBS is based on a multifactorial approach and includes establishment of an effective patient-provider relationship, education, reassurance, dietary alterations, pharmacotherapy, behavioral and psychological treatment. Patient-centered care is recommended, in which management is focused on the patient's most bothersome and impactful symptoms, their preferences and previous experiences with treatment, and addressing factors associated with the onset and exacerbation of symptoms. Pharmacotherapy is typically targeted against the predominant symptom. This Review discusses the current evidence-based recommendations for the diagnosis and management of IBS. An improved understanding of the recommended diagnostic and therapeutic approaches for IBS will lead to greater patient satisfaction, as well as reduced health-care costs.

Irritable bowel syndrome: can nutrient manipulation help?

PURPOSE OF REVIEW

To describe the evidences for the usefulness of dietary manipulations (including the use of probiotics and prebiotics) in the management of irritable bowel syndrome (IBS).

RECENT FINDINGS

Exclusion diets do not have a role in the management of these patients except in the case of malabsorbed sugars (lactose, fructose). However, recent work suggests that excluding these sugars is more effective in non-IBS than in IBS patients. Also, the first small open series on the use of very low (20 g/day) carbohydrate diet (VLCD) in IBS has been published with promising results. However, safety concerns do not allow us to recommend them. In the period of review, further evidence has been provided on the role of psyllium in IBS. Also, the available evidence on the use of probiotics in IBS has been meta-analyzed.

SUMMARY

IBS patients should eat a balanced diet without restrictions, and (except for malabsorbed sugars) exclusion diets are not useful in most of them. The role of VLCD remains to be established. The concept that increasing fiber intake is useful for IBS may not be true for all patients, and hydrophilic colloids (e.g. psyllium) are preferred. There is growing evidence for the effectiveness of probiotics in IBS.

Food allergy: separating the science from the mythology

Numerous genes are involved in innate and adaptive immunity and these have been modified over millions of years. During this evolution, the mucosal immune system has developed two anti-inflammatory strategies: immune exclusion by the use of secretory antibodies to control epithelial colonization of microorganisms and to inhibit the penetration of potentially harmful agents; and immunosuppression to counteract local and peripheral hypersensitivity against innocuous antigens, such as food proteins. The latter strategy is called oral tolerance when induced via the gut. Homeostatic mechanisms also dampen immune responses to commensal bacteria. The mucosal epithelial barrier and immunoregulatory network are poorly developed in newborns. The perinatal period is, therefore, critical with regard to the induction of food allergy. The development of immune homeostasis depends on windows of opportunity during which innate and adaptive immunity are coordinated by antigen-presenting cells. The function of these cells is not only orchestrated by microbial products but also by dietary constituents, including vitamin A and lipids, such as polyunsaturated omega-3 fatty acids. These factors may in various ways exert beneficial effects on the immunophenotype of the infant. The same is true for breast milk, which provides immune-inducing factors and secretory immunoglobulin A, which reinforces the gut epithelial barrier. It is not easy to dissect the immunoregulatory network and identify variables that lead to food allergy. This Review discusses efforts to this end and outlines the scientific basis for future food allergy prevention.

Does evidence exist to include dietary therapy in the treatment of Crohn's disease?

Prescription drugs and surgery are two common medical therapies for Crohn's disease (CD), an inflammatory bowel disease that affects the GI tract. Unfortunately, certain drugs can cause serious side effects, and surgeries must often be repeated. No diet has been established to alleviate the pain and suffering of CD patients. This is curious given the fact that a higher prevalence of food sensitivities exist in this population of patients, and enteral nutrition is not only the first-line of therapy in Japan, but a known research method used to place the majority of CD patients into remission. Although not all patients respond equally to diet, many simply remove symptom-provoking foods, such as dairy, wheat, corn and certain fruits and vegetables. We suggest assisting these patients in their self-assessment of irritating and symptom-provoking foods by educating them in the use of a food-symptom diary followed by a customized elimination diet trialed for 2-4 weeks to determine if there is any benefit to the individual patient.

Serologic investigations in children with inflammatory bowel disease and food allergy

The aim of the study was the evaluation of frequency and titre of IgA ASCA and IgG ASCA and p-ANCA, c-ANCA in children with IBD and occurrence of ASCA antibodies in relation to coexistence of FA. Patients and methods. The study comprised 95 children at the ages of 2 to 18 years. The diagnosis of IBD was established on the basis of Porto criteria. Tests of blood serum were performed in all children: IgA and IgG ASCA, p-ANCA, c-ANCA using ELISA method. Results. IgE-dependent FA was found in 32.5% children with UC and in 21% with CD. We did not observe any relation between the occurrence of FA and the frequency and ASCA titre. p-ANCA were significantly more frequent in the group of children with UC. The occurrence of ASCA antibodies was observed in 73.7% of children with CD, 17.5% with UC and almost 30% with allergic colitis. Conclusions. Patients with CD and the presence of ASCA revealed a significantly more frequent localization of lesions within the small bowel and a tendency towards older age. We observed a connection between the occurrence of antibodies and the examined mutations of gene NOD2/CARD15.

The role of mast cells in eosinophilic esophagitis

Eosinophilic esophagitis (EE) is a chronic inflammatory disease of the esophagus which is characterized by the presence of dense infiltrate of eosinophilic leukocytes restricted to this organ mucosa. Accumulating published evidence suggests a strong role of mast cells in the inflammatory infiltrate in the physiopathology of EE. We have reviewed published articles with relevant information about the presence and possible role of mast cells in EE. Although mast cells have been studied indirectly in EE, reported data allow us to confirm that the number of mast cells infiltrating the esophageal epithelium in adult and child patients with EE is higher with respect to the normal state and in gastroesophageal reflux disease. Mast cells linked to IgE, which are not found in other conditions, have been identified in EE. Despite that fact, an anaphylactic reaction history after exposure to allergens is not common in these patients. Therefore, the mast cells' function in EE could be dependent on T lymphocytes, as suggested by a mast cell gene expression analysis. Bi-directional crosstalk is established between mast cells and eosinophils, hence establishing interesting hypotheses regarding their relationship to EE physiopathology. Mast cells' function as an immune response leader seems to substitute for their effector functions in EE, while at the same time opening new research pathways for consideration of these cells as a therapeutic target in EE. However, the inefficiency of therapies that inhibit mast cell functions while they are effective in other respiratory tract diseases results in the need for specific studies to identify the real function of such complex cells in the physiopathology of EE. There is indirect proof of the role of mast cells in EE, while many doubts exist about their activation mechanism, which does not seem to be IgE-mediated. Specific approach studies are needed to clarify the function of these cells in the physiopathology of EE, which could be a possible therapeutic target.

Finnish Allergy Programme 2008-2018--time to act and change the course

BACKGROUND

The prevalence of allergic diseases has grown in Finland, similarly to many other western countries. Although the origin of allergy remains unresolved, increasing body of evidence indicates that the modern man living in urban built environment is deprived from environmental protective factors (e.g. soil microorganisms) that are fundamental for normal tolerance development. The current dogma of allergen avoidance has not proved effective in halting the 'epidemic', and it is the Finnish consensus that restoring and strengthening tolerance should more be in focus.

AIM

The national 10-year programme is aimed to reduce burden of allergies. The main goals are to (i) prevent the development of allergic symptoms; (ii) increase tolerance against allergens; (iii) improve the diagnostics; (iv) decrease work-related allergies; (v) allocate resources to manage and prevent exacerbations of severe allergies and (vi) decrease costs caused by allergic diseases.

METHODS

For each goal, specific tasks, tools and evaluation methods are defined. Nationwide implementation acts through the network of local co-ordinators (primary care physicians, nurses, pharmacists). In addition, three nongovernmental organizations (NGOs) take care of the programme implementation. The 21 central hospital districts carry out a three step educational process: (i) healthcare personnel; (ii) representatives and educators of NGOs and (iii) patients and the general population. For outcome evaluation, repeated surveys are performed and healthcare registers employed at the beginning, at 5 years, and at the end of the programme. The process will be evaluated by an independent external body.

CONCLUSION

The Finnish initiative is a comprehensive plan to reduce burden of allergies. The aim is to increase immunological tolerance and change attitudes to support health instead of medicalizing common and mild allergy symptoms. It is time to act, when allergic individuals are becoming a majority of western populations and their numbers are in rapid increase worldwide. The Programme is associated with the Global Alliance of Chronic Respiratory Diseases (GARD), WHO.

Interleukin-4 induces specific pp-GalNAc-T expression and alterations in mucin O-glycosylation in colonic epithelial cells

Mucus hypersecretion occurs as a consequence of the Th2 immune response in epithelia, yet it was not previously known whether the degree of O-glycosylation was modulated under such conditions. A colonic carcinoma cell line LS174T was used to assess the effect of interleukin (IL)-4 on the mRNA levels of eight pp-GalNAc-Ts. A three- to four-fold increase in pp-GalNAc-T1, T4, and T7 levels was observed. Lysates of untreated or IL-4-treated cells were examined for their ability to transfer GalNAc residues onto a peptide corresponding to the tandem repeat portion of human MUC2. The number of incorporated GalNAc residues was greater after incubation with lysates of IL-4-treated cells than with lysates of untreated cells. Mucin-like large glycoproteins secreted by IL-4-treated cells had higher binding capacity to PNA and VVA-B(4) than those secreted by untreated cells. The results indicated that IL-4-treated LS174T cells are able to produce mucins with a higher degree of O-glycosylation than untreated counterparts.

Noninvasive markers of eosinophilic esophagitis

There has been an increasing awareness and recognition of eosinophilic esophagitis (EE), a chronic condition with periods of exacerbation and remission, over the last decade. The complex pathophysiology of EE and eosinophil physiology provide several candidate biomarkers that could be studied on various noninvasively obtained body specimens. This article reviews several potential noninvasive biomarkers of EE.

Alterations of food antigen-specific serum immunoglobulins G and E antibodies in patients with irritable bowel syndrome and functional dyspepsia

BACKGROUND

Post-prandial worsening of symptoms as well as adverse reactions to one or more foods are common in the patients with functional gastrointestinal diseases, such as irritable bowel syndrome (IBS) and functional dyspepsia (FD). However, the role played by true food allergy in the pathogenesis of these diseases is still controversial and there are no well-established tests to identify food allergy in this condition.

OBJECTIVE

To investigate serum food antigen-specific IgG, IgE antibody and total IgE antibody titres in controls and patients with IBS and FD, and to correlate symptoms with the food antigen-specific IgG titres in IBS and FD patients.

METHODS

Thirty-seven IBS patients, 28 FD patients and 20 healthy controls participated in this study. Serum IgG and IgE antibody titres to 14 common foods including beef, chicken, codfish, corn, crab, eggs, mushroom, milk, pork, rice, shrimp, soybean, tomatoes and wheat were analysed by ELISA. Serum total IgE titres were also measured. Last, symptomatology was assessed in the study. Results IBS patients had significantly higher titres of IgG antibody to crab (P=0.000), egg (P=0.000), shrimp (P=0.000), soybean (P=0.017) and wheat (P=0.004) than controls. FD patients had significantly higher titres of IgG antibody to egg (P=0.000) and soybean (P=0.017) than controls. The percentage of individuals with detectable positive food antigen-specific IgE antibodies of the three groups did not show any significant differences (P=0.971). There were no significant differences between IBS patients, FD patients and controls in the serum total IgE antibody titres (P=0.978). Lastly, no significant correlation was seen between symptom severity and serum food antigen-specific IgG antibody titres both in IBS and FD patients.

CONCLUSION

Serum IgG antibody titres to some common foods increased in IBS and FD patients compared to controls. But there is no significant correlation between symptom severity and elevated serum food antigen-specific IgG antibodies in these patients.

Colorectal mucosal histamine release by mucosa oxygenation in comparison with other established clinical tests in patients with gastrointestinally mediated allergy

AIM: This study evaluated colorectal mucosal histamine release in response to blinded food challenge-positive and -negative food antigens as a new diagnostic procedure.

METHODS: 19 patients suffering from gastrointestinally mediated allergy confirmed by blinded oral provocation were investigated on grounds of their case history, skin prick tests, serum IgE detection and colorectal mucosal histamine release by ex vivo mucosa oxygenation. Intact tissue particles were incubated/stimulated in an oxygenated culture with different food antigens for 30 min. Specimens challenged with anti-human immunoglobulin E and without any stimulus served as positive and negative controls, respectively. Mucosal histamine release (% of total biopsy histamine content) was considered successful (positive), when the rate of histamine release from biopsies in response to antigens reached more than twice that of the spontaneous release. Histamine measurement was performed by radioimmunoassay.

RESULTS: The median (range) of spontaneous histamine release from colorectal mucosa was found to be 3.2 (0.1%-25.8%) of the total biopsy histamine content. Food antigens tolerated by oral provocation did not elicit mast cell degranulation 3.4 (0.4%-20.7%, P = 0.4), while anti-IgE and causative food allergens induced a significant histamine release of 5.4 (1.1%-25.6%, P = 0.04) and 8.1 (1.5%-57.9%, P = 0.008), respectively. 12 of 19 patients (63.1%) showed positive colorectal mucosal histamine release in accordance with the blinded oral challenge responding to the same antigen (s), while the specificity of the functional histamine release to accurately recognise tolerated foodstuffs was found to be 78.6%. In comparison with the outcome of blinded food challenge tests, sensitivity and specificity of history (30.8% and 57.1%), skin tests (47.4% and 78.6%) or antigen-specific serum IgE determinations (57.9% and 50%) were found to be of lower diagnostic accuracy in gastrointestinally mediated allergy.

CONCLUSION: Functional testing of the reactivity of colorectal mucosa upon antigenic stimulation in patients with gastrointestinally mediated allergy is of higher diagnostic efficacy.

Is there a role of food allergy in irritable bowel syndrome and functional dyspepsia? A systematic review

A significant proportion of adults believe they suffer from food allergy, and 20-65% of patients with irritable bowel syndrome (IBS) attribute their symptoms to something in food that activates an abnormal response. This systematic review evaluates the role of food allergy in aetiology and management of these disorders. Activation of gastrointestinal mucosal immune system may be one of the causative factors in the pathogenesis of functional dyspepsia and IBS. This activation may result from effects of bacterial infection or other luminal factors including commensal microbial flora and food antigens. Some studies have reported on the role of food allergy in IBS; only one epidemiological study on functional dyspepsia and food allergy has been published. The mechanism by which food activates mucosal immune system is uncertain, but food specific IgE and IgG4 appeared to mediate the hypersensitivity reaction in a subgroup of IBS patients. Exclusion diets based on skin prick test, RAST for IgE or IgG4, hypoallergic diet and clinical trials with oral disodium cromoglycate have been conducted, and some success has been reported in a subset of IBS patients. Further well-controlled studies are needed to establish whether food allergy plays a role in the pathophysiology of functional dyspepsia and IBS.

Evaluation of colonoscopic allergen provocation as a diagnostic tool in dogs with proven food hypersensitivity reactions

OBJECTIVE

To evaluate the colonoscopic allergen provocation (COLAP) test as a new tool for the diagnosis of IgE-mediated food allergy.

METHODS

Oral food challenges as well as COLAP testing were performed in a colony of nine research dogs with proven immediate-type food allergic reactions. In addition, COLAP was performed in five healthy dogs.

RESULTS

When compared with the oral challenge test, COLAP accurately determined 18 of 23 (73 per cent) positive oral challenge reactions (73 per cent) in dogs with food allergies and was negative in the healthy dogs.

CLINICAL SIGNIFICANCE

The accuracy of this new test may be higher than that for gastric sensitivity testing. Therefore, COLAP holds promise as a new test to confirm the diagnosis of suspect IgE-mediated food allergy in dogs.

Cytokine expression in normal and inflamed esophageal mucosa: a study into the pathogenesis of allergic eosinophilic esophagitis

OBJECTIVES

We studied the expression of cytokines and inflammatory cells in normal and inflamed esophageal mucosa of children with the aim of furthering our understanding of the pathophysiology of allergic eosinophilic esophagitis (AEE).

METHODS

Controls and AEE patients (>or=15 eosinophils/high-power field on esophageal mucosal biopsies) between the ages of 1 and 18 years were recruited. Esophageal biopsies were obtained for histologic examination, immunohistochemical studies, and cytokine analysis.

RESULTS

Eight controls (4 males; mean age 9.99 years) and 11 AEE patients (8 males; mean age 7.15 years) were studied. mRNA expression of interferon (IFN)-gamma, interleukin (IL)-4, IL-5, IL-13, eotaxin-1, eotaxin-2, eotaxin-3, and RANTES was studied. IFN-gamma and IL-5 expressions were significantly up-regulated in AEE patients compared with controls. Expressions of IL-4 and IL-13 were similar between AEE patients and controls. Eotaxin-1 expression was significantly up-regulated in AEE patients, whereas eotaxin-2 was up-regulated in controls. Expression of RANTES and eotaxin-3 was similar between the two groups. There was increased staining for mast cells in AEE patients compared with controls.

CONCLUSIONS

Our data suggests that AEE is primarily an IL-5 selective TH2 response, with a possible TH1 component, and a differential role of eosinophilic chemoattractants. The role of mast cells in the pathogenesis of AEE needs additional study.

Increased prevalence of anti-gliadin IgA-antibodies with aberrant duodenal histopathological findings in patients with IgA-nephropathy and related disorders

BACKGROUND

Antibodies present in coeliac disease may occur in IgA-nephropathy. This raises the question of food intolerance in the disease. Evidence for a true correlation between the two disorders has however been scarce.

DESIGN

Sera from 89 patients with IgA-nephropathy and 13 other patients with IgA deposits in the glomeruli of kidney biopsies were analysed for IgA-antibodies to gliadin, endomysium and tissue transglutaminase (92/102 patients).

RESULTS

Eleven out of 89 (12.4%) of the patients with IgA-nephropathy and five of the 13 others (38%) had elevated titres of IgA-antibodies to gliadin but, in all cases but one, normal IgA-antibodies to endomysium. Patients with IgA-nephropathy and elevated IgA-antibodies to gliadin had elevated total serum IgA more frequently than patients who had not (p<0.01). Two patients with IgA-nephropathy and one with Hennoch Schönlein's purpura had elevated IgA-antibodies to tissue transglutaminase. Small bowel biopsy in 7 out of 11 IgA-antibodies to gliadin positive patients with IgA-nephropathy was pathologic in three cases (two with Marsh I) . One patient with chronic glomerulnephritis also had Marsh I.

CONCLUSIONS

We found no increased frequency of verified coeliac disease in 89 patients with IgA-nephropathy. Two patients with IgA-nephropathy and one patient with chronic glomerulonephritis with IgA deposits in the kidney biopsy had a Marsh I histopathology. The findings suggest a possible link of celiac disease to IgA-nephropathy and a role for antibodies to food antigens in this disorder.

Gastrointestinal allergy in adults

The prevalence of food allergy reaches 3% in the adult population. Chronic gastrointestinal allergy is a rare entity: 4.2% of food allergies in adults, and represents 3.2% of all intestinal disorders. Non-specific symptoms are the rule but eosinophilic gastrointestinal disorders are the subject of much interest. Endoscopy and biopsies of the gastrointestinal tract help the differential diagnoses. Food allergy is suspected from the patient's history leading to skin tests and laboratory tests identifying a sensitization but allergy is only confirmed by standardized challenges or eviction diets over a sufficiently long period. New types of investigations coupling oral challenges to foods to gastroenterological techniques should be studied further.

Food allergy and irritable bowel syndrome

PURPOSE OF REVIEW

Irritable bowel syndrome is a common and likely a multifactorial gastrointestinal disorder in which a disturbed brain-gut axis has been thought to have a mandatory role. Recent clinical and experimental studies imply that dietary factors may be more important in the pathogenesis of irritable bowel syndrome than was earlier anticipated. The purpose of this review is to present those studies and discuss their findings in relation to the crosstalk between the gastrointestinal immune and nervous systems.

RECENT FINDINGS

Food elimination based on serum immunoglobulin G antibodies in irritable bowel syndrome has been found to result in a significant decrease in symptoms, compared with diets in which dietary restrictions are not guided by those antibodies. Both numbers of mast cells and their mediators have been shown to be increased in intestinal mucosa in patients with irritable bowel syndrome, especially in the close proximity of intestinal nerves. Animal studies have demonstrated that this increase in intestinal mast cell density could be a consequence of local hypersensitivity to food antigens. That kind of local gastrointestinal hypersensitivity seems to be beyond the reach of current diagnostic methods available in clinical practice.

SUMMARY

Dietary factors may significantly contribute to the pathophysiology of irritable bowel syndrome. Elimination diets based on the detection of local food hypersensitivity may offer a treatment option for irritable bowel syndrome patients in the future.

Different profiles of wheat antigens are recognised by patients suffering from coeliac disease and IgE-mediated food allergy

BACKGROUND

Dietary intake of wheat can cause two distinct immunologically mediated diseases with severe gastrointestinal manifestations, coeliac disease (CD) and IgE-mediated food allergy. The pathomechanisms underlying these diseases are different, but the profile of the target antigens in wheat has not been compared for the two diseases.

METHODS

We compared IgA- and IgE-reactive antigens in wheat using sera from patients with coeliac disease (n = 35) and food allergy to wheat (n = 16) by one- and two-dimensional immunoblotting. Furthermore, the IgG subclass (IgG1-IgG4) reactivity to wheat antigens was studied by enzyme-linked immunosorbent assay.

RESULTS

IgA antibodies from CD patients and IgE antibodies from allergic patients recognised distinct profiles of wheat antigens. Furthermore, the IgG subclass responses to wheat antigens were different in CD and wheat-allergic patients.

CONCLUSION

This study thus demonstrates that wheat contains antigens/epitopes which are preferentially recognised by CD patients, whereas others elicit IgE-mediated food allergy. This finding suggests that the nature of a food antigen may influence the quality of the pathological immune response in the gut and has implications for the diagnosis and therapy of hypersensitivity to wheat.

Development of an in vitro system for the study of allergens and allergen-specific immunoglobulin E and immunoglobulin G: Fce receptor I supercross-linking is a possible new mechanism of immunoglobulin G-dependent enhancement of type I allergic reactions

BACKGROUND

IgE-dependent activation of mast cells (MCs) is a key pathomechanism of type I allergies. In contrast, allergen-specific IgG Abs are thought to attenuate immediate allergic reactions by blocking IgE binding and by cross-linking the inhibitory Fcgamma receptor IIB on MCs.

OBJECTIVES

To establish a defined in vitro system using human MCs to study the biological activity of allergens and to investigate the role of allergen-specific IgE and IgG.

METHODS

Purified human intestinal MCs sensitized with different forms of specific IgE Abs were triggered by monomeric and oligomeric forms of recombinant Bet v 1, the major birch pollen allergen, in the presence or absence of allergen-specific IgG Abs. Results MCs sensitized with an anti-Bet v 1 IgE mAb or sera obtained from birch pollen allergic patients released histamine and sulphidoleukotrienes after exposure to oligomeric Bet v 1. Monomeric Bet v 1 provoked mediator release only in MCs sensitized with patients sera but not in MCs sensitized with anti-Bet v 1 IgE mAb. Interestingly, MC activation could be induced by supercross-linking of monomeric Bet v 1 bound to monovalent IgE on MCs with a secondary allergen-specific IgG pAb. By using IgG F(ab')2 fragments we provide evidence that this effect is not a result of IgG binding to Fcgamma receptors.

CONCLUSION

This assay represents a new tool for the in vitro study of MC activation in response to natural and genetically modified allergens. Fcepsilon receptor I supercross-linking by allergen-specific IgG Abs provides a possible new mechanism of IgG-dependent enhancement of type I allergic reactions.

Epsilon germ-line and IL-4 transcripts are expressed in human intestinal mucosa and enhanced in patients with food allergy

BACKGROUND

The mechanisms of gastrointestinal (GI) food allergy (FA) are poorly understood. Immunoglobulin E (IgE) is increased in stools from patients with FA, as well as the number of cells carrying IgE in intestinal mucosa, but the origin of IgE production remains unknown. To investigate a local production of IgE in intestine, we analysed the levels of transcripts for epsilon germ-line (epsilonGT), and potential regulators of IgE production, IL-4, IL-13, IFN-gamma, IL-4Ralpha, STAT6 and FcepsilonRIalpha in intestinal mucosa of adult patients with FA.

METHODS

Endoscopic biopsies were obtained from the caecum of 25 patients with FA and 14 control patients. The levels of epsilonGT, IL-4, IL-13, IFN-gamma, IL-4Ralpha, STAT6 and FcepsilonRIalpha mRNA were analysed by real-time RT-PCR and compared with unpaired nonparametric Mann-Whitney test.

RESULTS

The mean epsilonGT transcript level in caecum was increased in FA patients compared with control patients (P < 0.05). IL-4 mRNA expression was also increased in FA patients (P < 0.05), whereas mRNA expression for IL-13, IFN-gamma, IL-4Ralpha, STAT6 and FcepsilonRIalpha mRNA expression was not altered. However, the ratio of IL-4 mRNA/IFN-gamma mRNA was significantly increased in FA patients (P < 0.05). No correlation was observed between epsilonGT transcripts expression in intestinal mucosa and total IgE levels in serum.

CONCLUSIONS

This study shows that (i) epsilonGT transcripts are expressed in human intestinal mucosa; (ii) epsilonGT and IL-4 transcripts are increased in caecal mucosa from patients with FA. These results suggest local production of IgE in intestine that might be of importance for inflammatory reactions in the GI tract.

The influence of oxygenated water on the immune status, liver enzymes, and the generation of oxygen radicals: a prospective, randomised, blinded clinical study

BACKGROUND & AIMS

Oxygenated water with an oxygen concentration of 30-120 mg/l water is believed to improve the immune status, without any toxicological effects. The purpose of this clinical study was to assess the effects of long-term drinking of oxygenated water on the immune status.

METHODS

In this prospective, double-blinded, randomised study 24 volunteers of either sex (age 18-63 years) drank daily 3 times 500 ml either oxygenated (Verum-group: n=12) or normal mineral water (Placebo-group: n=12) for 28 days. On day 1 and day 28 standard laboratory tests, IgG, IgA and IgM, lymphocyte subpopulations and functional analysis of T-cells by flow cytometry, were done. Furthermore, the oxygen radicals were determined by the detection of the ascorbyl radicals.

RESULTS

Drinking of normal or oxygenated water had no effect on whole blood count or the liver enzymes. Interestingly the volunteers in the Verum-group showed a significant increase in ascorbyl radicals after drinking oxygenated water for 14 and 21 days. CD4+ and CD4+CD45RA+ lymphocytes as well as lymphocyte activation marker (CD69) and soluble IL-2 receptor increased in both groups, in contrast T-helper2 cells and IgG decreased during the study. The only differences between the two groups were a significant decrease of NK-cells form 13.42%+ or -5.04 to 10.83%+ or -4.82 (P<.002) and an increase of the Th1/Th2-ratio from 2.77%+ or -1.07 to 6.68%+ or -5.33 (P<.03) in the Verum-group.

CONCLUSION

Long-term consumption of oxygenated water has no apparent harmful effect on the liver, blood and the immune system. Moreover it leads to a transient moderate increase of oxygen radicals in the blood. An interesting observation is the increase of the Th1/Th2-ratio in the Verum group, whereas in both groups T-cell activation after mitogen stimulation, the soluble IL-2 receptor, the CD4+ and the naive CD4+CD45RA+ cells increased.

Gastrointestinal food allergy: new insights into pathophysiology and clinical perspectives

Adverse reactions to food that result in gastrointestinal symptoms are common in the general population; while only a minority of such individuals will have symptoms due to immunologic reactions to foods, gastrointestinal food allergies do exist in both children and adults. These immune reactions are mediated by immunoglobulin E-dependent and -independent mechanisms involving mast cells, eosinophils, and other immune cells, but the complexity of the underlying mechanisms of pathogenesis have yet to be fully defined. Knowledge of the spectrum of adverse reactions to foods that affect the digestive system, including gastrointestinal food allergy, is essential to correctly diagnose and manage the subset of patients with immunologically mediated adverse reactions to foods. Potentially fatal reactions to food necessitate careful instruction and monitoring on the part of health care workers involved in the care of individuals at risk of anaphylaxis. New methods of diagnosis and novel strategies for treatment, including immunologic modulation and the development of hypoallergenic foods, are exciting developments in the field of food allergy.

Hypersensitivity to ovalbumin induces chronic intestinal dysmotility and increases the number of intestinal mast cells

Undiagnosed food allergies have been proposed as possible causes of promoting and perpetuating irritable bowel syndrome . Our aim was to find out if sensitization could induce chronic functional motor disturbances in the intestine and the mechanisms implicated. Rats were sensitized to ovalbumin (OVA) following three hypersensitivity induction protocols, two parenteral and one oral. Rat mast cell protease II (RMCP II) release in response to OVA challenge and immunoglobulin E (IgE) concentration were measured in serum. At least 1 week after challenge, small intestinal motility was evaluated using strain gauges. Intestinal tissue samples from orally sensitized rats were checked for in vitro stimulation with OVA. Mucosal mast cells were counted from duodenum sections. All sensitized rats showed intestinal hypermotility. Only rats sensitized by parenteral procedure showed an increase in RMCP II after OVA challenge in serum. IgEs increased only in the Bordetella pertussis sensitized group. Small intestine sections from orally sensitized rats released more RMCP II than sections from control rats. All sensitized rats showed an increase in the number of mucosal mast cells in duodenum. In conclusion, hypersensitivity to food proteins induces chronic motor alteration that persists long after antigen challenge and an excited/activated state of sensitized mucosal mast cells.

Study of visceral hypersensitivity in irritable bowel syndrome

OBJECTIVE

Visceral hypersensitivity is highly prevalent in most functional bowel disorders, such as irritable bowel syndrome (IBS), and activation of intestinal mast cells (MC) may play a role because they have been found in close proximity to gastrointestinal mucosal sensory nerve terminals containing neuropeptides and a bi-directional pathway connecting the central nervous system, gut, and MC has been demonstrated. The current study appraised the status of rectal visceral perception, as well as the changes in the MC and substance P (SP) in the intestinal mucosa of patients with IBS.

METHODS

The study group comprised 42 patients with IBS and 19 healthy subjects who underwent anorectal manometry and rectal perception thresholds to balloon distension. The MC and the SP-ergic terminals in the mucosa were stained for respective histochemical and immunohistochemical investigations. The results were presented both qualitatively and quantitatively by color image analyzer, based on analysis of the intensity and area of stained fibrils. The structural relationship between the MC and nerve terminals was studied by electron microscopy, using an in situ embedding technique.

RESULTS

The anorectal resting pressure, squeezing pressure and relaxation pressure were normal in both groups. The sensation threshold, defecation threshold and pain threshold in diarrhea-predominant IBS and the pain thresholds in constipation-predominant IBS were much lower than in the controls. Rectal compliance decreased in IBS. The number of MC in the terminal ileum, the ileocecal junction and the ascending colon was significantly elevated in IBS (P < 0.01), and the MC showed great variation. A significantly increased concentration of SP was found in the colon of the IBS patients compared with the controls. There was a positive correlation between the profiles of mucosal MC and the SP-ergic terminals, and MC were closely adjacent to SP-ergic terminals in the lamina propria.

CONCLUSION

As altered rectal perception is present in almost all patients with IBS, it might be a reliable biological characteristic of the disease. Alterations in the MC and SP of the intestinal mucosa may be important factors in visceral hypersensitivity.

Yogurt and gut function

In recent years, numerous studies have been published on the health effects of yogurt and the bacterial cultures used in the production of yogurt. In the United States, these lactic acid-producing bacteria (LAB) include Lactobacillus and Streptococcus species. The benefits of yogurt and LAB on gastrointestinal health have been investigated in animal models and, occasionally, in human subjects. Some studies using yogurt, individual LAB species, or both showed promising health benefits for certain gastrointestinal conditions, including lactose intolerance, constipation, diarrheal diseases, colon cancer, inflammatory bowel disease, Helicobacter pylori infection, and allergies. Patients with any of these conditions could possibly benefit from the consumption of yogurt. The benefits of yogurt consumption to gastrointestinal function are most likely due to effects mediated through the gut microflora, bowel transit, and enhancement of gastrointestinal innate and adaptive immune responses. Although substantial evidence currently exists to support a beneficial effect of yogurt consumption on gastrointestinal health, there is inconsistency in reported results, which may be due to differences in the strains of LAB used, in routes of administration, or in investigational procedures or to the lack of objective definition of "gut health." Further well-designed, controlled human studies of adequate duration are needed to confirm or extend these findings.

Allergen-responsive CD4+CD25+ regulatory T cells in children who have outgrown cow's milk allergy

Cow's milk allergy in children is often of short duration, which makes this disorder an interesting clinical model for studies of tolerance to dietary antigens. Here, we studied T cell responses in 21 initially allergic children who, after a milk-free period of >2 mo, had cow's milk reintroduced to their diet. Children who outgrew their allergy (tolerant children) had higher frequencies of circulating CD4⁺CD25⁺ T cells and decreased in vitro proliferative responses to bovine β-lactoglobulin in peripheral blood mononuclear cells (PBMCs) compared with children who maintained clinically active allergy. No significant difference in proliferative activity stimulated by the polyclonal mitogen phytohemagglutinin was observed between the two groups. Depletion of CD25⁺ cells from PBMCs of tolerant children led to a fivefold increase in in vitro proliferation against β-lactoglobulin. This suggests that tolerance is associated with the appearance of circulating CD4⁺CD25⁺ regulatory T (Treg) cells that are capable of suppressing the effector T cells generated 1 wk after reintroduction of cow's milk. The suppressive function of the CD4⁺CD25⁺ Treg cells was shown to be partly cell contact dependent. Collectively, our study provides human data to suggest that mucosal induction of tolerance against dietary antigens is associated with the development of CD4⁺CD25⁺ Treg cells.

The role of antigen presenting cells at distinct anatomic sites: they accelerate and they slow down allergies

It has been repeatedly demonstrated that allergic reactions are driven by the continuous flow of antigen uptake and presentation processes, which are perpetuated mainly by dendritic cells (DC). The ability of allergens to cause allergic inflammation is contingent upon the presence of an immunological milieu and microenvironment that either privileges Th2 responses or prohibits these reactions by the induction of contraregulatory anti-inflammatory activities of the immune system. In the light of recent developments it appears that DC have to manage two opposing tasks: on the one hand they can favor pro-inflammatory reactions and actively induce a T-cell response, yet on the other hand they serve an important function as 'silencers' in the immune system by sending out anti-inflammatory, tolerance inducing signals. This unique capacity of DC has opened several exciting possibilities for a role of DC in both - accelerating and slowing down allergic reactions. It is therefore a challenge to understand in which way DC subtypes located at distinct anatomic sites with frequent allergen exposure, such as the skin, the nasal mucosa, the respiratory tree or the mucosa of the intestinal tract can have an impact on mechanisms involved in tolerance induction or effective immunity.

Canine gastritis

Gastritis--inflammation of the stomach--is a frequently cited differential yet rarely characterized diagnosis in cases of canine anorexia and vomiting. Although the list of rule-outs for acute or chronic gastritis is extensive, a review of the veterinary literature reveals fewer than 15 articles that have focused on clinical cases of canine gastritis over the last 25 years. The dog frequently appears in the human literature as an experimentally manipulated model for the study of endoscopic techniques or the effect of medications on gastric mucosa. In the veterinary patient, cases of acute gastritis are rarely pursued with the complete diagnostic armamentarium, and cases of chronic gastritis are rarely found to occur as an entity isolated from the rest of the gastrointestinal tract. This article focuses on those findings most clinically relevant to cases of canine gastritis in veterinary medicine.