Role Of Food Allergy Research Articles

Understanding and managing your child's food allergies

For children with food allergies, eating-one of the basic functions of life-can be a nightmare. Children who suffer or become dangerously ill after eating peanuts, seafood, milk, eggs, wheat, or a host of other foods require constant vigilance from caring, concerned parents, teachers, and friends. In this empathetic and comprehensive guide, Dr. Scott H. Sicherer, a specialist in pediatric food allergies, gives parents the information they need to manage their children's health and quality of life. He describes why children develop food allergy, the symptoms of food allergy (affecting the skin, the gastrointestinal tract, and the respiratory system), and the role of food allergy in behavioral problems and developmental disabilities. Parents will learn how to recognize emergency situations, how to get the most out of a visit with an allergist, what allergy test results mean, and how to protect their children-at home, at school, at summer camp, and in restaurants. Informative, compassionate, and practical, this guide will be indispensable for parents, physicians, school nurses, teachers, and everyone else who cares for children with food allergies.

Evaluating the effect of food processing on the potential human allergenicity of novel proteins: International workshop report

The ILSI Health and Environmental Sciences Institute Protein Allergenicity Technical Committee organized an international workshop in June 2006 in Estoril, Portugal, co-sponsored by the ILSI Research Foundation, ILSI International Food Biotechnology Committee and ILSI Europe. The objective was to discuss the effects of food processing on the allergenic potential of proteins and foods. The impact of food processing on the sensitization/induction phases of food allergy, and the bioavailability of allergens to the immune system were presented. Studies evaluating the stability, digestibility, and allergenicity of processed food allergens were identified, and their complexity and limitations discussed. Participants agreed that investigating food allergy mechanisms, validating appropriate methods for identifying allergenic proteins, and refining strategies to assess and manage the risks from food allergy were important before processing considerations are integrated into public-health decision-making for novel proteins. Other factors may also play a role in food allergy and include: food matrix; multiplicity of epitopes; geographic variation in patterns/prevalence of food allergies; and genetic factors, but required further exploration. Food processing may increase or decrease the intrinsic allergenicity of a protein, but current data do not facilitate the identification of specific variables that could be used to reliably determine how processing will influence protein allergenicity.

Transcytosis of IgE–Antigen Complexes by CD23a in Human Intestinal Epithelial Cells and Its Role in Food Allergy

Secreted immunoglobulins play an integral role in host defense at mucosal surfaces, and recent evidence shows that IgG can participate in antigen sampling from the intestinal lumen. We examined whether IgE also could facilitate transepithelial antigen sampling. Stool samples from food-allergic patients undergoing oral food challenge were analyzed for CD23 and food-specific IgE. CD23 isoform expression on primary human intestinal epithelial cells (IEC) was analyzed by polymerase chain reaction. The role of CD23 isoforms in transcytosis of antigen and IgE-antigen complexes was assessed using polarized human T84 cells retrovirally transfected with CD23a or CD23b. CD23 was expressed constitutively on IECs, and food-allergic patients had increased levels of soluble CD23 and food-specific IgE in the stool after challenge. CD23a, but not CD23b, was expressed by primary human IECs. We show in transcytosis assays that CD23a, but not CD23b, acts as a bidirectional transporter of IgE. In addition, specific IgE facilitated the uptake of antigen from the apical surface of an epithelial monolayer by diverting antigen from delivery to lysosomes. Finally, delivery of antigen-IgE complexes across the epithelial barrier could induce the degranulation of rat basophil leukemia cells transfected with the human high-affinity IgE receptor. These studies show that CD23a is expressed normally on human IECs, and in the presence of IgE can function as an antigen-sampling mechanism capable of activating subepithelial mast cells. IgE may serve as a secretory immunoglobulin that in concert with CD23 participates in food-induced pathophysiology of the gastrointestinal tract.

The Role of Food Allergy in Atopic Dermatitis

The Role of Food Allergy in Atopic Dermatitis

Patterns of care and referral in children with atopic dermatitis and concern for food allergy

Although many providers believe that up to 30% of atopic dermatitis (AD) is food induced, food challenge studies show that food-induced eczematous reactions are rare. When food allergy is suggested to cause AD, it often leads to allergy testing with a high false-positivity rate, in turn further focusing parents on food allergy. Study subjects were children less than 11 years old with AD and food allergy suspicion. Prior diagnoses, provider, and testing patterns were assessed by questionnaire given to the parents. Thirty-eight patients with AD were enrolled. Most subject's parents suspected food allergy induced AD. Initial skin diagnoses were made by pediatricians (79%) and family practitioners (18%) as eczema. Allergy was suggested by providers as cause for AD in 63% of the present study's patients. Seventy-nine percent had allergy testing. Greater than 90% of parents claimed their children had food allergy and food-induced AD. Sixty-six percent had positive food allergy tests and 37% had definite history of immediate IgE reactions to food. The majority of this population had allergy suggested as causative for eczema by their primary care provider and were subsequently evaluated by allergist and allergy testing. Consensus about the role of food allergy between the different providers of AD in children would result in more effective, efficient, and less costly health care.

Second symposium on the definition and management of anaphylaxis: Summary report—Second National Institute of Allergy and Infectious Disease/Food Allergy and Anaphylaxis Network symposium

There is no universal agreement on the definition of anaphylaxis or the criteria for diagnosis. In July 2005, the National Institute of Allergy and Infectious Disease and Food Allergy and Anaphylaxis Network convened a second meeting on anaphylaxis, which included representatives from 16 different organizations or government bodies, including representatives from North America, Europe, and Australia, to continue working toward a universally accepted definition of anaphylaxis, establish clinical criteria that would accurately identify cases of anaphylaxis with high precision, further review the evidence on the most appropriate management of anaphylaxis, and outline the research needs in this area.

Relationship Between Asthma and Irritable Bowel Syndrome: Role of Food Allergy

The increasing prevalence of both asthma and irritable bowel syndrome (IBS) are major health problems. One hundred twenty-five patients with asthma and 95 healthy subjects were included in this study. The rate of IBS was 29.6% and 12.7% (p < 0.005), and the incidence of food allergy was 7.2% and 2.1% (p > 0.05) respectively for asthma and control group. There was no significant association between asthma related parameters, IBS, and food allergy. There is not a single clear reason as to what causes IBS, so further studies are needed to clarify the potential pathogenic mechanisms underlying the association between IBS and asthma.

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.

CD23-Mediated IgE Transport Across Human Intestinal Epithelium: Inhibition by Blocking Sites of Translation or Binding

In previous studies in rodent models of food allergy, we identified that sensitization induces expression of CD23 on intestinal epithelial cells and results in enhanced IgE-dependent transepithelial antigen uptake; further studies in CD23-/- mice provided evidence that CD23 is involved in protected transport of antigen into the body. Little information exists in humans on receptor-mediated immunoglobulin (Ig)E transport across epithelia. The present study was designed to examine expression of CD23 by human epithelial cells, determine its isoform and regulation by interleukin (IL) 4, and identify the role of CD23 in transepithelial IgE transport. Epithelial expression of CD23 was studied in cell lines, ileal biopsy specimens, and explanted fetal intestine. Bidirectional transport of IgE was measured across filter-grown cells, either normal cells or those transfected with antisense CD23 oligonucleotides, or in the presence of blocking antibody. Expression of the low-affinity IgE receptor was demonstrated in cultured epithelial cells as well as in situ cells in human intestine. CD23b was the isoform expressed by HT29, T84, and Caco-2 cells. IL-4 up-regulated the expression of epithelial CD23. IgE was transported in both the basal-to-apical direction and the apical-to-basal direction across filter-grown epithelial cells, a process that was inhibited by transfection of cells with CD23 antisense oligonucleotides or pretreatment with nonspecific IgE or anti-CD23 antibody. These findings provide evidence that CD23 encodes a functional IgE receptor on human intestinal epithelial cells and that this epithelial receptor is likely to play an important role in food allergies.

Role of food allergy in children with asthma

RATIONALE: Food allergy is one of the causes of atopic dermatitis, acute urticaria, reactions of the gastrointestinal tract and of systemic anaphylaxis, but its role in asthma appears to be less clear. The purpose of the study was to examine the prevalence of food allergy in the group of school-aged children with atopic asthma.

Role of food allergy in atopic dermatitis.

Food allergy and atopic dermatitis often occur in the same patient. Based on clinical data from the past few decades, it is clear that foods such as cow's milk and hen's eggs can directly provoke flares of atopic dermatitis particularly in sensitized infants, whereas inhaled allergens and pollen-related foods are of greater importance in older children, adolescents and adults. Because the role and immunology of food allergy in atopic dermatitis remain controversial, here we review data that mainly focus on skin eczema and food allergy. Clinical studies have revealed that more than 50% of all children with atopic dermatitis that can be exacerbated by certain foods will react with a worsening of skin eczema alone or in addition to immediate symptoms. Adolescents and adults also react to foods, but reactions to 'classical' food allergens such as hen's eggs and cow's milk are not as common as in childhood. Subgroups of children and of adults with atopic dermatitis do, however, react to pollen-associated foods. Both immunoglobulin E associated and independent T-cell mediated responses appear to be involved in clinical eczematous reactions. Food-induced eczema should be diagnosed only by a thorough diagnostic procedure, taking into account the patient's history, the degree of sensitization and the clinical relevance of the sensitization. More clinical and immunological studies are needed to unravel the pathophysiology and the different rates of clinical responsiveness to different foodstuffs in patients with atopic dermatitis.

Antigen-specific secretory IgA antibodies in the gut are decreased in a mouse model of food allergy

Background A large body of evidence implicates IgA antibodies in the immune response to pathogens present in the gut. Whether IgA antibodies play a similar role in food allergy remains to be determined. Objective We sought to characterize β-lactoglobulin (BLG)–specific serum and secretory IgA antibody production in the gut and to define the role of antigen-induced cytokines in IgA production in a murine model of food allergy. Methods BLG-specific IgA antibodies were measured in the sera and feces of mice anaphylactic or tolerant to BLG. The number of antibody-secreting cells in the spleen and Peyer's patches was determined by means of ELISPOT. Mesenteric lymph node cells and Peyer's patch T cells were transferred to naive mice, and antibody production in the sera and feces in recipient mice, as well as antibody-secreting cell numbers, were measured. Results Serum IgA antibody titers were strongly increased in anaphylactic mice. In contrast, BLG-specific IgA antibody titers were increased in feces but not in sera from tolerant mice. These results were correlated with an increased number of BLG-specific IgA-secreting cells in Peyer's patches from tolerant mice. The adoptive transfer of Peyer's patch CD3 + cells from tolerant mice induced an increased number of IgA-secreting cells preferentially in the Peyer's patches of naive recipient mice. Furthermore, an increase of BLG-induced IL-10 and TGF-β levels was found at IgA production sites. Conclusions These results suggest a role for secretory IgA in tolerance mechanisms to foods. Peyer's patch CD3 + cells are primarily involved by favoring IgA production through the release of IL-10 and TGF-β.

The role of food allergy in otitis media with effusion

Objective To detect the relationship between food allergy and otitis media with effusion (OME). Materials and methods This study was performed on three different groups. The patient group was made up of 56 patients with OME (group I). There were 28 patients with food allergy in group II and these patients were investigated for OME. The control group consisted of 28 patients without any complaints concerning food allergy or OME (group III). Results Food allergy was detected in 25 patients with OME (44.6%) (group I). In patients with food allergy (group II), OME was detected in 7 patients (25%). In the control group (group III) food allergy was diagnosed in 5 patients (18%) and OME in 1 patient (3%). The incidence of food allergy in OME group was statistically significant when compared to the normal group ( P > 0.05). Conclusions This study demonstrates that food allergy may play a role in the etiopathogenesis of OME.

Adoptive transfer of dendritic cells from allergic mice induces specific immunoglobulin E antibody in naïve recipients in absence of antigen challenge without altering the T helper 1/T helper 2 balance.

Dendritic cells (DCs) are important in the regulation of immune responses and it has been proposed that these cells play an important role in asthma; however, their role in food allergy is still largely unknown. Our aim was to study specific immunoglobulin E (IgE) and immunoglobulin G (IgG) responses in naïve recipients following adoptive transfer of myeloid DCs from allergic and control mice. The phenotypic features and lymphokine production of DCs were also investigated. CD11c+/hi B220- DCs isolated from spleen and Peyer's patches (PP) of cow's milk (CM) allergic and control mice were transferred intravenously (i.v.) into naïve syngeneic recipients, and IgE- and IgG-specific responses were evaluated. Experiments were also carried out to determine the levels of interferon-gamma (IFN-gamma) and interleukin (IL)-4 produced by splenocytes from naïve recipients following the adoptive transfer, and CD40 ligand (CD40L)-mediated IL-10 production by DCs from allergic and control mice. DCs isolated from spleen and PP of allergic mice, but not control groups, induced CM-specific IgG and IgE antibody production in naïve recipients in the absence of previous immunization, but did not modify the T helper 1 (Th1) and T helper 2 (Th2) balance. Furthermore, although no difference was observed in the expression of canonical DC surface markers, PP DCs from allergic mice produced less IL-10 than DCs from controls. We interpret these data as showing that DCs play a pivotal role in allergen-specific IgE responses and that a Th2-skewed response may not be involved in the early phase of allergic responses. The identification of the mechanisms underlying these events may help to design novel strategies of therapeutic intervention in food allergy.

Respiratory Manifestations of Food Allergy

Food allergy may present with a variety of respiratory tract symptoms that generally involve immunoglobulin E antibody-mediated responses. Exposure is typically through ingestion, but in some cases, inhalation of airborne food particles may trigger these reactions. Upper and lower respiratory tract reactions are often a significant component of multisystem, anaphylactic reactions. However, chronic or isolated asthma or rhinitis induced by food is unusual. It is important to recognize that food allergy in early childhood is a marker indicating an increased risk to develop respiratory allergy. The role of food allergy in otitis media is controversial and probably is extremely rare. Likewise, asthmatic responses to food additives can occur but are uncommon. Studies using blinded oral food challenges have demonstrated that foods can elicit airway hyperreactivity and asthmatic responses. Therefore, an evaluation for food allergy should be considered in patients who are at risk, including those with recalcitrant or otherwise unexplained acute, severe asthma exacerbations, asthma triggered after ingestion of particular foods, and asthma that is accompanied by other manifestations of food allergy (e.g., anaphylaxis, moderate to severe atopic dermatitis).

Role of food allergy in asthma in childhood

Role of food allergy in asthma in childhood

Nature and function of gastrointestinal antigen-presenting cells.

Antigen-presenting cells (APCs) of the human gut are heterogeneous, including both macrophages, a variety of dendritic cells and B cells. They are found both in gut-associated lymphoid tissue and in the mucosal lamina propria, especially beneath the surface epithelium. APCs have diverse phenotypes and therefore probably different functions in various locations; their expression levels of a variety of costimulatory molecules are most likely important for immunological decision making of stimulated T cells, either locally in the gut or in regional lymph nodes to which migrating APCs (dendritic cells) carry antigen. Thus, APCs are involved in active immunity as well as in induction of oral tolerance. However, their precise role in food allergy remains to be defined.

Role of food allergy in asthma in childhood.

Atopy is the major predisposing factor for asthma identified up to now, and allergen exposure, particularly indoor allergens, is considered as a causal factor for asthma. Food allergy is frequently underestimated in association with asthma, however food allergy has been shown to trigger or exacerbate broncho-obstruction in 2 to 8.5% of children with asthma. There is also evidence that double-blind placebo-controlled oral challenge is able to increase unspecific bronchial hyperresponsiveness. Sensitization to food can occur early in life involving T cell response, mainly of the Th2 phenotype, but also IgE-mediated hypersensitivity. Moreover, it has been shown that sensitization to food allergens early in life is a risk factor for sensitization to inhalent allergens and respiratory symptoms later on. Epidemiological studies suggest that changes in the dietary composition, such as trans-fatty acids, could be involved in the increase of asthma prevalence. The introduction of formula during the first trimester of life increases the risk of having asthma. The diagnosis of food allergy associated with asthma is not easy, nevertheless is important for allergists, pulmonologists and paediatricians to consider food allergy in children with respiratory symptoms, especially when asthma symptoms start early in life and when they are associated with other manifestations of food allergy. Children sensitized to cow's milk proteins and also having atopic eczema are at higher risk for asthma. Since avoidance of the offending food is the first step in the management of children with asthma associated with food allergy, a careful identification should be done in order to avoid unnecessary elimination of foods.

Enhanced mstamine production in collagenous colitis (CC) during unrestricted and elimination (potato-rice) diet

Background: The cause of CC is unknown, but the activation of inflammatory cells like eosinophils or mast cells has been described, suggesting an allergic pathomechanism. Additionally, the therapeutic efficacy of fecal stream diversion shows that luminal factors play an important role in the pathogenesis of CC. Taken together, this is suggestive for a role of food allergy in CC. Methods: In 13 patients with CC, 12-h-urine (for histamine (UH) and methyl-histamine (UMH)) was collected during a non-restricted diet (NO) and a elimination diet (ED) consisting of potato and rice. The values obtained were compared with those of patients with food allergy (FA)(n=42) and healthy controls (n=27). Measurement was performed using a RIA (Methyl-Histamine: Pharmacia, Freiburg, Germany; Histamine: Coulter-Immunotech, Hamburg, Germany). Results: When tested during NO, 27 urine samples or patients with CC were available (for ED: 20). UMH was significantly elevated when compared with controls (p=0.02), but not UH. UMH was unchanged, when the patients were switched on a elimination diet in contrast to values obtained in patients with food allergy, who showed similar elevation of UH and UMH, but a significant reduction under ED (p=0.02 for both). Conclusion: In patients with CC, the extensive activation of mast cells appears not to be influenced by an elimination diet. This finding suggests an induction of histamine secretion by rice and potato. Since allergic reactions to potato or rice are rare, this could be realized by salicylates, which are present abundantly in potatoes. This could further add to the evidence of an association of NSAID-consumption and presence of Cc.

443 The role of food allergy in otitis media with effusion (OMF)

443 The role of food allergy in otitis media with effusion (OMF)