Baked egg is tolerated by a majority of egg-allergic children.
To characterize immunologic changes associated with ingestion of baked egg and evaluate the role that baked egg diets plays in the development of tolerance to regular egg.
Egg-allergic subjects who tolerated baked egg challenge incorporated baked egg into their diet. Immunologic parameters were measured at follow-up visits. A comparison group strictly avoiding egg was used to evaluate the natural history of the development of tolerance.
Of the 79 subjects in the intent-to-treat group followed for a median of 37.8 months, 89% now tolerate baked egg and 53% now tolerate regular egg. Of 23 initial baked egg-reactive subjects, 14 (61%) subsequently tolerated baked egg and 6 (26%) now tolerate regular egg. Within the initially baked egg-reactive group, subjects with persistent reactivity to baked egg had higher median baseline egg white (EW)-specific IgE levels (13.5 kUA/L) than those who subsequently tolerated baked egg (4.4 kUA/L; P=0.04) and regular egg (3.1 kUA/L, P=0.05). In subjects ingesting baked egg, EW-induced SPT wheal diameter and EW-, ovalbumin-, and ovomucoid-specific IgE levels decreased significantly, while ovalbumin- and ovomucoid-specific IgG4 levels increased significantly. Subjects in the per-protocol group were 14.6 times more likely to develop regular egg tolerance than subjects in the comparison group (P < 0.0001), and they developed tolerance earlier (median 50.0 versus 78.7 months; P<0.0001).
Initiation of a baked egg diet accelerates the development of regular egg tolerance compared to strict avoidance. Higher serum EW-specific IgE level is associated with persistent baked and regular egg reactivity, while initial baked egg reactivity is not.
egg allergy; hen’s egg allergy; baked egg; heated egg; food allergy; egg tolerance; oral food challenge; egg allergy immunotherapy
To examine circumstances of allergic reactions to foods in a cohort of preschool-aged children.
We conducted a prospective, 5-site observational study of 512 infants aged 3 to 15 months with documented or likely allergy to milk or egg, and collected data prospectively examining allergic reactions.
Over a median follow-up of 36 months (range: 0–48.4), the annualized reaction rate was 0.81 per year (367/512 subjects reporting 1171 reactions [95% confidence interval: 0.76–0.85]). Overall, 269/512 (52.5%) reported >1 reaction. The majority of reactions (71.2%) were triggered by milk (495 [42.3%]), egg (246 [21.0%]), and peanut (93 [7.9%]), with accidental exposures attributed to unintentional ingestion, label-reading errors, and cross-contact. Foods were provided by persons other than parents in 50.6% of reactions. Of 834 reactions to milk, egg, or peanut, 93 (11.2%) were attributed to purposeful exposures to these avoided foods. A higher number of food allergies (P < .0001) and higher food-specific immunoglobulin E (P < .0001) were associated with reactions. Of the 11.4% of reactions (n = 134) that were severe, 29.9% were treated with epinephrine. Factors resulting in undertreatment included lack of recognition of severity, epinephrine being unavailable, and fears about epinephrine administration.
There was a high frequency of reactions caused by accidental and nonaccidental exposures. Undertreatment of severe reactions with epinephrine was a substantial problem. Areas for improved education include the need for constant vigilance, accurate label reading, avoidance of nonaccidental exposure, prevention of cross-contamination, appropriate epinephrine administration, and education of all caretakers.
food allergy; IgE-mediated allergic reaction; epinephrine
Peanut allergy is relatively common, typically permanent, and often severe. Double-blind, placebo-controlled food challenge is considered the gold standard for the diagnosis of food allergy–related disorders. However, the complexity and potential of double-blind, placebo-controlled food challenge to cause life-threatening allergic reactions affects its clinical application. A laboratory test that could accurately diagnose symptomatic peanut allergy would greatly facilitate clinical practice.
We sought to develop an allergy diagnostic method that could correctly predict symptomatic peanut allergy by using peptide microarray immunoassays and bioinformatic methods.
Microarray immunoassays were performed by using the sera from 62 patients (31 with symptomatic peanut allergy and 31 who had outgrown their peanut allergy or were sensitized but were clinically tolerant to peanut). Specific IgE and IgG4 binding to 419 overlapping peptides (15 mers, 3 offset) covering the amino acid sequences of Ara h 1, Ara h 2, and Ara h 3 were measured by using a peptide microarray immunoassay. Bioinformatic methods were applied for data analysis.
Individuals with peanut allergy showed significantly greater IgE binding and broader epitope diversity than did peanut-tolerant individuals. No significant difference in IgG4 binding was found between groups. By using machine learning methods, 4 peptide biomarkers were identified and prediction models that can predict the outcome of double-blind, placebo-controlled food challenges with high accuracy were developed by using a combination of the biomarkers.
In this study, we developed a novel diagnostic approach that can predict peanut allergy with high accuracy by combining the results of a peptide microarray immunoassay and bioinformatic methods. Further studies are needed to validate the efficacy of this assay in clinical practice.
Epitope mapping; peptide microarray; peanut allergy; bioinformatics; machine learning; allergy diagnosis; epitope biomarker
For egg allergy, dietary avoidance is the only currently approved treatment. We evaluated oral immunotherapy using egg-white powder for the treatment of children with egg allergy.
In this double-blind, randomized, placebo-controlled study, 55 children, 5 to 11 years of age, with egg allergy received oral immunotherapy (40 children) or placebo (15). Initial dose-escalation, build-up, and maintenance phases were followed by an oral food challenge with egg-white powder at 10 months and at 22 months. Children who successfully passed the challenge at 22 months discontinued oral immunotherapy and avoided all egg consumption for 4 to 6 weeks. At 24 months, these children underwent an oral food challenge with egg-white powder and a cooked egg to test for sustained unresponsiveness. Children who passed this challenge at 24 months were placed on a diet with ad libitum egg consumption and were evaluated for continuation of sustained unresponsiveness at 30 months and 36 months.
After 10 months of therapy, none of the children who received placebo and 55% of those who received oral immunotherapy passed the oral food challenge and were considered to be desensitized; after 22 months, 75% of children in the oral-immunotherapy group were desensitized. In the oral-immunotherapy group, 28% (11 of 40 children) passed the oral food challenge at 24 months and were considered to have sustained unresponsiveness. At 30 months and 36 months, all children who had passed the oral food challenge at 24 months were consuming egg. Of the immune markers measured, small wheal diameters on skin-prick testing and increases in egg-specific IgG4 antibody levels were associated with passing the oral food challenge at 24 months.
These results show that oral immunotherapy can desensitize a high proportion of children with egg allergy and induce sustained unresponsiveness in a clinically significant subset. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00461097.)
This letter reports the largest series of open oral food challenges in the literature to date. It describes the feasibility and utility of oral food challenge, further justifying its use in the everyday practice of allergy.
Food Allergy; Oral Food Challenge; Outpatient; Skin Test; Peanut
antihistamines; diphenhydramine; cetirizine; acute food allergic reactions; oral food challenges
Data from many studies have suggested a rise in the prevalence of food allergies during the past 10 to 20 years. Currently, no curative treatments for food allergy exist, and there are no effective means of preventing the disease. Management of food allergy involves strict avoidance of the allergen in the patient's diet and treatment of symptoms as they arise. Because diagnosis and management of the disease can vary between clinical practice settings, the National Institute of Allergy and Infectious Diseases (NIAID) sponsored development of clinical guidelines for the diagnosis and management of food allergy. The guidelines establish consensus and consistency in definitions, diagnostic criteria, and management practices. They also provide concise recommendations on how to diagnose and manage food allergy and treat acute food allergy reactions. The original guidelines encompass practices relevant to patients of all ages, but food allergy presents unique and specific concerns for infants, children, and teenagers. To focus on those concerns, we describe here the guidelines most pertinent to the pediatric population.
food allergy; food hypersensitivity; infants; children; guidelines; anaphylaxis
Probiotic administration has been proposed for the prevention and treatment of specific allergic manifestations such as eczema, rhinitis, gastrointestinal allergy, food allergy, and asthma. However, published statements and scientific opinions disagree about the clinical usefulness.
A World Allergy Organization Special Committee on Food Allergy and Nutrition review of the evidence regarding the use of probiotics for the prevention and treatment of allergy.
A qualitative and narrative review of the literature on probiotic treatment of allergic disease was carried out to address the diversity and variable quality of relevant studies. This variability precluded systematization, and an expert panel group discussion method was used to evaluate the literature. In the absence of systematic reviews of treatment, meta-analyses of prevention studies were used to provide data in support of probiotic applications.
Despite the plethora of literature, probiotic research is still in its infancy. There is a need for basic microbiology research on the resident human microbiota. Mechanistic studies from biology, immunology, and genetics are needed before we can claim to harness the potential of immune modulatory effects of microbiota. Meanwhile, clinicians must take a step back and try to link disease state with alterations of the microbiota through well-controlled long-term studies to identify clinical indications.
Probiotics do not have an established role in the prevention or treatment of allergy. No single probiotic supplement or class of supplements has been demonstrated to efficiently influence the course of any allergic manifestation or long-term disease or to be sufficient to do so. Further epidemiologic, immunologic, microbiologic, genetic, and clinical studies are necessary to determine whether probiotic supplements will be useful in preventing allergy. Until then, supplementation with probiotics remains empirical in allergy medicine. In the future, basic research should focus on homoeostatic studies, and clinical research should focus on preventive medicine applications, not only in allergy. Collaborations between allergo-immunologists and microbiologists in basic research and a multidisciplinary approach in clinical research are likely to be the most fruitful.
probiotics; prevention of allergy; pediatric allergy
Lipopolysaccharide (LPS), a component of gram-negative bacterial cell walls, has been shown to have a strong adjuvant effect towards inhaled antigens contributing to airway inflammation. Isoflavones are anti-inflammatory molecules present in abundant quantities in soybeans. We investigated the effect of isoflavones on human dendritic cell (DC) activation via LPS stimulation and subsequent DC-mediated effector cell function both in vitro and in a mouse model of upper airway inflammation. Human monocyte-derived DCs (MDDC) were matured with LPS (or TNF-α) +/− isoflavones (genistein or daidzein). The surface expression levels of DC activation markers were analyzed by flow cytometry. Mature DCs +/− isoflavones were washed and cultured with freshly-isolated allogenic naïve CD4+ T cells for 5 days or with autologous natural killer (NK) cells for 2 hours. The percentages of proliferating IFN-γ+ CD4+ T cells and cytokine levels in culture supernatants were assessed. NK cell degranulation and DC cytotoxicity were measured by flow cytometry. Isoflavones significantly suppressed the activation-induced expression of DC maturation markers (CD83, CD80, CD86) and MHC class I but not MHC class II molecules in vitro. Isoflavone treatment inhibited the ability of LPS-DCs to induce IFN-γ in CD4+ T cells. NK cell degranulation and the percentage of dead DCs were significantly increased in isoflavone-treated DC-NK co-culture experiments. Dietary isoflavones suppressed the mucosal immune response to intra-nasal sensitization of mice to ovalbumin. Similar results were obtained when isoflavones were co-administered during sensitization. These results demonstrate that soybean isoflavones suppress immune sensitization by suppressing DC-maturation and its subsequent DC-mediated effector cell functions.
Studies have demonstrated that IgE-binding cross-reactive epitopes between shrimp, cockroach and house dust mite tropomyosins can account for the presence of detectable IgE to shrimp in people who have cockroach and dust mite allergies.
We investigated the correlation between IgE-mediated sensitization to shrimp, cockroach, and dust mite in relation to allergen exposure in inner-city children.
Five hundred and four serum samples from the National Cooperative Inner City Asthma Study (NCICAS) were evaluated for specific IgE to shrimp and the results were compared to specific IgE to cockroach (Blattella germanica) and dust mite (Dermatophagoides farinae). Associations between IgE sensitization to these allergens and environmental exposures were determined.
There was a strong positive correlation between shrimp, cockroach, and dust mite IgE levels. High exposure to cockroach (Bla g) in the home, particularly in the bedroom and television room, was significantly correlated with higher shrimp and cockroach IgE levels. In contrast, high exposure to dust mite in the home was highly correlated with IgE to D.farinae, but not with shrimp IgE levels. There is a synergistic relationship between cockroach IgE and exposure in predicting shrimp IgE levels.
For children with evidence of IgE-mediated sensitization to cockroach and shrimp, having high exposure to cockroach in the home can contribute to higher shrimp IgE levels, which may not correlate with clinical reactivity. Further patient evaluations with clinical histories of shrimp exposure and reactions as well as oral food challenges would have to be performed to confirm these findings.
cockroach; dust mite; shrimp; tropomyosin; cross-reactivity
The majority (∼75%) of cow's milk-allergic children tolerate extensively heated-(baked-) milk products. Long-term effects of inclusion of dietary baked-milk have not been reported.
We report on the outcomes of children who incorporated baked-milk products into their diets.
Children evaluated for tolerance to baked-milk (muffin) underwent sequential food challenges to baked-cheese (pizza) followed by unheated-milk. Immunologic parameters were measured at challenge visits. The comparison group were matched to active subjects (using age, sex, and baseline milk-specific IgE) to evaluate the natural history of tolerance development.
Over a median of 37 months (range 8-75 months), 88 children underwent challenges at varying intervals (range 6-54 months). Among 65 subjects initially tolerant to baked-milk, 39 (60%) now tolerate unheated-milk, 18 (28%) tolerate baked-milk/baked-cheese and 8 (12%) chose to avoid milk strictly. Among the baked-milk-reactive subgroup (n=23), 2 (9%) tolerate unheated-milk, 3 (13%) tolerate baked-milk/baked-cheese, while the majority (78%) avoid milk strictly. Subjects who were initially tolerant to baked-milk were 28 times more likely to become unheated-milk-tolerant compared to baked-milk-reactive subjects (P<.001). Subjects who incorporated dietary baked-milk were 16 times more likely than the comparison group to become unheated-milk-tolerant (P<.001). Median casein IgG4 levels in the baked-milk-tolerant group increased significantly (P<.001); median milk IgE values did not change significantly.
Tolerance of baked-milk is a marker of transient IgE-mediated cow's milk allergy whereas reactivity to baked-milk portends a more persistent phenotype. The addition of baked-milk to the diet of children tolerating such foods appears to accelerate development of unheated-milk tolerance compared to strict avoidance.
Addition of dietary baked-milk is safe, convenient, and well-accepted by patients. Prescribing baked-milk products to milk-allergic children represents an important shift in the treatment paradigm for milk allergy.
The majority of cow's milk-allergic children tolerate extensively baked-milk products, which is a marker of transient IgE-mediated cow's milk allergy. Dietary baked-milk appears to accelerate development of unheated-milk tolerance compared to strict avoidance.
cow's milk allergy; milk allergy; tolerance; extensively heated; baked; immunotherapy; immunomodulation
Therapies for peanut allergy (PNA) are urgently needed. Food Allergy Herbal Formula -2 (FAHF-2) has profound therapeutic effects in a murine peanut allergy model and is safe for food allergic adults in clinical trials. However the large FAHF-2 pill-load is not conducive to clinical studies in children. Thus refining FAHF-2 to decrease pill-load is essential for the inclusion of children in clinical trials and to facilitate studying FAHF-2 as a clinically useful botanical drug.
Testing long term efficacy and safety of a butanol-purified extract of FAHF-2 (B-FAHF-2) in a murine model of PNA, and to explore its immunological mechanisms of action.
FAHF-2 was purified by butanol extraction. C3H/HeJ mice with established PNA received the 1st course of B-FAHF-2 at 6 mg, twice daily for 7 weeks (PNA/B-FAHF-2) or water (PNA/Sham) and were then challenged immediately after completing the treatment and 6 more times every 1–2 months post treatment up to week 50. Mice then received a second course of B-FAHF-2 treatment at week 52 and were challenged at week 65. In vivo and in vitro immunological effects on T, B and mast cells were also determined.
Butanol purification reduced the volume of the effective dose ~5 fold. All PNA/B-FAHF-2 mice were completely protected from peanut anaphylaxis until the 5th challenge after the 1st course of treatment, as compared to PNA/sham mice. Partial protection persisted up to 50 weeks. A 2nd treatment course restored complete protection. B-FAHF-2 significantly suppressed Th2 cytokine, IgE and histamine levels in vivo, and showed direct inhibition of Th2, IgE-producing B cells and mast cell activation in vitro. B-FAHF-2 had a high margin of safety.
Conclusion and clinical relevance
B-FAHF-2 produced long-lasting protection against PN anaphylaxis for approximately half of the murine lifespan without side effects. B-FAHF-2 exhibited direct effects on multiple food allergy effector cells.
Chinese herbal medicine formula; FAHF-2; B-FAHF-2; Peanut Anaphylaxis; Th2 cytokines; Histamine; IgE
Food allergy is an increasingly prevalent problem in westernized countries and there is an unmet medical need for an effective form of therapy . A number of therapeutic strategies are under investigation targeting foods that most frequently provoke severe IgE-mediated anaphylactic reactions (peanut, tree nuts, shellfish) or are most common in children, such as cow’s milk and hen’s egg. Approaches being pursued are both food allergen-specific and non-specific. Allergen-specific approaches include oral, sublingual and epicutaneous immunotherapy (desensitization) with native food allergens, and mutated recombinant proteins, which have decreased IgE-binding activity, co-administered within heat-killed E.coli to generate maximum immune response. Diets containing extensively heated (baked) milk and egg represent an alternative approach to food oral immunotherapy and are already changing the paradigm of strict dietary avoidance for food-allergic patients. Non-specific approaches include monoclonal anti-IgE antibodies, which may increase the threshold dose for food allergen in food-allergic patients, and a Chinese herbal formulation, which prevented peanut-induced anaphylaxis in a mouse model, and is currently being investigated in clinical trials. The variety of strategies for treating food allergy increases the likelihood of success and gives hope that accomplishing an effective therapy for food allergy is within reach.
food allergy; oral immunotherapy; sublingual immunotherapy; probiotics; epicutaneous immunotherapy; desensitization; milk allergy; peanut allergy; egg allergy; anti-IgE; anti-IgE therapy; anti-IL-5 therapy
Dynamics and balance of allergen specific IgE, IgG4 and IgA binding may contribute to the development of tolerance in cow's milk allergy. Profiling of antibody binding to cow's milk protein epitopes may help in predicting natural history of allergy.
To investigate differences in IgE, IgG4 and IgA binding to cow's milk epitopes over time between patients with early recovery or with persisting cow's milk allergy.
We studied serum samples at the time of diagnosis (mean age 7 months), one year later and at follow-up (mean age 8.6 years) from 11 patients with persisting IgE-mediated cow's milk allergy at age 8-9 years, and 12 patients who recovered by age 3 years. We measured the binding of IgE, IgG4 and IgA antibodies to sequential epitopes derived from five major cow's milk proteins with a peptide microarray-based immunoassay. We analyzed the data with a novel image processing method together with machine learning prediction.
IgE epitope binding patterns were stable over time in patients with persisting cow's milk allergy, whereas binding decreased in patients who recovered early. Binding patterns of IgE and IgG4 overlapped. Among patients who recovered early, the signal of IgG4 binding increased while that of IgE decreased over time. IgE and IgG4 binding to a panel of αs1-, αs2-, β-and κ-casein regions predicted outcome with significant accuracy.
Attaining tolerance to cow's milk is associated with decreased epitope binding by IgE and a concurrent increase in corresponding epitope binding by IgG4.
cow's milk allergy; tolerance; epitope; IgE; IgG4; IgA
Previous studies have indicated that specific molecular properties of proteins may determine their allergenicity. Allergen interaction with epithelia as the first contact site could be decisive for a resulting immune response. We investigate here for the major peanut allergen Ara h 2 whether thermal processing results in structural changes which may impact the protein’s molecular interactions with enterocytes, subsequent cellular signalling response, and immunogenicity.
Ara h 2 was heat processed and analyzed in terms of patient IgE binding, structural alterations, interaction with human enterocytes and associated signalling as well as immunogenicity in a food allergy mouse model.
Heating of Ara h 2 led to significantly enhanced binding to Caco-2/TC7 human intestinal epithelial cells. Structural analyses indicated that heating caused persistent structural changes and led to the formation of Ara h 2 oligomers in solution. Heated protein exhibited a significantly higher immunogenic potential in vivo as determined by IgG and IgE serum antibody levels as well as IL-2 and IL-6 release by splenocytes. In human Caco-2/TC7 cells, Ara h 2 incubation led to a response in immune- and stress signalling related pathway components at the RNA level, whereas heated allergen induced a stress-response only.
We suggest from this peanut allergen example that food processing may change the molecular immunogenicity and modulate the interaction capacity of food allergens with the intestinal epithelium. Increased binding behaviour to enterocytes and initiation of signalling pathways could trigger the epimmunome and influence the sensitization capacity of food proteins.
Allergy; food processing; intestinal epithelium; oral mouse immunization; peanut allergen Ara h 2
Food allergies affect up to 6% of young children and 3%–4% of adults. They encompass a range of disorders that may be IgE and/or non-IgE mediated, including anaphylaxis, pollen food syndrome, food-protein–induced enterocolitis syndrome, food-induced proctocolitis, eosinophilic gastroenteropathies, and atopic dermatitis. Many complex host factors and properties of foods are involved in the development of food allergy. With recent advances in the understanding of how these factors interact, the development of several novel diagnostic and therapeutic strategies is underway and showing promise.
Food allergy is a common and increasing health concern in westernized countries. No effective treatment is available and accidental ingestion can be life threatening. Food allergy herbal formula-2 (FAHF-2) blocks peanut anaphylaxis in a murine model of peanut-induced anaphylaxis. It was found to be safe, and well tolerated in an acute phase I study of food allergic patients.
To assess the safety of FAHF-2 in an extended phase I clinical trial and determine potential effects on peripheral blood basophils from food allergic patients.
Patients in an open-label study received 3.3 grams (6 tablets) of FAHF-2 three times a day for 6 months. Vital signs, physical examinations, laboratory data, pulmonary function tests and electrocardiographic data were acquired at baseline and at 2 month intervals. During the course of the study, basophil activation and basophil and eosinophil numbers were evaluated using CCR3/ CD63 staining and flow cytometry.
Of eighteen patients enrolled, 14 completed the study. No significant drug-associated differences in laboratory parameters, pulmonary function studies, or electrocardiographic findings before and after treatment were found. There was a significant reduction (p<.010) in basophil CD63 expression in response to ex vivo stimulation at month 6. There was also a trend towards a reduction of eosinophil and basophil numbers after treatment.
FAHF-2 was safe, well-tolerated, and had an inhibitory effects on basophils in an extended phase I clinical study. A controlled phase II study is warranted.
FAHF-2 was safe, well-tolerated and inhibited basophils numbers and activation in a 6 month clinical trial for food allergic patients. FAHF-2 may provide a safe immunotherapeutic option for food allergic patients.
FAHF-2 was safe and well-tolerated in a six-month phase-I open label clinical trial for food allergy patients. Immunological beneficial effects of FAHF-2 were decreased basophil numbers and inhibition of activation.
Food allergy; FAHF-2; Basophil activation
Peanut allergy is typically severe, life-long and prevalent.
To identify factors associated with peanut sensitization.
We evaluated 503 infants 3–15 months of age (mean, 9.4 months) with likely milk or egg allergy but no previous diagnosis of peanut allergy. A total of 308 had experienced an immediate allergic reaction to cow’s milk and/or egg and 204 had moderate to severe atopic dermatitis and a positive allergy test to milk and/or egg. A peanut IgE level of ≥ 5 kUA/L was considered likely indicative of peanut allergy.
A total of 140 (27.8%) infants had PN-IgE levels ≥5 kUA/L. Multivariate analysis including clinical, laboratory and demographic variables showed frequent peanut consumption during pregnancy (OR 2.9, 95% CI 1.7–4.9, p < 0.001), IgE levels to milk (p = 0.001) and egg (p < 0.001), male sex (p = 0.02) and non-white race (p = 0.02) to be the primary factors associated with peanut IgE ≥5 kUA/L. Frequency of peanut consumption during pregnancy and breast feeding showed a dose-response association with peanut IgE ≥ 5 kUA/L, but only consumption during pregnancy was a significant predictor. Among 71 infants never breastfed, frequent consumption of peanut during pregnancy was strongly associated with peanut IgE ≥ 5 kUA/L (OR-4.99, 95% CI-1.69–14.74, p < 0.004).
In this cohort of infants with likely milk or egg allergy, maternal ingestion of peanut during pregnancy was strongly associated with a high level of peanut sensitization.
food allergy; sensitization; atopy; peanut allergy
Chronic allergic asthma is the result of a Th2- biased immune status. Current asthma therapies control symptoms in some patients, but a long lasting therapy has not been established. ASHMI™, a Chinese herbal formula improved symptoms and lung function, and reduced Th2 responses in a controlled trial of patients with persistent moderate to severe asthma.
We evaluated the persistence of ASHMI™ beneficial effects following therapy in a murine model of persistent asthma and the immunological mechanisms underlying such effects. BALB/c mice sensitized intraperitoneally with ovalbumin (OVA) received 3 weekly intratracheal OVA challenges to induce airway hyperreactivity (AHR) and inflammation (OVA mice). Additional OVA mice were treated with ASHMI™ (OVA/ASHMI™) or water (OVA/Sham) for 4 weeks, and then challenged immediately and eight weeks post-therapy. In other experiments OVA mice received ASHMI™ treatment with concomitant neutralization of IFN-γ or TGF-β. Effects on airway responses, cytokine and OVA-specific IgE levels were determined 8 weeks post-therapy.
Prior to treatment, OVA mice exhibited AHR and pulmonary eosinophilic inflammation following OVA challenge, which was almost completely resolved immediately after completing treatment with ASHMI™ and did not re-occur following OVA re-challenge up to 8 wks post-therapy. Reduced allergen-specific IgE and Th2 cytokine levels, and increased IFN-γ levels also persisted at least 8 wks post-therapy. ASHMI™ effects were eliminated by neutralization of IFN-γ, but not TGF-β, during therapy.
ASHMI™ induced long-lasting post-therapy tolerance to antigen-induced inflammation and AHR. IFN-γ is a critical factor in ASHMI™ effects.
Allergic asthma; Mice; Traditional Chinese Medicine; Th-2 cytokines; Interferon-γ; IgE
Lentils are oftentimes responsible for allergic reactions to legumes in Mediterranean children. Though the primary sequence of the major allergen, Len c 1 is known, the location of the IgE binding epitopes remains undefined.
We sought to identify IgE-binding epitopes of Len c 1 and relate epitope binding to clinical characteristics.
135 peptides corresponding to the primary sequence of Len c 1 were probed with sera from 33 lentil-allergic individuals and 15 non-atopic controls by means of microarray immunoassay. Lentil-specific IgE, Skin Prick Tests and clinical reactions to lentil were determined. Epitopes were defined as overlapping signal above inter- and intra-slide cut-offs and confirmed by inhibition assays using a peptide from the respective region. Hierarchical clustering of microarray data was used to correlate binding patterns with clinical findings.
The lentil-allergic patients specifically recognized IgE-binding epitopes located in the C-terminal region, between peptide 107 and 135. Inhibition experiments confirmed the specificity of IgE binding in this region, identifying different epitopes. Linkage of cluster results with clinical data and lentil specific IgE levels displayed a positive correlation between lentil-specific IgE levels, epitope recognition and respiratory symptoms.
Modeling based on the three-dimensional structure of a homologous soy vicilin suggests that the Len c 1 epitopes identified are exposed on the surface of the molecule.
Several IgE-binding sequential epitopes of Len c 1 have been identified. Epitopes are located in the C-terminal region, and are predicted to be exposed on the surface of the protein. Epitope diversity is positively correlated with IgE levels, pointing to a more polyclonal IgE response.
lentil allergy; peptide microarray; epitope recognition; epitope diversity; Len c 1
Delivery of allergens with bacterial adjuvants has been shown to be a successful immunotherapeutic strategy for food allergy treatment in animal models. How microbial signals, acting through the innate immune system, reshape ongoing allergic responses is poorly understood.
To investigate the contribution of Toll-like receptors in the response to bacterial adjuvants, we designed an in vitro system to characterize the effect of heat-killed E.coli on peanut-induced responses of dendritic cells (DCs) and T cells.
Wild-type or Toll-Like Receptor (TLR) signaling-deficient bone-marrow derived DCs were pulsed with crude peanut extract alone (CPE) (50 µg/mL) in the presence of heat-killed E.coli (HKE) (106/mL). DC maturation was analyzed by flow cytometry. Treated DCs were co-cultured with CFSE-labeled CD4+ T cells from sensitized mice. Cytokine production from DCs and T cells was measured by bioplex assays.
Peanut pulsed DCs induced the production of IL-4, IL-5, IL-13 as well as IL-17 and IFN-γ from primed T cells. Adding HKE to CPE-pulsed DCs resulted in a significant decrease in Th2 cytokine production, associated with an increase in IFN-γ and profound attenuation of T cell proliferation. These effects were linked to HKE-induced, TLR-dependent changes in DC reactivity to CPE, especially the production of polarizing cytokines such as IL-12.
TLR signals modulate peanut-induced DC maturation in vitro leading to changes in the T cell response to peanut. These TLR effects must be confirmed in vivo and may constitute another alternative for allergen immunotherapies.
Peanut allergy; EMP-123; Dendritic cell; Toll-like receptor; MyD88; IL-12
Peanut OIT has shown promise as a potential treatment for food allergy. However, there remain numerous unanswered questions surrounding this investigational treatment, including the risks of OIT compared to avoidance, dosing regimen issues, patient selection, post-desensitization strategy, allocation of clinical resources, and reimbursement. Further studies are needed to address these outstanding issues in order to determine if this type of therapy is appropriate for clinical use.
peanut allergy; oral immunotherapy; desensitization
Immune features of infants with food allergy have not been delineated.
To explore basic mechanisms responsible for food allergy and identify biomarkers, e.g. prick skin tests (PST), food-specific IgE, and mononuclear cell responses in a cohort of infants with likely milk/egg allergy at increased risk of developing peanut allergy.
Infants aged 3–15 months were enrolled with a positive PST to milk or egg and either a corresponding convincing clinical history of allergy to milk or egg, or with moderate to severe atopic dermatitis (AD). Infants with known peanut allergy were excluded.
Overall, 512 infants (67% males) were studied with 308 (60%) having a history of a clinical reaction. Skin tests and/or detectable food-specific IgE revealed sensitization as follows: milk-78%, egg-89% and peanut-69%. PST and food-specific IgE levels were discrepant for peanut: 15% IgE ≥ 0.35 kUA/L/PST- versus 8% PST+/IgE < 0.35, p = 0.001. Mononuclear cell allergen stimulation screening for CD25, CISH, FOXP3, GATA3, IL-10, IL-4, IFN-gamma and TBET expression using casein, egg white and peanut revealed that only allergen-induced IL-4 expression was significantly increased in those with clinical allergy to milk (compared to non-allergic) and in those sensitized to peanut, despite the absence of an increase in GATA-3 mRNA expression.
Infants with likely milk/egg allergy are at considerably high risk of having elevated peanut-specific IgE (potential allergy). Peanut-specific serum IgE was a more sensitive indicator of sensitization than PST. Allergen-specific IL-4 expression may be a marker of allergic risk. Absence of an increase in GATA-3 mRNA expression suggests that allergen-specific IL-4 may not be of T cell origin.
food allergy; sensitization; atopy