Oral Immunotherapy in Patients with IgE Mediated Reactions to Egg White: A Clinical Trial Study.

BACKGROUND: Oral immunotherapy (OIT) is under consideration as a promising treatment for desensitization of egg-allergic patients. The objective of this study was to assess the effectiveness of egg-white OIT in patients with IgE-mediated allergy to egg white and to compare the clinical and laboratory findings before and after OIT. METHODS: This clinical trial was performed from February to August 2018 in Rasool e Akram Hospital, Tehran, Iran. Patients' selection criteria included a history of allergic symptoms, skin prick test (SPT) reactivity to egg white, and the inability to pass the Oral Food Challenge (OFC). Egg-white OIT was done for eight patients in the OIT group for 6 months while egg-white-free products were administrated for controls. The SPT reactivity, specific IgE, and IgG4 for egg white and ovomucoid were evaluated before and after OIT. RESULTS: Hundred percent of the subjects in OIT group were desensitized and tolerated 40 cc raw egg white following 6-month maintenance whereas none of the controls was able to pass the OFC. The findings obtained from the evaluations indicated a significant decrease in the wheal size and specific IgE to egg white after OIT (P = .001). Furthermore, a significant decrease of IgE/IgG4 ratio to egg white was found in OIT group (P = .01). CONCLUSION: This OIT protocol was successful as all OIT patients were able to continue 6-month OIT process and the reaction threshold to egg white increased in the OIT group. Therefore, it could be regarded as an effective and safe protocol to treat egg-allergic patients.

Natural History of Allergy to Hen's Egg: A Prospective Study in Children Aged 6 to 12 Years.

INTRODUCTION: There are limited reports on the natural history of hen's egg (HE) allergy (HEA) in children <6 years. We aimed to investigate the natural history of HEA in children aged 6-12 years and the factors affecting its tolerance acquisition. METHODS: Using the database in our hospital, a total of 137 patients diagnosed with a definitive immediate-type reaction to HE when they turned 6 years were enrolled, and the natural course of HEA was prospectively examined until patients turned 12 years. Tolerance was defined as being able to pass an oral food challenge to consume a half or whole heated HE or consume heated HE freely without symptoms. Thirty patients (21.9%) who were enrolled for oral immunotherapy and 21 (15.3%) who discontinued follow-up were considered dropouts. Kaplan-Meier estimation was used to evaluate the rate of tolerance. RESULTS: Fifty-five of the 137 patients (40.1%) had a previous HE anaphylaxis history; 61 (44.5%) patients had acquired tolerance to HE by age 12 years; and 25 (18.2%) continued total or partial HE elimination. The estimated acquired tolerance rates by ages 7, 9, and 12 years were 14.6%, 40.8%, and 60.5%, respectively. A previous history of HE anaphylaxis before 6 years of age, reacting to small amounts of heated HE by 6 years of age, and higher ovomucoid-specific immunoglobulin E values at the same age were associated with persistent HEA. CONCLUSION: This study provides important insights into the natural course of HEA beyond early childhood, with the acquisition of HE tolerance continuing throughout the duration of the study.

Threshold of Reactivity and Tolerance to Precautionary Allergen-Labelled Biscuits of Baked Milk- and Egg-Allergic Children.

Extremely sensitive food-allergic patients may react to very small amounts of allergenic foods. Precautionary allergen labelling (PAL) warns from possible allergenic contaminations. We evaluated by oral food challenge the reactivity to a brand of PAL-labelled milk- and egg-free biscuits of children with severe milk and egg allergy. We explored the ability of proteomic methods to identify minute amounts of milk/egg allergens in such biscuits. Traces of milk and/or egg allergens in biscuits were measured by two different liquid-chromatography-mass spectrometry methods. The binding of patient's serum with egg/milk proteins was assessed using immunoblotting. None of the patients reacted to biscuits. Egg and milk proteins were undetectable with a limit of detection of 0.6 µg/g for milk and egg (method A), and of 0.1 and 0.3 µg /g for milk and egg, respectively (method B). The immunoblots did not show milk/egg proteins in the studied biscuits. Milk/egg content of the biscuits is far lower than 4 µg of milk or egg protein per gram of product, the minimal doses considered theoretically capable of causing reactions. With high sensitivity, proteomic assessments predict the harmlessness of very small amount of allergens in foods, and can be used to help avoiding unnecessary PAL.

Oral desensitization in egg acute food protein-induced enterocolitis syndrome.

OBJECTIVE: Strict avoidance of trigger food is the primary management of food protein-induced enterocolitis syndrome (FPIES). No published data are available on active induction of tolerance with oral desensitization (OD) in FPIES. CASE REPORT: We carried out an OD in a 9 and a half years old boy with persistent acute egg FPIES. OD was performed with increasing doses of raw egg every week, starting with an initial dose of 0.2 ml. The boy presented mild and transient gastrointestinal adverse reactions when the 4 ml dose was reached. He could tolerate a whole raw egg in less than 14 months. CONCLUSIONS: Even though randomized controlled clinical trials on patients including various phenotypes of FPIES are needed, our experience is encouraging about the possible efficacy and safety of OD in this food allergy.

Hyper-Inflammatory Monocyte Activation Following Endotoxin Exposure in Food Allergic Infants.

Several recent studies have reported a key role for innate cell hyper-responsiveness in food allergy. This has predominantly been observed in early life, with evidence that innate immune function may return to baseline if food allergy resolves in later childhood. Hallmarks of hyper-responsiveness include increased circulating frequency of monocytes and altered innate cell cytokine responses to in vitro exposure with bacterial endotoxin. These features mirror the defining signatures of trained innate immunity, seen in other complex diseases. In this study, detailed immune cell and cytokine profiling was performed on peripheral blood mononuclear cells at baseline from 27 1 year old infants in the HealthNuts cohort (n = 16 egg allergic and n = 11 non-allergic healthy controls) and following monocyte stimulation. We show that egg allergic infants have increased frequency of circulating monocytes, reduced numbers of regulatory CD4 T cells and increased monocyte: CD4 T cell ratios relative to healthy controls. Monocytes from both egg allergic and non-allergic infants responded to endotoxin stimulation with rapid cytokine production and downregulation of the surface receptor CD16, however monocytes from egg allergic infants were hyper-responsive, producing significantly more inflammatory cytokines (TNFα, IL-6, IL-1ß, IL-8) and innate cell recruiting factors (MIP-1α) than healthy controls. This work indicates that monocytes of food allergic infants are programmed to a hyper-inflammatory phenotype and that the development of food allergy may be associated with trained immunity in early life.

Adjuvant-free immunization with infective filarial larvae as lymphatic homing antigen carriers.

Controlled infection with intestinal nematodes has therapeutic potential for preventing the symptoms of allergic and autoimmune diseases. Here, we engineered larvae of the filarial nematode Litomosoides sigmodontis as a vaccine strategy to induce adaptive immunity against a foreign, crosslinked protein, chicken egg ovalbumin (OVA), in the absence of an external adjuvant. The acylation of filarial proteins with fluorescent probes or biotin was not immediately detrimental to larval movement and survival, which died 3 to 5 days later. At least some of the labeled and skin-inoculated filariae migrated through lymphatic vessels to draining lymph nodes. The immunization potential of OVA-biotin-filariae was compared to that of an OVA-bound nanoparticulate carrier co-delivered with a CpG adjuvant in a typical vaccination scheme. Production of IFNγ and TNFα by restimulated CD4+ cells but not CD8+ confirmed the specific ability of filariae to stimulate CD4+ T cells. This alternative method of immunization exploits the intrinsic adjuvancy of the attenuated nematode carrier and has the potential to shift the vaccination immune response towards cellular immunity.

Anaphylaxis to Beluga caviar.

Fish roe is an extremely rare cause of anaphylaxis and although its consumption has increased in recent years. We described the case of a 59-year-old man, who experienced an anaphylactic reaction after consuming caviar. Skin prick-test were performed with Beluga caviar, salmon caviar, cod, salmon, hen egg yolk and egg white, ovalbumin, ovomucoid, shrimp and mold. Only SPT to Beluga caviar was positive. The absence of sensitization to fish and hen egg was confirmed by undetectable specific IgEs to cod, parvalbumin (Gad c 1 and Cyp c 1), egg yolk and egg white, ovalbumin and ovomucoid. An immunoblot was also performed and showed an IgE-reactive band indicated that the patient was sensitized to a 26 kDa protein in Beluga caviar. In the present case, immunoblotting of the patient's serum revealed a single IgE-reactive band at 26 kDa band, which does not appear to correspond to the previous cases.

Molecular interaction of sulfonamides and ovalbumin, an allergenic egg protein, exploring biophysical, theoretical and biological studies.

Biophysical, theoretical and biological in vitro studies were carried out to evaluate the interaction of the main allergen protein of egg white (ovalbumin, OVA) with sulphonamides (SA): sulphathiazole (S1), sulfaquinoxaline (S2), sulfadimethoxine (S3) and sulfamethazine (S4). The binding constants for the OVA-SA supramolecular complexes ranged from 1.20 to 30.66 × 105 M-1, observing the following order of affinity: S1 > S2 > S4 > S3. The preferential forces in the stabilization of the OVA complexes with S2 and S3 were hydrogen bonds and Van der Waals forces, whereas for OVA-S1 and OVAS4, were electrostatic interactions. Interaction process led to a change in the native structure of the protein, which may potentiate its natural allergenicity. Cations Ca(II), Mg(II) and Fe(III) favor the interaction of OVA with S1 and S2. The theoretical studies performed were consistent with the spectroscopic data. Finally, it was found that the interaction process for sulfonamides evaluated with OVA change the inhibition activity profile these antibiotics against strains of Escherichia coli ATCC 25922 and Bacillus megaterium APFSG3isox, but not the minimal inhibitory concentration values.

Comparison of Glycated Ovalbumin-Monosaccharides in the Attenuation of Ovalbumin-Induced Allergic Response in a BALB/C Mouse Model.

The aim of the present study was to compare various glycated ovalbumin (OVA)-monosaccharides, including OVA-mannose (Man), -glucose, -ribose, and -fructose, in the attenuation of OVA-induced allergic response in a BALB/C mouse model and the potential mechanisms of immunological modulation. The glycated OVA forms were prepared by Maillard reactions. OVA-Man significantly reduced the frequency of allergic signs. Mouse mast cell protease enzyme concentration was significantly reduced in the OVA-Man group (549.80 ± 84.67 ng/mL, p < 0.05). The OVA-Man group also had a lower histamine concentration (30.96 ± 1.12 ng/mL) as compared with the positive control OVA group (44.43 ± 0.71 ng/mL, p < 0.05). Both specific IgG and IgE were significantly reduced in the OVA-Man-treated group (p < 0.05). The OVA-Man group exhibited decreased concentrations of IL-4 (67.98 ± 3.11 pg/mL) and IL-17 (67.98 ± 3.11 pg/mL) and an increased concentration of IL-12 (336.70 ± 18.69 pg/mL, p < 0.05) compared with the positive control. Mannosylation played a vital role in allergen recognition, implicating deleterious downstream Th2 cell activation, cytokine secretion, and IgE production. This result indicates that different glycans target specific DC receptors, and differential DC processing, antigen presentation, and T cell response leads to altered variation in allergic response. OVA-Man exhibited minimal DC internalization, DC processing, MHC antigen presentation, and antigen-specific T cell activation, resulting in an attenuated allergic response and validating its efficacy as a potential immunotherapeutic candidate to treat egg allergy.

Effect of Covalent Interaction with Chlorogenic Acid on the Allergenic Capacity of Ovalbumin.

Ovalbumin (OVA) is a major allergen in avian egg white. Here, we investigated the conjugation of OVA and chlorogenic acid (CHA) to reduce the allergenic capacity of OVA. OVA-CHA conjugate was characterized by SDS-PAGE, MALDI-TOF-MS, differential scanning calorimetry, and multispectroscopic methods. Sites of the OVA-CHA conjugate were identified by LC-MS/MS. CHA possibly conjugated with Lys20 and Lys17 in OVA, which resulted in the unfolding of OVA. ELISA and Western blot assay indicated that the OVA-CHA conjugate reduced the IgE binding capacity of OVA. The results also indicated that the ability of the OVA-CHA conjugate to activate histamine release was reduced. The decreased allergenic capacity of OVA was attributed to changes in the protein structure. Moreover, the CHA binding site in OVA might directly shield the linear IgE epitope, thereby reducing the IgE binding ability. Also, the OVA-CHA conjugate showed high antioxidant activity. OVA conjugated with CHA may be a promising method of OVA hyposensitization.

Egg Yolk Provides Th2 Adjuvant Stimuli and Promotes Sensitization to Egg White Allergens in BALB/c Mice.

SCOPE: Egg is the second most frequent source of allergic reactions in children. Egg yolk (EY) amounts to one-third in weight of a fresh whole egg, but its contribution to egg allergy has not been investigated in depth. This study assesses whether EY influences the capacity of egg white (EW) to sensitize and trigger allergic responses. METHODS AND RESULTS: BALB/c mice were exposed to EW, EY, and their mixture, using models of orally (with and without adjuvant) and adjuvant-free intraperitoneally induced allergy. In vitro assays were also conducted to examine epithelial and dendritic cell (DC) functions. Results showed that EY played a role during the sensitizing phase of allergy. EY exerted local Th2-biasing effects through the upregulation of intestinal IL-33 expression and it also favored Th2 polarization directly during DC presentation of allergens to T cells. CONCLUSION: The results obtained reveal that EY provides Th2-adjuvant stimuli to the immune system that may increase the susceptibility to develop egg allergy. The joint administration of EW and EY may be a trigger for initiation or maintenance of egg allergy with implications in prevention strategies regarding egg introduction in the diet of susceptible children.

Food allergy to previously tolerated foods: Course and patient characteristics.

BACKGROUND: The acquisition of food allergy (FA) to previously safely consumed basic food proteins is an unusual presentation of immunoglobulin E (IgE)-mediated allergic disease. OBJECTIVE: We sought to characterize patients who developed FA to previously tolerated foods (FA-PTF), including underlying reasons for and length of elimination diet of previously tolerated foods. METHODS: Patients (n = 30) with complaints consistent with FA to foods previously consumed safely were evaluated. Clinical history was obtained, and skin prick testing and graded oral food challenges (OFC) were performed. One fatal case of FA-PTF was reported by a physician. RESULTS: Twenty-two of 30 patients (ages 1.2-50 years) were diagnosed with FA-PTF by OFC to milk (n = 17), egg (n = 2), and peanuts (n = 3). One additional patient with FA-PTF had a fatal reaction to milk. Anaphylactic reactions were reported in 12 of these 23 FA-PT patients (52%); 8 experienced multiple episodes. Atopic dermatitis was diagnosed in 52% (12/23) of patients, 8 of 12 as severe; overall, 18 of 23 (78%) of patients had marked personal atopic background. Sixteen patients (70%) initiated an elimination diet, 12 of whom did so on advice from a health care provider, before the appearance of allergic symptoms. However, in 4 patients with FA-PTF, reactivity to the food protein emerged during uninterrupted consumption. CONCLUSION: Food allergy to previously tolerated foods primarily appears after an elimination diet in atopic patients. Anaphylactic reactions are common. Health care providers should consider these risks before recommending elimination diet of tolerated foods.

Search for a Novel Allergen in Hen's Egg Allergy Using an IgE Immunoblotting Assay.

BACKGROUND: Food allergy is a serious health issue affecting roughly 4% of children, with a substantial effect on quality of life. Chicken egg allergy is frequently observed in infants. Therefore, some of them have to exclude hen's eggs from their daily diet to avoid allergenic symptoms. Hen's egg is composed of 2 soluble parts; one is egg white, which has been characterized as the major source of allergenicity, while the other is egg yolk, which is estimated as a miner source. Only 2 allergens from egg yolk, α-livetin (Gal d 5) and YGP42 (Gal d 6), have been described to date. METHODS: Sera from 53 patients allergic to hen's eggs and 2 patients allergic to sesame were obtained from the Department of Pediatrics, Chiba University Hospital. The study was performed using SDS-PAGE, IgE immunoblotting, and dot blotting. RESULTS: Seven bands of egg yolk were detected by IgE immunoblotting. Out of these bands, a possible new allergen was further characterized by LC-MS/MS. The 33-kDa band was identified as yolk glycoprotein (YGP40) by LC-MS/MS. A total of 21 of the 53 patients (47%) had YGP40 detected by dot blotting. CONCLUSIONS: We identified YGP40 as a new hen's egg yolk allergen and detected 4 sites of YGP40 as linear epitopes.

Early-life gut microbiome and egg allergy.

BACKGROUND: Gut microbiota may play a role in egg allergy. We sought to examine the association between early-life gut microbiota and egg allergy. METHODS: We studied 141 children with egg allergy and controls from the multicenter Consortium of Food Allergy Research study. At enrollment (age 3 to 16 months), fecal samples were collected, and clinical evaluation, egg-specific IgE measurement, and egg skin prick test were performed. Gut microbiome was profiled by 16S rRNA sequencing. Analyses for the primary outcome of egg allergy at enrollment, and the secondary outcomes of egg sensitization at enrollment and resolution of egg allergy by age 8 years, were performed using Quantitative Insights into Microbial Ecology, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States, and Statistical Analysis of Metagenomic Profiles. RESULTS: Compared to controls, increased alpha diversity and distinct taxa (PERMANOVA P = 5.0 × 10-4 ) characterized the early-life gut microbiome of children with egg allergy. Genera from the Lachnospiraceae, Streptococcaceae, and Leuconostocaceae families were differentially abundant in children with egg allergy. Predicted metagenome functional analyses showed differential purine metabolism by the gut microbiota of egg-allergic subjects (Kruskal-Wallis Padj  = 0.021). Greater gut microbiome diversity and genera from Lachnospiraceae and Ruminococcaceae were associated with egg sensitization (PERMANOVA P = 5.0 × 10-4 ). Among those with egg allergy, there was no association between early-life gut microbiota and egg allergy resolution by age 8 years. CONCLUSION: The distinct early-life gut microbiota in egg-allergic and egg-sensitized children identified by our study may point to targets for preventive or therapeutic intervention.

Timing of food introduction and development of food sensitization in a prospective birth cohort.

BACKGROUND: The effect of infant feeding practices on the development of food allergy remains controversial. We examined the relationship between timing and patterns of food introduction and sensitization to foods at age 1 year in the Canadian Healthy Infant Longitudinal Development (CHILD) birth cohort study. METHODS: Nutrition questionnaire data prospectively collected at age 3, 6, 12, 18, and 24 months were used to determine timing of introduction of cow's milk products, egg, and peanut. At age 1 year, infants underwent skin prick testing to cow's milk, egg white, and peanut. Logistic regression models were fitted to assess the impact of timing of food exposures on sensitization outcomes, and latent class analysis was used to study patterns of food introduction within the cohort. RESULTS: Among 2124 children with sufficient data, delaying introduction of cow's milk products, egg, and peanut beyond the first year of life significantly increased the odds of sensitization to that food (cow's milk adjOR 3.69, 95% CI 1.37-9.08; egg adjOR 1.89, 95% CI 1.25-2.80; peanut adjOR 1.76, 95% CI 1.07-3.01). Latent class analysis produced a three-class model: early, usual, and delayed introduction. A pattern of delayed introduction, characterized by avoidance of egg and peanut during the first year of life, increased the odds of sensitization to any of the three tested foods (adjOR 1.78, 95% CI 1.26-2.49). CONCLUSIONS: Avoidance of potentially allergenic foods during the first year of life significantly increased the odds of sensitization to the corresponding foods.

A very unusual case of food allergy, between FPIES and IgE-mediated food allergy.

Food protein induced enterocolitis syndrome (FPIES) is a food-related gastrointestinal hypersensitivity disorder, probably non-IgE-mediated. Over the years, various diagnostic criteria have been proposed to identify FPIES. In the last few years, there was an increased interest from researchers about FPIES's syndrome, that frequently brought to discover new aspects of this disease. We describe an unusual case of FPIES to egg in a 21-months-old child, because of its clinical characteristics that reflect some aspects of IgE-mediated allergy and other of non IgE-mediated allergy. Although we believe that the most correct diagnosis for our case is FPIES, we think also that this is undoubtedly an atypical form. This is in fact, the first description of a patient who simultaneously has both clinical expressions of IgE-mediated FA that of FPIES. Our case highlights the need to review criteria for FPIES diagnosis.