Transcription activator-like effector nuclease-mediated deletion safely eliminates the major egg allergen ovomucoid in chickens.

Among the major egg allergens, ovomucoid (OVM) is very stable against heat and digestive enzymes, making it difficult to remove physiochemically and inactivate allergens. However, recent genome editing technology has made it possible to generate OVM-knockout chicken eggs. To use this OVM-knockout chicken egg as food, it is important to evaluate its safety as food. Therefore, in this study, we examined the presence or absence of mutant protein expression, vector sequence insertion, and off-target effects in chickens knocked out with OVM by platinum TALENs. The eggs laid by homozygous OVM-knockout hens showed no evident abnormalities, and immunoblotting showed that the albumen contained neither the mature OVM nor the OVM truncated variant. Whole genome sequencing (WGS) revealed that the potential TALEN-induced off-target effects in OVM-knockout chickens were localized in the intergenic and intron regions. The WGS information confirmed that plasmid vectors used for genome editing were only transiently present and did not integrate into the genome of edited chickens. These results indicate the importance of safety evaluation and reveal that the eggs laid by this OVM knockout chicken solve the allergy problem in food and vaccines.

Effective Model of Food Allergy in Mice Sensitized with Ovalbumin and Freud's Adjuvant.

To better explore the pathophysiology of FA and its therapy, we aimed to establish a simple and practicable FA model with Freund's adjuvant and introduce an easy and reliable laboratory evaluation method for assessment of inflammation in intestinal segments at different anatomical locations. BALB/c mice were sensitized with ovalbumin combined with Freund's adjuvant. Complete Freund's adjuvant was chosen for the first sensitization and two weeks later incomplete Freund's adjuvant was used for a second sensitization. Two weeks later, the sensitized mice were challenged with 50 mg ovalbumin every other day. After the 6 challenge, all mice were assessed for systemic anaphylaxis, and then sacrificed for sample collection. All sensitized mice showed anaphylactic symptoms and markedly increased levels of serum ovalbumin-specific IgE and IgG1. The activity of mast cell protease-1 (mMCPT-1) was significantly increased in the serum and interstitial fluid of the duodenum, jejunum, ileum, and colon. A successful FA model was established, of which inflammation occurred in the duodenum, jejunum, ileum, and colon. This model provides a reliable and simple tool for analysis of the mechanism of FA and methods of immunotherapy. Moreover, combined detection of ovalbumin-specific antibody and local mMCPT-1 levels could potentially be used as the major indicator for assessment of food allergy.

Integrative Transcriptomics Reveals Activation of Innate Immune Responses and Inhibition of Inflammation During Oral Immunotherapy for Egg Allergy in Children.

We previously reported the results of a randomized, open-label trial of egg oral immunotherapy (OIT) in 50 children where 44% were desensitized and 46% were partially desensitized after 8 months of treatment. Here we focus on cell-mediated molecular mechanisms driving desensitization during egg OIT. We sought to determine whether changes in genome-wide gene expression in blood cells during egg OIT correlate with humoral responses and the clinical outcome. The blood cell transcriptome of 50 children receiving egg OIT was profiled using peripheral blood mononuclear cell (PBMC) samples obtained at baseline and after 3 and 8 months of OIT. We identified 467 differentially expressed genes (DEGs) after 3 or 8 months of egg OIT. At 8 months, 86% of the DEGs were downregulated and played a role in the signaling of TREM1, IL-6, and IL-17. In correlation analyses, Gal d 1-4-specific IgG4 antibodies associated positively with DEGs playing a role in pathogen recognition and antigen presentation and negatively with DEGs playing a role in the signaling of IL-10, IL-6, and IL-17. Desensitized and partially desensitized patients had differences in their antibody responses, and although most of the transcriptomic changes were shared, both groups had also specific patterns, which suggest slower changes in partially desensitized and activation of NK cells in the desensitized group. OIT for egg allergy in children inhibits inflammation and activates innate immune responses regardless of the clinical outcome at 8 months. Changes in gene expression patterns first appear as posttranslational protein modifications, followed by more sustained epigenetic gene regulatory functions related to successful desensitization.

A Mouse Model of Oral Sensitization to Hen's Egg White.

Egg allergy is one of the most common food allergies in children, being the most important allergenic proteins found in the egg white (EW). Allergy to EW shows a complex phenotype that involves a multifaceted reaction that can only be assessed in vivo. Although other routes of sensitization have been described, oral exposure to food antigens is one of the most suitable in humans. In mice, oral administration of allergenic proteins results in the development of tolerance, and the use of adjuvants, such as cholera toxin (CT), is required to promote Th2-biased immune responses over tolerogenic responses. In this regard, among the mouse strains that readily display Th2 responses, Balb/c has been widely used. Here, we describe a frequently used protocol of oral EW sensitization by using CT as an adjuvant and we explain in detail the methods that we have developed to analyze the sensitizing and eliciting capacity of EW proteins including evaluation of signs, measurement of serum levels of specific immunoglobulins, mast cell degranulation, cytokine secretion profile of allergen-reactive T cells, phenotyping of mesenteric lymph node- and spleen-derived dendritic and T cells by flow cytometry, and quantification of intestinal gene expression.

Component-Resolved Diagnostic Study of Egg Allergy in Northern Chinese Children.

BACKGROUND: Egg component-specific IgE can be useful to evaluate and diagnose egg allergy, but their prevalence and clinical significance remain unclear in the local population. Previous studies have led to contradictory results regarding the value of specific IgG and specific IgG4 in sensitization. OBJECTIVE: We aimed to determine the level of specific IgE, IgG, and IgG4 antibodies to the major egg allergens in egg-allergic children. METHODS: Children from 6 months to 10 years of age were recruited. Egg allergy was confirmed by either a strong clinical history or an increased egg white-sIgE level. Other allergies were diagnosed by reactivity to other allergens but without egg-related symptoms and history. The serum sIgE, sIgG, and sIgG4 levels to major egg allergenic components (Gal d 1, Gal d 2, Gal d 3, Gal d 4, and Gal d 5), sIgE level to egg white, and tIgE level were determined by light-initiated chemiluminescent assay (LICA), ELISA, or ImmunoCAP. RESULTS: Egg-allergic children had significantly higher levels of sIgE, sIgG, and sIgG4 to egg components than nonallergic children. Gal d 2 was the predominant allergen, and Gal d 2 sIgE level correlated with the egg white-sIgE level. Ratios of sIgE/sIgG4 to egg components were highest before 1 year of age and dropped gradually in the first decade of life. CONCLUSION: Patterns of sIgE to egg components could distinguish different forms of egg allergy. Ratios of sIgE/sIgG4 could be useful in predicting tolerance in egg-sensitive subjects, but this needs further evaluation and investigation using more accurate models.

CRISPR/Cas9 gene editing in a chicken model: current approaches and applications.

Improvements in genome editing technology in birds using primordial germ cells (PGCs) have made the development of innovative era genome-edited avian models possible, including specific chicken bioreactors, production of knock-in/out chickens, low-allergenicity eggs, and disease-resistance models. New strategies, including CRISPR/Cas9, have made gene editing easy and highly efficient in comparison to the well-known process of homologous recombination. The clustered regularly interspaced short palindromic repeats (CRISPR) technique enables us to understand the function of genes and/or to modify the animal phenotype to fit a specific scientific or production target. To facilitate chicken genome engineering applications, we present a concise description of the method and current application of the CRISPR/Cas9 system in chickens. Different strategies for delivering sgRNAs and the Cas9 protein, we also present extensively. Furthermore, we describe a new gesicle technology as a way to deliver Cas9/sgRNA complexes into target cells, and we discuss the advantages and describe basal applications of the CRISPR/Cas9 system in a chicken model.

Potential benefits of gene editing for the future of poultry farming.

The chicken is an exemplar of efficient intensive animal agriculture and provides two valuable food products, chicken meat and eggs. Only aquaculture is better, by efficiency, but poultry is still top, by mass of animal protein produced as food in the global context. However this efficiency and intensive production comes with a number of challenges. Though the genetics of selective breeding have led to dramatic improvements in yield, efficiency and product quality, traits that relate to disease and welfare outcomes have not been so tractable. These two issues are major impacts to the industry in terms of production and in terms of public perception. Both transgenic technology and genome editing have clear potential for impact in these two important areas. The reproductive biology of birds requires techniques very specific to birds to achieve heritable (germline) edited traits. These are quite involved and, even though they are now well-defined and reliable, there is room for improvement and advances can be expected in the future. Currently the key targets for this technology are modifying chicken genes involved in virus-receptor interactions and cellular response involved in infection. For the egg industry the technology is being applied to the issue of sex-selection for layer hens (and the removal of males), removal of allergens from egg white and the tailoring of eggs system to enhance the yield of influenza vaccine doses. Regulation and trading of the animals generated, and resulting food products, will significantly impact the value and future development of genome editing for poultry.

Trajectories of class-switching-related egg and cow's milk allergen-specific immunoglobulin isotype formation and its modification by eczema with low- and high-affinity immunoglobulin E during early infancy.

INTRODUCTION: Allergen-specific immunoglobulin isotype formation associated with immunoglobulin class-switching during the lactation period is the immunological background for food allergy in infants. We analyzed the serial changes in the production of feeding type-related egg- and milk-specific immunoglobulin isotypes from birth to 6 months of age with or without eczema in 84 infants. METHODS: Allergen-specific immunoglobulin G1 (IgG1), IgG2, IgG3, IgG4, IgA, and IgE levels of hen's egg and bovine milk were measured in cord blood and blood samples from infants at 2, 4, and 6 months of age by the densely carboxylated protein microarray. RESULTS: Formula and mixed feeding were associated with a rapid increase in cow's milk allergen-specific immunoglobulins and feeding type-related significant differences in casein-specific immunoglobulin levels were detected. Breast and mixed feeding were associated with slow but significant increase in ovalbumin-specific IgG1 and IgE levels, but not other immunoglobulins. We found two different immunoglobulin isotype formation at 6 months of age with low- or high-affinity IgE against ovalbumin. One isotype formation pattern had relatively high ovalbumin-specific IgG1 levels, detectable IgG2, and low-affinity IgE, while the other had low ovalbumin-specific IgG1 levels, undetectable IgG2, and high levels of high-affinity IgE. The incidence of eczema was significantly higher in the latter pattern (84.6%), compared with the remaining infants (42.2%). CONCLUSIONS: Feeding practice-related allergen sensitization and immunoglobulin isotype formation were identified during the lactation period. The development of eczema during the lactation period could potentially modify the immunoglobulin isotype formation with high levels of high-affinity IgE.

Palmar hyperlinearity in early childhood atopic dermatitis is associated with filaggrin mutation and sensitization to egg.

BACKGROUND/OBJECTIVES: Palmar hyperlinearity is a typical clinical feature of Filaggrin gene (FLG) null mutations. There are reports of FLG mutations and allergic sensitization; however, reports on the relationship between palmar hyperlinearity to sensitization are limited. This study aimed to examine the association between palmar hyperlinearity and sensitization in atopic dermatitis (AD) children. METHODS: This cross-sectional, case-control study included children ˂ 6 years old with moderate-severe AD whose parents consented for mutation analysis and photographic documentation. Each child underwent genotyping to detect the eight most prevalent FLG mutations in the Japanese population: R501X, 3321delA, S1695X, Q1701X, S2554X, S2889X, S3296X, and K4022X. Clinical features and parameters including egg-specific IgE were examined, and palm photographs were evaluated by 12 trained dermatologists blinded to genotyping results. RESULTS: Of the 57 patients (age range, 2 months to 5 years; median, 22 months), 16 were heterozygotes and three were compound heterozygotes. Palmar hyperlinearity, as recognized by more than two-thirds of dermatologists, was significantly associated with FLG mutation (P = 0.002, OR = 6.98, 95% CI = 2.1-23.7), and this association was observed especially in children over 2 years. Cross-shaped crease of the thenar eminence, as known in previous reports, also demonstrated significant correlation with FLG mutation. When the children were divided according to the presence or absence of palmar hyperlinearity, the egg white-specific IgE was significantly higher in the hyperlinearity group (55.9 vs 18.3 IU/mL, P < 0.05). CONCLUSIONS: Palmar hyperlinearity indicates possible inherited barrier abnormalities of the skin in early childhood. Its identification may help to predict a more accurate prognosis, such as sensitization.

Allergen-specific IgG antibody signaling through FcγRIIb promotes food tolerance.

BACKGROUND: Patients with food allergy produce high-titer IgE antibodies that bind to mast cells through FcεRI and trigger immediate hypersensitivity reactions on antigen encounter. Food-specific IgG antibodies arise in the setting of naturally resolving food allergy and accompany the acquisition of food allergen unresponsiveness in oral immunotherapy. OBJECTIVE: In this study we sought to delineate the effects of IgG and its inhibitory Fc receptor, FcγRIIb, on both de novo allergen sensitization in naive animals and on established immune responses in the setting of pre-existing food allergy. METHODS: Allergen-specific IgG was administered to mice undergoing sensitization and desensitization to the model food allergen ovalbumin. Cellular and molecular mechanisms were interrogated by using mast cell- and FcγRIIb-deficient mice. The requirement for FcγRII in IgG-mediated inhibition of human mast cells was investigated by using a neutralizing antibody. RESULTS: Administration of specific IgG to food allergy-prone IL4raF709 mice during initial food exposure prevented the development of IgE antibodies, TH2 responses, and anaphylactic responses on challenge. When given as an adjunct to oral desensitization in mice with established IgE-mediated hypersensitivity, IgG facilitated tolerance restoration, favoring expansion of forkhead box protein 3-positive regulatory T cells along with suppression of existing TH2 and IgE responses. IgG and FcγRIIb suppress adaptive allergic responses through effects on mast cell function. CONCLUSION: These findings suggest that allergen-specific IgG antibodies can act to induce and sustain immunologic tolerance to foods.

Encapsulating an Immunosuppressant Enhances Tolerance Induction by Siglec-Engaging Tolerogenic Liposomes.

Unwanted antibody responses significantly impact human health, and current options for treating deleterious antibody responses largely rely on broad immunosuppressants that can compromise overall immunity. A desirable alternative is to induce antigen-specific immune tolerance. We have shown that co-presentation of antigen and ligands of B cell sialic acid-binding immunoglobulin-like lectins (Siglecs) on a liposomal nanoparticle induces antigen-specific tolerance. Although Siglec-engaging tolerance-inducing antigenic liposomes (STALs) induce robust B cell tolerance in naïve mice, the full potential of STALs requires long-term tolerance induction and suppression of an ongoing immune response. We hypothesized that STALs encapsulated with rapamycin (RAPA), an immunomodulator, could improve the efficacy of STALs and potentially enable their use in the context of immunological memory. Here, we showed that formulation of STALs with RAPA produced enhanced tolerance induction in naïve mice compared to STALs without RAPA but had minimal impact on inducing tolerance in previously sensitized mice. These findings indicate that the addition of immunomodulators to STALs could be beneficial in tolerance induction and support future development of STALs for the treatment of allergy and autoimmune diseases.

Transcriptional Profiling of Egg Allergy and Relationship to Disease Phenotype.

BACKGROUND: Egg allergy is one of the most common food allergies of childhood. There is a lack of information on the immunologic basis of egg allergy beyond the role of IgE. OBJECTIVE: To use transcriptional profiling as a novel approach to uncover immunologic processes associated with different phenotypes of egg allergy. METHODS: Peripheral blood mononuclear cells (PBMCs) were obtained from egg-allergic children who were defined as reactive (BER) or tolerant (BET) to baked egg, and from food allergic controls (AC) who were egg non-allergic. PBMCs were stimulated with egg white protein. Gene transcription was measured by microarray after 24 h, and cytokine secretion by multiplex assay after 5 days. RESULTS: The transcriptional response of PBMCs to egg protein differed between BER and BET versus AC subjects. Compared to the AC group, the BER group displayed increased expression of genes associated with allergic inflammation as well as corresponding increased secretion of IL-5, IL-9 and TNF-α. A similar pattern was observed for the BET group. Further similarities in gene expression patterns between BER and BET groups, as well as some important differences, were revealed using a novel Immune Annotation resource developed for this project. This approach identified several novel processes not previously associated with egg allergy, including positive associations with TLR4-stimulated myeloid cells and activated NK cells, and negative associations with an induced Treg signature. Further pathway analysis of differentially expressed genes comparing BER to BET subjects showed significant enrichment of IFN-α and IFN-γ response genes, as well as genes associated with virally-infected DCs. CONCLUSIONS: Transcriptional profiling identified several novel pathways and processes that differed when comparing the response to egg allergen in BET, BER, and AC groups. We conclude that this approach is a useful hypothesis-generating mechanism to identify novel immune processes associated with allergy and tolerance to forms of egg.

Associations between Milk and Egg Allergens and the HLA-DRB1/DQ Polymorphism: A Bioinformatics Approach.

BACKGROUND: Little is known about the associations between human leukocyte antigens (HLAs) and food allergies. Our aim was to analyze the associations between the HLA class II polymorphism and food allergy using bioinformatics. METHODS: A two-step algorithm was developed which mimics the food allergen processing in the human body. In the first step, the allergen is digested by pepsin, trypsin and chymotrypsin. In the second step, the digested fragments bind to the most frequent 12 HLA-DRB1 and 5 HLA-DQ alleles, and the binding affinities are predicted. RESULTS: The algorithm was applied to 13 well-known milk and egg allergens. The predicted HLA binders were compared to known T-cell and IgE epitopes originating from the same allergens, and 77% of them were found to overlap. We found that the peptides generated from milk allergens bind to DRB1*01:01, DQ7 and DQ8 but not to DRB1*03:01, DRB1*04:04, DRB1*12:01 and DRB1*15:01. The peptides generated from egg allergens bind to DRB1*01:01, DQ4, DQ7 and DQ8 but not to DRB1*03:01, DRB1*04:04 and DRB1*12:01. They bind to all the DQs studied. The alleles that bind to allergen peptides could be considered as susceptible to the particular allergy and the nonbinding alleles as protective. CONCLUSIONS: The alleles DRB1*01:01, DQ7 and DQ8 are considered as susceptible to cow's milk allergy and DRB1*03:01, DRB1*04:04, DRB1*12:01 and DRB1*15:01 as protective. The alleles DRB1*01:01, DQ4, DQ7 and DQ8 are considered as susceptible to egg allergy and DRB1*03:01, DRB1*04:04 and DRB1*12:01 as protective. Protective DQs against egg allergy were not revealed in this study.

TH9 cells are required for tissue mast cell accumulation during allergic inflammation.

BACKGROUND: IL-9 is important for the growth and survival of mast cells. IL-9 is produced by T cells, natural killer T cells, mast cells, eosinophils, and innate lymphoid cells, although the cells required for mast cell accumulation during allergic inflammation remain undefined. OBJECTIVE: We sought to elucidate the role of TH9 cells in promoting mast cell accumulation in models of allergic lung inflammation. METHODS: Adoptive transfer of ovalbumin-specific TH2 and TH9 cells was used to assess the ability of each subset to mediate mast cell accumulation in tissues. Mast cell accumulation was assessed in wild-type mice and mice with PU.1-deficient T cells subjected to acute and chronic models of allergic inflammation. RESULTS: Adoptive transfer experiments demonstrated that recipients of TH9 cells had significantly higher mast cell accumulation and expression of mast cell proteases compared with control or TH2 recipients. Mast cell accumulation was dependent on IL-9, but not IL-13, a cytokine required for many aspects of allergic inflammation. In models of acute and chronic allergic inflammation, decreased IL-9 levels in mice with PU.1-deficient T cells corresponded to diminished tissue mast cell numbers and expression of mast cell proteases. Mice with PU.1-deficient T cells have defects in IL-9 production from CD4(+) T cells, but not natural killer T cells or innate lymphoid cells, suggesting a TH cell-dependent phenotype. Rag1(-/-) mice subjected to a chronic model of allergic inflammation displayed reduced mast cell infiltration comparable with accumulation in mice with PU.1-deficient T cells, emphasizing the importance of IL-9 produced by T cells in mast cell recruitment. CONCLUSION: TH9 cells are a major source of IL-9 in models of allergic inflammation and play an important role in mast cell accumulation and activation.

MicroRNA-9 regulates steroid-resistant airway hyperresponsiveness by reducing protein phosphatase 2A activity.

BACKGROUND: Steroid-resistant asthma is a major clinical problem that is linked to activation of innate immune cells. Levels of IFN-γ and LPS are often increased in these patients. Cooperative signaling between IFN-γ/LPS induces macrophage-dependent steroid-resistant airway hyperresponsiveness (AHR) in mouse models. MicroRNAs (miRs) are small noncoding RNAs that regulate the function of innate immune cells by controlling mRNA stability and translation. Their role in regulating glucocorticoid responsiveness and AHR remains unexplored. OBJECTIVE: IFN-γ and LPS synergistically increase the expression of miR-9 in macrophages and lung tissue, suggesting a role in the mechanisms of steroid resistance. Here we demonstrate the role of miR-9 in IFN-γ/LPS-induced inhibition of dexamethasone (DEX) signaling in macrophages and in induction of steroid-resistant AHR. METHODS: MiRNA-9 expression was assessed by means of quantitative RT-PCR. Putative miR-9 targets were determined in silico and confirmed in luciferase reporter assays. miR-9 function was inhibited with sequence-specific antagomirs. The efficacy of DEX was assessed by quantifying glucocorticoid receptor (GR) cellular localization, protein phosphatase 2A (PP2A) activity, and AHR. RESULTS: Exposure of pulmonary macrophages to IFN-γ/LPS synergistically induced miR-9 expression; reduced levels of its target transcript, protein phosphatase 2 regulatory subunit B (B56) δ isoform; attenuated PP2A activity; and inhibited DEX-induced GR nuclear translocation. Inhibition of miR-9 increased both PP2A activity and GR nuclear translocation in macrophages and restored steroid sensitivity in multiple models of steroid-resistant AHR. Pharmacologic activation of PP2A restored DEX efficacy and inhibited AHR. MiR-9 expression was increased in sputum of patients with neutrophilic but not those with eosinophilic asthma. CONCLUSION: MiR-9 regulates GR signaling and steroid-resistant AHR. Targeting miR-9 function might be a novel approach for the treatment of steroid-resistant asthma.

Dendritic cell-bound IgE functions to restrain allergic inflammation at mucosal sites.

Antigen-mediated cross-linking of Immunoglobulin E (IgE) bound to mast cells/basophils via FcɛRI, the high affinity IgE Fc-receptor, is a well-known trigger of allergy. In humans, but not mice, dendritic cells (DCs) also express FcɛRI that is constitutively occupied with IgE. In contrast to mast cells/basophils, the consequences of IgE/FcɛRI signals for DC function remain poorly understood. We show that humanized mice that express FcɛRI on DCs carry IgE like non-allergic humans and do not develop spontaneous allergies. Antigen-specific IgE/FcɛRI cross-linking fails to induce maturation or production of inflammatory mediators in human DCs and FcɛRI-humanized DCs. Furthermore, conferring expression of FcɛRI to DCs decreases the severity of food allergy and asthma in disease-relevant models suggesting anti-inflammatory IgE/FcɛRI signals. Consistent with the improved clinical parameters in vivo, antigen-specific IgE/FcɛRI cross-linking on papain or lipopolysaccharide-stimulated DCs inhibits the production of pro-inflammatory cytokines and chemokines. Migration assays confirm that the IgE-dependent decrease in cytokine production results in diminished recruitment of mast cell progenitors; providing a mechanistic explanation for the reduced mast cell-dependent allergic phenotype observed in FcɛRI-humanized mice. Our study demonstrates a novel immune regulatory function of IgE and proposes that DC-intrinsic IgE signals serve as a feedback mechanism to restrain allergic tissue inflammation.

Occupational asthma and eosinophilic esophagitis in a patient with egg-bird syndrome

No disponible

Parental eczema increases the risk of double-blind, placebo-controlled reactions to milk but not to egg, peanut or hazelnut.

BACKGROUND: While genetic factors are known to be important in the development of sensitization to foods, it is not known whether they also play a role in clinical allergic reactivity to foods. OBJECTIVE: We aimed to determine whether parental atopic diseases are associated with a higher risk of a reaction to common allergenic foods when tested in a double-blind, placebo-controlled food challenge (DBPCFC). METHODS: Parents of children suspected of being food allergic were interviewed about their own and their child's atopic history. Specific IgE and skin prick tests to food allergens and the outcome of food challenges in the child were recorded. RESULTS: Data from 553 double-blind food challenges performed in 396 children were analyzed. The foods tested were milk (n = 185), egg (n = 110), peanut (n = 198) and hazelnut (n = 60). Only parental eczema was significantly associated with positive outcomes for food challenges with milk after correction for age, sex, atopic comorbidity in the child and milk-specific IgE test results (odds ratio 3.1, 95% confidence interval 1.5-6.3). CONCLUSIONS: Children with a positive DBPCFC to milk more frequently have parents with eczema than children with a negative test. This effect of parental eczema was not seen in children challenged with egg, peanut or hazelnut. Clinical reactivity to milk may be caused by genetic factors which are shared with parental eczema to a greater extent than clinical reactivity to other foods.

X-chromosome Forkhead Box P3 polymorphisms associate with atopy in girls in three Dutch birth cohorts.

BACKGROUND: The Forkhead Box P3 (FOXP3) gene, located on the X-chromosome, encodes a transcription factor that directs T cells toward a regulatory phenotype. Regulatory T cells may suppress development of atopy. We evaluated whether single-nucleotide polymorphisms (SNPs) of FOXP3 are associated with atopy development in childhood. METHODS: Seven SNPs in FOXP3 were genotyped in 3062 children (51% boys) participating in the Allergenic study, which consists of three Dutch birth cohorts (PIAMA, PREVASC and KOALA). Association of FOXP3 SNPs with total serum IgE and sensitisation (presence of specific serum IgE to egg, milk, and indoor, i.e. house-dust mite, cat, and/or dog allergens) was investigated at ages 1, 2, 4, and 8. Analysis of variance and logistic regression were performed, stratified for gender. RESULTS: Our most consistent finding was observed for sensitisation to egg and indoor allergens. In girls, five FOXP3 SNPs (rs5906761, rs2294021, rs2294019, rs6609857 and rs3761548) were significantly associated with sensitisation to egg at ages 1 and 2 and with sensitisation to indoor allergens at age 2 (P < 0.05), but not at 4 and 8, a finding that was observed across the three cohorts. Rs5906761 and rs2294021 were associated with remission of sensitisation to food allergens in boys, as tested in the PIAMA cohort. CONCLUSION: This is the first study showing across three cohorts that X-chromosomal FOXP3 genotypes may contribute to development of sensitisation against egg and indoor allergens in girls in early childhood. In addition, an association with remission of sensitisation to food allergens existed in boys only.