Epigenetic Features of FoxP3 in Children With Cow's Milk Allergy

Study Overview
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Brief Summary
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Epigenetic mechanisms have been implicated in the pathogenesis of food allergy. The investigators previously demonstrated that tolerance acquisition in children with Immunoglobulin E- (IgE) mediated cow's milk allergy (CMA) is driven by epigenetic modulation of the Th1 and Th2 cytokine genes. A regulatory T cell (Treg) suppressive phenotype, characterized by stable expression of the transcription factor Forkhead box Protein 3 (FoxP3), plays a pivotal role in food tolerance. FoxP3 mRNA expression is lower in children with atopic asthma or IgE-mediated food allergy than in healthy children. FoxP3 stable expression requires full CpG demethylation of its transcriptional regulatory regions, and, moreover, hypermethylation of the FoxP3 gene has been associated with reduced Treg function and allergy. DNA methylation is a biologically and chemically stable epigenetic modification that locks in long-term gene expression patterns. The demethylation status of FoxP3 at a highly conserved region within the Treg-specific-demethylated-region (TSDR), a CpG-rich, located on the 2nd conserved non-coding sequence of FoxP3 (CNS2), is restricted to Tregs. Transcriptional activity of the TSDR is essentially determined by its methylation status : it is completely inactive in its methylated state, but when the TSDR is demethylated, transcription factors such as Ets-1 and Creb can bind to the TSDR. TSDR demethylated and open chromatin conformation in the Foxp3 locus leads to stable phenotype differentiated Foxp3+ Treg. FoxP3 TSDR demethylation in peripheral blood mononuclear cells (PBMCs) has been associated with reduced atopic sensitization and asthma in children. Epigenetic regulation of antigen-induced T-cell subsets may predict a state of immune tolerance in food allergy. Indeed, DNA methylation of the FoxP3 gene in Tregs decreased during oral tolerance acquisition in patients with peanut allergy undergoing oral immunotherapy. The aim of this study was to evaluate further the epigenetic regulation of FoxP3 gene in children with IgE-mediated CMA.

Conditions
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Cow's Milk Allergy

Intervention / Treatment
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* Dietary Supplement: Extensively hydrolyzed casein formula plus LGG


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: IgE-mediated CMA children (aged 3 to 18 months) Exclusion Criteria: allergic disorders or food allergies other than cow's milk allergy eosinophilic disorders of the gastrointestinal tract food protein-induced enterocolitis syndrome concomitant chronic systemic diseases congenital cardiac defects active tuberculosis autoimmune diseases immunodeficiency chronic inflammatory bowel diseases celiac disease cystic fibrosis metabolic diseases lactose intolerance malignancy chronic pulmonary diseases malformations of the gastrointestinal tract

Ages Eligible for Study
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Minimum Age: 3 Months
Maximum Age: 18 Months

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Healthy controls<br>Healthy controls | |
| Children at diagnosis of cow's milk allergy<br>Children at diagnosis of cow's milk allergy | |
| Subjects outgrown cow's milk allergy with formula+probiotic<br>Tolerant with extensively hydrolyzed casein formula with Lactobacillus rhamnosus GG | Dietary Supplement: Extensively hydrolyzed casein formula plus LGG<br> <br> |
| Subjects outgrown cow's milk allergy assuming other formulas<br>Subjects tolerant with other formulas | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| DNA demethylation (rate, in %) of the Treg-specific-demethylated-region (TSDR) of FoxP3 |  | At enrollment |