Food allergies and hypersensitivity: a review of pharmacotherapy and therapeutic strategies

Transcriptional changes in peanut-specific CD4+ T cells over the course of oral immunotherapy

Oral immunotherapy (OIT) can successfully desensitize allergic individuals to offending foods such as peanut. Our recent clinical trial (NCT02103270) of peanut OIT allowed us to monitor peanut-specific CD4+ T cells, using MHC-peptide Dextramers, over the course of OIT. We used a single-cell targeted RNAseq assay to analyze these cells at 0, 12, 24, 52, and 104 weeks of OIT. We found a transient increase in TGFβ-producing cells at 52 weeks in those with successful desensitization, which lasted until 117 weeks. We also performed clustering and identified 5 major clusters of Dextramer+ cells, which we tracked over time. One of these clusters appeared to be anergic, while another was consistent with recently described TFH13 cells. The other 3 clusters appeared to be Th2 cells by their coordinated production of IL-4 and IL-13, but they varied in their expression of STAT signaling proteins and other markers. A cluster with high expression of STAT family members also showed a possible transient increase at week 24 in those with successful desensitization. Single cell TCRαβ repertoire sequences were too diverse to track clones over time. Together with increased TGFβ production, these changes may be mechanistic predictors of successful OIT that should be further investigated.

Specific oral tolerance induction in paediatric patients with persistent egg allergy

INTRODUCTION

Desensitisation or specific oral tolerance induction (SOTI) to food is a new topical-therapeutic approach of food allergy for those children who have not achieved tolerance spontaneously. The objective of this study is to induce clinical tolerance in children with persistent allergy using an oral desensitisation protocol with powdered pasteurised egg.

METHODS

Seventy-two patients with egg allergy confirmed by open oral challenge test were randomly assigned to SOTI or elimination diet as a control group. Forty children (5-15 years) underwent a SOTI beginning with 1mg and increasing the dosage weekly until a dose of 10g, equivalent to an egg. The control group included 32 patients (4-15 years).

RESULTS

The procedure's average duration was 10 weeks (range 4-28 weeks). Three patients were withdrawn from the protocol for persistent gastrointestinal symptoms. During SOTI, 21 children (52.5%) presented symptoms. In eight the symptoms were mild and required no treatment. In the other 13 (61.90%), the reactions were more severe. Seventeen children finished the treatment over a year ago and 20 in the past 6-12 months. Thirty-seven patients (92.5%) in the active group achieved tolerance to egg, versus 21.8% in the control group. We only found statistically significant differences (p<0.05) for skin prick tests with powdered egg at various dilutions and IgG levels with egg white after SOTI. Specific IgE concentration did not change significantly.

CONCLUSIONS

Our SOTI protocol is a safe, effective treatment for food allergy and of reasonable duration, confirming that tolerance can be induced in children who have not achieved it spontaneously.

Alternative and complementary treatment for food allergy

Despite increased consumer interest in complementary and alternative medicine (CAM) for the treatment of food allergy, there remains a relative paucity of knowledge regarding the clinical efficacy, mechanisms of action, and safety of most CAM treatments available to consumers. This article focuses on recent advances in CAM for food allergy, including acupuncture, herbal medicine, probiotics, and alternative approaches to allergen immunotherapy. The mechanism of action of several novel approaches to treatment of food allergy is reviewed, but FAHF-2 is the only investigational herbal formulation currently validated for use in human clinical trials.

Nutriproteomics: technologies and applications for identification and quantification of biomarkers and ingredients

Nutrition refers to the process by which a living organism ingests and digests food and uses the nutrients therein for growth, tissue maintenance and all other functions essential to life. Food components interact with our body at molecular, cellular, organ and system level. Nutrients come in complex mixtures, in which the presence and concentration of single compounds as well as their interactions with other compounds and the food matrix influence their bioavailability and bioefficacy. Traditionally, nutrition research mainly concentrated on supplying nutrients of quality to nourish populations and on preventing specific nutrient deficiencies. More recently, it investigates health-related aspects of individual ingredients or of complete diets, in view of health promotion, performance optimisation, disease prevention and risk assessment. This review focuses on proteins and peptides, their role as nutrients and biomarkers and on the technologies developed for their analysis. In the first part of this review, we provide insights into the way proteins are currently characterised and analysed using classical and emerging proteomic approaches. The scope of the second part is to review major applications of proteomics to nutrition, from characterisation of food proteins and peptides, via investigation of health-related food benefits to understanding disease-related mechanisms.

Multiple T cell epitope peptides suppress allergic responses in an egg allergy mouse model by the elicitation of forkhead box transcription factor 3- and transforming growth factor-beta-associated mechanisms

BACKGROUND

Peptide-based immunotherapy (PIT) represents an attractive approach for targeted interventions in immunological disorders, but has not been widely explored in the context of food allergy.

OBJECTIVE

In this study, we built on the information obtained from the recent identification of three immunodominant T cell epitopes of hen ovalbumin (OVA), a major egg allergen, to assess the therapeutic potential of PIT for food allergy, using the BALB/c mouse model.

METHODS

Groups of mice were sensitized to OVA by repeated oral gavages, and subsequently administered with single or multiple synthetic peptides containing OVA T cell epitopes. Following the peptide administration period, all mice were orally challenged with high doses of OVA to elicit active anaphylaxis. Serum, spleen, and intestinal tissues were collected for the determination of immunoglobulin levels, cytokine secretions, and intestinal gene expression.

RESULTS

Significantly lower anaphylactic scores were exhibited by mice that received multiple epitope-containing peptides, accompanied by lower serum histamine and OVA-specific IgE levels, compared with placebo-treated mice. Mechanistically, the quantification of cytokine secretions in splenocyte cultures revealed a T helper type 1-biased response (IFN-gamma) in all peptide-treated mice to the detriment of a T helper type 2-response (IL-4). Interestingly, a similar cytokine expression profile was determined in intestinal tissues, accompanied by a pronounced mRNA expression of regulatory molecules TGF-beta and forkhead box transcription factor 3 (FOXP3). These data suggest the activation of local repressive mechanisms mediated by subsets of regulatory T cells.

CONCLUSION

We demonstrated the therapeutic potential of PIT in a mouse model of food allergy model and provided evidence that mechanistic pathways entailing regulatory molecules TGF-beta and FOXP3, stand as promising trails for the further understanding of peptide-based strategies for food allergy.