Food allergies: Novel mechanisms and therapeutic perspectives

Childhood food allergy (FA) rates have rapidly increased with significant direct medical costs for the health care system and even larger costs for the families with a food-allergic child. The possible causes of food allergy become the target of intense scrutiny in recent years. Increasing evidence underline the importance in early life of gut microbiome in the development of allergic diseases. There are a range of factors in the modern environment that may be associated with changes to both the gut microbiome and risk of FA, such as mode of delivery, antibiotic exposure, infant feeding practices, farming environment, and country of origin. Knowledge of the relationship between early life gut microbiome and allergic diseases may facilitate development of novel preventive and treatment strategies. Based on our current knowledge, there are no currently available approved therapies for food allergy. More studies are needed to evaluate the safety and efficacy of allergen-specific and allergen-nonspecific approaches, as well as combination approaches

The Potential Immunonutritional Role of Parmigiano Reggiano Cheese in Children with Food Allergy

Parmigiano Reggiano (PR) is a ripened cheese with high nutritional value. Throughout ripening the bacteria contained in PR promote an extensive hydrolysis of cow’s milk proteins resulting in peptides that exhibit positive immunoregulatory activities. Additional modulatory activities on immune system are induced by butyrate, a short chain fatty acid widely expressed in PR. These findings suggest a possible immunonutritional role for PR able to stimulate oral tolerance in children with food allergy (FA)

Diagnosing and Treating Food Allergy

t Food allergy (FA) is defined as an abnormal immunological reaction to food proteins. Over 90 % of FAs in childhood are caused by eight foods: cow’s milk, hen’s egg, soy, peanuts, tree nuts, wheat, fish and shellfish. The diagnostic work up for a child with suspected FA includes detailed medical history, physical examination, FA screening tests and response to elimination diet and to oral food challenge. Sometimes additional diagnostic tools to explore intestinal damage and function could be adopted. Currently, the only treatment for FA relies on strict elimination diets supervised by the nutritionist. Main new therapeutic strategies for FA include allergen-specific (oral, sublingual, epicutaneous, subcutaneous immunotherapy and heat treatment of food) and nonallergen-specific therapies (humanized monoclonal antibodies, anti-IgE and anti-IL5, probiotics). An incorrect diagnosis is likely to result in unnecessary dietary restrictions, which, if prolonged, may adversely affect the child’s nutritional status and growt

Gut Microbiota as a Target for Preventive and Therapeutic Intervention against Food Allergy

The gut microbiota plays a pivotal role in immune system development and function. Modification in the gut microbiota composition (dysbiosis) early in life is a critical factor affecting the development of food allergy. Many environmental factors including caesarean delivery, lack of breast milk, drugs, antiseptic agents, and a low-fiber/high-fat diet can induce gut microbiota dysbiosis, and have been associated with the occurrence of food allergy. New technologies and experimental tools have provided information regarding the importance of select bacteria on immune tolerance mechanisms. Short-chain fatty acids are crucial metabolic products of gut microbiota responsible for many protective effects against food allergy. These compounds are involved in epigenetic regulation of the immune system. These evidences provide a foundation for developing innovative strategies to prevent and treat food allergy. Here, we present an overview on the potential role of gut microbiota as the target of intervention against food allergy

Extensively hydrolyzed casein formula alone or with L. rhamnosus GG reduces β-lactoglobulin sensitization in mice

Background: Extensively hydrolyzed casein formula (EHCF) has been proposed for the prevention and is commonly used for the treatment of cow's milk allergy (CMA). The addition of the probiotic Lactobacillus rhamnosus GG (LGG) to EHCF may induce faster acquisition of tolerance to cow's milk. The mechanisms underlying this effect are largely unexplored. We investigated the effects of EHCF alone or in combination with LGG on β-lactoglobulin (BLG) sensitization in mice. Methods: Three-week-old C3H/HeOuJ mice were sensitized by oral administration of BLG using cholera toxin as adjuvant at weekly intervals for 5 weeks (sensitization period). Two experimental phases were conducted: (i) EHCF or EHCF+LGG given daily, starting 2 weeks before the sensitization period and then given daily for 5 weeks and (ii) EHCF or EHCF+LGG given daily for 4 weeks, starting 1 week after the sensitization period. Diet free of cow's milk protein was used as control. Acute allergic skin response, anaphylactic symptom score, body temperature, intestinal permeability, anti-BLG serum IgE, and interleukin (IL)-4, IL-5, IL-10, IL-13, IFN-γ mRNA expression were analyzed. Peptide fractions of EHCF were characterized by reversed-phase (RP)-HPLC, MALDI-TOF mass spectrometry, and nano-HPLC/ESI-MS/MS. Results: Extensively hydrolyzed casein formula administration before or after BLG-induced sensitization significantly reduced acute allergic skin reaction, anaphylactic symptom score, body temperature decrease, intestinal permeability increase, IL-4, IL-5, IL-13, and anti-BLG IgE production. EHCF increased expression of IFN-γ and IL-10. Many of these effects were significantly enhanced by LGG supplementation. The peptide panels were similar between the two study formulas and contained sequences that could have immunoregulatory activities. Conclusions: The data support dietary intervention with EHCF for CMA prevention and treatment through a favorable immunomodulatory action. The observed effects are significantly enhanced by LGG supplementation. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Lt

Intestinal production of anti-tissue transglutaminase 2 antibodies in patients with diagnosis other than celiac disease

Abstract: It has been hypothesized that gluten-dependent production of anti-tissue-transglutaminase 2 (anti-TG2) antibodies may occur only at an intestinal level. We have investigated intestinal production of anti-TG2 antibodies in 136 patients with normal serum levels of anti-TG2 antibodies and normal duodenal mucosa. Intestinal deposits of anti-TG2 antibodies were evaluated by immunofluorescence and anti-TG2 antibodies released in organ culture supernatants measured by ELISA. Intestinal antibody libraries were obtained from 10 subjects. Immunohistochemistry for CD25+, CD3+, and TCR- + was assessed in subjects with positive (n = 32) and negative (n = 31) intestinal anti-TG2 antibodies. Globally 33/136 (24%) seronegative patients produced anti-TG2 autoantibodies at an intestinal level. Antibody libraries analysis confirmed the anti-TG2 antibodies mucosal production in all (n = 8) positive subjects. Lamina propria CD25+ cell count was significantly (p < 0.05) higher in patients with intestinal anti-TG2. Moreover, 13/32 (41%) of them showed high TCR- +/CD3+ ratios. Intestinal anti-TG2 antibody production does not show absolute specificity for CD. It is seen more often in association with inflamed mucosa. Further investigations are necessary to prove the possible role of dietary gluten

Epigenetic features of FoxP3 in children with cow’s milk allergy

BACKGROUND: DNA methylation of the Th1 and Th2 cytokine genes is altered during cow's milk allergy (CMA). Forkhead box transcription factor 3 (FoxP3) is essential for the development and function of regulatory T cells (Tregs) and is involved in oral tolerance acquisition. We assessed whether tolerance acquisition in children with IgE-mediated CMA is associated with DNA demethylation of the Treg-specific demethylated region (TSDR) of FoxP3. RESULTS: Forty children (aged 3-18 months) were enrolled: 10 children with active IgE-mediated CMA (group 1), 10 children who outgrew CMA after dietary treatment with an extensively hydrolyzed casein formula containing the probiotic Lactobacillus rhamnosus GG (group 2), 10 children who outgrew CMA after treatment with other formulas (group 3), and 10 healthy controls (group 4). FoxP3 TSDR demethylation and expression were measured in mononuclear cells purified from peripheral blood of the four groups of children. FoxP3 TSDR demethylation was significantly lower in children with active IgE-mediated CMA than in either children who outgrew CMA or in healthy children. Formula selection influenced the FoxP3 TSDR demethylation profile. The FoxP3 TSDR demethylation rate and expression level were correlated. CONCLUSIONS: Tolerance acquisition in children with IgE-mediated CMA involves epigenetic regulation of the FoxP3 gene. This feature could be a new target for preventive and therapeutic strategies against CMA

Lactobacillus rhamnosus GG-supplemented formula expands butyrate-producing bacterial strains in food allergic infants.

Dietary intervention with extensively hydrolyzed casein formula supplemented with Lactobacillus rhamnosus GG (EHCF+LGG) accelerates tolerance acquisition in infants with cow's milk allergy (CMA). We examined whether this effect is attributable, at least in part, to an influence on the gut microbiota. Fecal samples from healthy controls (n=20) and from CMA infants (n=19) before and after treatment with EHCF with (n=12) and without (n=7) supplementation with LGG were compared by 16S rRNA-based operational taxonomic unit clustering and oligotyping. Differential feature selection and generalized linear model fitting revealed that the CMA infants have a diverse gut microbial community structure dominated by Lachnospiraceae (20.5±9.7%) and Ruminococcaceae (16.2±9.1%). Blautia, Roseburia and Coprococcus were significantly enriched following treatment with EHCF and LGG, but only one genus, Oscillospira, was significantly different between infants that became tolerant and those that remained allergic. However, most tolerant infants showed a significant increase in fecal butyrate levels, and those taxa that were significantly enriched in these samples, Blautia and Roseburia, exhibited specific strain-level demarcations between tolerant and allergic infants. Our data suggest that EHCF+LGG promotes tolerance in infants with CMA, in part, by influencing the strain-level bacterial community structure of the infant gut