Food Allergy

Oral and Sublingual Immunotherapy for Treatment of IgE-Mediated Food Allergy

Development of active therapies for IgE-mediated food allergy is a critical action step toward alleviating the adverse medical, psychosocial, and economic burdens on affected patients and families. Significant progress has been observed specifically in the application of single-allergen oral and sublingual immunotherapy for treatment of IgE-mediated food allergy, with emphasis on milk, egg, and peanut as the primary allergens. Oral immunotherapy (OIT) has demonstrated efficacy in promoting immunomodulatory effects that lead to the clinical outcome of desensitization, defined as reduced reactivity while on active OIT, in the majority of treated individuals; however, achievement of sustained unresponsiveness following cessation of therapy has been observed in a smaller subset of treated subjects. The potential therapeutic benefits of OIT must be carefully considered in light of the significant potential for adverse events ranging from self-limited or easily treated oropharyngeal, respiratory or gastrointestinal symptoms, to persistent abdominal complaints that lead to cessation of therapy in an estimated 10-15% of treated individuals. To date, the majority of studies have focused on single-allergen OIT approaches; however, multi-allergen OIT has shown promise in initial trials and is the subject of ongoing investigation to address the complex needs of multi-food allergic individuals. Sublingual immunotherapy (SLIT) has been utilized for the treatment of food allergy and pollen-food allergy syndrome, demonstrating moderate efficacy, a favorable safety profile and variable tolerability, with oropharyngeal symptoms most commonly observed. Although studies directly comparing OIT and SLIT are limited, in general, the favorable safety profile associated with SLIT comes at the expense of reduced efficacy, while the more robust clinical effects observed with OIT come at the risk of potentially intolerable, treatment-limiting side effects. Future investigation to address specific knowledge gaps including optimal dose, duration, age of initiation, maintenance schedule, mechanisms, predictors of risk and therapeutic response will be important to maximize efficacy, minimize risk and develop personalized, effective approaches to targeting food allergy.

Allergen immunotherapy for food allergy from the Asian perspective: key challenges and opportunities

Introduction: Prevalence of food allergy is rising in different regions of the world. Asia has not been spared from this epidemic, but epidemiological data have revealed a different pattern of food allergens in this continent. Allergen-specific immunotherapy (AIT) for food allergy, which has been revolutionary as the main focus of research in recent years, needs to be adapted for the different populations in Asia. Areas covered: Recent evidence shows increasing popularity and superiority of AIT over strict food avoidance as the cornerstone of food allergy management. Asia is a distinctive continent with specific food allergy triggers, in particular, seafood, and wheat. Peanut, on the contrary, is not a common food allergen in most parts of Asia. The common Asian food allergens, as well as the rapidly developing food-specific AIT in this region will be covered in this article. Expert commentary: Evidence on oral immunotherapy for wheat allergy and preclinical data on shellfish AIT are promising. Further work should be done on resolving cross-sensitization between environmental allergens with wheat and shellfish allergens, and a modified AIT approach to enhance the safety and effectiveness of food-specific immunotherapy.

A light-initiated chemiluminescent assay for rapid quantitation of allergen-specific IgG4 in clinical samples

BACKGROUND

An increase in allergen-specific IgG₄ (sIgG₄), which serves as a blocking antibody, is associated with acquisition of immune tolerance after immunotherapy. In this study, we developed a rapid, sensitive, and homogeneous immunoassay based on the light-initiated chemiluminescent assay (LICA) technology for quantifying allergen sIgG₄ in serum samples.

METHODS

Allergen sIgG₄ was measured in vitro by incubating the sample with biotinylated allergens and chemiluminescent beads coated with anti-human IgG₄ antibody, followed by the addition of streptavidin-coated sensitizer beads. Multiple tests were performed to optimize the working conditions of the LICA and evaluate its performance.

RESULTS

We established the optimal concentration of biotinylated allergens (250 ng/mL), the optimal dilution range (1:8 for Gal d 1, Gal d 2 sIgG₄ and 1:4 for Gal d 3, Gal d 4 sIgG₄), and the optimal incubation time (20 min for Gal d 1, Gal d 2 sIgG₄ and 40 min for Gal d 3, Gal d 4 sIgG₄). The lower limit of quantification (LLOQ) was 0.261 ng/mL. The coefficient variation (CV) of the LICA was <10%. The assay was unaffected by general interfering substances at physiological concentrations. It exhibited excellent accuracy to detect allergen-sIgG₄ in human serum. Additionally, we demonstrated that the levels of Gal d 1, Gal d 2, and Gal d 3-sIgG₄ were significantly higher in the egg allergy group (p < .05), but no differences were found between the groups for Gal d 4-sIgG₄.

CONCLUSIONS

The LICA demonstrated satisfactory performance and can be used for quantifying allergen sIgG₄ in clinical practice.

Food immunotherapy for children with food allergies: state of the art and science

PURPOSE OF REVIEW

This review examines the current literature and provides insight into the role of food immunotherapy in the management of food-allergic children. Key food immunotherapy trials, benefits, and risks of the intervention, as well as areas requiring further study are all discussed.

RECENT FINDINGS

Research studies have reported encouraging results regarding the efficacy of food immunotherapy in desensitizing food-allergic patients with an acceptable safety profile and a documented improvement in quality of life. The role of biologics and long-term effects of food immunotherapy are still under investigation.

SUMMARY

The burden of food allergy is significant, multifaceted, and well documented. Food immunotherapy is a novel treatment option and an exciting area of research that has seen tremendous progress over the last decade, presenting encouraging results for the treatment of children with food allergies.

The Public Health Impact of Parent-Reported Childhood Food Allergies in the United States

: media-1vid110.1542/5840360268001PEDS-VA_2018-1235Video Abstract BACKGROUND: Childhood food allergy (FA) is a life-threatening chronic condition that substantially impairs quality of life. This large, population-based survey estimates childhood FA prevalence and severity of all major allergenic foods. Detailed allergen-specific information was also collected regarding FA management and health care use.

METHODS

A survey was administered to US households between 2015 and 2016, obtaining parent-proxy responses for 38 408 children. Prevalence estimates were based on responses from NORC at the University of Chicago's nationally representative, probability-based AmeriSpeak Panel (51% completion rate), which were augmented by nonprobability-based responses via calibration weighting to increase precision. Prevalence was estimated via weighted proportions. Multiple logistic regression models were used to evaluate FA predictors.

RESULTS

Overall, estimated current FA prevalence was 7.6% (95% confidence interval: 7.1%-8.1%) after excluding 4% of children whose parent-reported FA reaction history was inconsistent with immunoglobulin E-mediated FA. The most prevalent allergens were peanut (2.2%), milk (1.9%), shellfish (1.3%), and tree nut (1.2%). Among food-allergic children, 42.3% reported ≥1 severe FA and 39.9% reported multiple FA. Furthermore, 19.0% reported ≥1 FA-related emergency department visit in the previous year and 42.0% reported ≥1 lifetime FA-related emergency department visit, whereas 40.7% had a current epinephrine autoinjector prescription. Prevalence rates were higher among African American children and children with atopic comorbidities.

CONCLUSIONS

FA is a major public health concern, affecting ∼8% of US children. However, >11% of children were perceived as food-allergic, suggesting that the perceived disease burden may be greater than previously acknowledged.

Worms: Pernicious parasites or allies against allergies?

Type 2 immune responses are most commonly associated with allergy and helminth parasite infections. Since the discovery of Th1 and Th2 immune responses more than 30 years ago, models of both allergic disease and helminth infections have been useful in characterizing the development, effector mechanisms and pathological consequences of type 2 immune responses. The observation that some helminth infections negatively correlate with allergic and inflammatory disease led to a large field of research into parasite immunomodulation. However, it is worth noting that helminth parasites are not always benign infections, and that helminth immunomodulation can have stimulatory as well as suppressive effects on allergic responses. In this review, we will discuss how parasitic infections change host responses, the consequences for bystander immunity and how this interaction influences clinical symptoms of allergy.

Safety of Oral Food Challenges in Early Life

Oral food challenges are becoming more frequent in the allergy clinic due to an increased demand related to early food introduction in infants. We examined the safety of oral food challenges in 18 high-risk infants with prior allergic reactions, as well as infants with no known exposure to the food, presenting consecutively in a dedicated food allergy clinic for an oral food challenge. Foods challenged included peanut, tree nuts, sesame, baked egg, baked milk, and soy. A total of 17/18 (94%) infants had a negative challenge. Only 1/18 (6%) had a positive challenge, and in this case, symptoms were mild and limited to the skin. Our results suggest that food challenges in infants and young children up to the age of 2 years are safe with symptoms limited to the skin when reactions occur. In our cohort, the large majority of food challenges were negative, with most infants being sensitized rather than allergic to the food. Larger studies are needed to confirm this finding.

The Value of Food Allergy Prevention in Clinical Practice in Pediatrics: Targeting Early Life

Food allergies are common and increasing in prevalence, representing a major health concern in many countries around the world. In an effort to diminish the burden of food allergy, many research studies have focused on prevention, and recent findings have revolutionized the way we introduce allergenic foods in early life. We discuss the role of early allergenic food introduction and the value of food allergy prevention in this manuscript.

Food allergy

Food allergies manifest in a variety of clinical conditions within the gastrointestinal tract, skin and lungs, with the most dramatic and sometimes fatal manifestation being anaphylactic shock. Major progress has been made in basic, translational and clinical research, leading to a better understanding of the underlying immunological mechanisms that lead to the breakdown of clinical and immunological tolerance against food antigens, which can result in either immunoglobulin E (IgE)-mediated reactions or non-IgE-mediated reactions. Lifestyle factors, dietary habits and maternal-neonatal interactions play a pivotal part in triggering the onset of food allergies, including qualitative and quantitative composition of the microbiota. These factors seem to have the greatest influence early in life, an observation that has led to the generation of hypotheses to explain the food allergy epidemic, including the dual-allergen exposure hypothesis. These hypotheses have fuelled research in preventive strategies that seek to establish desensitization to allergens and/or tolerance to allergens in affected individuals. Allergen-nonspecific therapeutic strategies have also been investigated in a number of clinical trials, which will eventually improve the treatment options for patients with food allergy.