Recent Advances in Allergen-Specific Immunotherapy in Humans: A Systematic Review

Stabilization of activated mast cells by ORAI1 inhibitor suppresses peanut-induced anaphylaxis and acute diarrhea

Mast cell (MC) activation triggered by immunoglobulin E (IgE)-antigen crosslinking involves intracellular Ca2+ influx through the ORAI1 channel, which precedes granule exteriorization and de novo synthesis of mediators. Pharmacologically suppressing MCs via the inhibition of the ORAI1 Ca2+ channel may represent a potential strategy for preventing anaphylaxis. This study demonstrated that peanut-induced anaphylaxis in sensitized mice resulted in significant hypothermia and acute diarrhea. Utilizing the Mcpt5cre-DTA mouse model, we demonstrated that this anaphylactic response was mediated by IgE-antigen-induced MC activation. Prophylactic administration of MC suppressors was an effective means of preventing peanut-induced anaphylaxis. In addition, we observed the potent efficacy of an ORAI1 inhibitor in suppressing the FcεRI-mediated response of murine or human MCs, even when administered concurrently or post-allergen exposure. Mechanistically, the ORAI1 inhibitor was found to prevent the association of Synaptotagmin-2 with the SNARE complex. In an in vivo mouse model of peanut-induced anaphylaxis, the administration of the ORAI1 inhibitor after allergen challenge effectively suppressed allergic acute diarrhea and ameliorated anaphylaxis. Therefore, pharmacological intervention of ORAI1 channel inhibition in MCs represents a promising therapeutic avenue for the treatment of peanut-induced anaphylaxis and acute diarrhea in vivo.

Clinical outcomes of AIT in the elderly population

PURPOSE OF REVIEW

This review aims to present the current knowledge on the effectiveness and safety of allergen immunotherapy (AIT) in patients over 60 years of age with inhalant allergies.

RECENT FINDINGS

Over the last 10 years, the problem of immunoglobulin E allergy in seniors has been noticed by many authors. At the same time, in the 1990s, trials of desensitization to selected inhalant allergens were started, obtaining evidence of the effectiveness of AIT, both with the use of sublingual immunotherapy (SLIT) and injection immunotherapy (SCIT), in patients over 60 years of age with allergic rhinitis. Such data have been confirmed for AITs for grasses, birch, and house dust mites. Currently, these patients are being monitored to assess the long-term effect of AIT. All available observations confirm the high safety of AIT in seniors.

SUMMARY

Seniors with allergic rhinitis or asthma may qualify for AIT if they do not have contraindications. These patients can experience a sustained clinical benefit even after completing AIT treatment. Studies indicate that injectable and sublingual routes of administration may be effective in this age group, provided the suspect allergen is accurately diagnosed.

Expression, purification, characterization, and patient IgE reactivity of new macadamia nut iso-allergen

Structural and functional information about food allergens is essential for understanding the allergenicity of food proteins. All allergens belong to a small number of protein families. Various allergens from different families have been successfully produced recombinantly in E. coli for their characterization and applications in allergy diagnosis and treatment. However, recombinant hexameric 11S seed storage protein has not been reported, although numerous 11S legumins are known to be food allergens, including the recently identified macadamia nut allergen Mac i 2. Here we report the production of a macadamia nut legumin by expressing it in E. coli with a substrate site of HRV 3C protease and cleaving the purified protein with HRV 3C protease. The protease divided the protein into two chains and left a native terminus for the C-terminal chain, resulting in a recombinant hexameric 11S allergen for the first time after the residues upstream to the cleavage site flipped out of the way of the trimer-trimer interaction. The 11S allergens are known to have multiple isoforms in many species. The present study removed an obstacle in obtaining homogeneous allergens needed for studying allergens and mitigating allergenicity. Immunoreactivity of the protein with serum IgE confirmed it to be a new isoform of Mac i 2.

Biomaterial Strategies for Selective Immune Tolerance: Advances and Gaps

Autoimmunity and allergies affect a large number of people across the globe. Current approaches to these diseases target cell types and pathways that drive disease, but these approaches are not cures and cannot differentiate between healthy cells and disease-causing cells. New immunotherapies that induce potent and selective antigen-specific tolerance is a transformative goal of emerging treatments for autoimmunity and serious allergies. These approaches offer the potential of halting-or even reversing-disease, without immunosuppressive side effects. However, translating successful induction of tolerance to patients is unsuccessful. Biomaterials offer strategies to direct and maximize immunological mechanisms of tolerance through unique capabilities such as codelivery of small molecules or signaling molecules, controlling signal density in key immune tissues, and targeting. While a growing body of work in this area demonstrates success in preclinical animal models, these therapies are only recently being evaluated in human trials. This review will highlight the most recent advances in the use of materials to achieve antigen-specific tolerance and provide commentary on the current state of the clinical development of these technologies.

Strengthening the case for intralymphatic immunotherapy

PURPOSE OF REVIEW

Intralymphatic immunotherapy (ILIT) is a promising novel method of immunotherapy, that is short and convenient, and may be very effective. Results have been varied, and efforts to unravel the real value of the treatment are ongoing. Methods used to assess the effect in clinical trials have been so varied that it is difficult to compare studies with each other.

RECENT FINDINGS

Some advances have been made; the importance of injecting into the lymph node has been illustrated, and treatment with a range of medicines has proven to be successful. In meta-analyses the treatment has been shown to have no serious side effects and to be an effective short term desensitizing agent. Now it remains to be shown that ILIT also has long-term effects of tolerance. Preliminary data suggest that there is a long-term effect.

SUMMARY

Injecting allergen directly into a lymph node strengthens the protective immune response. ILIT is safe and induces desensitization and very likely also induces tolerance. Compliance will improve compared with other treatment forms. If ILIT holds its promise, it will become an attractive option for patients with allergy.

Assessing global fungal threats to humans

Fungi are an integral part of the earth's biosphere. They are broadly distributed in all continents and ecosystems and play a diversity of roles. Here, I review our current understanding of fungal threats to humans and describe the major factors that contribute to various threats. Among the 140,000 or so known species out of the estimated six million fungal species on Earth, about 10% directly or indirectly threaten human health and welfare. Major threats include mushroom poisoning, fungal allergies, infections of crop plants, food contamination by mycotoxins, and mycoses in humans. A growing number of factors have been identified to impact various fungal threats, including human demographics, crop distributions, anthropogenic activities, pathogen dispersals, global climate change, and/or the applications of antifungal drugs and agricultural fungicides. However, while models have been developed for analyzing various processes of individual threats and threat managements, current data are primarily descriptive and incomplete, and there are significant obstacles to integration of the diverse factors into accurate quantitative assessments of fungal threats. With increasing technological advances and concerted efforts to track the spatial and temporal data on climate and environmental variables; mycotoxins in the feed and food supply chains; fungal population dynamics in crop fields, human and animal populations, and the environment; human population demographics; and the prevalence and severities of fungal allergies and diseases, our ability to accurately assess fungal threats will improve. Such improvements should help us develop holistic strategies to manage fungal threats in the future.

Versatile Application of Nanobodies for Food Allergen Detection and Allergy Immunotherapy

The unique characteristics of camelid heavy-chain only antibody (HCAb) derived nanobodies (Nbs) have facilitated their employment as tools for research and application in extensive fields including food safety inspection, diagnosis and therapy of diseases, etc., to develop immune detecting techniques or alternative candidates of conventional antibodies as diagnostic and therapeutic reagents. The wide application in the fields of food allergen inspection and immunotherapy has not been addressed as not much results published in the literature. The robust properties and straightforward selecting strategy of Nbs impel the advantageous employment compared with monoclonal antibodies (mAbs) to establish immunoassay and serve as blocking antibodies to compete immunoglobulin E (IgE) binding epitopes on food allergens. More and more efforts have been invested to develop specific Nbs against food allergen proteins, such as macadamia allergen of Mac i 1, peanut allergen of Ara h 3, and lupine allergen of Lup an 1, which demonstrated the potential of Nbs for research and application in food allergen surveillance. Meanwhile, the paratopes of Nbs preferably targeting the unique epitopes of food allergens can provide more possibilities to serve as blocking antibodies to shield IgE binding epitopes for food allergy immunotherapy. Regardless, the research and application of Nbs in the field of food allergen and allergic reactions are expected to attract dramatic focus and produce promising research outputs.