Recombinant Mal d 1 facilitates sublingual challenge tests of birch pollen-allergic patients with apple allergy

Current GMP standards for the production of vaccines and antibodies: An overview

The manufacture of pharmaceutical products made under good manufacturing practices (GMP) must comply with the guidelines of national regulatory bodies based on international or regional compendia. The existence of this type of regulation allows pharmaceutical laboratories to count on the standardization of high-quality production processes, obtaining a safe product for human use, with a positive impact on public health. In addition, the COVID-19 pandemic highlights the importance of having more and better-distributed manufacturing plants, emphasizing regions such as Latin America. This review shows the most important GMP standards in the world and, in particular, their relevance in the production of vaccines and antibodies.

Identification of apple cultivars hypoallergenic for birch pollen-allergic individuals by a multidisciplinary in vitro and in vivo approach

BACKGROUND

Birch pollen-related apple allergy is the most frequent IgE-mediated food allergy in Central-Northern Europe with Mal d 1 as major allergen. Its concentration in apples varies with the cultivar and storage time. Year-round appealing, hypoallergenic cultivars still are needed to satisfy the nutritional needs of affected individuals. We characterized three promising cultivars by multidisciplinary in vitro assays including long-term storage and by clinical challenges of allergic individuals before and after the birch pollen season.

METHODS

Proteins were extracted from fruits of 'Santana', 'Golden Delicious' (GD), and three genuine cultivars in November 2018 and April 2019. Mal d 1-levels were analysed by mass spectrometry, SDS-PAGE, immunoblotting, competitive ELISA, and basophil activation tests. Twenty-eight allergic individuals underwent single-blinded open food challenges and skin testing with the cultivars and birch pollen in November 2018 and May 2019. Allergen-specific IgE-levels were determined.

RESULTS

After storage all cultivars except 'Santana' were of appealing appearance and taste. Their Mal d 1 content had increased, also reflected by significantly amplified basophil activation and stronger reactions in clinical challenges. Besides, individuals showed boosted reactivity after pollen exposure indicated by enhanced allergen-specific IgE-levels and skin reactions to birch pollen. Still, all cultivars remained significantly less allergenic than GD and comparable to Santana in November 2018 in all assessments except for skin testing.

CONCLUSIONS

Combined expertise in pomology and allergology identified promising new cultivars for allergic consumers. The evaluation of hypoallergenic apples should incorporate long-term storage and birch pollen exposure. Basophil activation tests may be suitable in the selection of promising cultivars for oral challenges.

Treatment Approaches to Food Allergy

IgE-mediated food allergies affect both children and adults and are associated with dramatic decreases in the quality of life. In the majority of cases, food allergens have to be avoided which may be difficult, particularly in patients who suffer from life-threatening symptoms following the ingestion of minimal doses of food allergens. Several novel therapeutic approaches have been studied during the recent past and are summarized in this review. Therapies with novel therapeutic monoclonal antibodies, innovative allergen-specific immunotherapies using subcutaneous, sublingual, or epicutaneous routes, and oral immunotherapies leading to increases of individual thresholds of tolerable foods upon their continuous ingestion showed promising results which may change future management strategies in moderate to severe food allergy.

A hybrid of two major Blomia tropicalis allergens as an allergy vaccine candidate

Introduction

Allergen‐specific immunotherapy (AIT) represents a curative approach for treating allergies. In the tropical and subtropical regions of the world, Blomia tropicalis (Blo t 5 and Blo t 21) is the likely dominant source of indoor allergens.

Aim

To generate a hypoallergenic Blo t 5/Blo t 21 hybrid molecule that can treat allergies caused by B tropicalis.

Methods

Using in silico design of B tropicalis hybrid proteins, we chose two hybrid proteins for heterologous expression. Wild‐type Blo t 5/Blo t 21 hybrid molecule and a hypoallergenic version, termed BTH1 and BTH2, respectively, were purified by ion exchange and size exclusion chromatography and characterized by physicochemical, as well as in vitro and in vivo immunological, experiments.

Results

BTH1, BTH2 and the parental allergens were purified to homogeneity and characterized in detail. BTH2 displayed the lowest IgE reactivity that induced basophil degranulation using sera from allergic rhinitis and asthmatic patients. BTH2 essentially presented the same endolysosomal degradation pattern as the shortened rBlo t 5 and showed a higher resistance towards degradation than the full‐length Blo t 5. In vivo immunization of mice with BTH2 led to the production of IgG antibodies that competed with human IgE for allergen binding. Stimulation of splenocytes from BTH2‐immunized mice produced higher levels of IL‐10 and decreased secretion of IL‐4 and IL‐5. In addition, BTH2 stimulated T‐cell proliferation in PBMCs isolated from allergic patients, with secretion of higher levels of IL‐10 and lower levels of IL‐5 and IL‐13, when compared to parental allergens.

Conclusions and Clinical Relevance

BTH2 is a promising hybrid vaccine candidate for immunotherapy of Blomia allergy. However, further pre‐clinical studies addressing its efficacy and safety are needed.

The Effect of Birch Pollen Immunotherapy on Apple and rMal d 1 Challenges in Adults with Apple Allergy

Background: A proportion of patients allergic to birch pollen are also allergic to pit fruit. The objective of this study was to investigate the effect of immunotherapy with birch pollen on birch-pollen-related apple allergy. Method: Patients with birch pollen immunotherapy underwent a skin-prick test with birch pollen, apple and rMal d 1, global assessments and nasal challenges with birch pollen, open food challenge with apple and a double-blind, placebo-controlled test with rMal d 1 at the start of and during the immunotherapy. Measurements of specific IgE in response to Bet v 1 and rMal d 1 and IgG4 in response to Bet v 1 and rMal d 1 took place. Results: Six of eight patients demonstrated an improvement of nasal challenge test results and all patients improved on global assessment during the immunotherapy. The median oral dose of apple required to elicit a reaction increased but was not statistically significant. The patients showed a decrease in skin-prick test values in response to birch pollen (1.05 to 0.36), apple (0.78 to 0.25) and rMal d 1 (0.51 to 0.10) with p-values of 0.04, 0.03 and 0.06, respectively and a decrease of specific IgE in response to Bet v 1 (10.66 kU/L to 5.19 kU/L) and rMal d 1 (0.99 to 0.61 kU/L) with p-values of 0.01 and 0.05, respectively. Only the median specific IgG4 value to Bet v 1 increased from 0.05 to 1.85 mg/L (p-value of 0.02) and not to IgG4 rMal d 1 (0.07 to 0.08 kU/L). Conclusion: The beneficial effects of immunotherapy for birch pollen were accompanied by a limited effect on apple allergy.

Recent developments and highlights in rhinitis and allergen immunotherapy

This review paper aims to provide an overview of recent developments in the field of allergic and non-allergic rhinitis, as well as allergen immunotherapy. Recent advances in phenotyping and endotyping various forms of rhinitis have brought us one step closer towards tailoring treatment more appropriately for a given patient. Updates on local allergic rhinitis are also covered. Allergen immunotherapy (AIT) is an area of significant interest, with multiple original papers and recent position papers and guidelines published. Evidence related to the application of AIT in seasonal and perennial allergic rhinitis (AR), local allergic rhinitis and novel and expanded applications is discussed in the publication.

Food allergy in EAACI journals (2016)

Over the last years we have observed considerable progress in the area of food allergy, particularly in children. This review article focusses on important contributions which have lately been published in the three journals of the European Academy of Allergy and Clinical Immunology. A better understanding of allergens as well as the mechanisms of sensitization and tolerance induction may hopefully lead to a more targeted management of food allergy in the near future.

Efficacy and safety of 4 months of sublingual immunotherapy with recombinant Mal d 1 and Bet v 1 in patients with birch pollen-related apple allergy

BACKGROUND

Birch pollen-related apple allergy is among the most prevalent food allergies in adolescent/adult subjects and mainly results from sensitization to the major birch pollen allergen Bet v 1 and subsequent cross-reaction with the apple protein Mal d 1. However, specific immunotherapy with birch pollen has inconsistent effects on apple allergy.

OBJECTIVE

We sought to compare the safety and efficacy of sublingual immunotherapy (SLIT) with 2 formulations containing either rMal d 1 or rBet v 1 on birch pollen-related apple allergy.

METHODS

Sixty participants with birch pollen-related apple allergy were randomized to daily sublingual application of placebo (n = 20) or 25 μg of rMal d 1 (n = 20) or rBet v 1 (n = 20) for 16 weeks. Adverse events were regularly recorded. Sublingual challenges with standardized doses of rMal d 1, skin prick tests with recombinant allergens, and measurements of allergen-specific IgE and IgG₄ antibodies were performed before and after treatment.

RESULTS

Both formulations caused comparable, mainly local adverse events. No systemic reactions occurred. Compared with the placebo and rBet v 1-treated groups, SLIT with rMal d 1 reduced rMal d 1-induced oral symptoms (P = .001 and P = .038) accompanied by longitudinally reduced rMal d 1-specific cutaneous reactions (P = .022) and enhanced IgG₄/IgE ratios (P = .012). SLIT with rBet v 1 neither improved the clinical reactivity to rMal d 1 nor enhanced rMal d 1-specific IgG₄/IgE ratios. Participants receiving placebo showed no allergen-specific changes.

CONCLUSION

Sublingual treatment with a recombinant food allergen was safe and clinically effective, as determined by using standardized challenges. We present a promising approach for the effective treatment of birch pollen-related apple allergy.

Assessment of endogenous allergenicity of genetically modified plants exemplified by soybean - Where do we stand?

According to EU regulation, genetically modified (GM) plants considered to be allergenic have to be assessed concerning their endogenous allergens before placement on the EU market, in line with the international standards described in Codex Alimentarius. Under such premises, a quantitative relevant increase in allergens might occur in GM plants as an unintended effect compared with conventionally produced crops, which could pose a risk to consumers. Currently, data showing a connection between dose and allergic sensitisation are scarce since the pathophysiological mechanisms of sensitisation are insufficiently understood. In contrast, data on population dose-distribution relationships acquired by oral food challenge are available showing a connection between quantity of allergenic protein consumed and the population of allergic individuals experiencing reactions. Soybean is currently the only recognised allergenic GM food by law for which EFSA has received applications and was therefore taken as an example for defining an assessment strategy. Identification of potential allergens, methodology for quantification as well as risk assessment considerations, are discussed. A strategy is proposed for the identification, assessment and evaluation of potential hazards/risks concerning endogenous allergenicity in food derived from plants developed by biotechnology. This approach could be expanded to other allergenic foods in the future, whenever required.

Standardization of double blind placebo controlled food challenge with soy within a multicentre trial

Background

Multicentre trials investigating food allergies by double blind placebo controlled food challenges (DBPCFC) need standardized procedures, challenge meals and evaluation criteria. We aimed at developing a standardized approach for identifying patients with birch related soy allergy by means of DBPCFC to soy, including determination of threshold levels, in a multicentre setting.

Methods

Microbiologically stable soy challenge meals were composed of protein isolate with consistent Gly m 4 levels. Patients sensitized to main birch allergen Bet v 1 and concomitant sensitization to its soy homologue Gly m 4 underwent DBPCFC. Outcome was defined according to presence and/or absence of ten objective signs and intensity of eight subjective symptoms as measured by visual analogue scale (VAS).

Results

138 adult subjects (63.8% female, mean age 38 years) underwent DBPCFC. Challenge meals and defined evaluation criteria showed good applicability in all centres involved. 45.7% presented with objective signs and 65.2% with subjective symptoms at soy challenge. Placebo challenge meals elicited non-cardiovascular objective signs in 11.6%. In 82 (59.4%) subjects DBPCFC was judged as positive. 70.7% of DPBCFC+ showed objective signs and 85.4% subjective symptoms at soy challenge. Subjective symptoms to soy challenge meal in DBPCFC+ subjects started at significantly lower dose levels than objective signs (p < 0.001). Median cumulative eliciting doses for first objective signs in DBPCFC+ subjects were 4.7 g [0.7–24.7] and 0.7 g [0.2–4.7] total soy protein for first subjective symptoms (p = 0.01).

Conclusions

We present the hitherto largest group of adults with Bet v 1 and Gly m 4 sensitization being investigated by DBPCFC. In this type of food allergy evaluation of DBPCFC outcome should not only include monitoring of objective signs but also scoring of subjective symptoms. Our data may contribute to standardize DBPCFC in pollen-related food allergy in multicentre settings.

Trial registration

EudraCT: 2009-011737-27.

Recombinant Mal d 1 facilitates sublingual challenge tests of birch pollen-allergic patients with apple allergy

It is still unclear whether allergen‐specific immunotherapy (AIT) with birch pollen improves birch pollen‐related food allergy. One reason for this may be the lack of standardized tests to assess clinical reactions to birch pollen‐related foods, for example apple. We tested the applicability of recombinant (r) Mal d 1, the Bet v 1‐homolog in apple, for oral challenge tests. Increasing concentrations of rMal d 1 in 0.9% NaCl were sublingually administered to 72 birch pollen‐allergic patients with apple allergy. The dose of 1.6 μg induced oral allergy syndromes in 26.4%, 3.2 μg in 15.3%, 6.3 μg in 27.8%, 12.5 μg in 8.3%, 25 μg in 11.1%, and 50 μg in 4.2% of the patients. No severe reactions occurred. None of the patients reacted to 0.9% NaCl alone. Sublingual administration of 50 μg of rMal d 1 induced no reactions in three nonallergic individuals. Our approach allows straight forward, dose‐defined sublingual challenge tests in a high number of birch pollen‐allergic patients that inter alia can be applied to evaluate the therapeutic efficacy of birch pollen AIT on birch pollen‐related food allergy.