Adjuvants in Allergen-Specific Immunotherapy: Modulating and Enhancing the Immune Response

Elevated aluminum excretion in patients by long-term subcutaneous immunotherapy - A cross-sectional case-control study

BACKGROUND

Aluminum (Al) adjuvants have been used in vaccines and subcutaneous immunotherapy (SCIT) for decades. Despite indisputable neurotoxic properties of Al, there is no clear evidence of a causal relationship between their use and any neurotoxic side effects. However, recent rat studies have shown an accumulation of Al from adjuvants in tissues, especially in bones.

OBJECTIVES

Since the human toxicokinetics of Al-adjuvants are poorly understood, this study aimed to evaluate whether up-dosed or long-term SCIT with Al-coupled extracts leads to increased Al load in humans.

METHODS

This observational cross-sectional case-control study explored Al excretion in hymenoptera venom allergy patients recruited in 2020 before initiation (n = 10) and during ongoing (n = 12) SCIT with Al-based preparations. Urine samples were collected before and 24 h after the SCIT injections and analyzed for aluminum content by using atomic absorption spectrometry. The cumulative administered Al dose was extracted from patient records. Patients receiving long-term immunotherapy were treated between 2.8 and 13.6 years (mean 7.1). Other potential sources of Al exposure were surveyed.

RESULTS

Patients who had received Al-coupled immunotherapy for several years showed significantly (p < 0.001) higher Al excretion than the controls at initiation of immunotherapy (mean 18.2 μg/gC vs. 7.9 μg/gC) and predominantly (73%) were above the 95th percentile of the general populations' exposure (>15 μg/gC), however, without reaching levels of toxicological concern (>50 μg/gC). Taking both groups together excreted Al levels correlated with the cumulative administered Al dose from SCIT (linear regression: Alurine = 8.258 + 0.133*Alcum; p = 0.001).

DISCUSSION

These results suggest a relevant iatrogenic contribution of long-term SCIT to human internal Al burden and potential accumulation. Considering the medical benefits of Al-adjuvants and SCIT a differentiated risk-benefit analysis is needed. For certain scenarios of potential toxicological concern in clinical practice biomonitoring might be advisable.

Allergen specific immunotherapy regulates macrophage property in the airways

BACKGROUND

Allergen specific immunotherapy (AIT) has been widely used in allergy clinics. The therapeutic effects of it are to be improved. Macrophages occupy the largest proportion of airway immune cells. The aim of this study is to measure the effects of nasal instillation AIT (nAIT) on airway allergy by regulating macrophage functions.

METHODS

An airway allergy mouse model was established with the ovalbumin-alum protocol. nAIT was conducted for mice with airway allergy through nasal instillation. The effects of nAIT were compared with subcutaneous injection AIT (SCIT) and sublingual AIT (SLIT).

RESULTS

Mice with airway allergy showed the airway allergic response, including lung inflammation, airway hyper responsiveness, serum specific IgE, increase in the amounts of eosinophil peroxidase, mouse mast cell protease-1, and Th2 cytokines in bronchoalveolar lavage fluid. nAIT had a much better therapeutic effect on the airway allergic response than SCIT and SLIT. Mechanistically, we observed better absorption of allergen in macrophages, better production of IL-10 by macrophages, and better immune suppressive functions in macrophages in mice received nAIT than SCIT and SLIT.

CONCLUSIONS

The nAIT has a much better therapeutic effect on suppressing the airway allergic response, in which macrophages play a critical role.

Risedronate-functionalized manganese-hydroxyapatite amorphous particles: A potent adjuvant for subunit vaccines and cancer immunotherapy

The cGAS-STING pathway and the Mevalonate Pathway are druggable targets for vaccine adjuvant discovery. Manganese (Mn) and bisphosphonates are known to exert adjuvant effects by targeting these two pathways, respectively. This study found the synergistic potential of the two pathways in enhancing immune response. Risedronate (Ris) significantly amplified the Mn adjuvant early antibody response by 166-fold and fortified its cellular immunity. However, direct combination of Mn2+ and Ris resulted in increased adjuvant toxicity (40% mouse mortality). By the combination of doping property of hydroxyapatite (HA) and its high affinity for Ris, we designed Ris-functionalized Mn-HA micro-nanoparticles as an organic-inorganic hybrid adjuvant, named MnHARis. MnHARis alleviated adjuvant toxicity (100% vs. 60% survival rate) and exhibited good long-term stability. When formulated with the varicella-zoster virus glycoprotein E (gE) antigen, MnHARis triggered a 274.3-fold increase in IgG titers and a 61.3-fold surge in neutralization titers while maintaining a better long-term humoral immunity compared to the aluminum adjuvant. Its efficacy spanned other antigens, including ovalbumin, HPV18 VLP, and SARS-CoV-2 spike protein. Notably, the cellular immunity elicited by the group of gE + MnHARis was comparable to the renowned Shingrix®. Moreover, intratumoral co-administration with an anti-trophoblast cell surface antigen 2 nanobody revealed synergistic antitumor capabilities. These findings underscore the potential of MnHARis as a potent adjuvant for augmenting vaccine immune responses and improving cancer immunotherapy outcomes.

Aluminum hydroxide nanoparticle adjuvants can reduce the inflammatory response more efficiently in a mouse model of allergic asthma than traditional aluminum hydroxide adjuvants

Traditional aluminum hydroxide is widely used as a vaccine adjuvant. Despite its favorable safety profile, it can cause an inflammatory response at the injection sites. However, multiple studies have shown that aluminum hydroxide nanoparticles have more potent adjuvant activity than their traditional aluminum hydroxide counterparts as antigen carriers; it has also been found that the local inflammation caused by aluminum hydroxide nanoparticle adjuvants is milder than that of other adjuvants. The aim of the present study was to compare the degree of inflammatory response between the aluminum hydroxide nanoparticle adjuvants and the traditional aluminum hydroxide adjuvants in the desensitization treatment of a mouse model of house dust mite (HDM)-induced allergic asthma. Mice were sensitized intraperitoneally with HDM. Subcutaneous desensitization was performed with PBS, traditional aluminum hydroxide adjuvants and aluminum hydroxide nanoparticle adjuvants. The mice were challenged and subsequently euthanized. The skin tissue at the local injection sites was assessed and specific indices were measured, such as the response of specific immunoglobulins, the airway hyper-responsiveness (AHR), and the inflammation in the bronchoalveolar lavage and lung tissues. Early hypersensitivity responses were suppressed in mice treated with subcutaneous immunotherapy (SCIT). Both traditional aluminum hydroxide-SCIT and aluminum hydroxide nanoparticle-SCIT could inhibit AHR. However, aluminum hydroxide nanoparticle-SCIT was able to significantly inhibit the secretion of eosinophils in the lung tissue and the production of type 2 cytokine Interleukin (IL)-5 in blood compared with the corresponding effects noted by traditional aluminum hydroxide adjuvants. Moreover, the aluminum hydroxide nanoparticle group reduced the inflammatory response at the local injection site. Collectively, the data indicated that allergen-specific immunotherapy using aluminum hydroxide nanoparticle adjuvants reduces lung and local inflammation compared with traditional aluminum hydroxide adjuvants.

Dupilumab and subcutaneous immunotherapy for the treatment of refractory moderate to severe atopic dermatitis: A preliminary report

Subcutaneous immunotherapy (SCIT) and dupilumab are important treatments for patients with moderate to severe atopic dermatitis (AD). However, in clinical practice, poor response to allergen immunotherapy (AIT) or dupilumab has been observed in some patients. It is unknown whether combining dupilumab and SCIT can improve treatment responses in patients with moderate to severe AD that is resistant to dupilumab or SCIT monotherapy. This single-centre, retrospective, observational, real-world study evaluated the efficacy and safety of dupilumab and SCIT for refractory moderate to severe AD. The data of ten patients with moderate to severe atopic dermatitis who were treated with dupilumab and SCIT were retrospectively analysed. The scoring atopic dermatitis (SCORAD) score, numerical rating scale (NRS), and atopic dermatitis control test (ADCT) scores and eosinophil and total IgE levels before and after add-on therapy were compared and analysed. The SCORAD, NRS, and ADCT scores decreased significantly at four and 12 weeks after the initiation of add-on therapy and plateaued during maintenance treatment. The eosinophil and total IgE levels were not significantly different before and after add-on therapy. No serious adverse reactions were reported in any patient during add-on therapy. This study indicates that the combination of dupilumab and SCIT safely improves the treatment response of patients with moderate to severe AD who are resistant to dupilumab or SCIT monotherapy.

Exploring the potential and safety of quantum dots in allergy diagnostics

Biomedical investigations in nanotherapeutics and nanomedicine have recently intensified in pursuit of new therapies with improved efficacy. Quantum dots (QDs) are promising nanomaterials that possess a wide array of advantageous properties, including electronic properties, optical properties, and engineered biocompatibility under physiological conditions. Due to these characteristics, QDs are mainly used for biomedical labeling and theranostic (therapeutic-diagnostic) agents. QDs can be functionalized with ligands to facilitate their interaction with the immune system, specific IgE, and effector cell receptors. However, undesirable side effects such as hypersensitivity and toxicity may occur, requiring further assessment. This review systematically summarizes the potential uses of QDs in the allergy field. An overview of the definition and development of QDs is provided, along with the applications of QDs in allergy studies, including the detection of allergen-specific IgE (sIgE), food allergens, and sIgE in cellular tests. The potential treatment of allergies with QDs is also described, highlighting the toxicity and biocompatibility of these nanodevices. Finally, we discuss the current findings on the immunotoxicity of QDs. Several favorable points regarding the use of QDs for allergy diagnosis and treatment are noted.

The chemistry of gut microbiome-derived lipopolysaccharides impacts on the occurrence of food allergy in the pediatric age

Introduction: Food allergy (FA) in children is a major health concern. A better definition of the pathogenesis of the disease could facilitate effective preventive and therapeutic measures. Gut microbiome alterations could modulate the occurrence of FA, although the mechanisms involved in this phenomenon are poorly characterized. Gut bacteria release signaling byproducts from their cell wall, such as lipopolysaccharides (LPSs), which can act locally and systemically, modulating the immune system function. Methods: In the current study gut microbiome-derived LPS isolated from fecal samples of FA and healthy children was chemically characterized providing insights into the carbohydrate and lipid composition as well as into the LPS macromolecular nature. In addition, by means of a chemical/MALDI-TOF MS and MS/MS approach we elucidated the gut microbiome-derived lipid A mass spectral profile directly on fecal samples. Finally, we evaluated the pro-allergic and pro-tolerogenic potential of these fecal LPS and lipid A by harnessing peripheral blood mononuclear cells from healthy donors. Results: By analyzing fecal samples, we have identified different gut microbiome-derived LPS chemical features comparing FA children and healthy controls. We also have provided evidence on a different immunoregulatory action elicited by LPS on peripheral blood mononuclear cells collected from healthy donors suggesting that LPS from healthy individuals could be able to protect against the occurrence of FA, while LPS from children affected by FA could promote the allergic response. Discussion: Altogether these data highlight the relevance of gut microbiome-derived LPSs as potential biomarkers for FA and as a target of intervention to limit the disease burden.

Allergen immunotherapy: progress and future outlook

INTRODUCTION

Allergy, the immunological hypersensitivity to innocuous environmental compounds, is a global health problem. The disease triggers, allergens, are mostly proteins contained in various natural sources such as plant pollen, animal dander, dust mites, foods, fungi and insect venoms. Allergies can manifest with a wide range of symptoms in various organs, and be anything from just tedious to life-threatening. A majority of all allergy patients are self-treated with symptom-relieving medicines, while allergen immunotherapy (AIT) is the only causative treatment option.

AREAS COVERED

This review will aim to give an overview of the state-of-the-art allergy management, including the use of new biologics and the application of biomarkers, and a special emphasis and discussion on current research trends in the field of AIT.

EXPERT OPINION

Conventional AIT has proven effective, but the years-long treatment compromises patient compliance. Moreover, AIT is typically not offered in food allergy. Hence, there is a need for new, effective and safe AIT methods. Novel routes of administration (e.g. oral and intralymphatic), hypoallergenic AIT products and more effective adjuvants holds great promise. Most recently, the development of allergen-specific monoclonal antibodies for passive immunotherapy may also allow treatment of patients currently not treated or treatable.

Clinical and experimental treatment of allergic asthma with an emphasis on allergen immunotherapy and its mechanisms

Allergen immunotherapy (AIT) is currently the only form of treatment that modifies allergic asthma. Pharmacotherapy alone seeks to control the symptoms of allergic asthma, allergic rhinitis, and other atopic conditions. In contrast, AIT can induce long-term physiological modifications through the immune system. AIT enables individuals to live improved lives many years after treatment ends, where they are desensitized to the allergen(s) used or no longer have significant allergic reactions upon allergen provocation. The leading forms of treatment with AIT involve injections of allergen extracts with increasing doses via the subcutaneous route or drops/tablets via the sublingual route for several years. Since the initial attempts at this treatment as early as 1911 by Leonard Noon, the mechanisms by which AIT operates remain unclear. This literature-based review provides the primary care practitioner with a current understanding of the mechanisms of AIT, including its treatment safety, protocols, and long-term efficacy. The primary mechanisms underlying AIT include changes in immunoglobulin classes (IgA, IgE, and IgG), immunosuppressive regulatory T-cell induction, helper T cell type 2 to helper T cell type 1 cell/cytokine profile shifts, decreased early-phase reaction activity and mediators, and increased production of IL-10, IL-35, TGF-β, and IFN-γ. Using the databases PubMed and Embase, a selective literature search was conducted searching for English, full-text, reviews published between 2015 and 2022 using the keywords (with wildcards) "allerg*," "immunotherap*," "mechanis*," and "asthma." Among the cited references, additional references were identified using a manual search.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Stimulation of naïve B cells with a fusion protein consisting of FlaA and Bet v 1 induces regulatory B cells ex vivo

BACKGROUND

The experimental fusion protein rFlaA:Betv1 was shown to efficiently suppress allergen-specific sensitization in mice. However, the detailed mechanism of rFlaA:Betv1-mediated immune modulation is not fully understood. In this study, we investigated the effect of rFlaA:Betv1 on naïve murine B cells.

METHODS

Immune modulating capacity of rFlaA:Betv1 was screened in IL-10 reporter mice. B cells were isolated from spleens of naïve C57Bl/6, TLR5^-/- , or MyD88^-/- mice, stimulated with rFlaA:Betv1 and controls, and monitored for the expression of the regulatory B cell markers CD1d, CD24, CD38, and surface IgM by flow cytometry. Secreted cytokines, antibodies, and reactivity of the induced antibodies were investigated by ELISA and intracellular flow cytometry. Suppressive capacity of rFlaA:Betv1-stimulated B cells was tested in mDC:CD4⁺ T cell:B cell triple cultures.

RESULTS

Upon in vivo application of rFlaA:Betv1 into IL-10-GFP reporter mice, CD19⁺ B cells were shown to produce anti-inflammatory IL-10, suggesting B cells to contribute to the immune-modulatory properties of rFlaA:Betv1. rFlaA:Betv1-induced IL-10 secretion was confirmed in human B cells isolated from buffy coats. In vitro stimulation of naïve murine B cells with rFlaA:Betv1 resulted in an mTOR- and MyD88-dependent production of IL-10 and rFlaA:Betv1 induced Bet v 1-reactive IgG production, which was not observed for IgA. rFlaA:Betv1-stimulated B cells formed a CD19⁺ CD24⁺ CD1d⁺ IgM⁺ CD38⁺ Breg subpopulation capable of suppressing Bet v 1-induced TH2 cytokine secretion in vitro.

CONCLUSION

rFlaA:Betv1 can act as a thymus-independent B cell antigen, stimulating the mTOR- and MyD88-dependent differentiation of B cells displaying a regulatory phenotype, IL-10 secretion, antigen-binding antibody production, and a suppressive capacity in vitro.

Immunoinformatics-aided design of a new multi-epitope vaccine adjuvanted with domain 4 of pneumolysin against Streptococcus pneumoniae strains

BACKGROUND

Streptococcus pneumoniae (Pneumococcus) has remained a leading cause of fatal infections such as pneumonia, meningitis, and sepsis. Moreover, this pathogen plays a major role in bacterial co-infection in patients with life-threatening respiratory virus diseases such as influenza and COVID-19. High morbidity and mortality in over one million cases, especially in very young children and the elderly, are the main motivations for pneumococcal vaccine development. Due to the limitations of the currently marketed polysaccharide-based vaccines, non-serotype-specific protein-based vaccines have received wide research interest in recent years. One step further is to identify high antigenic regions within multiple highly-conserved proteins in order to develop peptide vaccines that can affect various stages of pneumococcal infection, providing broader serotype coverage and more effective protection. In this study, immunoinformatics tools were used to design an effective multi-epitope vaccine in order to elicit neutralizing antibodies against multiple strains of pneumococcus.

RESULTS

The B- and T-cell epitopes from highly protective antigens PspA (clades 1-5) and PhtD were predicted and immunodominant peptides were linked to each other with proper linkers. The domain 4 of Ply, as a potential TLR4 agonist adjuvant candidate, was attached to the end of the construct to enhance the immunogenicity of the epitope vaccine. The evaluation of the physicochemical and immunological properties showed that the final construct was stable, soluble, antigenic, and non-allergenic. Furthermore, the protein was found to be acidic and hydrophilic in nature. The protein 3D-structure was built and refined, and the Ramachandran plot, ProSA-web, ERRAT, and Verify3D validated the quality of the final model. Molecular docking analysis showed that the designed construct via Ply domain 4 had a strong interaction with TLR4. The structural stability of the docked complex was confirmed by molecular dynamics. Finally, codon optimization was performed for gene expression in E. coli, followed by in silico cloning in the pET28a(+) vector.

CONCLUSION

The computational analysis of the construct showed acceptable results, however, the suggested vaccine needs to be experimentally verified in laboratory to ensure its safety and immunogenicity.

Screening of B-cell epitopes of Der-p1 and Der-p2 major aeroallergens by computational approach for designing immunotherapeutics

Introduction and Aim: Allergic diseases are IgE-mediated hypersensitivity reactions affecting approximately 30% of the general population globally. Dermatophagoides pteronyssinus (Der-p) is the most prevalent house dust mite (HDM) species consisting of 23 mite allergen groups. Among these, group 1 and 2 are major allergenic proteins, which causes allergic asthma in 80% of sensitized individuals, with elevated IgE titres in the serum. This study involves in silico analysis of potential B-cell epitopes of group 1 and group 2 of Der-p, which can be utilized in designing immunotherapeutic vaccines.   Materials and Methods: Allergen sequences obtained from the database- International Union of Immunological Societies (IUIS), for predicting of B-cell epitopes. The physiochemical properties and secondary structures of the obtained sequence were evaluated. The sequences were further subjected to determining antigenicity, surface accessibility, and prediction of linear and discontinuous B-cell epitope by utilizing IEDB tools.   Results: The linear and discontinuous B-cell epitopes of Der-p1 and Der-p2 aeroallergen were predicted. Further, Der-p1 and Der-p2 showed 6 linear epitopes each respectively. Conformational epitopes predicted were 123 of Der-p1 and 72 of Der-p2 respectively, by the ElliPro tool. Based on the structure, antigenicity, and surface accessibility, only 10% of Der-p1 and Der-p2 which binds to B-cell epitopes are linear and the majority are discontinuous.   Conclusion: The linear and conformational epitopes of Der-p1 and Der-p2 are predicted using in silico tools. These identified epitopes might be useful for developing epitope-based immunotherapeutics for HDM allergy.

Treating allergies via skin - Recent advances in cutaneous allergen immunotherapy

Subcutaneous allergen immunotherapy has been practiced clinically for decades to treat airborne allergies. Recently, the cutaneous route, which exploits the immunocompetence of the skin has received attention, which is evident from attempts to use it to treat peanut allergy. Delivery of allergens into the skin is inherently impeded by the barrier imposed by stratum corneum, the top layer of the skin. While the stratum corneum barrier must be overcome for efficient allergen delivery, excessive disruption of this layer can predispose to development of allergic inflammation. Thus, the most desirable allergen delivery approach must provide a balance between the level of skin disruption and the amount of allergen delivered. Such an approach should aim to achieve high allergen delivery efficiency across various skin types independent of age and ethnicity, and optimize variables such as safety profile, allergen dosage, treatment frequency, application time and patient compliance. The ability to precisely quantify the amount of allergen being delivered into the skin is crucial since it can allow for allergen dose optimization and can promote consistency and reproducibility in treatment response. In this work we review prominent cutaneous delivery approaches, and offer a perspective on further improvisation in cutaneous allergen-specific immunotherapy.

On the role of allergen-specific IgG subclasses for blocking human basophil activation

Successful treatment of IgE mediated allergies by allergen-specific immunotherapy (AIT) usually correlates with the induction of allergen-specific IgG4. However, it is not clear whether IgG4 prevents the allergic reaction more efficiently than other IgG subclasses. Here we aimed to compare allergen-specific monoclonal IgG1 and IgG4 antibodies in their capacity to inhibit type I allergic reactions by engaging FcγRIIb. We found that IgG1, which is the dominant subclass induced by viruses, binds with a similar affinity to the FcγRIIb as IgG4 and is comparable at blocking human basophil activation from allergic patients; both by neutralizing the allergen as well as engaging the inhibitory receptor FcγRIIb. Hence, the IgG subclass plays a limited role for the protective efficacy of AIT even if IgG4 is considered the best correlate of protection, most likely simply because it is the dominant subclass induced by classical AITs.

RNA viruses in the house dust mite Dermatophagoides pteronyssinus, detection in environmental samples and in commercial allergen extracts used for in vivo diagnosis

BACKGROUND

Allergy to house dust mites (HDM), the most important source of indoor allergens worldwide, is diagnosed and treated using natural extracts from cultures that can contain immunoactive components from the HDM microbiome, including mite-infecting viruses. This study aimed to contribute to the discovery and characterization of RNA viruses from Dermatophagoides pteronyssinus, followed by their detection in different mite-derived sources.

METHODS

Viruses were assembled after in silico metatranscriptomic analysis of D. pteronyssinus RNA samples, visualized by electron microscopy, and RNA detected by direct RT-PCR or data mining. Mite culture performance was evaluated in vivo.

RESULTS

Seven RNA viruses were identified in our laboratory stock colony. Picornavirus-like viral particles were detected in epithelial cells of the digestive system and in fecal pellets. Most of these viruses could be persistently transmitted to an inbred virus-free colony by inoculating fecal material from the stock colony. Upon viral infection, no significant effect could be seen on mite population growth. Transcriptomic screening confirmed the presence of homolog sequences to these viruses in independent laboratory stocks of D. pteronyssinus and in other Astigmata mites. Noteworthy, RNA from most of the viruses could be detected by RT-PCR on house dust samples, reference standards, and/or commercial diagnostic D. pteronyssinus extracts.

CONCLUSIONS

Our results show that viral infections are common and widespread in D. pteronyssinus, both in natural and culture-based growth conditions. Potential effects on the mites themselves and consequences toward allergenicity in humans whether exposed naturally or after immunotherapy are discussed.

Role of nanostructures in allergy: Diagnostics, treatments and safety

Nanotechnology is science, engineering and technology conducted at the nanoscale, which is about 1-100 nm. It has led to the development of nanomaterials, which behave very differently from materials with larger scales and can have a wide range of applications in biomedicine. The physical and chemical properties of materials of such small compounds depend mainly on the size, shape, composition and functionalization of the system. Nanoparticles, carbon nanotubes, liposomes, polymers, dendrimers and nanogels, among others, can be nanoengineeried for controlling all parameters, including their functionalization with ligands, which provide the desired interaction with the immunological system, that is dendritic cell receptors to activate and/or modulate the response, as well as specific IgE, or effector cell receptors. However, undesired issues related to toxicity and hypersensitivity responses can also happen and would need evaluation. There are wide panels of accessible structures, and controlling their physico-chemical properties would permit obtaining safer and more efficient compounds for clinical applications goals, either in diagnosis or treatment. The application of dendrimeric antigens, nanoallergens and nanoparticles in allergy diagnosis is very promising since it can improve sensitivity by increasing specific IgE binding, mimicking carrier proteins or enhancing signal detection. Additionally, in the case of immunotherapy, glycodendrimers, liposomes, polymers and nanoparticles have shown interest, behaving as platforms of allergenic structures, adjuvants or protectors of allergen from degradation or having a depot capacity. Taken together, the application of nanotechnology to allergy shows promising facts facing important goals related to the improvement of diagnosis as well as specific immunotherapy.

Changes in epidemiology and clinical practice in IgE-mediated Allergy in children

In the last decades, allergic diseases have increased exponentially and although pediatric asthma prevalence is stabilizing, it is estimated around 10% in Spain. Not the same with food allergy and anaphylaxis which are clearly increasing, becoming a significant public health problem. Taking into account epidemiological trends, the European Academy of Allergy and Clinical Immunology (EAACI) estimates that in less than 15 years more than half of the European population will suffer from some type of allergic disorder. The advances in diagnostic methods in food allergy, especially component resolved diagnosis, allow us to know the patient's sensitization profile and explain possible cross reactivity, anticipate potential risk of food trangressions, and prescribe correct avoidance diet in each patient. Thus, the development of molecular biology and nanotechnology have led to the appearance of new technologies (microarrays) which facilitate the study, specially of the polysensitized patients, allowing allergen immunotherapy (AIT) to be more personalized. The latest advances in the use of biologics are having an impact, not only in disease evolution, but also in quality of life.

[Changes in epidemiology and clinical practice in IgE-mediated allergy in children]

In the last decades, allergic diseases have increased exponentially and although pediatric asthma prevalence is stabilizing, in Spain is estimated around 10%. Not the same with food allergy and anaphylaxis which are clearly increasing, becoming a public health problem of the first magnitude. Considering epidemiological trends, the European Academy of Allergy and Clinical Immunology (EAACI) estimates that in less than 15 years more than half of European population will suffer from some type of allergy. The advances in diagnostic methods in food allergy, especially component resolved diagnosis, allow us to know the patient's sensitization profile and explain the possible cross reactivity, anticipate potential risk of food transgressions, and prescribe the correct avoidance diet in each patient. Thus, the development of molecular biology and nanotechnology have led to the appearance of new technologies (microarrays) which facilitate the study, specially of the polysensitized patients, allowing allergen immunotherapy (AIT) to be more personalized. The latest advances in the use of biologics are having an impact, not only in disease evolution, but also in patients quality of life.

One Hundred Ten Years of Allergen Immunotherapy: A Broad Look Into the Future

Allergen immunotherapy (AIT) is the only disease-modifying treatment option for patients with type 1-mediated allergic diseases such as allergic rhinitis/rhinoconjunctivitis with/without allergic asthma. Although many innovations have been developed since the first clinical report of Noon et al in 1911, the improvement of clinical efficacy and tolerability of this treatment is still an important unmet need. Hence, much progress has been made in the characterization of the cell types, cytokines, and intracellular signaling events involved in the development, maintenance, and regulation of allergic reactions, and also in the understanding of the mechanisms of tolerance induction in AIT. This comprehensive review aims to summarize the current innovative approaches in AIT, but also gives an outlook on promising candidates of the future. On the basis of an extensive literature review, integrating a clinical point of view, this article focuses on recent and future innovations regarding biologicals, allergen-derived peptides, recombinant allergens, "Toll"-like receptor agonists and other adjuvants, and novel application routes being developed for future AIT.

High dose vitamin D3 empowers effects of subcutaneous immunotherapy in a grass pollen-driven mouse model of asthma

Allergen-specific immunotherapy (AIT) has the potential to provide long-term protection against allergic diseases. However, efficacy of AIT is suboptimal, while application of high doses allergen has safety concerns. The use of adjuvants, like 1,25(OH)2VitD3 (VitD3), can improve efficacy of AIT. We have previously shown that low dose VitD3 can enhance suppression of airway inflammation, but not airway hyperresponsiveness in a grass pollen (GP)-subcutaneous immunotherapy (SCIT) mouse model of allergic asthma. We here aim to determine the optimal dose and formulation of VitD3 for the GP SCIT. GP-sensitized BALBc/ByJ mice received three SCIT injections of VitD3-GP (30, 100, and 300 ng or placebo). Separately, synthetic lipids, SAINT, was added to the VitD3-GP-SCIT formulation (300 nmol) and control groups. Subsequently, mice were challenged with intranasal GP, and airway hyperresponsiveness, GP-specific IgE, -IgG1, and -IgG2a, ear-swelling responses (ESR), eosinophils in broncho-alveolar lavage fluid and lung were measured. VitD3 supplementation of GP-SCIT dose-dependently induced significantly enhanced suppression of spIgE, inflammation and hyperresponsiveness, while neutralizing capacity was improved and ESR were reduced. Addition of VitD3 further decreased Th2 cytokine responses and innate cytokines to allergens in lung tissue by GP-SCIT. However, addition of synthetic lipids to the allergen/VitD3 mixes had no additional effect on VitD3-GP-SCIT. We find a clear, dose dependent effect of VitD3 on GP-SCIT-mediated suppression of allergic inflammation and airway hyperresponsiveness. In contrast, addition of synthetic lipids to the allergen/VitD3 mix had no therapeutic effect. These studies underscore the relevance of VitD3 as an adjuvant to improve clinical efficacy of SCIT treatment regimens.

Dust mite-derived Enterobacterial fimbriae H protein enforces the allergen specific immunotherapy in asthma mice

BACKGROUND

The mite alimentary canal contains plenty of microbiota. It is accepted that some of the microbial products function as adjuvants to speed up immune responses.

OBJECTIVES

We identified five bacterial proteins from dust mite, and Enterobacterial fimbriae H (FimH) was one of them. This study aims to test a hypothesis that the FimH protein enforces immunotherapy in asthmatic mice.

METHODS

Asthmatic mice were treated by allergen specific immunotherapy (ASIT) with rDer f1/f2 or rDer f1/f2 plus FimH. Changes in inflammatory cell infiltration, airway hyperreactivity, frequency of Tregs, splenic CD4⁺IFN-γ⁺ cells, and serum levels of TGF-β, IL-10, IL-13 and IL-17A of asthmatic mice were checked.

RESULTS

ASIT with rDer f1/f2 plus FimH reduced inflammatory cell infiltration, airway hyperreactivity (AHR), and levels of IgE and IgG1 compared to ASIT with rDer f1/f2 alone, but the levels of IgG2a increased. Asthmatic mice that underwent ASIT with rDer f1/f2 plus FimH showed increased frequency of Tregs, splenic CD4⁺IFN-γ⁺ cells, serum levels of TGF-β and IL-10; and deceased splenic CD4⁺IL-4⁺ cells, and serum levels of IL-13 and IL-17A. In vitro study showed FimH triggered IL-10 expression in a concentration dependent manner and facilitated the differentiation of Tregs.

CONCLUSION

Used as an adjuvant, FimH enforces the effect of ASIT in asthmatic mice via augmenting Tregs.

Safety and effectiveness of a microcrystalline tyrosine-associated mite extract immunotherapy for allergic rhinitis

Aim: To assess the safety and effectiveness of an allergen immunotherapy (AIT) with a microcrystalline tyrosine-associated mite allergoid in real-world patients with allergic rhinitis (AR). Materials & methods: Retrospective, multicenter study assessing the safety of AIT in patients aged 5 to 65 years with AR, with or without asthma, sensitized to mites. Secondary objective was effectiveness, measured as unscheduled visits to healthcare centers and emergency rooms, rhinitis and asthma evolution, medication use and patients' and physicians' disease perception 12 months before and after treatment. Results: The 306 patients evaluated, with a mean (standard deviation) age of 29.68 (14.66) years, received different treatment compositions and regimens, and 25 (8.2%) experienced nonserious adverse reactions. Unscheduled visits to the specialist and emergency room admissions significantly decreased after immunotherapy (mean [standard deviation] 2.11 [1.95] and 0.3 [0.93] vs 0.66 [1.09] and 0.02 [0.2], before and after treatment, respectively). Rhinitis and asthma classification ('AR and its impact on asthma' and 'Guía Española para el Manejo del Asma', respectively) significantly changed (p < 0.0001 for all classifications), showing symptom reduction after AIT. Median (interquartile range)-combined rhinitis and combined asthma medication scores significantly decreased (4.0 [1.33, 7.0] vs 0.25 [0, 10.0]; p < 0.0001 and 6.94 [1.5, 6.0] vs 0.67 [0, 4.67]; p < 0.0001) within 12 months before and after starting AIT, respectively. Conclusion: AIT with microcrystalline tyrosine-associated mite allergoid appears to be safe and effective in treating rhinitis caused by mites.

Allergen Immunotherapy in children with respiratory allergic diseases

Allergen immunotherapy (AIT) is a well-established treatment for allergic respiratory diseases. It represents a cornerstone in the clinical management of allergic children since it is the only curative option to date able to modify the natural history of Ig-E mediated allergic diseases. Through a well-defined immunologic mechanism, AIT promotes regulatory T cells and cuts down the immune response induced by allergens. According to current guidelines based on up-to-date evidence, AIT should be offered to children with moderate-severe allergic rhinitis and/or controlled asthma starting from 5 years of age, further to an adequate risk-benefit assessment which includes patient's adherence to the treatment and a proper selection of the right product. Younger age and mild disease could be considered based on an individual evaluation. Both subcutaneous (SCIT) and sublingual (SLIT) routes of administration have a good efficacy and safety profile with safer outcomes for SLIT compared to SCIT. Only standardized products with documented evidence of clinical efficacy should be used. Although AIT is used worldwide, there are still gaps and limitations, including the lack of reliable biomarkers predictive of the clinical outcome. Novel adjuvants are currently under investigations to boost the strength and efficiency of the immune response, as well as new formulations with better efficacy and better patient's adherence to the treatment. Herein, we aim to provide an overview of current key evidence with major regard to clinical practice as well as knowledge gaps and future research needs in the context of AIT in children with respiratory allergic diseases.

Modulation of immune responses using adjuvants to facilitate therapeutic vaccination

Therapeutic vaccination offers great promise as an intervention for a diversity of infectious and non-infectious conditions. Given that most chronic health conditions are thought to have an immune component, vaccination can at least in principle be proposed as a therapeutic strategy. Understanding the nature of protective immunity is of vital importance, and the progress made in recent years in defining the nature of pathological and protective immunity for a range of diseases has provided an impetus to devise strategies to promote such responses in a targeted manner. However, in many cases, limited progress has been made in clinical adoption of such approaches. This in part results from a lack of safe and effective vaccine adjuvants that can be used to promote protective immunity and/or reduce deleterious immune responses. Although somewhat simplistic, it is possible to divide therapeutic vaccine approaches into those targeting conditions where antibody responses can mediate protection and those where the principal focus is the promotion of effector and memory cellular immunity or the reduction of damaging cellular immune responses as in the case of autoimmune diseases. Clearly, in all cases of antigen-specific immunotherapy, the identification of protective antigens is a vital first step. There are many challenges to developing therapeutic vaccines beyond those associated with prophylactic diseases including the ongoing immune responses in patients, patient heterogeneity, and diversity in the type and stage of disease. If reproducible biomarkers can be defined, these could allow earlier diagnosis and intervention and likely increase therapeutic vaccine efficacy. Current immunomodulatory approaches related to adoptive cell transfers or passive antibody therapy are showing great promise, but these are outside the scope of this review which will focus on the potential for adjuvanted therapeutic active vaccination strategies.

Can food allergy be cured? What are the future prospects?

Food allergies have become a significant heath burden as prevalence continues to rise, affecting 6%-13% of the global population. In the absence of drugs approved by regulatory agencies, the current standard of care remains avoidance of allergenic foods and management of acute allergic reactions with antihistamines and epinephrine autoinjectors. Allergen immunotherapy has been shown to increase the threshold of reactivity in the majority of food-allergic individuals. However, challenges include long treatment periods, high rates of adverse reactions, and lack of permanence of desensitization and established protocols. To address these limitations, adjunctive allergen-specific immunotherapy, vaccines, and non-allergen-specific therapies (eg, monoclonal antibodies) are being explored. The future of food allergy treatment is promising with a number of clinical trials in progress. Currently, although desensitization can be achieved for the majority of individuals with food allergy through immunotherapy, continued ingestion of allergen is needed for most individuals to maintain desensitization. Further understanding of the mechanisms of food allergy and identification of biomarkers to distinguish between temporary and permanent resolution of allergies is needed before a cure, where reactivity to the allergen is permanently lost enabling the individual to consume the allergen in any amount at any time, can be envisioned.

Nanoparticle-based immunotherapy: state of the art and future perspectives

INTRODUCTION

For several years now, medicine has been benefiting from the contribution of nanoparticles (NPs) technology for both diagnosis and therapy. They can be used as adjuvants, being capable per se of immune-modulating activity, or as carriers for molecules to be transported to a specific target, eventually loaded with specific ligands favoring specific uptake.

AREAS COVERED

The review focuses on experimental use of NPs as adjuvants/carriers for allergen immunotherapy (AIT). Human clinical trials conducted so far are discussed.

EXPERT OPINION

Results of experimental studies and recent clinical trials support the use of NPs as carrier/adjuvant in AIT. Comparisons between NP-based and classical AIT are needed, to show the usefulness of the NP-based approach. However, there are still unsolved problems: the persistence of non-degradable NPs with possible toxicological consequences, and the formation of the protein corona around the NPs, which could alter their activity and fate. Virus-like particles seem the most promising NPs for allergy treatment, as for other vaccines. Over the next decade, NP-based AIT will be largely used to treat allergic disorders.

EAACI Allergen Immunotherapy User's Guide

Allergen immunotherapy is a cornerstone in the treatment of allergic children. The clinical efficiency relies on a well-defined immunologic mechanism promoting regulatory T cells and downplaying the immune response induced by allergens. Clinical indications have been well documented for respiratory allergy in the presence of rhinitis and/or allergic asthma, to pollens and dust mites. Patients who have had an anaphylactic reaction to hymenoptera venom are also good candidates for allergen immunotherapy. Administration of allergen is currently mostly either by subcutaneous injections or by sublingual administration. Both methods have been extensively studied and have pros and cons. Specifically in children, the choice of the method of administration according to the patient's profile is important. Although allergen immunotherapy is widely used, there is a need for improvement. More particularly, biomarkers for prediction of the success of the treatments are needed. The strength and efficiency of the immune response may also be boosted by the use of better adjuvants. Finally, novel formulations might be more efficient and might improve the patient's adherence to the treatment. This user's guide reviews current knowledge and aims to provide clinical guidance to healthcare professionals taking care of children undergoing allergen immunotherapy.

Recent development and applications of nanomaterials for cancer immunotherapy

Immunotherapy, which utilizes the patient’s own immune system to fight against cancer, further results in durable antitumor responses and reduces metastasis and recurrence, has become one of the most effective and important cancer therapies along with surgery, radiotherapy, and chemotherapy. Nanomaterials with the advantages of large specific surface, delivery function, and controllable surface chemistry are used to deliver antigens or adjuvants, or both, help to boost immune responses with the imaging function or just act as adjuvants themselves and modulate tumor microenvironment (TME). In this review, recent development and applications of nanomaterials for cancer immunotherapy including delivery systems based on nanomaterials, uniting imaging, self-adjuvants, targeting functions, artificial antigen presenting cells, and TME modulation are focused and discussed.

Immunization of Cats against Fel d 1 Results in Reduced Allergic Symptoms of Owners

An innovative approach was tested to treat cat allergy in humans by vaccinating cats with Fel-CuMV (HypoCat^TM), a vaccine against the major cat allergen Fel d 1 based on virus-like particles derived from cucumber mosaic virus (CuMV-VLPs). Upon vaccination, cats develop neutralizing antibodies against the allergen Fel d 1, which reduces the level of reactive allergen, thus lowering the symptoms or even preventing allergic reactions in humans. The combined methodological field study included ten cat-allergic participants who lived together with their cats (n = 13), that were immunized with Fel-CuMV. The aim was to determine methods for measuring a change in allergic symptoms. A home-based provocation test (petting time and organ specific symptom score (OSSS)) and a general weekly (or monthly) symptom score (G(W)SS) were used to assess changes in allergic symptoms. The petting time until a pre-defined level of allergic symptoms was reached increased already early after vaccination of the cats and was apparent over the course of the study. In addition, the OSSS after provocation and G(W)SS recorded a persistent reduction in symptoms over the study period and could serve for long-term assessment. Hence, the immunization of cats with HypoCat^TM (Fel-CuMV) may have a positive impact on the cat allergy of the owner, and changes could be assessed by the provocation test as well as G(W)SS.

Immunization of Cats against Fel d 1 Results in Reduced Allergic Symptoms of Owners

An innovative approach was tested to treat cat allergy in humans by vaccinating cats with Fel-CuMV (HypoCat^TM), a vaccine against the major cat allergen Fel d 1 based on virus-like particles derived from cucumber mosaic virus (CuMV-VLPs). Upon vaccination, cats develop neutralizing antibodies against the allergen Fel d 1, which reduces the level of reactive allergen, thus lowering the symptoms or even preventing allergic reactions in humans. The combined methodological field study included ten cat-allergic participants who lived together with their cats (n = 13), that were immunized with Fel-CuMV. The aim was to determine methods for measuring a change in allergic symptoms. A home-based provocation test (petting time and organ specific symptom score (OSSS)) and a general weekly (or monthly) symptom score (G(W)SS) were used to assess changes in allergic symptoms. The petting time until a pre-defined level of allergic symptoms was reached increased already early after vaccination of the cats and was apparent over the course of the study. In addition, the OSSS after provocation and G(W)SS recorded a persistent reduction in symptoms over the study period and could serve for long-term assessment. Hence, the immunization of cats with HypoCat^TM (Fel-CuMV) may have a positive impact on the cat allergy of the owner, and changes could be assessed by the provocation test as well as G(W)SS.

Safety of uSCIT-MPL-4: prevalence and risk factors of systemic reactions in real life

Aim: We assessed the safety of allergoid adjuvanted by monophosphoryl lipid A (uSCIT-MPL-4) in a real-life setting. Materials & methods: Patients treated with uSCIT-MPL-4 were followed-up for 1 year. Systemic reactions (SRs) were registered and the association with potential risk factors was evaluated. Results: 2929 patients were included. Grade 0, 1, 2, 3 and 4 SR reactions were observed respectively in 3.3, 1.5, 0.31, 0.07 and 0.07% of patients. A significant association was detected between Grade ≥1 SRs and: female gender, number of administrations, previous local reactions. Conclusion: uSCIT-MPL-4 is safe. Local reactions should be accurately assessed as they may represent a risk factor for Grade ≥1 SRs, together with gender and number of doses/year.