Mechanisms of allergen immunotherapy supporting its disease-modifying effect

Allergen Immunotherapy for the Prevention and Treatment of Asthma

Allergic asthma is the predominant phenotype among asthmatics. Although conventional pharmacotherapy is a central component in the management of asthma, it does not enable control of asthma symptoms in all patients. In recent decades, some uncontrolled asthmatic patients, especially those with allergic asthma, have benefited from biological therapies. However, biologics do not address all the unmet needs left by conventional pharmacotherapy. Furthermore, it is noteworthy that neither conventional pharmacotherapy nor biological therapies have disease-modifying properties. In this context, allergen immunotherapy (AIT) represents an indispensable component of the therapeutic arsenal against allergic asthma, due to its disease-modifying immunological effects. In this review article, funded by an AIT manufacturer, we find clinical trials support AIT as the only treatment option able both to improve allergic asthma symptoms and to prevent the onset and worsening of the condition. For patients with severe asthma or other safety concerns, the combination of AIT and biologics offers very promising new treatment modalities for the management of allergic asthma. Trial Registration: clinicaltrials.gov identifier: NCT06027073.

Confronting allergies: strategies for combating pollution and safeguarding our health

Increasing evidence demonstrates a robust link between environmental pollutants and allergic reactions, with air and indoor pollution exacerbating respiratory allergies and climate change intensifying seasonal allergies. Comprehensive action, including government regulations, public awareness, and individual efforts, is essential to mitigate pollution's impact on allergies and safeguard public health and ecological balance. Recent findings indicate a strong correlation between environmental pollutants and allergic reactions, with air pollution from vehicular emissions and industrial activities exacerbating respiratory allergies like asthma and allergic rhinitis. Additionally, indoor pollutants such as mold and volatile organic compounds are significant triggers of allergic responses, especially among vulnerable populations. Furthermore, climate change, driven by pollution, is intensifying seasonal allergies due to altered weather patterns and increased pollen production. This review emphasizes the critical importance of addressing pollution and allergies, highlighting the growing concerns in contemporary society. This review highlights the urgent need to address pollution and allergies, emphasizing their increasing significance in modern society and outlining effective allergy management strategies.

IgE versus IgG and IgA: Differential roles of allergen-specific antibodies in sensitization, tolerization, and treatment of allergies

The prevalence of asthma, rhinitis, and food allergies has increased dramatically over the last few decades. This increase originally started in western countries, but is now also evident in many other regions of the world. Given the fact that the increase is so quick, the noted increase cannot be linked to a genetic effect, and many environmental factors have been identified that are associated with increased or reduced prevalence of allergies, like changing dietary habits, increased urbanization, pollution, exposure to microorganisms and LPS, and the farming environment and raw milk consumption. Although the key role of allergen-specific IgE in allergies is well known, the role of allergen-specific IgG and IgA antibodies is less well defined. This review will provide an overview of the functions of allergen-specific IgE in allergy, the role of allergen-specific antibodies (IgG (4) and IgA) in allergen immunotherapy (AIT), the possibility to use allergen-specific antibodies for treatment of ongoing allergies, and the potential role of allergen-specific antibodies in tolerance induction to allergens in a preventive setting. In the last, more speculative, section we will present novel hypotheses on the potential role of allergen-specific non-IgE antibodies in allergies by directing antigen presentation, Th2 development, and innate immune training.

Evaluation of Clinical Remission in Best-Performing Severe Asthmatic Patients Treated for Three Years with Mepolizumab

BACKGROUND

In its severe form, where possible, asthma is treated using biological drugs in order to reduce, as much as possible, the use of systemic steroids. Mepolizumab is effective for severe asthma based on key outcomes such as exacerbation and steroid dependence. Its efficacy in terms of the criteria for clinical remission in the short and long term has become of interest.

OBJECTIVE

We aimed to evaluate the effect of mepolizumab in the achievement of clinical remission after 3 years of administration.

METHODS

In this study, 71 patients who continued mepolizumab for 3 years were assessed for clinical remission according to six different published sets of remission criteria.

RESULTS

According to the criteria, 39-52% of patients experienced complete remission in the first year, increasing to 51-73% at 3 years. By classifying patients according to partial and complete remission criteria, proposed by the SANI, we observe 22% of patients in partial remission at one year, achieving complete remission after three years. The baseline factors associated with earlier remission were a higher FEV1, if we consider classifications requiring an FEV1 ≥ 80%, a low OCS dose, and low FeNO levels, in the patients requiring FEV1 stabilization.

CONCLUSIONS

Clinical remission is possible for patients treated with mepolizumab. The observations at three years compared with the first year indicated that the factors negatively affecting remission delayed rather than prevented it. Earlier treatment could increase the chances of remission.

Preventive allergen immunotherapy with inhalant allergens in children

The efficacy and safety of preventive allergen immunotherapy (pAIT) in children are currently under investigation. Here, we provide an overview of pAIT with respiratory allergens concerning the prevention of new sensitizations, allergic disease onset and progression as well as further immunomodulatory effects. Three databases were searched for clinical pAIT studies in children. Selected publications were reviewed for preventive outcomes according to prevention level (primary, secondary, and tertiary), allergen type, administration route, dose, and treatment duration. The primary prevention approach appears safe but showed no allergen-specific effect on new sensitizations. Secondary prevention seems feasible and may induce regulatory T cell-mediated immunotolerance. The number of studies at these prevention levels is limited. Tertiary prevention with grass and/or tree pollen-based pAIT has shown efficacy in preventing disease progression from allergic rhinitis/conjunctivitis to asthma. Data on tertiary pAIT with house dust mites and other allergen types are inconclusive. Subcutaneous and sublingual routes appear similarly effective, but head-to-head comparative paediatric studies are scarce. Additionally, there are fewer placebo-controlled studies. Nevertheless, immunomodulatory outcomes of pAIT are encouraging. Currently, limited but favourably suggestive evidence is available for preventing respiratory allergic diseases in children by pAIT. Primary and secondary prevention have potential and warrant further investigation through well-designed studies.

Advancements in Allergen Immunotherapy for the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin condition that affects individuals of all age groups, manifesting as a spectrum of symptoms varying from mild to severe. Allergen immunotherapy (AIT) involves the administration of allergen extracts and has emerged as a potential treatment strategy for modifying immune responses. Its pathogenesis involves epidermal barrier dysfunction, microbiome imbalance, immune dysregulation, and environmental factors. Existing treatment strategies encompass topical steroids to systemic agents, while AIT is under investigation as a potential immune-modifying alternative. Several studies have shown reductions in the severity scoring of atopic dermatitis (SCORAD) scores, daily rescue medication use, and visual analog scale (VAS) scores following AIT. Biomarker changes include increased IgG4 levels and decreased eosinophil counts. This review provides valuable insights for future research and clinical practice, exploring AIT as a viable option for the management of AD.

Modelling the impact of sublingual immunotherapy versus subcutaneous immunotherapy on patient travel time and CO2 emissions in Sweden

In Sweden, allergy immunotherapy (AIT) is available as either subcutaneous immunotherapy (SCIT) injections or sublingual immunotherapy (SLIT) tablets and is used to treat moderate-severe allergic rhinitis (AR). This study sought to determine treatment-related CO2 emissions and travel times in Swedish patients receiving either SCIT or SLIT-tablets. A list of specialized Swedish AR clinics that administer AIT was determined, and respective co-ordinates retrieved. Swedish municipality population data were obtained from a national database. The mean distance from each Swedish municipality to the nearest AR clinic was calculated, adjusted using a detour index, and weighted by estimated patient population size. Transport modality data were obtained from a Swedish urban transport study and CO2 emissions were obtained from Government sources. The mean number of annual SLIT-tablets and SCIT doses required were calculated based on product labels and clinical expert input. The annual number of healthcare professional interactions were layered into the model to estimate changes in mean patient travel time, distance, and travel-related CO2 emissions associated with using SCIT versus SLIT-tablets. Mean annual travel-related CO2 emissions were 410 tonnes (to two significant figures [s.f.]; standard deviation [SD] 90) with SLIT-tablets, versus 1700 tonnes (SD 380) for SCIT, resulting in mean annual savings of approximately 1300 tonnes (SD 290) of CO2 if all AIT patients were to receive SLIT-tablets instead of SCIT, over 380 times greater than 2021 average Swedish CO2 emissions per capita. Approximate mean annual travel times for patients taking SLIT-tablets were 66,500 h (three s.f.; SD 14,400), and 278,000 h (SD 60,200) for SCIT, resulting in mean annual savings of 211,000 h (SD 45,800) if all AIT patients were to receive SLIT-tablets instead of SCIT. Compared with SCIT injections, SLIT-tablets led to substantial reductions in treatment-related CO2 emissions and travel times for Swedish patients.