House Dust Mite Precision Allergy Molecular Diagnosis (PAMD@) in the Th2-prone Atopic Dermatitis Endotype

360° approach to the patient with mite allergy: from scientific evidence to clinical practice

In the recent years, several important advances have been made in the diagnosis of allergy using molecular techniques. The aetiological diagnosis of allergy using molecular components of allergens allows a more precise definition of the patient's IgE repertoire. Precision medicine is a structural model aimed at personalising healthcare and places the patient at the centre of the specialist's decision-making process. To this end, an accurate characterisation of the external exposome at a molecular level and their putative role as clinically relevant allergens is essential to elucidate the phenotypic diversity of atopic disease, with a view to personalising diagnosis and therapy. It has been proposed a decision algorithm, the Top-Down approach, where the clinical history is set first and is followed by the use of skin tests or specific IgE techniques, which facilitates the clinicians to make decisions. The therapeutic intervention driven by the standard diagnostic approach, but supported by these innovative tools, can lead to a better phenotyping of highly complex patients, and a more appropriate prescription of AIT. To this end, the allergen extracts used for diagnosis require to be of proven quality and contain the most relevant allergens. Likewise, allergen vaccines must gather efficacy, safety, duration, and patient compliance, hence the demand for new vaccines to overcome these drawbacks.

Molecular profiling of allergen-antibody IgE might decide about the efficacy of allergen immunotherapy in a patient with atopic dermatitis and allergy to house dust mites

Introduction

Allergen immunotherapy (AIT) has no clear recommendation for atopic dermatitis (AD).

Aim

To evaluate the effect of AIT on house dust mites (HDM) in AD patients sensitised to HDM with different baseline molecular profiles of antigens.

Material and methods

In this placebo-controlled study, 61 patients with moderate-to-severe AD allergy symptoms and HDM allergy were included. They received a 12 months' AIT with the use of HDM allergen extract or placebo. The authors adopted their AD improvement criterion after 1 year of AIT as a reduction of all examined indicators by at least 50% from the baseline for %BSA, TMS, and EASI scores. Additionally, the influence of individual HDM molecules on the final AIT effect was analysed.

Results

Finally, from the 24 desensitised patients, 15 achieved a positive expected effect after 12 months of HDM AIT. None of the patients who received a placebo had an improvement in AD of at least 50% after 1 year of follow-up. Patients with polysensitisation less frequently achieved the expected HDM AIT effect than patients monosensitised to mites (p < 0.05). The presence of sensitisation to rDer p 1 (odds ratio = 4.35, 95% CI: 4.01-4.56) and/or rDer p 2 (OR = 2.16, 95% CI: 1.98-2.33) and/or rDer f 2 (OR = 1.41, 95% CI: 1.55-1.78) molecules significantly increased the efficacy of AIT. HDM AIT could be helpful for patients with moderate-to-severe AD and sensitised to HDM as an add-on therapy. Various HDM molecules may affect the effectiveness of the expected AIT effect. The presence of sensitisation to rDer p 1 (OR = 4.35, 95% CI: 4.01-4.56) and/or rDer p 2 (OR = 2.16, 95% CI: 1.98-2.33) and/or rDer f 2 (OR = 1.41, 95% CI: 1.55-1.78) molecules significantly increased the efficacy of AIT.

Conclusions

HDM AIT could be helpful for patients with moderate-to-severe AD and sensitised to HDM as an add-on therapy. Various HDM molecules may affect the effectiveness of the expected AIT.

Molecular Mapping of Allergen Exposome among Different Atopic Phenotypes

Climate change and exposure to environmental pollutants play a key role in the onset and aggravation of allergic diseases. As different climate-dependent patterns of molecular immunoglobulin E (IgE) reactivity have been regionally described, we sought to investigate the evolving allergen exposome in distinctive allergic phenotypes and subtropical weather conditions through a Precision Allergy Molecular Diagnosis (PAMD@) model. Concurrent sensitization to several house dust mites (HDM) and storage mite molecules were broadly dominant in the investigated cohort, followed by the major cat allergen Fel d 1, and regardless of the basal allergic disease. Although a complex repertoire of allergens was recognized, a steadily increasing number of IgE binding molecules was associated with the complexity of the underlying atopic disease. Besides the highly prevalent IgE responses to major HDM allergens, Der p 21, Der p 5, and Der p 7 also showed up as serodominant molecules, especially in subjects bothered by asthma and atopic dermatitis. The accurate characterization of the external exposome at the molecular level and their putative role as clinically relevant allergens is essential to elucidate the phenotypic diversity of atopic disease in terms of personalized diagnosis and therapy.

House dust mite allergy: The importance of house dust mite allergens for diagnosis and immunotherapy

House dust mite (HDM) allergy belongs to the most important allergies and affects approximately 65-130 million people worldwide. Additionally, untreated HDM allergy may lead to the development of severe disease manifestations such as atopic dermatitis or asthma. Diagnosis and immunotherapy of HDM allergic patients are well established but are often hampered by the use of mite extracts that are of bad quality and lack important allergens. The use of individual allergens seems to be a promising alternative to natural allergen extracts, since they represent well-defined components that can easily be produced and quantified. However, a thorough characterization of the individual allergens is required to determine their clinical relevance and to identify those allergens that are required for correct diagnosis of HDM allergy and for successful immunotherapy. This review gives an update on the individual HDM allergens and their benefits for diagnosis and immunotherapy of HDM allergic patients.

Dupilumab modulates specific IgE mite responses at the molecular level in severe T2-high atopic dermatitis: A real-world experience

Background

Atopic dermatitis (AD) is regarded as a chronic systemic disease which is characterized by a robust overexpression of type 2 related cytokines, with increased total IgE levels and a concomitant sensitization to common allergens. Dupilumab, a fully human monoclonal antibody (mAb) to IL-4Rα that inhibits both IL-4 and IL-13 signaling, has previously shown a marked and rapid improvement when treating the moderate-to-severe forms of AD. We sought to evaluate the real-world evidence (RWE) of dupilumab in the modulation of total and specific IgE (sIgE) serum levels to a panel of molecular house dust mites (HDM) and storage mites (SM) allergens in patients with severe AD.

Methods

Demographic and clinical data for severe AD adult patients receiving dupilumab treatment (300 mg every 2 weeks) were reviewed. Mean (standard deviations SD) values and percent changes from baseline in total and sIgE to the complete HDM and SM extracts, and 14 individual molecular allergens were measured over 52 weeks.

Results

Significant (p < 0.05) changes in mean total IgE levels were observed from baseline to week-52 after treatment with dupilumab. Despite no changes were found in sIgE against the extract of HDM during the 52-week treatment with dupilumab, baseline mean levels from 7 out of 14 individual molecular mite allergens -Der p 1, Der p 2, Der p 5, Der p 7, Der p 21, Der p 23, and Lep d 2- were significantly (p < 0.05) decreased—after 52 weeks of treatment with dupilumab.

Conclusions

Dupilumab therapy for 52 weeks resulted in a profound reduction in blood levels of total IgE and allergen-specific IgE to both HDM and SM at the molecular level in adults with severe AD under RWE conditions. The potential benefits of these concomitant immunomodulatory effects after treatment with dupilumab should be explored to a greater extent.