Sublingual allergen immunotherapy with a liquid birch pollen product in patients with seasonal allergic rhinoconjunctivitis with or without asthma

IL-10-modulated dendritic cells from birch pollen- and hazelnut-allergic patients facilitate Treg-mediated allergen-specific and cross-reactive tolerance

BACKGROUND

Approximately 70% of individuals allergic to birch pollen (Bet v 1.01 [Bet]) develop a secondary food allergy (e.g., hazelnut: Cor a 1.04 [Cor]), due to allergen cross-reactivity. However, standard immunotherapy for type I allergies often does not improve the food allergy sufficiently. We analyzed the allergen-specific and cross-reactive suppressive capacity of primary human regulatory T cells (Treg) induced by autologous IL-10-modulated dendritic cells (IL-10 DC) in vitro and in vivo.

METHODS

CD4+ T cells of patients with birch pollen and associated hazelnut allergies were differentiated into Bet-specific or non-specific induced Treg (iTreg). After Bet- or Cor-specific restimulation the phenotype, proliferation, and suppressive capacity of iTreg subsets were analyzed. iTreg function was further investigated in humanized mouse models of airway and intestinal allergy, generated by engraftment of peripheral blood mononuclear cells from allergic donors into immunodeficient animals.

RESULTS

After IL-10 DC priming and allergen-specific restimulation (Bet or Cor), non-specific control iTreg remained anergic, whereas Bet-specific iTreg proliferated extensively and exhibited a regulatory phenotype (enhanced expression of CTLA-4, PD-1, TNFR2, IL-10). Accordingly, activated Bet-specific iTreg displayed a high capacity to suppress Bet- and Cor-induced responder Th2 cell responses in vitro, indicating induction of both allergen-specific (birch) and cross-reactive tolerance (hazelnut). In vivo, the beneficial effect of Bet-specific iTreg was verified in humanized mouse models of allergic airway and intestinal inflammation, resulting in reduced allergen-induced clinical symptoms, and immune responses.

CONCLUSION

Human IL-10 DC-induced iTreg facilitate allergen-specific and cross-reactive tolerance. Therefore, they are potential candidates for regulatory cell therapy in allergic and autoimmune diseases.

Allergen Immunotherapy: The Evidence Supporting the Efficacy and Safety of Subcutaneous Immunotherapy and Sublingual Forms of Immunotherapy for Allergic Rhinitis/Conjunctivitis and Asthma

Allergen immunotherapy (AIT) is a recognized key therapeutic modality for the treatment of allergic respiratory disease. Definitive studies have provided evidence-based data to demonstrate its effectiveness in allergic rhinitis and asthma due to the inhalation of proteinaceous allergic substances from specific seasonal pollens, dust mites, animal allergens, and certain mold spores. Over the ensuing decades, laboratory investigations have provided objective evidence to demonstrate immunologic changes, including production of protective IgG antibody, suppression of IgE antibody, upregulation of regulatory T cells, and induction of a state of immune tolerance to the offending allergen(s). Tangential to this work were carefully designed clinical studies that defined allergen dose and duration of treatment, established the importance of preparing extracts with standardized allergens (or well-defined extracts) based on major protein moieties, and used allergen provocation models to demonstrate efficacy superior to placebo. In the United States, the use of subcutaneous immunotherapy extracts for AIT was grandfathered in by the Food and Drug Administration based on expert literature review. In contrast, sublingual tablet immunotherapy underwent formal clinical development programs (phase I-III clinical trials) that provided the necessary clinical evidence for safety and efficacy that led to regulatory agency approvals for the treatment of allergic rhinitis in properly characterized patients with allergy. The allergy specialist's treatment options currently include traditional subcutaneous AIT and specific sublingual tablets approved for grass, ragweed, house dust mites, trees belonging to the birch-homologous group, and Japanese cedar. Tangential to this are sublingual drops that are increasingly being used off-label (albeit not approved by the Food and Drug Administration) in the United States. This article will review the evidence-based literature supporting the use of these forms of AIT, as well as focus on several current controversies and gaps in our knowledge base that have relevance for the appropriate selection of patients for treatment with specific AIT.

A randomized, double-blind, placebo-controlled trial with mannan-conjugated birch pollen allergoids

BACKGROUND

There is still great need to develop new strategies to improve the efficacy of allergen immunotherapies with optimal safety standards for patients. A new promising approach is to couple allergoids to mannan. The objective of this phase IIa/IIb study was to identify the optimal dose of mannan-conjugated birch pollen allergoids for the short-course treatment of birch pollen-induced allergic rhinoconjunctivitis.

METHODS

For this prospective, randomized, double-blind, placebo-controlled, dose-finding study, 246 birch pollen-allergic adults received 0.5 mL placebo or 1000, 3000 or 10,000 mTU/mL of mannan-conjugated birch pollen allergoids at five pre-seasonal visits. Efficacy was assessed by comparing allergic rhinoconjunctivitis symptoms and use of anti-allergic medication during the peak of the birch pollen season 2020. Immunologic, tolerability and safety effects were also analysed.

RESULTS

The highest dose of mannan-conjugated birch pollen allergoids reduced the combined symptom and medication score during the peak birch pollen season by a median of 24.7% compared to placebo. The production of Bet v 1 specific IgG4 significantly increased in a dose-dependent manner (3.6- and 4.5-fold) in the 3000 and 10,000 mTU/mL groups. The Bet v 1 specific IgE/IgG4 ratio was also strongly reduced (up to -70%). No fatalities nor serious adverse events were reported, and no adrenaline was used. In total, four systemic reactions occurred (two grade I and two grade II).

CONCLUSION

All doses of mannan-conjugated birch pollen allergoids can be considered as safe. Since the application of 10,000 mTU/mL resulted in the highest efficacy, this dose qualifies for further investigation.

Clinical relevance of pre- and coseasonal sublingual immunotherapy with a 300 index of reactivity 5-grass SLIT tablet in allergic rhinoconjunctivitis

BACKGROUND

There is considerable interest in improving the scoring methods for evaluating the efficacy of allergen immunotherapy (AIT) and to show if this is associated with clinically meaningful results from the patient's perspective. We aimed to assess the efficacy and clinical relevance of a 300 index of reactivity (IR) 5-grass pollen sublingual immunotherapy (SLIT) tablet in children, adolescents and adults with moderate to severe grass-induced allergic rhinoconjunctivitis (ARC) with or without controlled asthma using the combined symptom and medication score CSMS0-36 .

METHODS

The data of the European population that participated in 3 Phase III, international, randomized double-blind placebo-controlled clinical trials were analyzed post hoc.

RESULTS

A total of 864 patients randomized to 300 IR 5-grass tablet or placebo were analyzed. Over the primary evaluation period, the difference in CSMS0-36 between the 300 IR and placebo groups was statistically significant (point estimates: -2.51, CI95% [-3.88; -1.14], p < 0.0001 in clinical trial1; -2.31, CI95% [-3.39; -1.23], p < 0.0001 in CT2; and -2.31, CI95% [-3.58; -1.03], p = 0.0004 in CT3). The relative differences between the 300 IR 5-grass tablet and placebo were -29.7%, -33.8%, and -26.3%, respectively. The results based on CSMS0-36 were consistent with those obtained with the primary endpoints of the trials and support the consideration of the 2-point threshold of the CSMS0-36 for clinical relevance of AIT.

CONCLUSION

Post hoc analysis of 3 CTs with the 300 IR 5-grass SLIT tablet confirmed its significant and clinically relevant effect in the European population with grass pollen-induced ARC with or without controlled asthma.

Tolerability and Safety of Sublingual Immunotherapy in Patients with Tree Pollen Allergy in Daily Practice-An Open, Prospective, Non-Interventional Study

To investigate the tolerability and safety of two sublingual tree pollen extracts approved in 2018, a non-interventional study (NIS) was performed. This NIS was an 8-month observational study conducted at 84 sites throughout Germany. Study participants received either a sublingual liquid allergen extract of birch pollen (SBPE) or a liquid allergen extract consisting of a mixture of birch, hazel, and alder tree pollen (STPE). Data from 432 patients were analyzed for the occurrence of adverse events and patient compliance. At least one local reaction occurred in 69 (22.2%) patients, whereas systemic reactions were only observed in 27 (6.3%) patients. STPE-treated patients developed systemic reactions more frequently than SBPE-treated patients (SBPE: 9 (4.3%) vs. STPE: 18 (8.0%)). Only one patient developed a systemic grade III reaction. Severe systemic grade IV reactions were not observed. A total of 348 (98.6%) of the patients who completed all visits were satisfied or very satisfied with the sublingual immunotherapy (SLIT), and 322 (71%) patients completed all visits. Both investigated products were well tolerated by the patients and demonstrated a good safety profile. AEs were observed less frequently than in the preceding clinical phase III trial, and no new safety concerns were identified.

Correlation of the combined symptom and medication score with quality of life, symptom severity and symptom control in allergic rhinoconjunctivitis

Background

The European Academy of Allergy and Clinical Immunology recommended the Combined Symptom and Medication Score (CSMS) as primary endpoint in clinical trials on allergen‐specific immunotherapy (AIT) in allergic rhinoconjunctivitis. Here, the correlation between the CSMS and the validated standardised Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ(S)), Rhinitis Control Assessment Test (RCAT) and Visual Analogue Scale (VAS) was analysed.

Methods

Two prospective, multicentre, non‐interventional studies on tree pollen, grass pollen and house dust mite allergic patients were performed. The first study comprised 167 patients receiving AIT (AIT population), and the second included 56 patients treated with symptomatic medication only (control population). For up to two seasons (pollen)/exposure periods (house dust mites), participants documented their symptoms and medication intake in a CSMS diary, including VAS. In addition, the standardised RQLQ(S) and the RCAT were completed during study visits.

Results

Comparison between CSMS and RQLQ(S) revealed a positive correlation in the AIT population (r = 0.426) and in the control population (r = 0.569). For CSMS and RCAT, a negative correlation with r = −0.409 (AIT) and r = −0.547 (control) was shown. Positive correlation between CSMS and VAS was also demonstrated with r = 0.585 (AIT) and r = 0.563 (control).

Conclusion

These results support the assumption that the CSMS correlates with quality of life, symptom severity and symptom control on the one hand, while the moderate strength of correlations on the other hand mirrors distinctions of the CSMS compared to the assessments used here.

Effect of acupuncture at the sphenopalatine ganglion for the treatment of moderate to severe seasonal allergic rhinitis: Study protocol for a three-armed randomized controlled trial

Introduction

Seasonal allergic rhinitis (SAR) is a major health problem with a relatively high worldwide prevalence that severely limits the quality of life for sufferers. Acupuncture is widely used for SAR treatment in China; however, the evidence on the efficacy of acupuncture at the sphenopalatine ganglion (SPG) for SAR is inconclusive. Therefore, this study aims to investigate the efficacy and safety of acupuncture at the SPG acupoint for the treatment of SAR.

Methods and analysis

A total of 120 participants with SAR will be recruited and randomly assigned to the acupuncture group, placebo acupuncture (PA) group, or rescue medication (RM) group with a 1:1:1 allocation ratio. Participants in the acupuncture group and PA group will receive 8 sessions of acupuncture stimulus at the SPG plus RM or 8 sessions of shallow needling at the SPG acupoint plus RM for 4 weeks with a 4-week follow-up in the first year and a 1-week follow-up in the second year. Participants in the RM group will only receive RM throughout the study. The primary outcome is the change from baseline in the average daily combined symptoms and medication score (CSMS) over weeks 1–4. All analysis will be based on an intention-to-treat principle. All statistical tests will be two-sided and a p-value < 0.05 will be considered to be statistically significant.

The Role of Allergen-Specific Immunotherapy in ENT Diseases: A Systematic Review

Previous studies have demonstrated that both subcutaneous (SCIT) and sublingual specific immunotherapy (SLIT) are effective in treating allergic rhinitis (AR). Further studies have evaluated the efficacy of allergen-specific immunotherapy (AIT) on different ear, nose, and throat (ENT) manifestations, in which allergy might have an etiopathogenetic role, such as local allergic rhinitis (LAR), rhinosinusitis (RS), otitis media (OM), and adenotonsillar (AT) disease. Nevertheless, the management of allergy in ENT diseases is still debated. To the best of our knowledge, this is the first systematic review assessing the efficacy of AIT in ENT diseases aside from AR. Literature data confirmed that AIT might be an effective therapeutic option in LAR, although its effect is restricted to studies with short-term follow-up. Furthermore, previous research demonstrated that AIT may improve symptoms and surgical outcomes of chronic rhinosinusitis when used as an adjunctive treatment. Few studies supported the hypothesis that AIT may exert positive therapeutic effects on recurrent upper airway infections as adenotonsillar disease. Finally, some clinical observations suggested that AIT may add some benefits in the management of otitis media with effusion (OME). The results of this systematic review allow us to conclude that the efficacy of AIT in ENT disorders has been only slightly investigated and additional studies are needed.

One hundred and ten years of Allergen Immunotherapy: A journey from empiric observation to evidence

One hundred and ten years after Noon's first clinical report of the subcutaneous application of allergen extracts, allergen immunotherapy (AIT) has evolved as the most important pillar of the treatment of allergic patients. It is the only disease-modifying treatment option available and the evidence for its clinical efficacy and safety is broad and undisputed. Throughout recent decades, more insights into the underlying mechanisms, in particular the modulation of innate and adaptive immune responses, have been described. AIT is acknowledged by worldwide regulatory authorities, and following the regulatory guidelines for product development, AIT products are subject to a rigorous evaluation before obtaining market authorization. Knowledge and practice are anchored in international guidelines, such as the recently published series of the European Academy of Allergy and Clinical Immunology (EAACI). Innovative approaches continue to be further developed with the focus on clinical improvement by, for example, the usage of adjuvants, peptides, recombinants, modification of allergens, new routes of administration, and the concomitant use of biologicals. In addition, real-life data provide complementary and valuable information on the effectiveness and tolerability of this treatment option in the clinical routine. New mobile health technologies and big-data approaches will improve daily treatment convenience, adherence, and efficacy of AIT. However, the current coronavirus disease 2019 (COVID-19) pandemic has also had some implications for the feasibility and practicability of AIT. Taken together, AIT as the only disease-modifying therapy in allergic diseases has been broadly investigated over the past 110 years laying the path for innovations and further improvement.

Dogmas, challenges, and promises in phase III allergen immunotherapy studies

The concept of treatment of an allergy with the offending allergen was introduced more than a century ago. Allergen immunotherapy (AIT) is the only disease modifying treatment of allergic diseases caused by inhalational allergens and insect venoms. Despite this, only few AIT products have reached licensure in the US or an official marketing authorization status in European countries. Moreover, most of these AIT products are provided on an individual patient basis as named patient products (NPP) in Europe, while individualized preparations of (mixed) allergenic extract vials for subcutaneous administration (compounding) is common practice in the US. AIT products are generally considered safe and well tolerated, but the major practical clinical development challenge is to define the optimal dose and prove the efficacy and safety of these products using state-of-the art Phase II and pivotal Phase III studies. In planning Phase II-III AIT studies, a thorough understanding of the study challenges is essential (e.g. variability and non-validated status of subjective primary endpoints, limitations of pollen season definitions) and dogmas of these products (e.g., for sublingual immunotherapy (SLIT) trials double-blinding conditions cannot be maintained, resulting in stronger placebo responses in the active treatment group and inflated treatment effects in Phase III). There is future promise for more objective biomarker endpoints (e.g. basophil activation (CD63 and CD203c), subsets of regulatory dendritic, T and B cells, IL-10–producing group 2 innate lymphoid cells; alone or in combination) to overcome several of these dogmas and challenges; innovation in AIT clinical trials can only progress with integral biomarker research to complement the traditional endpoints in Phase II-III clinical development. The aim of this paper is to provide an overview of these dogmas, challenges and recommendations based on published data, to facilitate the design of Phase III studies and improve the evidence basis of safe and effective AIT products.

Pollen forecasting and its relevance in pollen allergen avoidance

Pollinosis and allergic asthma are respiratory diseases of global relevance, heavily affecting the quality of life of allergic subjects. Since there is not a decisive cure yet, pollen allergic subjects need to avoid exposure to high pollen allergens concentrations. For this purpose, pollen forecasting is an essential tool that needs to be reliable and easily accessible. While forecasting methods are rapidly evolving towards more complex statistical and physical models, the use of simple and traditional methods is still preferred in routine predictions. In this review, we summarise and explain the main parameters considered when forecasting pollen, and classify the different forecasting methods in two groups: observation-based and process-based. Finally, we compare these approaches based on their usefulness to allergic patients, and discuss possible future developments of the field.

Management of adult asthma and chronic rhinitis as one airway disease

Introduction: Chronic rhinitis is defined as nasal inflammation with the presence of minimum two symptoms such as nasal obstruction, rhinorrhea, sneezing and/or itching one hour daily for a minimum of 12 weeks/year. According their etiology, four groups of rhinitis are described: allergic, infectious, non-allergic non-infectious and mixed.Chronic rhinitis is frequently associated with asthma, shares similar mechanisms of the pathogenesis and has a negative impact of its outcomes sustaining the concept of unified airways disease.Areas covered: The present review summarizes the complex relationship between chronic rhinitis and asthma on the basis of recent epidemiological data, clinical characteristics, diagnosis and therapeutic management. All four groups are discussed with the impact of their specific treatment on asthma outcomes. Some medications are common for chronic rhinitis and asthma while others are more specific but able to treat the associated comorbidity.Expert opinion: The systematic assessment of chronic rhinitis in patients with asthma and its specific treatment improves both disease outcomes. Conversely, several therapies of asthma demonstrated beneficial effects on chronic rhinitis. Treating both diseases at the same time by only one medication is an interesting option to explore in the future in order to limit drugs administration, related costs and side effects.

Advancement of antigen-specific immunotherapy: knowledge transfer between allergy and autoimmunity

Targeted restoration of immunological tolerance to self-antigens or innocuous environmental allergens represents the ultimate aim of treatment options in autoimmune and allergic disease. Antigen-specific immunotherapy (ASI) is the only intervention that has proven disease-modifying efficacy as evidenced by induction of long-term remission in a number of allergic conditions. Mounting evidence is now indicating that specific targeting of pathogenic T cells in autoinflammatory and autoimmune settings enables effective restoration of immune homeostasis between effector and regulatory cells and alters the immunological course of disease. Here, we discuss the key lessons learned during the development of antigen-specific immunotherapies and how these can be applied to inform future interventions. Armed with this knowledge and current high-throughput technology to track immune cell phenotype and function, it may no longer be a matter of ‘if’ but ‘when’ this ultimate aim of targeted tolerance restoration is realised.

Subcutaneous Versus Sublingual Immunotherapy for Adults with Allergic Rhinitis: A Systematic Review with Meta-Analyses

OBJECTIVES

To determine whether subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT) better improves patient outcomes and quality of life for adults with allergic rhinitis or rhinoconjunctivitis (AR/C) with or without mild to moderate asthma.

METHODS

Systematic review methodology was based on the Cochrane Collaboration handbook and Preferred Reporting Items for Systematic Reviews and Meta-analyses. Four databases (PubMed, Cochrane Library, EMBASE, and Web of Science) were queried from inception to July 30, 2020. Two independent reviewers screened potentially relevant studies and assessed risk of bias. Outcomes of interest were symptom score (SS), medication score (MS), combined symptom medication score (CSMS), and Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ). Meta-analyses with an adjusted indirect comparison were conducted in RevMan 5.4.1.

RESULTS

Seven SCIT versus SLIT randomized controlled trials (RCTs) demonstrated no significant differences for any outcomes, but insufficient data precluded direct meta-analysis. For the adjusted indirect comparison, 46 RCTs over 39 studies were included for SCIT versus placebo (n = 13) and SLIT versus placebo (n = 33). Statistically significant results favoring SCIT were found for SS (standardized mean difference [SMD] = 0.40; 95% confidence interval [CI] = 0.31-0.49), MS (SMD = 0.26; 95% CI = 0.14-0.39), CSMS (SMD = 0.42; 95% CI = 0.17-0.67), and RQLQ (MD = 0.24; 95% CI = 0.04-0.44). Statistically significant results favoring SLIT were found for SS (SMD = 0.42; 95% CI = 0.32-0.53), MS (SMD = 0.40; 95% CI = 0.28-0.53), CSMS (SMD = 0.37; 95% CI = 0.29-0.45), and RQLQ (MD = 0.32; 95% CI = 0.20-0.43). No significant differences were found between SCIT and SLIT for SS (SMD = -0.02; 95% CI = -0.15 to 0.11), MS (SMD = -0.14; 95% CI = -0.31 to 0.03), CSMS (SMD = 0.05; 95% CI = -0.21 to 0.31), or RQLQ (MD = -0.08; 95% CI = -0.31 to 0.15).

CONCLUSION

SCIT and SLIT are comparably effective treatments for adults with AR/C. More RCTs analyzing SCIT versus SLIT are needed to directly compare the two. Laryngoscope, 2021.

Placebo effects in allergen immunotherapy-An EAACI Task Force Position Paper

The placebo (Latin "I will please") effect commonly occurs in clinical trials. The psychological and physiological factors associated with patients' expectations about a treatment's positive and negative effects have yet to be well characterized, although a functional prefrontal cortex and intense bidirectional communication between the central nervous system and the immune system appear to be prerequisites for a placebo effect. The use of placebo raises certain ethical issues, especially if patients in a placebo group are denied an effective treatment for a long period of time. The placebo effect appears to be relatively large (up to 77%, relative to pretreatment scores) in controlled clinical trials of allergen immunotherapy (AIT), such as the pivotal, double-blind, placebo-controlled (DBPC) randomized clinical trials currently required by regulatory authorities worldwide. The European Academy of Allergy and Clinical Immunology (EAACI) therefore initiated a Task Force, in order to better understand the placebo effect in AIT and its specific role in comorbidities, blinding issues, adherence, measurement time points, variability and the natural course of the disease. In this Position Paper, the EAACI Task Force highlights several important topics regarding the placebo effect in AIT such as a) regulatory aspects, b) neuroimmunological and psychological mechanisms, c) placebo effect sizes in AIT trials, d) methodological limitations in AIT trial design and e) potential solutions in future AIT trial design. In conclusion, this Position Paper aims to examine the methodological problem of placebo in AIT from different aspects and also to highlight unmet needs and possible solutions for future trials.

Oral birch pollen immunotherapy with apples: Results of a phase II clinical pilot study

BACKGROUND

Seventy percent of patients suffering from birch pollen allergy (BPA) develop a pollen-related food allergy (prFA), especially to apples, due to a clinically relevant cross-reactivity between the major allergen in birch Bet v 1 and Mal d 1 in apples. Therefore allergen-specific immunotherapy with fresh apples (AITA) could be a promising natural treatment of both BPA and prFA.

OBJECTIVE

To assess the clinical efficacy of immunotherapy by daily apple consumption for patients with BPA and prFA.

METHODS

A daily defined increasing amount of selected cultivars (Red Moon®, Pink Lady®, Topaz, Golden Delicious) was continuously consumed by 16 patients (12 female; median age; 50; range, 23-68 years), leading to increased intake of allergen over a period of at least 8 months. Specific IgE and IgG₄ to Bet v 1 and Mal d 1, conjunctival and oral provocation tests, skin reactivity, and the average daily rhinoconjunctivitis combined symptom and medication score (CSMS) were measured during the peak birch pollen season.

RESULTS

After 8 months of therapy, patients showed increased tolerance to apples (p < .001) and a decreased skin reactivity to apples. Oral allergy syndrome to other birch prFA than apple also decreased (p < .05). Moreover, daily rhinoconjunctivitis CSMS declined by 34% (p < .001), as did conjunctival reactivity to birch pollen extract by 27% (p < .01), while specific IgG₄ to Mal d 1 and Bet v 1 increased (p < .01).

Insights Into Mucosal Innate Immune Responses in House Dust Mite-Mediated Allergic Asthma

The prevalence of asthma has been rising steadily for several decades, and continues to be a major public health and global economic burden due to both direct and indirect costs. Asthma is defined as chronic heterogeneous inflammatory diseases characterized by airway obstruction, mucus production and bronchospasm. Different endotypes of asthma are being recognized based on the distinct pathophysiology, genetic predisposition, age, prognosis, and response to remedies. Mucosal innate response to environmental triggers such as pollen, cigarette smoke, fragrances, viral infection, and house dust mite (HDM) are now recognized to play an important role in allergic asthma. HDM are the most pervasive allergens that co-habitat with us, as they are ubiquitous in-house dusts, mattress and bedsheets, and feed on a diet of exfoliated human skin flakes. Dermatophagoides pteronyssinus, is one among several HDM identified up to date. During the last decade, extensive studies have been fundamental in elucidating the interactions between HDM allergens, the host immune systems and airways. Moreover, the paradigm in the field of HDM-mediated allergy has been shifted away from being solely a Th2-geared to a complex response orchestrated via extensive crosstalk between the epithelium, professional antigen presenting cells (APCs) and components of the adaptive immunity. In fact, HDM have several lessons to teach us about their allergenicity, the complex interactions that stimulate innate immunity in initiating and perpetuating the lung inflammation. Herein, we review main allergens of Dermatophagoides pteronyssinus and their interactions with immunological sentinels that promote allergic sensitization and activation of innate immunity, which is critical for the development of the Th2 biased adaptive immunity to HDM allergens and development of allergic asthma.

Biomarkers for diagnosis and prediction of therapy responses in allergic diseases and asthma

Modern health care requires a proactive and individualized response to diseases, combining precision diagnosis and personalized treatment. Accordingly, the approach to patients with allergic diseases encompasses novel developments in the area of personalized medicine, disease phenotyping and endotyping, and the development and application of reliable biomarkers. A detailed clinical history and physical examination followed by the detection of IgE immunoreactivity against specific allergens still represents the state of the art. However, nowadays, further emphasis focuses on the optimization of diagnostic and therapeutic standards and a large number of studies have been investigating the biomarkers of allergic diseases, including asthma, atopic dermatitis, allergic rhinitis, food allergy, urticaria and anaphylaxis. Various biomarkers have been developed by omics technologies, some of which lead to a better classification of distinct phenotypes or endotypes. The introduction of biologicals to clinical practice increases the need for biomarkers for patient selection, prediction of outcomes and monitoring, to allow for an adequate choice of the duration of these costly and long‐lasting therapies. Escalating healthcare costs together with questions about the efficacy of the current management of allergic diseases require further development of a biomarker‐driven approach. Here, we review biomarkers in diagnosis and treatment of asthma, atopic dermatitis, allergic rhinitis, viral infections, chronic rhinosinusitis, food allergy, drug hypersensitivity and allergen immunotherapy with a special emphasis on specific IgE, the microbiome and the epithelial barrier. In addition, EAACI guidelines on biologicals are discussed within the perspective of biomarkers.

Decreased numbers of metachromatic cells in nasal swabs in Japanese cedar pollinosis following sublingual immunotherapy

Background and Objective

Nasal symptoms were reduced following allergen‐specific sublingual immunotherapy (SLIT) for allergic rhinitis. The mechanisms underlying the effectiveness of SLIT for Japanese cedar pollinosis are poorly understood. We studied changes in the numbers of metachromatic cells, eosinophils, and neutrophils following SLIT for Japanese cedar pollinosis.

Methods

Nasal swabs were taken in the preseason (n = 32) and in pollinosis season (n = 49) from subjects given sublingual drop immunotherapy for an average duration of 1.5 years. The numbers of metachromatic cells (mast cells and basophils), eosinophils and neutrophils were determined and compared with those from untreated subjects in preseason (n = 65) and in season (n = 54).

Results

SLIT subjects had a significantly reduced frequency of moderate to most severe symptoms in comparison to untreated subjects in preseason (P < .001, the Mann‐Whitney U test), and (P < .00001) in season. Metachromatic cell counts in nasal swabs of SLIT subjects in preseason and in season were lower than those of untreated subjects (P = .014, the Mann‐Whitney U test) and (P = .00001) respectively. Eosinophil numbers in SLIT subjects were not significantly different than in untreated subjects in both preseason (P = .29) and in season (P = .09). However, when SLIT subjects in season were divided into those with greater than or equal to 1.5 years, or <1.5 years of SLIT duration, the degree of eosinophilia in those with SLIT greater than or equal to 1.5 years was significantly lower (P = .011) than in untreated patients, but not in those with SLIT less than 1.5 years (P = .9). There were no significant differences in neutrophil numbers in nasal swabs between untreated and SLIT subjects in preseason and in season.

Conclusion

One of mechanisms underlying the effectiveness of sublingual drop immunotherapy for Japanese cedar pollinosis is a reduction of the number of metachromatic cells in preseason and in season. Eosinophilia was also reduced in season in those given SLIT for greater than or equal to 1.5 years.

Clinical trials in allergen immunotherapy in the age group of children and adolescents: current concepts and future needs

Allergen immunotherapy (AIT) is the only treatment option available for allergic patients with disease-modifying intention. Both efficacy and safety has been demonstrated for multiple trials in children, adolescents and adults. Though regulatory requirements for marketing authorization have been clearly outlined and an increasing number of high quality trials has been initiated, multiple concepts and details in study design may be further elaborated, harmonized and improved. An international group of experts in the field of AIT has thoroughly reviewed and discussed current concepts and provided an outlook on further improvement especially in the age group of children and adolescents. Emphasis of the group's discussion as a basis for this article was put on (i) the regulatory background of marketing authorization of AIT products including the 'Pediatric Investigational Plan', (ii) patient reported outcomes and endpoints in AIT trials, (iii) considerations regarding the 'minimal clinically important difference', (iv) the role of placebo effects in AIT clinical trials and clinical routine and (v) the potential of mobile Health for future development of AIT. Current concepts in AIT have been optimized throughout the recent decades, but there remains room for improvement e.g., in the topics outlined in this article.

Allergen-specific immunotherapy with apples: selected cultivars could be a promising tool for birch pollen allergy

Background

Most birch pollen‐allergic patients develop allergic cross‐reactions to the major allergen found in apples Mal d1, known as pollen‐related food allergy (prFA). This is due to a strong clinically relevant homology between the major allergen in birch Bet v 1 and Mal d 1. Daily apple consumption induces oral tolerance in prFA, but its effect on the inhalational allergy has not been investigated.

Objectives

As continuous apple consumption might also mitigate the inhalational allergy, this study aimed to uncover apple cultivars suitable for treatment of birch pollen rhinoconjunctivitis and apple allergy in a controlled and established dosage.

Methods

Patients (n = 52) with birch pollen allergy and prFA to apples were subjected to a prick‐to‐prick test (SPT) with 23 cultivars (red‐fleshed, old traditional and new commercial). By SPT, the apple parts flesh, peel equatorial and peel apical near the stalk were compared for their reactivity. One apple cultivar of each allergenicity class (low, middle and high) was subsequently tested in an oral provocation test (OPT).

Results

According to the SPTs, we provide a ranking of all 23 cultivars. Red‐fleshed apples displayed the lowest reactivity, followed by old and new cultivars. Four cultivars showed disagreement from their allergenicity class: Santana and Pink Lady®, new cultivars that provoked only low to moderate. In contrast, White Rosemary and Goldparmäne, two old cultivars, induced strong reactions. Skin reactivity increased from flesh to peel to stalk, and SPT results could predict the severity of prFA of each allergenicity class.

Conclusions

Herein, we propose a treatment protocol for allergen immunotherapy to birch pollen and prFA with daily apple consumption. Red‐fleshed, old and the new cultivars Santana and Pink Lady® provoke less allergic reactions and are suitable for initial induction. After a controlled and well‐tolerated increase of intake, also moderate and finally high allergenic apple cultivars should be integrated into treatment of birch pollen allergenic patients.

Linked Commentary: K.‐C. Bergmann. J Eur Acad Dermatol Venereol 2020; 34: 1130–1130. https://doi.org/10.1111/jdv.16556.

Perspectives in allergen immunotherapy: 2019 and beyond

The seventh "Future of the Allergists and Specific Immunotherapy (FASIT)" workshop held in 2019 provided a platform for global experts from academia, allergy clinics, regulatory authorities and industry to review current developments in the field of allergen immunotherapy (AIT). Key domains of the meeting included the following: (a) Biomarkers for AIT and allergic asthma; (b) visions for the future of AIT; (c) progress and data for AIT in asthma and the updates of GINA and EAACI Asthma Guidelines (separated for house dust mite SCIT, SLIT tablets and SLIT drops; patient populations) including a review of clinically relevant endpoints in AIT studies in asthma; (d) regulatory prerequisites such as the "Therapy Allergen Ordinance" in Germany; (e) optimization of trial design in AIT clinical research; (f) challenges planning and conducting phase III (field) studies and the future role of Allergen Exposure Chambers (AEC) in AIT product development from the regulatory point of view. We report a summary of panel discussions of all six domains and highlight unmet needs and possible solutions for the future.

Advances in aeroallergen immunotherapy

PURPOSE OF REVIEW

Allergic rhinoconjunctivitis is the most common manifestation of allergic disease. This break in the normal natural function of the immune system to ignore harmless molecules such as pollen and pet dander to now aggressively react has lead to a substantial disease burden that is not always recognized and adequately treated.

RECENT FINDINGS

Individual molecular component testing may increase the predictive value of blood sIgE and clinical symptoms. Defining the most symptoms inducing allergenic protein has led to advances in peptide-based allergen immunotherapy. There have been steady consistent reports that allergy immunotherapy for children with symptomatic allergic rhinitis prevents the onset of asthma.

SUMMARY

Allergy immunotherapy is an effective disease-modulating treatment that alters the underlying immune dysfunction which is a currently underutilized therapy especially as it is likely effective in preventing the onset of asthma in children, at least in the short term.

Allergen immunotherapy in asthma: current evidence

Background: Allergic asthma is the predominant phenotype in clinical practice. Allergen immunotherapy is the only curative and specific approach for the treatment of allergies with clinical benefits for several years after its discontinuation. Despite advances, the use of allergen immunotherapy in allergic asthma is still suboptimal and controversial.Objective: The purpose of this article is to review the published data about the impact of allergen immunotherapy with the most commonly used allergen extracts on allergic asthma outcomes, including both clinical parameters and patients' subjective experience (quality of life).Methods: As data sources several databases were used, including PubMed, Scopus, Web of Science (2002-2019) and search in English and Spanish languages was performed using the following terms: "allergen immunotherapy" and "asthma" in combination with "house dust mite", "birch pollen", "grass pollen", "olive tree pollen", "molds", "pets" and "asthma quality of life". Randomised control trials and meta-analysis from reviewed publications were selected.Results: Emerging data relating to the positive impact on asthma outcomes of allergen immunotherapy allows the addition of this treatment as a therapeutic option in mild to moderate asthmatics sensitized to house dust mite and pollens. Limited data are available for patients sensitized to molds and pets, as well in severe allergic asthma population.Conclusion: Allergen immunotherapy remains a potential therapeutic option for some patients with allergic asthma. Further research is needed to define the optimal period of treatment, the possible therapeutic role in the treatment of severe allergic asthma, and the cost-effectiveness of allergen immunotherapy in asthmatic patients.

Birch pollen allergy in Europe

Birch and other related trees of the families Betulaceae and Fagaceae (alder, hazel, oak, hornbeam, chestnut, and beech) constitute the birch homologous group. This grouping is primarily based on the extensive IgE cross-reactivity of allergen homologs to the major birch allergen Bet v 1. Birch pollen is the most dominant tree pollen in Northern and Central Europe and is a major cause of allergic rhinitis and, possibly, asthma symptoms. Over the last few decades, levels of birch pollen have risen and the period of exposure has increased due to climate changes. Subsequently, the prevalence of birch pollen sensitization has also increased. The cross-reactivity and sequential pollen seasons within the birch homologous group create a prolonged symptomatic allergy period beyond birch pollen alone. Furthermore, many plant food allergens contain homologs to Bet v 1, meaning that the majority of patients with birch pollen allergy suffer from secondary pollen food syndrome (PFS). As a result, the negative impact on health-related quality of life (HRQoL) in patients allergic to birch pollen is significant. The purpose of this manuscript was to narratively review topics of interest such as taxonomy, cross-reactivity, prevalence, clinical relevance, PFS, and HRQoL with regard to birch pollen allergy from a European perspective.