Effect of grass pollen immunotherapy on clinical and local immune response to nasal allergen challenge

Allergen immunotherapy in asthma

Allergen immunotherapy (AIT), including SCIT and SLIT, is a treatment that involves the administration of allergens to which patients with allergic diseases have been sensitized. HDM-SCIT for asthma is indicated in cases of HDM-sensitized allergic asthma with normal lung function. HDM-SCIT improves asthma symptoms and AHR, and decreases the medication dose. Importantly, AIT can improve other allergic diseases complicated by asthma, such as allergic rhinitis, which can also contribute to the improvement of asthma symptoms. Several studies have suggested that HDM-SLIT also attenuates the risk of asthma exacerbations, and improves lung function in asthma cases with allergic rhinitis. Furthermore, AIT can modify the natural course of allergic diseases, including asthma. For example, the effects of AIT are maintained for at least several years after treatment discontinuation. AIT can prevent the onset of asthma when introduced in allergic rhinitis, and can also inhibit or reduce new allergen sensitizations. Recent data have suggested that AIT may suppress non-targeted allergen-induced immune responses in addition to targeted allergen-induced responses, and suppress infections of the lower respiratory tract by enhancing IFN responses.

Blood and local eosinophil levels in chronic rhinitis: Observations during seasonal allergen exposure and non-exposure

Background

Allergic rhinitis (AR) is a typical type 2 inflammatory disease and eosinophils play a critical role of cardinal effectors in type 2 inflammation. However, the distribution of eosinophils in patients with different subtypes of rhinitis and the effect of allergen exposure on them remain understudied. The aim of this study was to investigate the characteristics and factors influencing the distribution of systemic and local eosinophils in patients with non-AR (NAR), perennial AR (PAR), and seasonal AR (SAR), as well as the effect of seasonal allergen exposure levels on eosinophils.

Methods

This was a population-based, cross-sectional observational study of consecutive chronic rhinitis (CR) outpatients who volunteered to participate in the survey during the spring pollen season and non-pollen season of 2023 in Beijing. All participants underwent serum allergen testing, blood routine examination, and nasal secretion smear cytology, and completed questionnaires mainly involving basic information, history review, and symptom assessment. Spring pollen dispersal concentration were considered.

Results

A total of 558 CR patients eligible for enrollment were collected, including 198 NAR, 204 PAR, and 156 SAR patients. PAR had the highest blood eosinophil levels and the most severe overall nasal and ocular symptoms of SAR. Compared with subjects with blood eosinophil counts <0.3 × 109/L, those with ≥0.3 × 109/L had significantly more severe nasal and ocular symptoms and a significantly higher rate of comorbid asthma and allergic conjunctivitis. Blood eosinophil levels were significantly higher in SAR patients during the pollen season compared to the non-pollen season, and pollen concentrations were positively correlated with systemic and local eosinophil levels.

Conclusions

Blood eosinophil levels varied in patients with different subtypes of rhinitis. Patients with high blood eosinophil levels had more severe overall nasal and ocular symptoms, and that blood eosinophils levels were significantly higher in patients with asthma or allergic conjunctivitis than patients without comorbidities. There was a positive trend between allergen exposure and systemic and local eosinophil levels. Further longitudinal cohort studies are still needed to better analyze the influence of eosinophil levels on the clinical traits of AR.

Utility of silver birch and house dust mite extracts derived from licensed sublingual tablets for nasal allergen challenge

BACKGROUND

Nasal allergen challenge (NAC) is used to investigate the effects of allergen exposure and assess treatment efficacy in allergic rhinitis (AR). This study aims to establish dose-responses to NAC using licensed silver birch (SB) pollen and house dust mite (HDM) sublingual tablets as sources of the allergen extracts in participants with AR.

METHODS

Sixteen volunteers with HDM-induced perennial AR and 15 volunteers with SB pollen-induced seasonal rhinitis underwent a graded up-dosing NAC with extracts derived from HDM allergen (Acarizax®) and SB (Itulazax®) tablets, respectively. Total nasal symptom score (TNSS, range 0-12) and peak nasal inspiratory flow (PNIF) were recorded before, at 10 min and at the end of the NAC. The dose of each allergen that provoked a TNSS of at least 7 ("provoking dose 7") in most allergic participants was identified. NACs using the "provoking dose 7" were performed on 5 non-allergic individuals to test for irritant effects. The "provoking dose 7" of HDM extract was used in a subgroup of two SB allergic, non-HDM allergic, volunteers, and vice versa for SB extract, to test for allergen specificity of the responses.

RESULTS

Most patients experienced a TNSS of at least 7/12 at a median concentration of 1500 AU/mL for both SB pollen and HDM. The average decline in PNIF at this dose was 63.15% for SB and 63.99% for HDM. NACs using the 1500 AU/mL concentrations were performed on 5 non-allergic individuals with no symptomatic or PNIF response. 1500 AU/mL of HDM extract produced no symptoms in SB allergics nor 1500 AU/mL SB extract in HDM allergics.

CONCLUSION

For both SB and HDM extracts, the optimal allergen dose for NAC to cause a moderate-severity response ("provoking dose 7/12") was 1500 AU/mL. Licensed sublingual allergen tablets provide a readily available and inexpensive source of SB and HDM extracts for use in future interventional studies in AR.

[Peak nasal inspiratory flow in the assessment of nasal airway obstruction]

RELEVANCE

Nasal congestion is one of the most common complaints in otolaryngology practice and can significantly impact the quality of life for patients. Objective and subjective assessments provide different information, but objective assessment of nasal obstruction is crucial for accurate diagnosis and appropriate treatment. This review demonstrates that peak nasal inspiratory flow (PNIF) is a reproducible and reliable measure of objective nasal patency. It is inexpensive, easy to use, suitable for serial measurements, and can be applied to patients of different age groups. PNIF is recommended for use in every outpatient clinic that treats patients with nasal congestion.

OBJECTIVE

To summarize the data on the application of PNIF in diagnosing conditions of the nasal airways.

MATERIAL AND METHODS

Publications (articles and relevant abstracts) available in the PubMed and eLibrary databases were analyzed.

CONCLUSION

PNIF offers an objective and non-invasive assessment of nasal airflow, aiding in diagnosis, therapy monitoring, and preoperative planning. Further research, standardization, and establishment of normative data will enhance the informative value of peak nasal inspiratory flow in assessing nasal obstruction.

Nasal IL-13 production identifies patients with late-phase allergic responses

BACKGROUND

There is limited knowledge on how local cytokine secretion patterns after nasal allergen challenge correlate with clinical symptoms especially with regard to the "late allergic response," which occurs in approximately 40% to 50% of patients with allergy.

OBJECTIVE

We sought to characterize the immunologic and clinical nasal responses to birch pollen allergen challenge with a special focus on the late allergic response.

METHODS

In this randomized, double-blind, placebo-controlled trial, birch pollen-allergic participants were challenged with birch pollen extract (n = 20) or placebo (n = 10) on 3 consecutive days. On days 1 and 3, nasal secretions were collected at selected time points over a 24-hour time course for the measurement of 33 inflammatory mediators. Clinical responses were determined through subjective symptom scores and objective nasal airflow measurements.

RESULTS

Provoked participants had significantly greater clinical responses and showed significant increases in tryptase and the soluble IL-33 receptor serum stimulation 2 (sST2) in nasal secretions within minutes compared with the placebo group. Eight of 20 provoked participants displayed high IL-13 levels 2 to 8 hours after allergen provocation. This group also showed significant changes in clinical parameters, with a secondary drop in nasal airflow measured by peak nasal inspiratory flow and increased symptoms of nasal obstruction, which significantly differed from IL-13 nonresponders after 6 hours.

CONCLUSIONS

IL-13 response status correlates with clinical responses and type 2 cytokine responses in the late phase after allergen provocation.

Immunologic, genetic, and ecological interplay of factors involved in allergic diseases

An allergic or type I hypersensitivity reaction involves a misdirected immune overreaction to innocuous environmental and dietary antigens called allergens. The genetic predisposition to allergic disease, referred to as atopy, can be expressed as a variety of manifestations-e.g., allergic rhinitis, allergic conjunctivitis, atopic dermatitis, allergic asthma, anaphylaxis. Globally, allergic diseases are one the most common types of chronic conditions. Several factors have been identified to contribute to the pathogenesis and progression of the disease, leading to distinctively variable clinical symptoms. The factors which can attenuate or exacerbate allergic reactions can range from genetic heterozygosity, the prominence of various comorbid infections, and other factors such as pollution, climate, and interactions with other organisms and organism-derived products, and the surrounding environment. As a result, the effective prevention and control of allergies remains to be one of the most prominent public health problems. Therefore, to contextualize the current knowledge about allergic reactions, this review paper attempts to synthesize different aspects of an allergic response to describe its significance in the global health scheme. Specifically, the review shall characterize the biomolecular mechanisms of the pathophysiology of the disease based on underlying disease theories and current findings on ecologic interactions and describe prevention and control strategies being utilized. An integrated perspective that considers the underlying genetic, immunologic, and ecologic aspects of the disease would enable the development of more effective and targeted diagnostic tools and therapeutic strategies for the management and control of allergic diseases.

Development of a method of nasal secretions sampling for local nasal inflammation studies

BACKGROUND

Analysis of immune markers in nasal secretions has become crucial in the study of nasal diseases. We proposed the cotton piece method, a modified method, for the collection and processing of nasal secretions.

METHODS

The nasal secretions of 31 healthy control participants and 32 patients with nasal diseases were collected by the traditional sponge method and the cotton piece method, respectively. The concentrations of 14 cytokines and chemokines related to nasal diseases were detected.

RESULTS

The properties of nasal secretions collected by the cotton piece method were more uniform than the sponge method. The concentration of IL-6 in the disease group collected by the cotton piece method was significantly higher than that in the control group (P = 0.002), and the cotton piece method could distinguish the positive detection rates of IL-1β (P = 0.031) and TNF-α (P = 0.001) between the control and disease groups. The levels of inflammatory mediators in nasal secretions could preliminarily distinguish different nasal diseases.

CONCLUSIONS

The cotton piece method is a noninvasive and reliable method for collecting nasal secretions, which is beneficial for detecting local inflammatory and immune responses of the nasal mucosa.

Potential Effects of AIT on Nonspecific Allergic Immune Responses or Symptoms

Allergen immunotherapy (AIT) is a treatment in which clinically corresponding allergens are administered to patients with allergic diseases, either by subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT), or by oral immunotherapy (OIT) in the case of food allergy. Since etiological allergens are administered to patients, AIT is presumed to modify mainly allergen-specific immune responses. In bronchial asthma, AIT with house dust mites (HDM) alleviates clinical symptoms, suppresses airway hyperresponsiveness, and reduces medication doses of HDM-sensitive asthmatics. Moreover, AIT can suppress the symptoms of other allergic diseases associated with asthma including allergic rhinitis. However, AIT sometimes reduces allergic symptoms not induced by the responsible allergens, such as non-targeted allergens, in clinical settings. Furthermore, AIT can suppress the spread of sensitization to new allergens that are not targeted allergens by AIT, suggesting the suppression of allergic immune responses in an allergen-nonspecific manner. In this review, the nonspecific suppression of allergic immune responses by AIT is discussed. AIT has been reported to increase regulatory T cells that produce IL-10, transforming growth factor-β, and IL-35, IL-10-producing regulatory B cells, and IL-10-producing innate lymphoid cells. These cells can suppress type-2 mediated immune responses mainly through the production of anti-inflammatory cytokines or a cell-cell contact mechanism, which may be involved in the nonspecific suppression of allergic immune responses by AIT.

Mechanisms of Allergen Immunotherapy and Potential Biomarkers for Clinical Evaluation

Allergen-immunotherapy (AIT) is an efficacious and disease-modifying treatment option for IgE-mediated diseases. Among these allergic rhinitis, insect venom allergy, food allergy, and allergic asthma are the most common candidates for AIT. AIT gives rise to clinical immunotolerance which may last for years after the treatment cessation. Mechanisms of AIT include suppression of allergic inflammation in target tissues and stimulation of the production of blocking antibodies, especially IgG4 and IgA. These mechanisms are followed by a reduction of underlying allergen-specific Th2 cell-driven responses to the allergens. Tolerance induction takes place through the desensitization of effector cells and stimulation of regulatory T cells that show their effects by mechanisms involving cell-cell cross-talk, but also other mechanisms, e.g., by the production of immunomodulatory cytokines such as, e.g., IL-10 and TGF-beta. From a personalized medical perspective, there is a need for clinical biomarkers of value in selecting responders and optimizing patient care during AIT. Also, a deeper understanding of underlying mechanistic processes will improve AIT's future outcomes. In this paper, the current knowledge of mechanisms in AIT is reviewed with a special focus on biomarkers of this therapy.

Immune checkpoint molecules in prevention and development of asthma

Allergic asthma is a respiratory disease initiated by type-2 immune responses characterized by secretion of alarmins, interleukin-4 (IL-4), IL-5, and IL-13, eosinophilic inflammation, and airway hyperresponsiveness (AHR). Immune checkpoints (ICPs) are inhibitory or stimulatory molecules expressed on different immune cells, tumor cells, or other cell types that regulate immune system activation and maintain immune homeostasis. Compelling evidence indicates a key role for ICPs in both the progression and prevention of asthma. There is also evidence of asthma development or exacerbation in some cancer patients receiving ICP therapy. The aim of this review is to provide an updated overview of ICPs and their roles in asthma pathogenesis, and to assess their implications as therapeutic targets in asthma.

Allergen challenge tests in allergen immunotherapy: State of the art

INTRODUCTION

Treatment effects in allergen immunotherapy (AIT) studies are based on symptomatic improvement, and evaluations of naturally exposed patients do often show weak efficacy. Allergen challenge tests, such as conjunctival (CAC), nasal (NAC), or bronchial (BAC) challenge tests, or challenges in allergen exposure chambers (AEC) are accepted by regulators for AIT phase II studies only.

MATERIALS AND METHODS

This review aims to describe different allergen challenge test methods, summarizes safety and limitations for each, and discusses their potential for use in AIT trials.

RESULTS

Organ-specific allergen challenges provide information about individual reactivity, reaction threshold, and organ-specific efficacy of AIT. AECs, targeting all affected organs simultaneously, were developed to investigate disease mechanisms and treatment effects under controlled and reproducible conditions.

CONCLUSION

A high level of standardization is existing for NAC only; in CAC and BAC, the toolbox is limited to subjective symptom scoring with no validated objective parameters identified yet. AECs are complex and heterogenous; correlation of systems and comparability of study data is claimed. All challenge methods are safe when conducted by experienced staff.

Nasal cytology can predict clinical efficacy of subcutaneous immunotherapy in intermittent allergic rhinitis

Introduction

Allergen immunotherapy (AIT) is the only disease-modifying treatment option available for patients with IgE-mediated allergic rhinitis. The identification of specific biomarkers, which may predict response to AIT, is currently an active field of research in the aspect of recommended personalization of medicine.

Aim

To assess the changes in rhinological parameters in intermittent allergic rhinitis (IAR) patients resulting from subcutaneous immunotherapy (SCIT).

Material and methods

Forty-two patients (female: 19; 45%) with IAR qualified for subcutaneous immunotherapy were enrolled in this study. Fourteen (33.3%) patients were desensitized with grass pollen allergen extracts, 12 (28.6%) with tree pollen allergen extracts, and 16 (38.1%) with grass and tree pollen allergen extracts. The patients were evaluated before AIT during the pollen season and in the next pollen season after introduction of subcutaneous immunotherapy. On both occasions, determination of total nasal symptom score (TNSS), rhinomanometry and nasal cytology were performed.

Results

All examined parameters significantly improved after one course of allergen immunotherapy: the percentage of eosinophils in nasal mucosa, TNSS and nasal resistance decreased, whereas the nasal flow rate increased. The decrease in percentage of nasal eosinophils significantly correlated with improvement in TNSS (r_s = 0.39, p < 0.05) and was the highest in the subgroup sensitive to grass pollen (44.5 (40-52)).

Conclusions

The rhinological assessment confirmed high effectiveness of SCIT in intermittent allergic rhinitis. A high percentage of eosinophils in nasal cytology before subcutaneous immunotherapy can predict its clinical efficacy for intermittent allergic rhinitis, especially in grass pollen allergy.

lncRNA FR215775 Regulates Th2 Differentiation in Murine Allergic Rhinitis

To identify the effect of long noncoding RNA (lncRNA) FR215775 in regulating CD4+ T cells on murine models of allergic rhinitis (AR), the expression of lncRNA FR215775 in primary Th2 cells was detected through qRT-PCR. After knocking down the expression of lncRNA FR215775 via Sh-FR215775-Ads, Cell Counting Kit-8, cytometric bead array, and fluorescence-activated cell sorting were performed to determine its functions in vitro. Moreover, lncRNA FR215775-silencing or nonsilencing cells were injected intravenously into AR mice. Then, hematoxylin and eosin, Alcian blue-periodic acid Schiff, and toluidine blue staining were performed, and the levels of IL-2, IL-4, IL-5, IL-6, IL-10, IL-17A, IFN-γ, and TNF in the AR mice were also determined. We found that the expression of lncRNA FR215775 was specifically higher in the murine primary Th2 cells. After the knockdown of lncRNA FR215775, the proliferation of CD4+ T cells was inhibited, and the expressions of IL-4 and IL-5 in the cell culture supernatant were significantly decreased (P < 0.001), along with the percentage of Th2 cells (P < 0.05). The lncRNA FR215775-silencing AR group showed less serious allergic symptoms and a low level of ovalbumin-specific immunoglobulin E (P < 0.01). Meanwhile, the eosinophilia inflammation, goblet cell hyperplasia, and mast cell inflammation in the nasal mucosa all decreased, which indicated attenuated allergic inflammation in the lncRNA FR215775-silencing AR group. In addition, the Th2-related cytokines IL-4 and IL-5 were downregulated in the serum and nasal lavage fluid of this group (P < 0.01). In conclusion, lncRNA FR215775 may play a vital role in the function and differentiation of Th2 cells, which may encourage allergic inflammation. These results may provide significant insights into AR pathogenesis and offer new treatment targets for alleviating AR.

Comorbid allergic rhinitis and asthma: important clinical considerations

INTRODUCTION

The numerous links between allergic rhinitis and asthma have been extensively explored in the last two decades, gaining great concern within the scientific community. These two conditions frequently coexist in the same patient and share numerous pathogenetic and pathophysiological mechanisms.

AREAS COVERED

We reviewed major pathophysiological, epidemiological, and clinical links between allergic rhinitis and asthma. We also provided a comprehensive discussion of allergic rhinitis treatment according to current guidelines, with a particular focus on the relevance of allergic rhinitis therapies in patients with comorbid asthma.

EXPERT OPINION

We believe that there are several unmet needs for our patients, however, there are promising advances forecasted for the future. Although allergic rhinitis is a recognized risk factor for asthma, a proper asthma detection and prevention plan in allergic rhinitis patients is not available. Allergen immunotherapy (AIT) represents a promising preventive strategy and may deserve an earlier positioning in allergic rhinitis management. A multidisciplinary approach should characterize the journey of patients with respiratory allergies, with an adequate referral to specialized Allergy/Asthma centers. Molecular Allergy Diagnosis may provide support for optimal AIT use. Finally, a possible evolution of biological treatment can be envisaged, mainly if biosimilars decrease such therapies' costs.

Effects of sublingual immunotherapy with tablets or drops containing Japanese cedar pollen antigens on nasal symptoms and sleep disturbance in patients with Japanese cedar pollinosis

OBJECTIVE

We examined the effects of SLIT with tablets containing JCP antigens on nasal symptoms and sleep disturbance in patients with Japanese cedar pollinosis during pollen dispersal season.

METHODS

A total of 128 patients with Japanese cedar pollinosis were categorized into four groups:19 one-year SLIT with tablets group, 16 two-year SLIT with drops group, 19 antihistamine group, and 74 untreated group. The scores of nasal symptoms and sleep disturbance were evaluated based on the Japanese guidelines for allergic rhinitis and the Athens Insomnia Scale.

RESULTS

The scores of nasal symptoms and sleep disturbance at the peak cedar pollen period in the two-year SLIT with drop group and the one-year SLIT with tablets group were significantly lower than those in untreated group. Additionally, these scores were significantly lower in the one-year SLIT with tablets group than those in the antihistamine group.

CONCLUSION

It is suggested that SLIT with JCP tablets improved both nasal symptoms and sleep disturbances at peak pollen period in patients with Japanese cedar pollinosis. SLIT with JCP tablets for one year was more effective than SLIT with JCP drops for two years and prophylactic treatment with antihistamines. J. Med. Invest. 69 : 97-100, February, 2022.

The role of allergen-specific IgE, IgG and IgA in allergic disease

Immunoglobulin E (IgE)‐mediated allergy is the most common hypersensitivity disease affecting more than 30% of the population. Exposure to even minute quantities of allergens can lead to the production of IgE antibodies in atopic individuals. This is termed allergic sensitization, which occurs mainly in early childhood. Allergen‐specific IgE then binds to the high (FcεRI) and low‐affinity receptors (FcεRII, also called CD23) for IgE on effector cells and antigen‐presenting cells. Subsequent and repeated allergen exposure increases allergen‐specific IgE levels and, by receptor cross‐linking, triggers immediate release of inflammatory mediators from mast cells and basophils whereas IgE‐facilitated allergen presentation perpetuates T cell–mediated allergic inflammation. Due to engagement of receptors which are highly selective for IgE, even tiny amounts of allergens can induce massive inflammation. Naturally occurring allergen‐specific IgG and IgA antibodies usually recognize different epitopes on allergens compared with IgE and do not efficiently interfere with allergen‐induced inflammation. However, IgG and IgA antibodies to these important IgE epitopes can be induced by allergen‐specific immunotherapy or by passive immunization. These will lead to competition with IgE for binding with the allergen and prevent allergic responses. Similarly, anti‐IgE treatment does the same by preventing IgE from binding to its receptor on mast cells and basophils. Here, we review the complex interplay of allergen‐specific IgE, IgG and IgA and the corresponding cell receptors in allergic diseases and its relevance for diagnosis, treatment and prevention of allergy.

Allergen Immunotherapy in Asthma

Allergen immunotherapy (AIT) is a specific treatment involving the administration of relevant allergens to allergic patients, with subtypes including subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT). In asthma, AIT using the house dust mite (HDM) alleviates clinical symptoms and decreases airway hyper responsiveness and medication dose. In addition, AIT can improve the natural course of asthma. For example, the effects of AIT can be preserved for at least a few years, even after ending treatment. AIT may increase the remission rate of asthma in children and suppress sensitization to new allergens. If AIT is introduced in pollinosis, AIT may prevent the development of asthma. Moreover, AIT can control other allergic diseases complicated by asthma, such as allergic rhinitis, which also improves the control of asthma. The indication of HDM-SCIT for asthma is mild-to-moderate HDM-sensitized allergic asthma in a patient with normal respiratory function. To date, HDM-SLIT is applicable in Japan for allergic rhinitis, not for asthma. However, the effect of SLIT on asthma has been confirmed internationally, and SLIT is available for asthma in Japan if allergic rhinitis is present as a complication.

Allergic Rhinitis: What Do We Know About Allergen-Specific Immunotherapy?

Allergic rhinitis (AR) is an IgE-mediated disease that is characterized by Th2 joint inflammation. Allergen-specific immunotherapy (AIT) is indicated for AR when symptoms remain uncontrolled despite medication and allergen avoidance. AIT is considered to have been effective if it alleviated allergic symptoms, decreased medication use, improved the quality of life even after treatment cessation, and prevented the progression of AR to asthma and the onset of new sensitization. AIT can be administered subcutaneously or sublingually, and novel routes are still being developed, such as intra-lymphatically and epicutaneously. AIT aims at inducing allergen tolerance through modification of innate and adaptive immunologic responses. The main mechanism of AIT is control of type 2 inflammatory cells through induction of various functional regulatory cells such as regulatory T cells (Tregs), follicular T cells (Tfr), B cells (Bregs), dendritic cells (DCregs), innate lymphoid cells (IL-10⁺ ILCs), and natural killer cells (NKregs). However, AIT has a number of disadvantages: the long treatment period required to achieve greater efficacy, high cost, systemic allergic reactions, and the absence of a biomarker for predicting treatment responders. Currently, adjunctive therapies, vaccine adjuvants, and novel vaccine technologies are being studied to overcome the problems associated with AIT. This review presents an updated overview of AIT, with a special focus on AR.

Efficacy and Safety of Subcutaneous Immunotherapy for Local Allergic Rhinitis: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Subcutaneous immunotherapy (SCIT) has been used for treating local allergic rhinitis (LAR) patients. However, the clinical efficacy and safety were still questioned.

OBJECTIVE

This study was designed to estimate the efficacy and safety of SCIT for treating LAR patients through meta-analysis.

METHODS

We systemically searched MEDLINE, Cochrane Library, and Embase publications. Randomized, double-blind, clinical trials for the efficacy and safety of Allergen Immunotherapy (AIT) for LAR were included. A meta-analysis of 4 clinical endpoints (combined symptom and medication scores [CSMS], symptom scores [SS], medication scores [MS] and rhinoconjunctivitis quality of life questionnaire [RQLQ]) and adverse events (AEs)) was performed after bias and heterogeneity assessments. The immunologic response results were summarized.

RESULTS

Four RCTs with 134 patients were included. Four studies for analyzing primary outcomes (CSMS, SS, MS) and AEs, three for RQLQ results. The results indicated an important significant difference between SCIT and placebo groups, list as follows: CSMS (SMD = -2.42, 95% CI: -3.60 to -1.25, P < .0001), SS (SMD = -2.08, 95% CI -3.68 to -0.48, P = .01), MS (SMD = -1.43, 95% CI: -2.65 to -0.21, P = 0.02), RQLQ (SMD = -0.70, 95% CI -1.29 to -0.12, P = .02), Local AEs (RR = 4.13, 95% CI 1.08 to 15.77, P = .04). For immunologic response, significantly increased serum sIgG4 levels and improvements of allergen tolerance was observed after SCIT.

CONCLUSIONS

Our meta-analysis suggests that SCIT has a significant effect on improving symptoms and reducing medicine consumption for LAR patients. Larger and multicenter clinical trials are needed to clarify the safety and long-term efficacy.

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.

Allergen immunotherapy for pediatric asthma: current evidence and knowledge gaps

PURPOSE OF REVIEW

The introduction of high-quality and standardized extracts for immunotherapy has renewed the interest in the treatment of pediatric allergic asthma that represents a high-prevalence disease.

RECENT FINDINGS

In addition to clinical trials, several systematic reviews and metaanalyses were published, confirming overall the clinical efficacy of allergen immunotherapy in pediatric asthma. In addition, new data on the preventive effect of the treatment on asthma onset were published. Despite this, many intriguing questions emerged, in parallel to the development of knowledge.

SUMMARY

Allergen immunotherapy is overall effective for the treatment of asthma in children, but a class-effect should not be claimed, rather the efficacy of each single product. According to the recent findings, the challenge for the future research will be to clarify: when to start immunotherapy in children, which are (if they exist) the predictive biomarkers for efficacy in the single individual, the magnitude of the preventive effect and the optimal duration of the treatment.

Mast Cells as a Double Edged Sword in Immunity: Disorders of Mast Cell Activation and Therapeutic Management. Second of Two Parts

Mast cells (MCs) bear many receptors that allow them to respond to a variety of exogenous and endogenous stimuli. However, MC function is dual since they can initiate pathological events or protect the host against infectious challenges. The role of MCs in disease will be analyzed in a broad sense, describing cellular and molecular mechanisms related to their involvement in auto-inflammatory diseases, asthma, autoimmune diseases and cancer. On the other hand, their protective role in the course of bacterial, fungal and parasitic infections will also be illustrated. As far as treatment of MC-derived diseases is concerned, allergen immunotherapy as well as other attempts to reduce MC-activation will be outlined according to the recent data. Finally, in agreement with current literature and our own data polyphenols have been demonstrated to attenuate type I allergic reactions and contact dermatitis in response to nickel. The use of polyphenols in these diseases will be discussed also in view of MC involvement.

Immunological Responses and Biomarkers for Allergen-Specific Immunotherapy Against Inhaled Allergens

Long-term efficacy that occurs with allergen immunotherapy of proven value is associated with decreases in IgE-dependent activation of mast cells and tissue eosinophilia. This suppression of type 2 immunity is accompanied by early induction of regulatory T cells, immune deviation in favor of T_H1 responses, and induction of local and systemic IgG, IgG₄, and IgA antibodies. These "protective" antibodies can inhibit allergen-IgE complex formation and consequent mast cell triggering and IgE-facilitated T_H2-cell activation. Recent studies have highlighted the importance of innate responses mediated by type 2 dendritic cells and innate lymphoid cells in allergic inflammation. These cell types are under the regulation of cytokines such as thymic stromal lymphopoietin and IL-33 derived from the respiratory epithelium. Novel subsets of regulatory cells induced by immunotherapy include IL-35-producing regulatory T cells, regulatory B cells, a subset of T follicular regulatory cells, and IL-10-producing group 2 innate lymphoid cells. These mechanisms point to biomarkers that require testing for their ability to predict clinical response to immunotherapy and to inform novel approaches for better efficacy, safety, and long-term tolerance.

Modulating Th2 Cell Immunity for the Treatment of Asthma

It is estimated that more than 339 million people worldwide suffer from asthma. The leading cause of asthma development is the breakdown of immune tolerance to inhaled allergens, prompting the immune system's aberrant activation. During the early phase, also known as the sensitization phase, allergen-specific T cells are activated and become central players in orchestrating the subsequent development of allergic asthma following secondary exposure to the same allergens. It is well-established that allergen-specific T helper 2 (Th2) cells play central roles in developing allergic asthma. As such, 80% of children and 60% of adult asthma cases are linked to an unwarranted Th2 cell response against respiratory allergens. Thus, targeting essential components of Th2-type inflammation using neutralizing antibodies against key Th2 modulators has recently become an attractive option for asthmatic patients with moderate to severe symptoms. In addition to directly targeting Th2 mediators, allergen immunotherapy, also known as desensitization, is focused on redirecting the allergen-specific T cells response from a Th2-type profile to a tolerogenic one. This review highlights the current understanding of the heterogeneity of the Th2 cell compartment, their contribution to allergen-induced airway inflammation, and the therapies targeting the Th2 cell pathway in asthma. Further, we discuss available new leads for successful targeting pulmonary Th2 cell responses for future therapeutics.

Induction of IL-10-producing type 2 innate lymphoid cells by allergen immunotherapy is associated with clinical response

The role of innate immune cells in allergen immunotherapy that confers immune tolerance to the sensitizing allergen is unclear. Here, we report a role of interleukin-10-producing type 2 innate lymphoid cells (IL-10⁺ ILC2s) in modulating grass-pollen allergy. We demonstrate that KLRG1⁺ but not KLRG1^- ILC2 produced IL-10 upon activation with IL-33 and retinoic acid. These cells attenuated Th responses and maintained epithelial cell integrity. IL-10⁺ KLRG1⁺ ILC2s were lower in patients with grass-pollen allergy when compared to healthy subjects. In a prospective, double-blind, placebo-controlled trial, we demonstrated that the competence of ILC2 to produce IL-10 was restored in patients who received grass-pollen sublingual immunotherapy. The underpinning mechanisms were associated with the modification of retinol metabolic pathway, cytokine-cytokine receptor interaction, and JAK-STAT signaling pathways in the ILCs. Altogether, our findings underscore the contribution of IL-10⁺ ILC2s in the disease-modifying effect by allergen immunotherapy.

From Allergy to Cancer-Clinical Usefulness of Eotaxins

Simple Summary

Eotaxins are small proteins included in the group of chemokines. They act mainly on blood cells called eosinophils which are involved in the pathogenesis of inflammatory processes. This connection leads to involvement of eotaxins in the pathogenesis of all inflammatory related diseases, such as allergic diseases and cancer. This paper summarizes the current knowledge about eotaxins, showing their usefulness as markers that can be used not only in the detection of these diseases, but also to determine the effectiveness of treatment.

Abstract

Eotaxins are proteins which belong to the group of cytokines. These small molecules are secreted by cells that are mainly involved in immune-mediated reactions in the course of allergic diseases. Eotaxins were discovered in 1994 and their main role was considered to be the selective recruitment of eosinophils. As those blood cells are involved in the course of all inflammatory diseases, including cancer, we decided to perform an extensive search of the literature pertaining to our investigation via the MEDLINE/PubMed database. On the basis of available literature, we can assume that eotaxins can be used as markers for the detection and determination of origin or type of allergic disease. Many publications also confirm that eotaxins can be used in the determination of allergic disease treatment. Moreover, there are also studies indicating a connection between eotaxins and cancer. Some researchers revealed that CCL11 (C-C motif chemokine ligand 11, eotaxin-1) concentrations differed between the control and tested groups indicating their possible usefulness in cancer detection. Furthermore, some papers showed usefulness of eotaxins in determining the treatment efficacy as markers of decreasing inflammation. Therefore, in this paper we present the current knowledge on eotaxins in the course of allergic and cancerous diseases.

Mechanisms of Allergen Immunotherapy in Allergic Rhinitis

PURPOSE OF REVIEW

Allergic rhinitis (AR) is a chronic inflammatory immunoglobulin (Ig) E-mediated disease of the nasal mucosa that can be triggered by the inhalation of seasonal or perennial allergens. Typical symptoms include sneezing, rhinorrhea, nasal itching, nasal congestion and symptoms of allergic conjunctivitis. AR affects a quarter of the population in the United States of America and Europe.

RECENT FINDINGS

AR has been shown to reduce work productivity in 36-59% of the patients with 20% reporting deteriorated job attendance. Moreover, 42% of children with AR report reduced at-school productivity and lower grades. Most importantly, AR impacts the patient's quality of life, due to sleep deprivation. However, a proportion of patients fails to respond to conventional medication and opts for the allergen immunotherapy (AIT), which currently is the only disease-modifying therapeutic option. AIT can be administered by either subcutaneous (SCIT) or sublingual (SLIT) route. Both routes of administration are safe, effective, and can lead to tolerance lasting years after treatment cessation. Both innate and adaptive immune responses that contribute to allergic inflammation are suppressed by AIT. Innate responses are ameliorated by reducing local mast cell, basophil, eosinophil, and circulating group 2 innate lymphoid cell frequencies which is accompanied by decreased basophil sensitivity. Induction of allergen-specific blocking antibodies, immunosuppressive cytokines, and regulatory T and B cell phenotypes are key pro-tolerogenic adaptive immune responses.

CONCLUSION

A comprehensive understanding of these mechanisms is necessary for optimal selection of AIT-responsive patients and monitoring treatment efficacy. Moreover, it could inspire novel and more efficient AIT approaches.

Role of Allergen Immunotherapy in Asthma Treatment and Asthma Development

Allergen immunotherapy may modify the natural course of allergic diseases and induce remission. It includes subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT). For asthma, allergen immunotherapy using house dust mite (HDM) improves clinical symptoms and airway hyperresponsiveness and decreases drug requirements. Furthermore, it has been suggested that allergen immunotherapy also has the following effects: (1) the effect can be maintained for more than a year even if the treatment is terminated, (2) the remission rate of childhood asthma can be increased, (3) new allergen sensitization can be suppressed, and (4) asthma development can be prevented if allergen immunotherapy was performed in the case of pollinosis. Allergen immunotherapy differs from conventional drug therapy, in particular the effect of modifying the natural course of allergic diseases and the effect of controlling complicated allergic diseases such as rhinoconjunctivitis. The general indication for HDM-SCIT in asthma is HDM-sensitized atopic asthma with mild-to-moderate disease and normal respiratory function. HDM allergens should be involved in the pathogenesis of asthma, and a duration of illness of less than 10 years is desirable. HDM-SLIT is available for allergic rhinitis but not for asthma in Japan. However, as the efficacy of SLIT for asthma has been fully proven internationally, SLIT is also applied in asthmatics with complicated allergic rhinitis in Japan.

Altered chromatin landscape in circulating T follicular helper and regulatory cells following grass pollen subcutaneous and sublingual immunotherapy

BACKGROUND

Allergen-specific immunotherapy is a disease-modifying treatment that induces long-term T-cell tolerance.

OBJECTIVE

We sought to evaluate the role of circulating CXCR5⁺PD-1⁺ T follicular helper (cT_FH) and T follicular regulatory (T_FR) cells following grass pollen subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) and the accompanying changes in their chromatin landscape.

METHODS

Phenotype and function of cT_FH cells were initially evaluated in the grass pollen-allergic (GPA) group (n = 28) and nonatopic healthy controls (NAC, n = 13) by mathematical algorithms developed to manage high-dimensional data and cell culture, respectively. cT_FH and T_FR cells were further enumerated in NAC (n = 12), GPA (n = 14), SCIT- (n = 10), and SLIT- (n = 8) treated groups. Chromatin accessibility in cT_FH and T_FR cells was assessed by assay for transposase-accessible chromatin sequencing (ATAC-seq) to investigate epigenetic mechanisms underlying the differences between NAC, GPA, SCIT, and SLIT groups.

RESULTS

cT_FH cells were shown to be distinct from T_H2- and T_H2A-cell subsets, capable of secreting IL-4 and IL-21. Both cytokines synergistically promoted B-cell class switching to IgE and plasma cell differentiation. Grass pollen allergen induced cT_FH-cell proliferation in the GPA group but not in the NAC group (P < .05). cT_FH cells were higher in the GPA group compared with the NAC group and were lower in the SCIT and SLIT groups (P < .01). Time-dependent induction of IL-4, IL-21, and IL-6 was observed in nasal mucosa following intranasal allergen challenge in the GPA group but not in SCIT and SLIT groups. T_FR and IL-10⁺ cT_FH cells were induced in SCIT and SLIT groups (all, P < .01). ATAC-seq analyses revealed differentially accessible chromatin regions in all groups.

CONCLUSIONS

For the first time, we showed dysregulation of cT_FH cells in the GPA group compared to NAC, SCIT, and SLIT groups and induction of T_FR and IL-10⁺ cT_FH cells following SCIT and SLIT. Changes in the chromatin landscape were observed following allergen-specific immunotherapy in cT_FH and T_FR cells.

Mechanisms of allergen-specific immunotherapy and allergen tolerance

Allergen-specific immunotherapy (AIT) is the mainstay treatment for the cure of allergic disorders, with depicted efficacy and safety by several trials and meta-analysis. AIT impressively contributes to the management of allergic rhinitis, asthma and venom allergies. Food allergy is a new arena for AIT with promising results, especially via novel administration routes. Cell subsets with regulatory capacities are induced during AIT. IL-10 and transforming growth factor (TGF)-β are the main suppressor cytokines, in addition to surface molecules such as cytotoxic T-lymphocyte-associated antigen-4 (CTLA-4) and programmed cell death protein-1 (PD-1) within the micro milieu. Modified T- and B-cell responses and antibody isotypes, increased activity thresholds for eosinophils, basophils and mast cells and consequent limitation of inflammatory cascades altogether induce and maintain a state of sustained allergen-specific unresponsiveness. Established tolerance is reflected into the clinical perspectives as improvement of allergy symptoms together with reduced medication requirements and evolved disease severity. Long treatment durations, costs, reduced patient compliance and risk of severe, even life-threatening adverse reactions during treatment stand as major limiting factors for AIT. By development of purified non-allergenic, highly-immunogenic modified allergen extracts, and combinational usage of them with novel adjuvant molecules via new routes may shorten treatment durations and possibly reduce these drawbacks. AIT is the best model for custom-tailored therapy of allergic disorders. Better characterization of disease endotypes, definition of specific biomarkers for diagnosis and therapy follow-up, as well as precision medicine approaches may further contribute to success of AIT in management of allergic disorders.

Mechanisms of allergen-specific immunotherapy for allergic rhinitis and food allergies

Allergen-specific immunotherapy (AIT) is currently the only potential treatment for allergies including allergic rhinitis (AR) and food allergies (FA) that can modify the underlying course of the diseases. Although AIT has been performed for over a century, the precise and detailed mechanism for AIT is still unclear. Previous clinical trials have reported that successful AIT induces the reinstatement of tolerance against the specific allergen. In this review, we aim to provide an updated summary of the knowledge on the underlying mechanisms of IgE-mediated AR and FA as well as the immunological changes observed after AIT and discuss on how better understanding of these can lead to possible identification of biomarkers and novel strategies for AIT.

Nasal allergen challenge and environmental exposure chamber challenge: A randomized trial comparing clinical and biological responses to cat allergen

BACKGROUND

The direct-instillation nasal allergen challenge (NAC) and the environmental exposure chamber (EEC) are 2 methods of conducting controlled allergen provocations. The clinical and biological comparability of these methods has not been thoroughly investigated.

OBJECTIVE

We sought to compare clinical and immunologic responses to cat allergen in NAC versus EEC.

METHODS

Twenty-four participants were randomized to receive either NAC followed by a 2-day challenge in an EEC or a 2-day challenge in an EEC followed by NAC. Challenges were separated by 28-day washout periods. We measured total nasal symptom scores, peak nasal inspiratory flow, nasal (0-8 hours) and serum cytokines, serum antibodies, peripheral blood antigen-specific T lymphocytes, and gene expression in nasal scrapings. The primary outcome was the total nasal symptom score area under the curve for the first 3 hours after allergen exposure in NAC or after initiation of exposure in EEC.

RESULTS

Both challenges increased IL-5 and IL-13 in nasal fluids and serum and resulted in altered nasal cell expression of gene modules related to mucosal biology and transcriptional regulation. Changes in gene modules, more so than cytokine measurements, showed significant associations with total nasal symptom score and peak nasal inspiratory flow. Overall, EEC exposure generated larger responses and more early terminations compared with NAC. Although the 2 challenges did not correlate in symptom magnitude or temporality, striking correlations were observed in cytokine levels.

CONCLUSIONS

Although clinical outcomes of NAC and EEC were temporally different and nonequivalent in magnitude, immunologic responses were similar. Selection of a particular allergen challenge method should depend on considerations of study objectives and cost.

Relationship between serum inhibitory activity for IgE and efficacy of Artemisia pollen subcutaneous immunotherapy for allergic rhinitis: a preliminary self-controlled study

Background

Biomarkers of clinical efficacy for subcutaneous immunotherapy (SCIT) on allergic rhinitis (AR) have not been identified yet. This study aims to assess the clinical relevance of serum inhibitory activity for IgE by the method of enzyme-linked immunosorbent facilitated antigen binding (ELIFAB) during SCIT for Artemisia-sensitized AR patients.

Methods

19 AR patients were studied who had undergone Artemisia-specific SCIT for more than 8 months (19.68 months on average, ranging from 9 to 33 months). Peripheral bloods were collected before and after treatment. The serum inhibitory activity for IgE was tested by ELIFAB and the level of Artemisia-specific IgG4 (Artemisia-sIgG4) was determined by ELISA. Clinical improvement was evaluated based on the symptom scores and rescue medication use (SMS). The 2-tailed Wilcoxon signed-rank test and the Spearman rank test (two-tailed) were used to analyze data by using SPSS 20.0, with P values of less than 0.05 considered as significant.

Results

The SMS decreased significantly after SCIT (before: 12.79 ± 4.250, after: 6.11 ± 3.828, P = 0.000 < 0.01), the treatment was remarkably effective for 6 patients, effective for 10 and ineffective for 3, along with a total effective rate 84.21%. The serum inhibitory activity for IgE increased significantly after SCIT (P < 0.05) and was correlated with the levels of Artemisia-sIgG4 (r = − 0.501, P = 0.002 < 0.01). The levels of Artemisia-sIgG4 elevated dramatically after treatment (P < 0.01) and were related with the duration of treatment (r = 0.558, P = 0.000 < 0.01). But there was no relationship between clinical improvements and the serum inhibitory activity for IgE.

Conclusions

The serum inhibitory activity for IgE increased significantly after SCIT, however, there was no correlation between it and clinical improvements by statistics analysis. So whether the serum inhibitory activity for IgE can act as biomarker of efficacy for SCIT or not needs to be studied further.

Effect of Dermatophagoides pteronyssinus Immunotherapy on Upper and Lower Airway Eosinophilic Inflammatory Response to Nasal Allergen Challenge

Purpose

It remains unknown whether allergen-specific immunotherapy (AIT) could attenuate airway inflammatory response triggered by allergen exposure.

Methods

We performed Dermatophagoides pteronyssinus (Der-p) nasal provocation tests (NPTs) in allergic rhinitis (AR) and/or asthma patients without AIT (non-AIT), or at 16, 52, 104, or 156 weeks after Der-p AIT. Rhinitis and asthma visual analog scale (VAS; VAS of nasal symptoms [VAS-NS], VAS of asthma symptoms), the rhinoconjunctivitis quality of life questionnaire (RQLQ), nasal lavage, sputum induction, fractional exhaled nitric oxide (FeNO), nasal airway resistance, pulmonary function, and airway hyperresponsiveness were performed before and after NPT.

Results

Non-AIT subjects demonstrated significantly higher VAS-NS before and after NPT compared to AIT subjects (P < 0.05). NPT response was positive in 14 (100%) non-AIT, 7 (70%) 16 weeks-AIT, 6 (60%) 52 weeks-AIT, 6 (60%) 104 weeks-AIT, and 2 (20%) 156 weeks-AIT subjects. The NPT grade significantly correlated with AIT duration and baseline RQLQ score (r = −0.561, P < 0.001 and r = 0.525, P < 0.001, respectively). Sputum and nasal lavage eosinophil count, and FeNO in non-AIT subjects were significantly increased 6 hours after NPT (P < 0.05). AIT subjects did not change their sputum or nasal lavage eosinophil count before and after NPT. Subjects with 156 weeks-AIT demonstrated significantly lower levels of sputum and nasal lavage eosinophil count before and after NPT when compared with non-AIT patients (P < 0.05). Sputum eosinophil counts positively correlated with nasal lavage eosinophil counts at baseline and 6 hours after NPT (r = 0.719, P = 0.006 and r = 0.823, P < 0.001, respectively) in non-AIT patients.

Conclusion

Our results show that AIT can attenuate both upper and lower airway immune response to nasal allergen exposure in patients with AR and/or asthma.

Recent developments and highlights in immune monitoring of allergen immunotherapy

Allergic diseases are the most common chronic immune-mediated disorders and can manifest with an enormous diversity in clinical severity and symptoms. Underlying mechanisms for the adverse immune response to allergens and its downregulation by treatment are still being revealed. As a result, there have been, and still are, major challenges in diagnosis, prediction of disease progression/evolution and treatment. Currently, the only corrective treatment available is allergen immunotherapy (AIT). AIT modifies the immune response through long-term repeated exposure to defined doses of allergen. However, as the treatment usually needs to be continued for several years to be effective, and can be accompanied by adverse reactions, many patients face difficulties completing their schedule. Long-term therapy also potentially incurs high costs. Therefore, there is a great need for objective markers to predict or to monitor individual patient's beneficial changes in immune response during therapy so that efficacy can be identified as early as possible. In this review, we specifically address recent technical developments that have generated new insights into allergic disease pathogenesis, and how these could potentially be translated into routine laboratory assays for disease monitoring during AIT that are relatively inexpensive, robust and scalable.

Transcriptome analysis and safety profile of the early-phase clinical response to an adjuvanted grass allergoid immunotherapy

Background

Specific immunotherapy is the only type of disease-modifying treatment, which induces rapid desensitization and long-term sustained unresponsiveness in patients with seasonal allergic rhinoconjunctivitis. The safety and tolerability of a new cumulative dose regimen of 35600 SU Grass MATA MPL for subcutaneous immunotherapy were assessed in pre-seasonal, single-blind, placebo controlled Phase I clinical study. Underlying immunological mechanisms were explored using transcriptome analysis of peripheral blood mononuclear cells.

Methods

Study subjects with a history of moderate to severe seasonal allergic rhinitis and/or conjunctivitis (SAR) due to grass (Pooideae) pollen exposure were randomized on a 1:1 ratio to receive either six 1.0 mL injections of cumulative dose regimen 35600 SU of Grass MATA MPL or placebo. The study consisted of three periods: screening, randomization and treatment and End of Study period. Blood samples were taken for clinical safety laboratory assessments and for the assessment of gene expression analysis during screening visit and End of Study visit. The safety statistics was calculated using Fisher's exact test. Delta Delta Ct method analysis of RT² Profiler PCR Array gene expression results was used to calculate changes in gene expression level. Genes with the absolute value of log₂ fold change greater than ±1.1 and p-value less than 0.05 were identified as differentially expressed and underwent IPA data analysis.

Results

The results of the study indicated that the higher cumulative dose regimen of the immunotherapy was well-tolerated. Changes in gene expression profile were associated with early immune responses implicating innate and adaptive immune mechanisms. Pathways and mechanistic network analysis via IPA mapped differentially expressed genes onto canonical pathways related to T cell differentiation, cytokine signalling and Th1/Th2 activation pathways. The transcriptome findings of the study could be further verified in large-scale field studies in order to explore their potential as predictive markers of successful immunotherapy.

Conclusions

The higher dose cumulative regime 35600 SU of Grass MATA MPL vaccine was well tolerated and safe. Molecular markers IL-27, IL-10, IL-4, TNF, IFNγ, TGFβ and TLR4 were the main predicted molecular drivers of the observed gene expression changes following early stages of SIT with Grass MATA MPL immunotherapy.

Is it worthy to take full-course immunotherapy for allergic rhinitis? About efficacy biomarker of allergen immunotherapy

Nowadays, people pay more attention to biomarkers that can predict clinical efficacy of immunotherapy for allergic rhinitis. As the only recognized aetiological treatment, the efficacy of allergen immunotherapy (AIT) has been proved by many studies. However, treatment success depends on compliance and persistence greatly, which can be impaired by the lengthy duration of AIT and socioeconomic status of patients. Besides, ineffectiveness is another factor that accounts for non-adherence. If the clinical efficacy can be predicted in the early stage of immunotherapy, it can help patients choose appropriate treatment plans, increase patient compliance and optimize the allocation of medical resources. This paper mainly focuses on five candidate biomarkers, the sIgE/tIgE ratio before treatment, serum inhibitory activity for IgE, decreased basophil activation, upregulation of Tregs and tolerogenic DCs, reviews the time when potential biomarkers can predict or monitor the efficacy of AIT, discusses the reason why these indicators could serve as efficacy biomarkers and interactions among potential biomarkers.

Tear cytokine levels in allergic rhinitis without ocular symptoms

OBJECTIVE

To compare cytokine levels in the pre-corneal tear film between patients with allergic rhinitis, allergic rhinoconjunctivitis and the normal population.

DESIGN

A comparative cross sectional study.

PARTICIPANTS

Patients were divided into Group 1 (allergic rhinitis without conjunctivitis), Group 2 (allergic rhinoconjunctivitis), and Group 3 (normal population).

METHODS

A comparative cross-sectional study was conducted. Patients were divided into; Group 1 (allergic rhinitis without conjunctivitis), Group 2 (allergic rhinoconjunctivitis), and Group 3 (normal controls). Tears were collected using Schirmer strips and cytokine analysis performed using enzyme linked immunosorbent assay.

RESULTS

There were a total of 68 subjects. Median values of cytokines in the allergic rhinitis group were as follows; TNFa (45.34 pg/ml), IL-4 (61.91 pg/ml), IL-5 (8.92 pg/ml), IL-6 (538.37 pg/ml) and IL-8 (1438.72 pg/ml). Cytokine levels in the group with allergic rhinoconjunctivitis were approximately two-fold higher than in the group with allergic rhinitis only. The median cytokine level in the control group was lowest. A significant inter-group difference was observed for TNF-alpha, IL-4, IL-6 and IL-8 levels, with allergic rhinoconjunctivitis patients demonstrating significantly elevated cytokines compared to those with allergic rhinitis only (p<0.001). These four cytokines were also significantly higher in those with allergic rhinitis than in controls (p<0.005). Although the group with allergic rhinoconjunctivitis had the highest levels of IL-5, no statistically significant inter-group difference was noted (p=0.479).

CONCLUSION

This study demonstrated the presence of raised tear film inflammatory cytokines even in allergic rhinitis patients without ocular symptoms. These patients may be at increased risk of developing allergic conjunctivitis. These findings not only substantiate the immunological theory of the naso-ocular reflex, but have clinical and therapeutic implications for the holistic management of allergic rhinitis and conjunctivitis.

Nasal challenges in allergen immunotherapy trials

PURPOSE OF REVIEW

The nasal allergen challenge (NAC) model can be a valuable diagnostic tool for allergic rhinitis. Alongside its clinical use, NACs can be used as primary and secondary endpoints in studies evaluating allergen immunotherapy (AIT) products for allergic rhinitis treatment. This review will discuss the technical aspects of the NAC model and provide a summary of recent studies using NACs to assess existing and new AIT treatments.

RECENT FINDINGS

Over the last 2 years, both titrated and single-dose nasal challenge protocols have been used to evaluate immunotherapies targeting grass, birch, house dust mite, and cat allergens. Early efficacy and dose-finding trials showed improvements in allergic symptoms and nasal tolerance to allergens after AIT treatment with standardized extracts or modified forms of whole allergen. NACs were also used in two proof-of-concept studies to illustrate the efficacy of intralymphatic immunotherapy with two concomitant allergens and subcutaneous immunotherapy with Fel d 1-specific IgG-blocking antibodies.

SUMMARY

Along with existing therapies, nasal challenges are useful in evaluating AIT treatments in the very early stages of clinical development. However, because of the variety in challenge techniques and symptom assessments available, special attention must be placed in the protocol design in order to compare the study results with existing NAC publications.

Der p 1-specific regulatory T-cell response during house dust mite allergen immunotherapy

BACKGROUND

Allergen-specific immunotherapy (AIT) is the only available treatment for allergic diseases that can induce specific immune tolerance to allergens. The key mechanisms involved in this process include changes in allergen-specific regulatory T (Treg) cells.

METHODS

We studied 25 allergic rhinitis patients undergoing subcutaneous house dust mite-specific immunotherapy. Peripheral blood mononuclear cells were studied before and after 10, 30 weeks, and 3 years of AIT. Der p 1-specific T regulatory cell responses were investigated by characterization of Der p 1-MHC class II tetramer-positive cells and correlated with nasal symptom score.

RESULTS

Twelve of 25 AIT patients matched with their MHC class II expression to the Der p 1 peptide-MHC class II tetramers. A significant increase in the numbers of Der p 1-specific FOXP3⁺ Helios⁺ CD25⁺ CD127^- Treg cells after 30 weeks was observed, which slightly decreased after 3 years of AIT. In contrast, Der p 1-specific immunoglobulin-like transcript 3 (ILT3)⁺ CD25⁺ Treg cells decreased substantially from baseline after 3 years of AIT. ILT3⁺ Treg cells displayed compromised suppressive function and low FOXP3 expression. In addition, Der p 1-specific IL-10 and IL-22 responses have increased after 30 weeks, but only IL-10⁺ Der p 1-specific Treg cells remained present at high frequency after 3 years of AIT. Increased number of FOXP3⁺ Helios⁺ and IL-10⁺ and decreased ILT3⁺ Treg cell responses correlated with improved allergic symptoms.

CONCLUSION

The results indicate that AIT involves upregulation of the activated allergen-specific Treg cells and downregulation of dysfunctional allergen-specific Treg cell subset. Correction of dysregulated Treg cells responses during AIT is associated with improved clinical response.

Allergen-Specific Antibodies Regulate Secondary Allergen-Specific Immune Responses

Immunoglobulin E (IgE)-associated allergy is the most common immunologically-mediated hypersensensitivity disease. It is based on the production of IgE antibodies and T cell responses against per se innocuous antigens (i.e., allergens) and subsequent allergen-induced inflammation in genetically pre-disposed individuals. While allergen exposure in sensitized subjects mainly boosts IgE production and T cell activation, successful allergen-specific immunotherapy (AIT) induces the production of allergen-specific IgG antibodies and reduces T cell activity. Under both circumstances, the resulting allergen-antibody complexes play a major role in modulating secondary allergen-specific immune responses: Allergen-IgE complexes induce mast cell and basophil activation and perpetuate allergen-specific T cell responses via presentation of allergen by allergen presenting cells to T cells, a process called IgE-facilitated antigen presentation (FAP). In addition, they may induce activation of IgE memory B cells. Allergen-induced production of specific IgGs usually exerts ameliorating effects but under certain circumstances may also contribute to exacerbation. Allergen-specific IgG antibodies induced by AIT which compete with IgE for allergen binding (i.e., blocking IgG) inhibit formation of IgE-allergen complexes and reduce activation of effector cells, B cells and indirectly T cells as FAP is prevented. Experimental data provide evidence that by binding of allergen-specific IgG to epitopes different from those recognized by IgE, allergen-specific IgG may enhance IgE-mediated activation of mast cells, basophils and allergen-specific IgE⁺ B cells. In this review we provide an overview about the role of allergen-specific antibodies in regulating secondary allergen-specific immune responses.

EAACI Position paper on the standardization of nasal allergen challenges

Nasal allergen challenge (NAC) is an important tool to diagnose allergic rhinitis. In daily clinical routine, experimentally, or when measuring therapeutic success clinically, nasal allergen challenge is fundamental. It is further one of the key diagnostic tools when initiating specific allergen immunotherapy. So far, national recommendations offered guidance on its execution; however, international divergence left many questions unanswered. These differences in the literature caused EAACI to initiate a task force to answer unmet needs and find a consensus in executing nasal allergen challenge. On the basis of a systematic review containing nasal allergen challenges of the past years, task force members reviewed evidence, discussed open issues, and studied variations of several subjective and objective assessment parameters to propose a standardized way of a nasal allergen challenge procedure in clinical practice. Besides an update on indications, contraindications, and preparations for the test procedure, main recommendations are a bilaterally challenge with standardized allergens, with a spray device offering 0.1 mL per nostril. A systematic catalogue for positivity criteria is given for the variety of established subjective and objective assessment methods as well as a schedule for the challenge procedure. The task force recommends a unified protocol for NAC for daily clinical practice, aiming at eliminating the previous difficulty of comparing NAC results due to unmet needs.

Biomarkers of immunotherapy response in patients with allergic rhinitis

INTRODUCTION

Allergen immunotherapy represents the only disease-modifying therapy available for immunoglobulin E-mediated diseases such as allergic rhinitis and asthma. Allergen immunotherapy induces allergen tolerance by interfering with the immune-pathogenic mechanisms of the allergic response and is potentially able to provide long-term relief of symptoms of allergic rhinitis and asthma and alter the natural course of allergic diseases. Areas covered: Since allergen immunotherapy (AIT) is actually considered an individualized treatment on patient's clinical and immunological profile, the identification of specific biomarkers, which may guide diagnosis, management, and predict response to AIT treatment in allergic rhinitis (AR) patients, is essential and is currently an active field of research. Expert commentary: The identification and validation of biomarkers of successful AIT for AR is an urgent need to definitively establish the role of AIT as a therapeutic tool of personalized medicine.

Mechanisms of allergen-specific immunotherapy: Diverse mechanisms of immune tolerance to allergens

OBJECTIVE

The aim of this review is to provide an overview of the current knowledge on the mechanisms of allergen immunotherapy based on the recent publications and clinical trials.

DATA SOURCES

PubMed literature review.

STUDY SELECTIONS

In this review, we focus on diverse mechanisms of AIT and provide an insight into alternative routes of administration. Additionally, we review and discuss the most recent studies investigating potential biomarkers and highlight their role in clinical settings.

RESULTS

Successful allergen-specific immunotherapy (AIT) induces the reinstatement of tolerance toward allergens and represents a disease-modifying treatment. In the last decades, substantial progress in understanding the mechanisms of AIT has been achieved. Establishment of long-term clinical tolerance to allergens engages a complex network of interactions, modulating the functions of basophils, mast cells, allergen-specific regulatory T and B cells, and production of specific antibodies. The reduction of symptoms and clinical improvement is achieved by skewing the immune response away from allergic inflammation.

CONCLUSION

Although the complex nature of AIT mechanisms is becoming more clear, the need to discover reliable biomarkers to define patients likely to respond to the treatment is emerging.