Allergen immunotherapy in allergic respiratory diseases: from mechanisms to meta-analyses

Efficacy and safety of sublingual versus subcutaneous immunotherapy in children with allergic rhinitis: a systematic review and meta-analysis

Aim

To systematically compare the efficacy and safety of subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) in children with allergic rhinitis (AR).

Methods

PubMed, Embase, Cochrane Library, and Web of Science were searched from inception to March 2, 2023. Outcomes included symptom scores (SSs), medication scores (MSs), symptom and medication scores (SMSs), new sensitizations, development of asthma, improvement, and treatment-related adverse events (TRAEs). The quality of the included studies was assessed by the modified Jadad scale and Newcastle-Ottawa scale (NOS). Meta-regression was carried out to explore the source of heterogeneity. Subgroup analysis was further conducted in terms of study design [randomized controlled trials (RCTs), cohort studies], allergen [house dust mites (HDMs), grass pollen], treatment duration (≥ 24, 12-23 or < 12 months), allergen immunotherapy (AIT) modality (drops or tablets), and AIT protocol [continuous, pre-seasonal, co-seasonal, or after the grass pollen season (GPS)]. Sensitivity analysis was conducted for all outcomes. A Bayesian framework and a Monte Carlo Markov Chain (MCMC) model were developed for indirect comparison.

Results

Totally 50 studies with 10813 AR children were included, with 4122 treated with SLIT, 1852 treated with SCIT, and 4839 treated with non-SLIT or non-SCIT therapy. For direct comparison, the SLIT group had a similar SS to the SCIT group [pooled standardized mean difference (SMD): 0.41, 95% confidence interval (CI): -0.46, 1.28, P = 0.353]. Comparable MSs were observed in the SLIT and SCIT groups (pooled SMD: 0.82, 95%CI: -0.88, 2.53, P = 0.344). For indirect comparison, no significant differences were found in SSs (pooled SMD: 1.20, 95% credibility interval (CrI): -1.70, 4.10), MSs (pooled SMD: 0.57, 95%CrI: -1.20, 2.30), SMSs (pooled SMD: 1.80, 95%CrI: -0.005, 3.60), new sensitizations [pooled relative risk (RR): 0.34, 95%CrI: 0.03, 3.58], and development of asthma (pooled RR: 0.68, 95%CrI: 0.01, 26.33) between the SLIT and SCIT groups; the SLIT group illustrated a significantly lower incidence of TRAEs than the SCIT group (pooled RR: 0.17, 95%CrI: 0.11, 0.26).

Conclusion

Considering both efficacy and safety, SLIT might be a more favorable AIT than SCIT in the treatment of pediatric AR, which may serve as a decision-making reference for clinicians.

Systematic review registration

PROSPERO (CRD42023460693).

The Prevalence and Impact of Allergic Rhinitis on Academic Performance and Quality of Life Among Medical Students in Saudi Arabia

BACKGROUND

Allergic Rhinitis (AR) has a negative impact on both patients and society. Our study aims to assess the impact of allergic rhinitis on the academic performance and quality of life of medical students in Saudi Arabia.

METHODOLOGY

A cross-sectional survey targeted medical students in Saudi Arabia; a total of 851 students were included. The survey included questions on sociodemographic characteristics, academic year and GPA, Score for Allergic Rhinitis (SFAR), and Rhino-sinusitis Disability Index (RSDI).

RESULTS

We found that about 340 students (39.9%) had AR. The RSDI for students with AR was 34.9 ‡ 28.8, significantly higher than those with no AR (17.0 + 23.6),p<0.001. The relationship between AR and students* GPAs showed that those who had not experienced AR significantly had comparatively good PAs and above. In contrast, those who had experienced AR had poor GPAs (p<0.001). Similarly, students with AR had significantly missed classes more than those who had not experienced AR (p<0.001).

CONCLUSION

The study showed that Allergic rhinitis negatively impacted Medical Students' academic performance and quality of life. It impacts wakefulness, and sleeping patterns can have a negative impact on academic performance.

Allergen immunotherapy for allergic asthma: The future seems bright

Allergen specific immunotherapy (AIT) is the only causal therapeutic option for allergic airway diseases including asthma and allergic rhinitis. AIT has been shown to restore the allergen immune tolerance, can modify both the early and late-onset allergen-specific airway hyperreactivity, helps to achieve disease control/remission and prevents new sensitisations. Recent real life data on long-term effectiveness of house dust mite (HDM) AIT in a large group of patients with HDM-driven asthma further underscored its unique therapeutic potential as well as confirmed previous data with pollen AIT. More widespread use of this causal treatment in select patient populations should further move this promising therapeutic field. In this mini-review, we discuss updates on new insights based on real world patient data.

Phenotypes and Endotypes in Asthma

Asthma is a broadly encompassing diagnosis of airway inflammation with significant variability in presentation and response. Advances in molecular techniques and imaging have unraveled the delicate mechanistic tapestry responsible for the underlying inflammatory pathways in asthma. The elucidation of biomarkers and cellular components specific to these inflammatory pathways allowed for the categorization of asthma from generic phenotypes to more specific mechanistic endotypes, with two prominent subgroups emerging based on the level of Type 2 inflammation present - T2 high and T2 low (or non-T2). Sophisticated modeling and cluster analyses using a combination of clinical, physiologic, and biomarker parameters have permitted the identification of subendotypes within the broader T2 umbrella. This mechanistic-driven classification schema for asthma has dramatically altered the landscape of asthma management with the discovery and approval of targeted biologic therapies and has ushered in a new era of personalized precision medicine in asthma.

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.

Alteration of lung tissues proteins in birch pollen induced asthma mice before and after SCIT

Subcutaneous immunotherapy (SCIT) is a classic form of allergen-specific immunotherapy that is used to treat birch pollen induced allergic asthma. To investigate the underlying molecular mechanisms of SCIT, we aimed to profile lung samples to explore changes in the differential proteome before and after SCIT in mice with allergic asthma. Fresh lungs were collected from three groups of female BALB/c mice: 1) control mice, 2) birch pollen-induced allergic mice, and 3) birch pollen-induced allergic mice with SCIT. Tandem mass tag (TMT) labelling coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to analyze the lung proteome in the mice. Ingenuity pathway analysis (IPA) and Gene Ontology (GO) classification analysis were applied to identify differentially expressed proteins (DEPs) and crucial pathways. The screened DEPs were validated by immunohistochemistry analysis. A total of 317 proteins were upregulated and 184 proteins were downregulated in the asthma group compared to those of the control group. In contrast, 639 DEPs (163 upregulated and 456 downregulated proteins) were identified after SCIT in comparison with those of the asthma group. Among the 639 DEPs, 277 proteins returned to similar levels as those of the relative non-asthma condition. Bioinformatic analysis revealed that the 277 proteins played a significant role in the leukocyte extravasation signaling pathway. The leukocyte extravasation signaling pathway and related DEPs were of crucial importance in birch pollen SCIT.

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.

EAACI Allergen Immunotherapy User's Guide

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

Nanoparticles for mucosal vaccine delivery

Mucosal surfaces represent important routes of entry into the human body for the majority of pathogens, and they constitute unique sites for targeted vaccine delivery. Nanoparticle-based drug delivery systems are emerging technologies for delivering and improving the efficacy of mucosal vaccines. Recent studies have provided new insights into formulation and delivery aspects of importance for the design of safe and efficacious mucosal subunit vaccines based on nanoparticles. These include novel nanomaterials, their physicochemical properties and formulation approaches, nanoparticle interaction with immune cells in the mucosa, and mucosal immunization and delivery strategies. Here, we present recent progress in the application of nanoparticle-based approaches for mucosal vaccine delivery and discuss future research challenges and opportunities in the field.

Severe/uncontrolled asthma and overall survival in atopic patients with eosinophilic granulomatosis with polyangiitis

BACKGROUND

Although asthma, rhinitis/rhinosinusitis and peripheral eosinophilia are present in virtually all patients with eosinophilic granulomatosis with polyangiitis (EGPA), the role of atopy in these patients is not well defined.

OBJECTIVE

To clarify the role of atopy in patients affected with EGPA.

METHODS

Clinical, laboratory and standard spirometry data have been abstracted from medical records. Only patients who underwent skin and/or specific IgE testing for common aeroallergens before the vasculitic phase were included.

RESULTS

Overall, 33.5% (63) of our patients underwent skin and/or specific IgE testing to aeroallergens. Atopy related to aeroallergens was confirmed in 22.3% (two-third of those tested), and was associated with more severe/uncontrolled asthma (p < 0.001), including a greater use of oral glucocorticoids for respiratory manifestations the year before the diagnosis of EGPA (p = 0.013). Atopic patients with EGPA had higher total serum IgE levels and less renal disease at EGPA diagnosis compared to non-atopic patients (p < 0.05). Among atopic patients, the majority had multiple sensitizations (76%); dust mite and grass pollen were the most common respiratory allergens identified. The number of allergens did not correlate with peripheral eosinophilia, total serum IgE, ESR, or measures of airway obstruction (p > 0.05 in all cases). The presence of atopy increased the risk of severe/uncontrolled asthma, but not the risk of severe vasculitis (Five Factor Score≥1). Atopic patients had a better overall survival (p = 0.027).

CONCLUSION

In EGPA, atopy is associated with better prognosis and more severe/uncontrolled asthma manifestations in the year before the development of vasculitis, but not with more severe vasculitis at presentation.

Allergy immunotherapy restores airway epithelial barrier dysfunction through suppressing IL-25 -induced endoplasmic reticulum stress in asthma

Constant exposure to allergen triggers destructive type 2 cell-mediated inflammation. The effect of allergen specific immunotherapy (SIT) in maintaining airway epithelial barrier function in asthma remains unknown. In the current study, we showed that SIT maintained airway epithelial homeostasis in mice exposed to dermatophagoides farinae (Der f), which induced increased expression of IL-25, endoplasmic reticulum (ER) stress and airway epithelial apoptosis. Meanwhile, SIT treatment ameliorated airway inflammatory infiltration and hyper-responsiveness in allergic mice. SIT treatment restored the airway epithelial integrity, attenuated Der f -induced airway epithelial ER stress and epithelial apoptosis. We also found that 4-PBA, an inhibitor of ER stress, suppressed airway epithelial ER stress and apoptosis in vitro. The pathological changes were partially induced by IL-25-induced ER stress, epithelial tight junction damage, and cell apoptosis in airways following allergen exposure. Furthermore, IL-25 induced ER stress in airway epithelial cells in vitro. The IL-25-induced airway epithelial apoptosis dependent on PERK activity was inhibited by 4-PBA. Taken together, we demonstrate that SIT is effective in allergic asthma and dependent on its depressive effect on the expression of IL-25, epithelial integrity damage, and epithelial ER stress.

Accelerated subcutaneous immunotherapy in pediatric population - Systematic review

BACKGROUND

Accelerated subcutaneous immunotherapy (SCIT) schedules represent an alternative to conventional SCIT, providing immunotherapy benefits in a shorter period of time. The objectives of this systematic review were to assess clinical and immunological efficacy as well as safety of accelerated SCIT build-up schedules for the treatment of respiratory allergy in pediatric patients.

METHODS

Studies were located by searching PubMed, using "immunotherapy" and "desensitization" as keywords. The selection of studies, published from January 1st, 2006, to December 31th, 2015, was performed in two stages: screening of titles and abstracts, and assessment of the full papers identified as relevant, considering the inclusion criteria. Data were extracted in a standardized way and synthesized qualitatively to assess efficacy and safety of accelerated schedules in respiratory allergy.

RESULTS

Eleven trials were included: two evaluated rush SCIT and nine assessed cluster SCIT. This review demonstrated that rush and cluster schedules are clinically and immunological efficacious, with faster effect than conventional schedules. No relevant difference with respect to clinical outcomes was noticed between subgroups (pediatric, adult and mixed populations). Regarding safety, most local adverse reactions were mild and there were neither life-threatening systemic reactions nor fatal events. No relevant differences in the incidence and severity of either local or systemic reactions between the accelerated schedule group and control group were registered.

CONCLUSIONS

Accelerated SCIT build-up schedules are effective in the treatment of respiratory allergy in pediatric patients, representing a safe alternative to the conventional schedules with the advantage of achieving clinical effectiveness sooner.

Chinese Guideline on allergen immunotherapy for allergic rhinitis

The present document is based on a consensus reached by a panel of experts from Chinese Society of Allergy (CSA) and Chinese Allergic Rhinitis Collaborative Research Group (C2AR2G). Allergen immunotherapy (AIT), has increasingly been used as a treatment for allergic rhinitis (AR) globally, as it has been shown to provide a long-term effect in improving nasal and ocular symptoms, reducing medication need, and improving quality of life. AIT is currently the only curative intervention that can potentially modify the immune system in individuals suffering from AR and prevent the development of new sensitization and the progression of disease from AR to asthma. Although the use of AIT is becoming more acceptable in China, to date no AR immunotherapy guideline from China is available for use by the international community. This document has thus been produced and covers the main aspects of AIT undertaken in China; including selection of patients for AIT, the allergen extracts available on the Chinese market, schedules and doses of allergen employed in different routes of AIT, assessment of effect and safety, patients' administration and follow-up, and management of adverse reactions. The Chinese guideline for AR immunotherapy will thus serve as a reference point by doctors, healthcare professionals and organizations involved in the AIT of AR in China. Moreover, this guideline will serve as a source of information for the international community on AIT treatment strategies employed in China.

Identification and characterization of major cat allergen Fel d 1 mimotopes on filamentous phage carriers

Cat allergy is one of the most prevalent allergies worldwide and can lead to the development of rhinitis and asthma. Thus far, only allergen extracts from natural sources have been used for allergen-specific immunotherapy. However, extracts and whole allergens in immunotherapy present an anaphylaxis risk. Identification of allergen epitopes or mimotopes has an important role in development of safe and effective allergen-specific immunotherapy. Moreover, with a suitable immunogenic carrier, the absence of sufficient immune response elicited by short peptides could be surmounted. In this study, we identified five structural mimotopes of the major cat allergen Fel d 1 by immunoscreening with random peptide phage libraries. The mimotopes were computationally mapped to the allergen surface, and their IgE reactivity was confirmed using sera from cat-allergic patients. Importantly, the mimotopes showed no basophil activation of the corresponding cat-allergic patients, which makes them good candidates for the development of hypoallergenic vaccine. As bacteriophage particles are becoming increasingly recognized as immunogenic carriers, we constructed bacteriophage particles displaying multiple copies of each selected mimotope on major phage coat protein. These constructed phages elicited T cell-mediated immune response, which was predominated by the type 1 T cell response. Mimotopes alone contributed to the type 1 T cell response by promoting IL-2 production. Fel d 1 mimotopes, as well as their filamentous phage immunogenic carriers, represent promising candidates in the development of hypoallergenic vaccine against cat allergy.

Specific allergen immunotherapy: effect on IgE, IgG4 and chemokines in patients with allergic rhinitis

BACKGROUND

Allergen-specific immunotherapy (SIT) is considered as the most effective treatment for Immunoglobulin E (IgE)-mediated allergies. However, how specific immunotherapy attenuates allergic responses is still not clear, but could potentially involve cytokines as well as IgG4-mediated responses. Based on the role of chemokines in IgE-mediated inflammation, we examined the SIT-induced chemokine response in patients with allergic rhinitis.

METHODS

We included 35 patients with allergic rhinitis; 20 patients received SIT and 15 patients were not treated with specific immunotherapy. The patients were followed for 3 years. Blood samples were collected before SIT and 3, 5, 7 and 21 weeks and 1, 2 and 3 years after the start of therapy. Total IgE, specific IgE, IgG4 and chemokine levels were assessed.

RESULTS

Our main findings were: (i) SIT was associated with an early increase in total and specific IgE during the first 7 weeks, with a subsequent decline, accompanied by a marked increase in specific IgG4 when IgE started to decline; (ii) these SIT-induced responses were accompanied by and in some degree correlated with increased plasma concentrations of the chemokines, monocyte chemoattractant protein (MCP)-1, and eotaxin; and (iii) within the SIT group, these correlations with chemokines were restricted to IgE and IgG4 against birch tree pollen.

CONCLUSION

Our findings further support a role for IgG4-mediated mechanisms in the beneficial effects of SIT in patients with allergic rhinitis (AR) and that increased levels of certain chemokines also could be of importance for the effect of such therapy.

Focusing the mechanism of action to dissect the different treatments of respiratory allergy

The treatment of respiratory allergy is based on several drugs with different mechanisms of action, which encompass an effect only on symptoms, limited factors of inflammation or the whole process of inflammation. Dissecting the different treatments by their mechanism of action is relevant for the management of allergic patients. Corticosteroids, administered as nasal sprays in rhinitis or by inhalation devices in asthma, and allergen immunotherapy (AIT) are the most effective treatments for respiratory allergy, achieving the control on inflammation by a number of cellular and molecular mechanisms. What distinguishes corticosteroids from AIT is the duration of clinical outcomes that ends with treatment withdrawal for the former but persists after stopping for AIT, due to its disease-modifying effect.

The effect of a new communication template on anticipated willingness to initiate or resume allergen immunotherapy: an internet-based patient survey

Background

A patient’s knowledge of his/her allergic condition and treatment is a key factor in adherence and effectiveness.

Methods

To assess patients’ understanding of allergy and acceptance of allergen immunotherapy on the basis of (i) information given by their physician at the time of prescription and (ii) a new communication template viewed some months later, we performed an Internet-based survey of patient panels in France, Germany, Spain, the USA and Russia. The survey participants were either recent “early abandoners” (having discontinued allergen immunotherapy before the end of the prescribed course) or “non-starters” (having decided not to initiate a course of allergen immunotherapy recommended by their physician). All participants completed an on-line questionnaire immediately before and immediately after viewing the new communication template. The study’s main objectives were to validate the new communication template and to assess its impact on anticipated willingness to initiate or resume allergen immunotherapy.

Results

We surveyed a total of 261 patients (France: 57; Germany: 51; Spain: 52; USA: 51; Russia: 50), comprising 127 “early abandoners” and 134 “non-starters”. The mean time since symptom onset and selection for the study was 14.5 years. Subcutaneous allergen immunotherapy had been prescribed in 60 % of cases. Twenty-eight percent of the participants did not know for which allergy they were being treated. Early abandoners reported a perception of low effectiveness (39 %) and complained about expense (39 %) and practical constraints (32 %). Twenty-two percent of the non-starters feared side effects. The communication template was considered to be clear (by 92 % of the patients), convincing (by 75 %) and reassuring (by 89 %); 80 % of the participants felt better informed afterwards, and 67 % stated that viewing the communication template would have made them more likely to continue or initiate allergen immunotherapy (overall willingness score: 5.65 out of 10 before viewing and 7.1 out of 10 afterwards).

Conclusions

After viewing a new communication template on allergy and allergen immunotherapy, patients participating in the survey felt better informed and more likely to initiate or complete this therapy. It now remains to investigate the communication template’s effect on actual acceptance of and adherence to allergen immunotherapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s13223-015-0083-z) contains supplementary material, which is available to authorized users.

"The value of pre- and co-seasonal sublingual immunotherapy in pollen-induced allergic rhinoconjunctivitis"

Allergen immunotherapy (AIT) is a guidelines-approved, disease-modifying treatment option for respiratory allergies, including allergic rhinitis (AR) induced by pollen. The various AIT regimens employed to date in pollen-induced AR can be classified as continuous (i.e. year-round) or discontinuous (i.e. pre-seasonal alone, co-seasonal alone or pre- and co-seasonal). Pre-and co-seasonal regimens are typically used for sublingual allergen immunotherapy (SLIT) and have economic and compliance advantages over perennial (year-round) regimens. However, these advantages must not come at the expensive of poor efficacy or safety. The results of recent double-blind, placebo-controlled, randomized clinical trials show that pre- and co-seasonal SLIT is safe and effective in patients with AR induced by grass pollen (treated with a tablet formulation) or by birch pollen (treated with a liquid formulation). Progress in SLIT has been made in defining the optimal dose of major allergen, the administration frequency (daily), the duration of pre-seasonal treatment (four months) and the number of treatment seasons (at least three). Post-marketing, "real-life" trials of pre- and co-seasonal birch or grass pollen SLIT regimens have confirmed the efficacy and safety observed in the clinical trials. In the treatment of pollen-induced AR, pre- and co-seasonal SLIT regimens appear to be at least as effective and safe as perennial SLIT regimens, and are associated with lower costs and good compliance. Good compliance may mean that pre- and co-seasonal SLIT regimens are inherently more effective and safer than perennial SLIT regimens. When considering the pre- and co-seasonal discontinuous regimen in particular, a 300 IR five-grass-pollen formulation is the only SLIT tablet with a clinical development programme having provided evidence of short-term, sustained and post-treatment efficacy.

Vaccine development and new attempts of treatment for ragweed allergy

Ragweeds are flowering plants in the genus Ambrosia in the aster family, Asteraceae. They are distributed in the tropical and subtropical regions of the New World, especially North America. Short ragweed is the most important weed. The ragweed flowering occurs late in the summer and the pollination period extends from the beginning of August to mid-October. Sensitization to ragweed pollen has risen in United States in the past decade and probably worldwide. The major allergenic compound in the pollen has been identified as Amb a 1. Ragweed allergies usually cause allergic rhinitis and asthma. Ragweed allergic patients may show signs of oral allergy syndrome caused by crossreactivity between ragweed allergens and food allergens. In the present article, an update about vaccine development and new knowledge for ragweed allergy is exhaustively revised.

Sublingual immunotherapy in allergic rhinitis: efficacy, safety, adherence and guidelines

Allergic rhinitis (AR) is a globally increasing health problem affecting the quality of life. Specific immunotherapy is an available causal treatment changing the basic allergic mechanisms of the disease. Over one hundred years, subcutaneous immunotherapy (SCIT) was developed and proved its efficacy but many adverse effects were recorded including anaphylaxis. In 1986, sublingual immunotherapy (SLIT) was introduced as an alternative solution to solve this problem. Our study aims to discuss SLIT from the points of efficacy, safety, adherence and guidelines developed. A literature search was conducted in Medline/PubMed and the Cochrane Library in January 2013 using the keywords "allergic rhinitis, sublingual immunotherapy, efficacy, safety, compliance, adherence, guidelines." All types of publications were included. We augmented our study by searching the reference lists of identified reviews. SLIT has been established in many guidelines as an evidence-based effective treatment in AR with safer profile than SCIT. The meta-analyses confirmed its efficacy and showed a significant reduction in both symptoms and medication scores. The most common recorded adverse effects were minor local effects in the mouth, gastrointestinal reactions with few cases of anaphylaxis and no fatality. Adherence is more favorable for SLIT mainly because it is safe, noninvasive and easily taken at home. We support the call to conduct large multi-centric studies to gain more statistical power and overcome the problem of heterogeneity observed in the meta-analyses.

Five-grass-pollen sublingual immunotherapy tablet for the treatment of grass-pollen-induced allergic rhinoconjunctivitis: 5 years of experience

Oralair(®) (OA) (Stallergenes, Antony, France) is a unique pre- and co-seasonal 5-grass-pollen sublingual immunotherapy tablet launched in 2008, and now approved in 31 countries worldwide for the treatment of grass-pollen allergic rhinitis and rhinoconjunctivitis. OA is the first oral treatment with a consistent, well-balanced allergen extract that mimics natural exposure and sensitization. A wealth of data exists from over 5 years of clinical and real-world experience demonstrating the efficacy and safety of OA for grass-pollen-allergy treatment. OA is highly effective from the first pollen season in all patient subgroups, including children and those with comorbid mild asthma, irrespective of sensitization status and symptom severity. OA also has sustained long-term benefits for symptom control and quality of life. This article provides an overview of the pharmacodynamics and pharmacology of OA; its efficacy, safety, tolerability and cost-effectiveness for the treatment of allergic rhinitis and rhinoconjunctivitis and its role in clinical practice.

Sublingual immunotherapy: World Allergy Organization position paper 2013 update

We have prepared this document, "Sublingual Immunotherapy: World Allergy Organization Position Paper 2013 Update", according to the evidence-based criteria, revising and updating chapters of the originally published paper, "Sublingual Immunotherapy: World Allergy Organization Position Paper 2009", available at http://www.waojournal.org. Namely, these comprise: "Mechanisms of sublingual immunotherapy;" "Clinical efficacy of sublingual immunotherapy" - reporting all the data of all controlled trials published after 2009; "Safety of sublingual immunotherapy" - with the recently published Grading System for adverse reactions; "Impact of sublingual immunotherapy on the natural history of respiratory allergy" - with the relevant evidences published since 2009; "Efficacy of SLIT in children" - with detailed analysis of all the studies; "Definition of SLIT patient selection" - reporting the criteria for eligibility to sublingual immunotherapy; "The future of immunotherapy in the community care setting"; "Methodology of clinical trials according to the current scientific and regulatory standards"; and "Guideline development: from evidence-based medicine to patients' views" - including the evolution of the methods to make clinical recommendations.Additionally, we have added new chapters to cover a few emerging crucial topics: "Practical aspects of schedules and dosages and counseling for adherence" - which is crucial in clinical practice for all treatments; "Perspectives and new approaches" - including recombinant allergens, adjuvants, modified allergens, and the concept of validity of the single products. Furthermore, "Raising public awareness about sublingual immunotherapy", as a need for our patients, and strategies to increase awareness of allergen immunotherapy (AIT) among patients, the medical community, all healthcare stakeholders, and public opinion, are also reported in detail.

Respiratory allergies: a general overview of remedies, delivery systems, and the need to progress

The spread of respiratory allergies is increasing in parallel with the alarm of the scientific community. Evidently, our knowledge of the onset mechanisms of these diseases and, as a consequence, of the available remedies is inadequate. This review provides a brief, general description of current therapeutic resources and the state of research with regard to both drugs and medical devices in order to highlight their limits and the urgent need for progress. Increasing the amount of basic biochemical research will improve our knowledge of such onset mechanisms and the potential efficacy of therapeutic preparations.

Allergen-specific immunotherapy in asthmatic children: from the basis to clinical applications

Atopic asthma in childhood with the tendency to persist into adult life is an important issue in pediatrics. Allergen-specific immunotherapy (SIT) is the only curative treatment option for these children, being directed to the causes of the disease. The Th2 phenotype is a predominant immunological pattern in atopic asthma and SIT leads to apoptosis/anergy of T cells and induces immune-regulatory responses and immune deviation towards Th1. Many factors can affect the safety and efficacy of SIT, such as pattern of sensitization, allergy vaccine (allergen extracts, adjuvants and conjugated molecules), route of administration (subcutaneous or sublingual) and different treatment schedules. Overall, asthma symptoms and medication scores usually decrease following a SIT course and the most common observed side effects are restricted to local swelling, erythema and pruritus. Compared with conventional pharmacotherapy, SIT may be more cost effective, providing a benefit after discontinuation and a steroid-sparing effect. In addition, it can prevent new sensitizations in monosensitized asthmatic children. Microbial supplements such as probiotics, immunomodulatory substances like anti-IgE/leukotrienes, antibodies and newer allergen preparations such as recombinant forms have been tested to improve the efficacy and safety of SIT with inconclusive results. In conclusion, SIT provides an appropriate solution for childhood asthma that should be employed more often in clinical practice. Further studies are awaited to improve current knowledge regarding the mechanisms behind SIT and determine the most appropriate materials and schedule of immunotherapy for children with asthma.

Allergen immunotherapy: routes, safety, efficacy, and mode of action

Allergic rhinitis, allergic conjunctivitis, and allergic asthma have been steadily increasing in prevalence in recent years. These allergic diseases have a major impact on quality of life and are a major economic burden in the US. Although allergen avoidance and pharmacotherapy are currently the mainstays of therapy, they are not always successful in treating patients' symptoms effectively. If a patient fails allergen avoidance and medical therapy, immunotherapy may be indicated. Furthermore, immunotherapy is the only therapy that may change the course of the disease and induce long-term remission. Though subcutaneous administration has been the standard route for immunotherapy for many decades, there are several other routes of administration that have been and are currently being studied. The goal of utilizing alternative routes of immunotherapy is to improve safety without decreasing the efficacy of treatment. This paper will review the novel routes of immunotherapy, including sublingual, oral, local nasal, epicutaneous, and intralymphatic.

Sublingual delivery of vaccines for the induction of mucosal immunity

The mucosal surfaces are constantly exposed to incoming pathogens which can cause infections that result in severe morbidity and/or mortality. Studies have reported that mucosal immunity is important for providing protection against these pathogens and that mucosal vaccination is effective in preventing local infections. For many years, the sublingual mucosa has been targeted to deliver immunotherapy to treat allergic hypersensitivities. However, the potential of vaccine delivery via sublingual mucosal has received little attention until recently. Recent studies exploring such potential have documented the safety and effectiveness of sublingual immunization, demonstrating the ability of sublingual immunization to induce both systemic and mucosal immune responses against a variety of antigens, including soluble proteins, inter particulate antigens, and live-attenuated viruses. This review will summarize the recent findings that address the promising potential of sublingual immunization in proving protection against various mucosal pathogens.

Sublingual vs oral immunotherapy for food allergy: identifying the right approach

The incidence of food allergy in developed countries has increased in recent years, escalating the need to find a suitable form of treatment as an alternative to current management, which includes strict avoidance and ready availability of injectable epinephrine (adrenaline). Allergen immunotherapy is currently being studied for use in the treatment of IgE-mediated food allergy to the most common foods, including peanut, tree nut, milk and egg. Two modalities, oral immunotherapy (OIT) and sublingual immunotherapy (SLIT), have shown great promise. Both OIT and SLIT have been able to desensitize subjects to varying degrees, but the two treatment methods differ in doses that can be achieved, duration of treatment, safety profile and ease of use outside the research setting, among other aspects. More research is needed to conclude which mode of treatment is more effective in inducing long-term tolerance with the least amount of serious adverse reactions. However, OIT and SLIT show great promise, and a widespread treatment for food allergy may be within reach.

Severe asthma: an expanding and mounting clinical challenge

Although all patients with asthma have variable airflow obstruction, airway inflammation, and bronchial hyperresponsiveness, some have disease that is severe in many aspects: persistent airflow obstruction, ongoing symptoms, increased frequency of exacerbations, and, most importantly, a diminished response to medications. A number of definitions have emerged to characterize the clinical features of severe asthma, but a central feature of this phenotype is the need for high doses of medications, especially corticosteroids, in attempts to achieve disease control. The prevalence of severe asthma is also undergoing reevaluation from the usual estimate of 10% to larger numbers on the basis of medication needs and the lack of disease control achieved. At present, the underlying mechanisms of severe asthma are not established but likely reflect a heterogeneous pattern, rather than a single unifying process. Guideline-directed treatment for severe asthma has limits with usual approaches centered on high doses of inhaled corticosteroids, long-acting β-agonists, and trials with omalizumab, the monoclonal antibody to IgE. With the development of approaches to recognize asthma phenotypes with distinct pathogenesis and hence unique therapeutic targets, it is hoped that a personalized strategy in treatment directed toward disease-specific features will improve outcomes for this high-risk, severely affected population of patients.