Sublingual-swallow immunotherapy with standardized 3-grass pollen extract: a double-blind, placebo-controlled study

Sublingual immunotherapy for asthma

BACKGROUND

Asthma is a common long-term respiratory disease affecting approximately 300 million people worldwide. Approximately half of people with asthma have an important allergic component to their disease, which may provide an opportunity for targeted treatment. Sublingual immunotherapy (SLIT) aims to reduce asthma symptoms by delivering increasing doses of an allergen (e.g. house dust mite, pollen extract) under the tongue to induce immune tolerance. Fifty-two studies were identified and synthesised in the original Cochrane Review in 2015, but questions remained about the safety and efficacy of sublingual immunotherapy for people with asthma.

OBJECTIVES

To assess the efficacy and safety of sublingual immunotherapy compared with placebo or standard care for adults and children with asthma.

SEARCH METHODS

The original searches for trials from the Cochrane Airways Group Specialised Register (CAGR), ClinicalTrials.gov, WHO ICTRP, and reference lists of all primary studies and review articles found trials up to 25 March 2015. The most recent search for trials for the current update was conducted on 29 October 2019.

SELECTION CRITERIA

We included parallel randomised controlled trials, irrespective of blinding or duration, that evaluated sublingual immunotherapy versus placebo or as an add-on to standard asthma management. We included both adults and children with asthma of any severity and with any allergen-sensitisation pattern. We included studies that recruited participants with asthma, rhinitis, or both, providing at least 80% of trial participants had a diagnosis of asthma. We selected outcomes to reflect recommended outcomes for asthma clinical trials and those most important to people with asthma. Primary outcomes were asthma exacerbations requiring a visit to the emergency department (ED) or admission to hospital, validated measures of quality of life, and all-cause serious adverse events (SAEs). Secondary outcomes were asthma symptom scores, exacerbations requiring systemic corticosteroids, response to provocation tests, and dose of inhaled corticosteroids (ICS).

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results for included trials, extracted numerical data, and assessed risk of bias, all of which were cross-checked for accuracy. Any disagreements were resolved by discussion. We analysed dichotomous data as odds ratios (ORs) or risk differences (RDs) using study participants as the unit of analysis; we analysed continuous data as mean differences (MDs) or standardised mean differences (SMDs) using random-effects models. We considered the strength of evidence for all primary and secondary outcomes using the GRADE approach.

MAIN RESULTS

Sixty-six studies met the inclusion criteria for this update, including 52 studies from the original review. Most studies were double-blind and placebo-controlled, varied in duration from one day to three years, and recruited participants with mild or intermittent asthma, often with comorbid allergic rhinitis. Twenty-three studies recruited adults and teenagers; 31 recruited only children; three recruited both; and nine did not specify. The pattern of reporting and results remained largely unchanged from the original review despite 14 further studies and a 50% increase in participants studied (5077 to 7944). Reporting of primary efficacy outcomes to measure the impact of SLIT on asthma exacerbations and quality of life was infrequent, and selective reporting may have had a serious effect on the completeness of the evidence; 16 studies did not contribute any data, and a further six studies could only be included in a post hoc analysis of all adverse events. Allocation procedures were generally not well described; about a quarter of the studies were at high risk of performance or detection bias (or both); and participant attrition was high or unknown in around half of the studies. The primary outcome in most studies did not align with those of interest to the review (mostly asthma or rhinitis symptoms), and only two small studies reported our primary outcome of exacerbations requiring an ED or hospital visit; the pooled estimate from these studies suggests SLIT may reduce exacerbations compared with placebo or usual care, but the evidence is very uncertain (OR 0.35, 95% confidence interval (CI) 0.10 to 1.20; n = 108; very low-certainty evidence). Nine studies reporting quality of life could not be combined in a meta-analysis and, whilst the direction of effect mostly favoured SLIT, the effects were often uncertain and small. SLIT likely does not increase SAEs compared with placebo or usual care, and analysis by risk difference suggests no more than 1 in 100 people taking SLIT will have a serious adverse event (RD -0.0004, 95% CI -0.0072 to 0.0064; participants = 4810; studies = 29; moderate-certainty evidence). Regarding secondary outcomes, asthma symptom and medication scores were mostly measured with non-validated scales, which precluded meaningful meta-analysis or interpretation, but there was a general trend of SLIT benefit over placebo. Changes in ICS use (MD -17.13 µg/d, 95% CI -61.19 to 26.93; low-certainty evidence), exacerbations requiring oral steroids (studies = 2; no events), and bronchial provocation (SMD 0.99, 95% CI 0.17 to 1.82; low-certainty evidence) were not often reported. Results were imprecise and included the possibility of important benefit or little effect and, in some cases, potential harm from SLIT. More people taking SLIT had adverse events of any kind compared with control (OR 1.99, 95% CI 1.49 to 2.67; high-certainty evidence; participants = 4251; studies = 27), but events were usually reported to be transient and mild. Lack of data prevented most of the planned subgroup and sensitivity analyses.

AUTHORS' CONCLUSIONS

Despite continued study in the field, the evidence for important outcomes such as exacerbations and quality of life remains too limited to draw clinically useful conclusions about the efficacy of SLIT for people with asthma. Trials mostly recruited mixed populations with mild and intermittent asthma and/or rhinitis and focused on non-validated symptom and medication scores. The review findings suggest that SLIT may be a safe option for people with well-controlled mild-to-moderate asthma and rhinitis who are likely to be at low risk of serious harm, but the role of SLIT for people with uncontrolled asthma requires further evaluation.

Options of immunotherapeutic treatments for children with asthma

Introduction: Asthma is the most common chronic disease in children. Avoiding triggers, and pharmacologic treatment with short acting beta-agonist, inhaler corticosteroids and anti-leukotriene are often enough to obtain symptoms control. Nevertheless, there is a subset of children with severe asthma and poor symptom control despite maximal therapy. In these patients, anti-IgE and anti-IL5 monoclonal antibodies are suggested as the fifth step of Global Initiative for Asthma guidelines. Area covered: Immunotherapeutic treatments are now suggested for asthma management. This article will discuss the available evidence on allergen immunotherapy and biologic drugs in pediatric asthma treatment. Expert opinion: Previously published studies demonstrated a good efficacy and safety profile of Allergen Immunotherapy in patients with mild-moderate asthma and sensitization to one main allergen. New understanding of mechanisms underlying severe asthma inflammation has allowed the identifications of specific biomarkers guiding the clinician in the choice of patient specific drug. Among the suggested immunotherapeutic options, omalizumab (blocking IgE) remains the first choice for atopic 'early onset' asthma in patients aged over 6 years. Instead, mepolizumab (blocking the IL5 ligand) should be considered for 'eosinophilic' asthma. Other biologic drugs are under consideration but data on the pediatric population are still lacking.

Sublingual allergen immunotherapy for respiratory allergy: a systematic review

The objective of the systematic review is to provide complete and updated information on efficacy and safety of sublingual immunotherapy (SLIT) formulations for the treatment of allergic respiratory diseases (ARDs). The literature search was conducted on PubMed database, involving double-blind, randomized clinical trials published between January 1992 and 2018, written in English, and performed in humans. The number of articles finally selected for review was 112. Data from the majority of properly controlled clinical trials demonstrate that SLIT is effective not only with short-term use (first year) but also with long-term use (up to the third year of active therapy), for treating ARDs in children and adults. Both continuous and discontinuous schemes of administration showed significant reductions in symptom and medication scores. Moreover, a SLIT-induced disease-modifying effect has been documented mainly with grass pollen extracts, since improvement is maintained during at least 2 years of follow-up after a 3-year treatment period. Additionally, allergen immunotherapy should also be considered a preventive strategy, especially for decreasing bronchial asthma incidence in children and adolescents with allergic rhinitis treated with SLIT. This therapy is also safe, producing only a few mainly local and mild-to-moderate adverse events, and usually self-limited in time. The registration and authorization of allergen SLIT preparations (grasses and house-dust mite tablets) as drugs by regulatory agencies, such as the United States Food and Drug Administration (FDA) and the European Medicines Agency (EMA), has represented a landmark in allergy immunotherapy research. Further long-term studies, specially designed with allergens other than grass pollen or house-dust mites, not only in allergic rhinoconjunctivitis but also on asthmatic subjects, as well as studies comparing different administration schedules and/or routes, are required in order to continue the progress in the modern development of this particularly promising therapy.

Allergen immunotherapy for allergic rhinoconjunctivitis: A systematic review and meta-analysis

BACKGROUND

The European Academy of Allergy and Clinical Immunology (EAACI) is in the process of developing Guidelines on Allergen Immunotherapy (AIT) for Allergic Rhinoconjunctivitis. To inform the development of clinical recommendations, we undertook a systematic review to assess the effectiveness, cost-effectiveness, and safety of AIT in the management of allergic rhinoconjunctivitis.

METHODS

We searched nine international biomedical databases for published, in-progress, and unpublished evidence. Studies were independently screened by two reviewers against predefined eligibility criteria and critically appraised using established instruments. Our primary outcomes of interest were symptom, medication, and combined symptom and medication scores. Secondary outcomes of interest included cost-effectiveness and safety. Data were descriptively summarized and then quantitatively synthesized using random-effects meta-analyses.

RESULTS

We identified 5960 studies of which 160 studies satisfied our eligibility criteria. There was a substantial body of evidence demonstrating significant reductions in standardized mean differences (SMD) of symptom (SMD -0.53, 95% CI -0.63, -0.42), medication (SMD -0.37, 95% CI -0.49, -0.26), and combined symptom and medication (SMD -0.49, 95% CI -0.69, -0.30) scores while on treatment that were robust to prespecified sensitivity analyses. There was in comparison a more modest body of evidence on effectiveness post-discontinuation of AIT, suggesting a benefit in relation to symptom scores.

CONCLUSIONS

AIT is effective in improving symptom, medication, and combined symptom and medication scores in patients with allergic rhinoconjunctivitis while on treatment, and there is some evidence suggesting that these benefits are maintained in relation to symptom scores after discontinuation of therapy.

[Allergen specific immunotherapy for rhinitis allergica : New applications]

BACKGROUND

Allergic diseases are among the most common diseases of humans. The immune response towards allergens is regulated by T-lymphozytes and characterized by an interleukin (IL)-4, IL-5 and IL-13 dominated Th2 cytokine profile.

RESULTS

Allergen-specific immunotherapy (AIT) is the only causative treatment option and able to change the course of disease, e. g. to prevent the development of asthma and new sensitizations. The intralymphatic delivery of allergenes named intralymphatic immunotherapy (ILIT) has been evaluated in clinical trials and was demonstrated to be a highly potent application route with low effort and side effects while having equal efficacy if compared with current standard AIT forms. However, studies that verify important questions like optimal dose, new allergen forms, use of adjuvants etc. are still missing. Moreover, it has to be evaluated, whether different indications like rhinitis, or atopic dermatitis are suitable for ILIT and whether it is useful in children. Epicutaneous immunotherapy (EPIT) is a possible alternative application form. It is minimally invasive and basically consists of the affixation of allergen containing patches to the epidermis over 6 weeks. From the studies performed so far, the authors concluded, that epicutaneous immunotherapy is safe and efficacious in a dose-dependent manner after 6 patches only.

CONCLUSIONS

AIT is accepted to be the only causative treatment option for allergies. New application routes in ILIT and EPIT may become more important and allow for different delivery methods in the future, however further clinical studies are required and in preparation.

Sublingual immunotherapy for asthma

BACKGROUND

Asthma is a common long-term respiratory disease affecting approximately 300 million people worldwide. Approximately half of people with asthma have an important allergic component to their disease, which may provide an opportunity for targeted treatment. Sublingual immunotherapy (SLIT) aims to reduce asthma symptoms by delivering increasing doses of an allergen (e.g. house dust mite, pollen extract) under the tongue to induce immune tolerance. However, it is not clear whether the sublingual delivery route is safe and effective in asthma.

OBJECTIVES

To assess the efficacy and safety of sublingual immunotherapy compared with placebo or standard care for adults and children with asthma.

SEARCH METHODS

We identified trials from the Cochrane Airways Group Specialised Register (CAGR), ClinicalTrials.gov (www.ClinicalTrials.gov), the World Health Organization (WHO) trials portal (www.who.int/ictrp/en/) and reference lists of all primary studies and review articles. The search is up to date as of 25 March 2015.

SELECTION CRITERIA

We included parallel randomised controlled trials (RCTs), irrespective of blinding or duration, that evaluated sublingual immunotherapy versus placebo or as an add-on to standard asthma management. We included both adults and children with asthma of any severity and with any allergen-sensitisation pattern. We included studies that recruited participants with asthma, rhinitis, or both, providing at least 80% of trial participants had a diagnosis of asthma.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results for included trials, extracted numerical data and assessed risk of bias, all of which were cross-checked for accuracy. We resolved disagreements by discussion.We analysed dichotomous data as odds ratios (ORs) or risk differences (RDs) using study participants as the unit of analysis; we analysed continuous data as mean differences (MDs) or standardised mean differences (SMDs) using random-effects models. We rated all outcomes using GRADE (Grades of Recommendation, Assessment, Development and Evaluation) and presented results in the 'Summary of findings' table.

MAIN RESULTS

Fifty-two studies met our inclusion criteria, randomly assigning 5077 participants to comparisons of interest. Most studies were double-blind and placebo-controlled, but studies varied in duration from one day to three years. Most participants had mild or intermittent asthma, often with co-morbid allergic rhinitis. Eighteen studies recruited only adults, 25 recruited only children and several recruited both or did not specify (n = 9).With the exception of adverse events, reporting of outcomes of interest to this review was infrequent, and selective reporting may have had a serious effect on the completeness of the evidence. Allocation procedures generally were not well described, about a quarter of the studies were at high risk of bias for performance or detection bias or both and participant attrition was high or unknown in around half of the studies.One short study reported exacerbations requiring a hospital visit and observed no adverse events. Five studies reported quality of life, but the data were not suitable for meta-analysis. Serious adverse events were infrequent, and analysis using risk differences suggests that no more than 1 in 100 are likely to suffer a serious adverse event as a result of treatment with SLIT (RD 0.0012, 95% confidence interval (CI) -0.0077 to 0.0102; participants = 2560; studies = 22; moderate-quality evidence).Within secondary outcomes, wide but varied reporting of largely unvalidated asthma symptom and medication scores precluded meaningful meta-analysis; a general trend suggested SLIT benefit over placebo, but variation in scales meant that results were difficult to interpret.Changes in inhaled corticosteroid use in micrograms per day (MD 35.10 mcg/d, 95% CI -50.21 to 120.42; low-quality evidence), exacerbations requiring oral steroids (studies = 2; no events) and bronchial provocation (SMD 0.69, 95% CI -0.04 to 1.43; very low-quality evidence) were not often reported. This led to many imprecise estimates with wide confidence intervals that included the possibility of both benefit and harm from SLIT.More people taking SLIT had adverse events of any kind compared with control (OR 1.70, 95% CI 1.21 to 2.38; low-quality evidence; participants = 1755; studies = 19), but events were usually reported to be transient and mild.Lack of data prevented most of the planned subgroup and sensitivity analyses.

AUTHORS' CONCLUSIONS

Lack of data for important outcomes such as exacerbations and quality of life and use of different unvalidated symptom and medication scores have limited our ability to draw a clinically useful conclusion. Further research using validated scales and important outcomes for patients and decision makers is needed so that SLIT can be properly assessed as clinical treatment for asthma. Very few serious adverse events have been reported, but most studies have included patients with intermittent or mild asthma, so we cannot comment on the safety of SLIT for those with moderate or severe asthma. SLIT is associated with increased risk of all adverse events.

Dosing of sublingual immunotherapy for allergic rhinitis: evidence-based review with recommendations

BACKGROUND

Since the mid 1980s, the clinical use of sublingual immunotherapy (SLIT) has dramatically increased. However, 1 of the primary barriers to providing SLIT is lack of a published dosing recommendations. The purpose of this work is to provide a range of effective SLIT dosing based upon a rigorous review of the existing evidence base. An appendix with SLIT dosing recommendations is also included.

METHODS

A comprehensive search of the past 25 years of the medical literature using PubMed was performed for specific antigens. Inclusion criteria for articles included: randomized, placebo-controlled studies of SLIT, studies with clinical allergic rhinitis outcomes, and dosing units available to determine the micrograms per month of major allergen administered. The extracted data was used to compile a range of effective SLIT dosing for individual antigens.

RESULTS

Seventy-five articles met the inclusion criteria, providing a range of effective dosing for some allergens. There was commonly a wide range in doses for particular antigens between the individual studies. For some antigens, there was significant overlap in dosage amount between studies showing efficacy and lack of efficacy. Clinical trials meeting inclusion criteria are not available for many allergens.

CONCLUSION

This study provided a comprehensive review of the published sublingual dosing ranges for specific antigens. The review provided a range of effective sublingual doses for some allergens, whereas for other allergens there was insufficient published data to determine specific doses. Recommendations for SLIT dosing were produced based on the data revealed in the review and expert opinion.

Dropouts in sublingual allergen immunotherapy trials - a systematic review

Participant dropouts can reduce the power of allergen immunotherapy clinical trials. Evaluation of the dropout rate and reasons for dropout are important not only in the planning of clinical studies but are also relevant for adherence to immunotherapy in daily clinical practice. A systematic review was carried out in order to establish the overall dropout rate among published double-blind, placebo-controlled randomized clinical trials of sublingual immunotherapy for respiratory allergic diseases. Dropouts were analysed in regards to allergen, formulation, treatment schedule, participant age, study size, number of centres and type of allergic disease. Relative dropout rates in placebo and active groups as well as reasons for dropout were also assessed. A total of 81 studies, comprising 9998 patients, were included. Dropout rates in sublingual immunotherapy controlled studies do not appear to be a major problem with a composite dropout percentage of 14% (95% CI:11.9-16). Furthermore, they are not different for active compared to placebo-treated participants. This lends support to the positive clinical outcomes seen in meta-analyses of these trials.

Efficacy of subcutaneous and sublingual immunotherapy with grass allergens for seasonal allergic rhinitis: a meta-analysis-based comparison

BACKGROUND

Subcutaneous (SCIT) and sublingual (SLIT) immunotherapy are the 2 most prescribed routes for administering allergen-specific immunotherapy. They were shown to be effective in control of symptoms and in reducing rescue medication use in patients with allergic diseases, but their effectiveness has to be balanced against side effects. In recent years, SLIT has been increasingly prescribed, instead of SCIT, because of improved safety and easy administration.

OBJECTIVE

We assessed which route is the most effective in the treatment of patients with seasonal allergic rhinitis to grass pollen.

METHODS

An indirect meta-analysis-based comparison between SCIT and SLIT was performed. Treatment efficacy was determined as the standardized mean difference (SMD) in symptom and medication scores obtained with active treatment, SCIT or SLIT, compared with placebo. Studies were included if they were double-blind randomized controlled trials comparing SCIT or SLIT with placebo. Thirty-six randomized controlled trials (3014 patients; 2768 controls) were analyzed.

RESULTS

The overall effect size of SCIT for symptom score (SMD, -0.92; 95%CI, -1.26 to -0.58) was significantly higher than SLIT, both administered via drops (SMD, -0.25; 95% CI, -0.45 to -0.05) and tablets (SMD, -0.40; 95%CI, -0.54 to -0.27). Similar results were reported for medication score (SCIT: SMD, -0.58; 95% CI, -0.86 to -0.30. SLIT drops: SMD, -0.37; 95% CI, -0.74 to -0.00. SLIT tablets SMD, -0.30; 95% CI, -0.44 to -0.16).

CONCLUSIONS

Our results provide indirect but solid evidence that SCIT is more effective than SLIT in controlling symptoms and in reducing the use of antiallergic medications in seasonal allergic rhinoconjuntivitis to grass pollen.

Determinants of patient compliance in allergic rhinoconjunctivitis

PURPOSE OF REVIEW

Noncompliance to the prescribed therapeutic regimen is a worldwide problem, especially for diseases in which symptoms can vary with different patient factors and with seasons. The consequences are poor health outcomes, progression of disease and increased healthcare costs. Reviews conducted across countries and addressing different diseases are consistent in estimating noncompliance between 30 and 50%. To implement strategies and interventions that enhance compliance, a comprehensive analysis of its determinants is essential.

RECENT FINDINGS

Lack of efficacy was reported as the number one reason for discontinuing the intake of medications prescribed for nasal allergies. Studies on glucocorticosteroids, allergen-specific immunotherapy and antihistamines highlighted the importance of patient education, demographic factors, duration of therapy, side-effects and treatment costs, as well as minor details, such as taste and odour, in improving compliance.

SUMMARY

The variation in the methodologies used and the durations of treatments assessed in current compliance research in the field of allergic rhinoconjunctivitis decreases the comparability of results. Therefore, a clear definition of compliance measured in clinical trials with allergic rhinoconjunctivitis sufferers is needed. Moreover, a gold standard for measuring and reporting compliance should be determined to enable better interstudy comparability of the rates and determinants of compliance.

Sublingual immunotherapy for treating allergic conjunctivitis

BACKGROUND

Allergic ocular symptoms, although frequently trivialised, are common and represent an important comorbidity of allergic rhinitis. Sublingual Immunotherapy (SLIT) is an effective and well-tolerated treatment for allergic rhinitis, but its effects on symptoms of ocular allergy have not been well established.

OBJECTIVES

To evaluate the efficacy of SLIT compared with placebo for reductions in ocular symptoms, topical ocular medication requirements and conjunctival immediate allergen sensitivity.

SEARCH STRATEGY

We searched CENTRAL (which contains the Cochrane Eyes and Vision Group Trials Register) (The Cochrane Library 2011, Issue 1), MEDLINE (January 1950 to January 2011), EMBASE (January 1980 to January 2011), Latin American and Caribbean Literature on Health Sciences (LILACS) (January 1982 to January 2011), Web of Science (January 1970 to January 2011), Biosis Previews, (January 1979 to January 2011), the metaRegister of Controlled Trials (mRCT) (www.controlled-trials.com) (January 2011), ClinicalTrials.gov (www.clinicaltrials.gov) (January 2011), the Australian New Zealand Clinical Trials Registry (ANZCTR) (www.actr.org.au) (July 2010), SCOPUS (November 2008) and the UK Clinical Trials Gateway (January 2010). There were no language or date restrictions in the search for trials. All electronic databases except for SCOPUS, the UK Clinical Trials Gateway and ANZCTR were last searched on 19 January 2011.

SELECTION CRITERIA

Randomised controlled trials (RCTs), double-masked and placebo controlled, which evaluated the efficacy of SLIT in patients with symptoms of allergic rhinoconjunctivitis (ARC) or allergic conjunctivitis (AC).

DATA COLLECTION AND ANALYSIS

The primary outcome was the total ocular symptom scores. Secondary endpoints included individual ocular symptom scores (such as itchy eyes, red eyes, watery eyes, swollen eyes), ocular medication scores (eye drops) and conjunctival immediate allergen sensitivity (CIAS). Data were analysed and reported as standardised mean differences (SMDs) using Review Manager software.

MAIN RESULTS

Forty-two trials (n = 3958 total participants; n= 2011 SLIT and n = 1947 placebo) had available data to evaluate the efficacy of SLIT on AC and were included in the meta-analyses. Heterogeneity among studies (I(2) statistic) was around 50% or below for all endpoints. Sublingual immunotherapy induced a significant reduction in both total ocular symptom scores (SMD -0.41; 95% confidence interval (CI) -0.53 to -0.28; P < 0.00001; I(2) = 59%) and individual ocular symptom scores for red eyes (SMD -0.33; 95% CI -0.45 to -0.22; P < 0.00001; I(2) = 27%), itchy eyes (SMD -0.31; 95% CI -0.42 to -0.20; P < 0.00001; I(2) = 46%) and watery eyes (SMD -0.23; 95% CI -0.34 to -0.11; P < 0.0001; I(2) = 42%) compared to placebo. Those participants having active treatment showed an increase in the threshold dose for the conjunctival allergen provocation test (SMD 0.35; 95% CI 0.00 to 0.69; P = 0.05; I(2) = 43%). No significant reduction was observed in ocular eye drops use (SMD -0.10; 95% CI -0.22 to 0.03; P = 0.13; I(2) = 34%).

AUTHORS' CONCLUSIONS

Overall, SLIT is moderately effective in reducing total and individual ocular symptom scores in participants with ARC and AC. There were however some concerns about the overall quality of the evidence-base, this relating to inadequate descriptions of allocation concealment in some studies, statistical heterogeneity and the possibility of publication bias. There is a need for further large rigorously designed studies that study long-term effectiveness after discontinuation of treatment and establish the cost-effectiveness of SLIT.

Apolipoprotein A-IV is a candidate target molecule for the treatment of seasonal allergic rhinitis

BACKGROUND

Allergic rhinitis is a global health problem that causes major illnesses and disability worldwide. Allergen-specific immunotherapy (SIT) is the only available treatment that can alter the natural course of allergic disease. However, the precise mechanism underlying allergen-SIT is not well understood.

OBJECTIVE

The aim of the current study was to identify protein expression signatures reflective of allergen-SIT-more specifically, sublingual immunotherapy (SLIT).

METHODS

Serum was taken twice from patients with seasonal allergic rhinitis caused by Japanese cedar: once before the pollen season and once during the season. A total of 25 patients was randomly categorized into a placebo-treated group and an active-treatment group. Their serum protein profiles were analyzed by 2-dimensional electrophoresis.

RESULTS

Sixteen proteins were found to be differentially expressed during the pollen season. Among the differentially expressed proteins, the serum levels of complement C4A, apolipoprotein A-IV (apoA-IV), and transthyretin were significantly increased in SLIT-treated patients but not in placebo-treated patients. Among these proteins, the serum levels of apoA-IV correlated with the clinical symptom-medication scores (r = -0.635; P < .05) and with quality of life scores (r = -0.516; P < .05) in the case of SLIT-treated patients. The amount of histamine released from the basophils in vitro was greatly reduced after the addition of recombinant apoA-IV in the medium (P < .01).

CONCLUSION

Our data will increase the understanding of the mechanism of SLIT and may provide novel insights into the treatment of allergic rhinitis.

Clinical practice: Allergen-specific immunotherapy in children: facts and FAQs

Allergen-specific immunotherapy (SIT) in its various application forms represents the main treatment approach of IgE-mediated allergic diseases in adults and children. Despite this clear recommendation, many particularities of products, patient characteristics, and product availability in different countries hamper the use of allergen-specific immunotherapy in particular in children. The frequently asked questions by parents, patients, and physicians are the backbone of this review. Thus, the potentials and limitations of allergen-specific immunotherapy in children and adolescents will be highlighted. IgE-mediated allergic diseases are affecting about 20% of the population. They manifest commonly early in life, and hence, the use of SIT should be considered also early in the course of the disease.

Certainties and doubts about sublingual and oral immunotherapy in children

PURPOSE OF REVIEW

Sublingual (SLIT) and oral immunotherapy (OIT) are two variants of immunotherapy that might be especially of interest for children. After adult studies, lately many trials in children are published. However, the quality of published material varies. In the present review we analyze paediatric SLIT publications from the past 2 years in the light of a new system of evaluation of quality of evidence, the grading of recommendations assessment, development and evaluation system.

RECENT FINDINGS

High quality evidence in children: high-dose daily grass SLIT reduces symptoms and medication use; low-dose pollen SLIT reduces the development of new sensitizations. Low-dose SLIT reduces symptoms and medication in mild-moderate atopic dermatitis. Latex SLIT for 3 years results in a negative glove test. The evidence for the effectiveness of SLIT for seasonal and perennial asthma is still of moderate-low quality, as is the evidence for asthma prevention. Too high dose of mite SLIT seems ineffective for asthma. Oral allergen immunotherapy is promising for some food allergies. Some definite immunological changes are seen with SLIT; facilitated antibody presentation and IL-17 might correlate with efficacy.

SUMMARY

Even after a hundred years of immunotherapy, it is still an ever changing field with SLIT and OIT making fast progress.

Towards evidence-based medicine in specific grass pollen immunotherapy

When initiating grass pollen immunotherapy for seasonal allergic rhinoconjunctivitis, specialist physicians in many European countries must choose between modalities of differing pharmaceutical and regulatory status. We applied an evidence-based medicine (EBM) approach to commercially available subcutaneous and sublingual Gramineae grass pollen immunotherapies (SCIT and SLIT) by evaluating study design, populations, pollen seasons, treatment doses and durations, efficacy, quality of life, safety and compliance. After searching MEDLINE, Embase and the Cochrane Library up until January 2009, we identified 33 randomized, double-blind, placebo-controlled trials (including seven paediatric trials) with a total of 440 specific immunotherapy (SIT)-treated subjects in seven trials (0 paediatric) for SCIT with natural pollen extracts, 168 in three trials (0 paediatric) for SCIT with allergoids, 906 in 16 trials (five paediatric) for natural extract SLIT drops, 41 in two trials (one paediatric) for allergoid SLIT tablets and 1605 in five trials (two paediatric) for natural extract SLIT tablets. Trial design and quality varied significantly within and between SIT modalities. The multinational, rigorous trials of natural extract SLIT tablets correspond to a high level of evidence in adult and paediatric populations. The limited amount of published data on allergoids prevented us from judging the level of evidence for this modality.

An update on the safety of specific immunotherapy

PURPOSE OF REVIEW

As allergen sublingual immunotherapy becomes more widely used in Europe and draws the attention of physicians of the USA, it is important to compare and contrast the safety aspects of this therapy versus allergen subcutaneous immunotherapy.

RECENT FINDINGS

There are reports of severe systemic reactions associated with sublingual immunotherapy, but no fatalities. There are various studies of systemic reactions, including those that result in death, associated with subcutaneous immunotherapy over its nearly 100-year worldwide experience. Local reactions are common to both forms of the treatment.

SUMMARY

If both forms of therapy are equally effective, a cost (including safety aspects) -benefit analysis of sublingual immunotherapy versus subcutaneous immunotherapy is necessary to determine how best to incorporate both forms of specific immunotherapy into the management of allergic patients. Adherence to published guidelines will reduce the likelihood of adverse reactions.

Administration regimens for sublingual immunotherapy to pollen allergens: what do we know?

The modalities of administration of sublingual immunotherapy (SLIT), including dosing, build-up phase, duration of the treatment, and frequency of the maintenance dose are largely variable. In the case of pollen (SLIT), the complexity increases, since preseasonal, coseasonal and pre-coseasonal regimens can be used. The administration regimens are of relevance from a practical point of view, but can also have economic implications. We review herein the available literature (randomized double blind controlled studies) on pollen SLIT, in order to derive experimentally-supported suggestions about the regimens of administration that should be preferred.

[Immunological principles of allergen-specific immune therapy]

The immunological mechanisms of healthy and allergic immune responses, as well as allergen-specific immune therapy (ASIT) are determined by the activation of defined subpopulations of specific T-cells and the resulting cytokine pattern. Suppression of a Th2 cytokine pattern by regulatory T-cells (Treg) with IL-10 and/or TGF-beta is decisive for the success of an ASIT. A prerequisite for achieving immunologic tolerance is that sufficiently high amounts of the individual allergen components are present in the allergen extract used. This is true for all forms of application of allergens. Chemically or genetically modified allergens, which will not be recognized by the existing IgE antibodies, can be utilized to attain the high doses required.

Sublingual Desensitization in Patients with Wasp Venom Allergy: Preliminary Results

The aim of this paper is to assess in an open prospective pilot case-control study the tolerability, safety and efficacy of an ultra-rush sublingual immunotherapy (SLIT) protocol with Vespula venom in wasp allergic patients compared to subcutaneous immunotherapy (SCIT). Forty-one wasp allergic patients were treated with sublingual (SLIT group) or subcutaneous (SCIT group) ultrarush immunotherapy with Vespula venom extract. All patients underwent skin tests and serum specific IgE and IgG4 detection before enrolment and after 6, 12 and 24 months of immunotherapy. The SLIT group consisted of 21 (6 females and 15 males) patients who received increasing doses of Vespula venom (Aquagen, ALK-Abelló) until the final dose of 30 drops of extract in 3 hours, containing 100,000 SQ-U/ml. The maintenance dose was of 10 drops of pure venom extract 3 times a week, for a total dose of 100,000 SQ-U weekly (corresponding to 100 μg of venom extract). The SCIT group consisted of 20 patients (16 males and 4 females) who were treated with subcutaneous ultrarush immunotherapy with Vespula venom extract (Pharmalgen, Alk-Abelló). Patients received 101.1 μg of Vespula venom in 3 hours and were treated with 100 μg of wasp venom monthly. During the ultrarush sublingual treatment 2 patients (9.5%) experienced mild side-effects. Specific IgE and specific IgG to wasp venom did not show any significant modification. Four patients were field-stung by a wasp during the treatment (for a total of 6 stings). Two patients (3 stings), with a previous clinical history of a grade III and IV reaction, did not experience any reaction. One patient, with a previous grade II reaction, showed a large local reaction. The fourth patient, with a previous grade III reaction, was re-stung twice (after 12 and 24 months) with two systemic reactions (SR) (mild throat constriction). During the ultrarush SCIT phase, 3 (15%) patients experienced side-effects: 2 of them showed a large local reaction and 1 had headache and stomach ache. Specific IgE showed a significant (P=0.001) increase after 6 months of treatment and then returned to baseline levels while specific IgG showed a significant (P=0.001) increase after 6, 12 and 24 months in comparison with baseline. Nine patients were field-stung during the treatment: 8 of them experienced large local reactions; one patient (11%) experienced an SR (dizziness). Our results, even if in a small number of patients, suggest that in patients with Hymenoptera sting allergy SLIT could be efficacious with a good tolerability profile when compared to SCIT. Larger studies are needed to assess efficacy, safety and tolerability profile of wasp venom SLIT.