Sublingual immunotherapy in children: complete and updated review supporting evidence of effect

Alternatives to Subcutaneous Immunotherapy for Allergic Rhinitis

Allergic rhinitis (AR) is an important public health issue worldwide due to its increasing prevalence and impact on quality of life, school performance, and work productivity. Subcutaneous immunotherapy (SCIT) is used to treat AR and involves repeated injections of allergen extracts. SCIT is used for cases of severe AR with symptoms that are not adequately controlled by medication, when the side effects of medication limit treatment options, or where the aim is to cure rather than symptomatically treat. Although SCIT is effective, it is not necessarily curative. Furthermore, there is also a low but present risk of systemic allergic reactions, with systemic side effects occurring in less than 0–1% of treated patients. Sublingual immunotherapy (SLIT) has emerged as an effective and safe alternative to SCIT. SCIT and SLIT are the only immunotherapies currently available for AR. In addition to sublingual administration as an alternative to SCIT, other routes of antigen administration have been attempted with the goal of increasing safety while maintaining efficacy. This review discusses the efficacies of SCIT and SLIT, their mechanisms, the utility of intralymphatic immunotherapy (ILIT) as an alternative route of antigen administration, and the potential for immunotherapy using other routes of antigen administration.

Sublingual immunotherapy for pediatric patients with mite allergies

Sublingual immunotherapy (SLIT) has been increasingly used instead of subcutaneous immunotherapy. SLIT was initially approved for use among adults; however, it has become more widely accepted for children. Few studies have evaluated the effectiveness of SLIT in the treatment of dust mite allergies among children, including adverse effects. This study aimed to investigate the effectiveness of SLIT in children with dust mite allergies, as well as its adverse effects, at a pediatric general outpatient clinic.I analyzed the data of 181 patients aged 4 to 12 years who tested positive for mite antigen-specific immunoglobulin E, exhibited nasal and/or eye symptoms, and received Miticure. Symptoms were evaluated using the Japanese rhino-conjunctivitis quality of life (QOL) questionnaire no. 1. Wilcoxon tests were used to compare the pretreatment and post-treatment symptom scores. Adverse events were tallied, and Kaplan-Meier curves and Wilcoxon tests were used to assess the proportion of dropouts.The mean QOL score at the baseline was 2.17 (standard deviation [SD] 1.45). After 1 week, the mean symptom QOL score was 1.63 (SD 1.32); the lowest mean score was found in week 41 (0.48, SD 0.63). A significant decline in the occurrence of all symptoms, including sneezing, nasal discharge, nasal congestion, itchy eyes, and teary eyes, was observed. Adverse effects were observed in 76 (42.0%) patients; the most common adverse effect was itchy mouth.SLIT improves symptoms with minimal adverse effects in pediatric patients.

Differences and similarities between sublingual immunotherapy of allergy and oral tolerance

Allergen immunotherapy is the only treatment altering the natural course of IgE-mediated allergies. Whereas the subcutaneous route for immunotherapy (SCIT) has been historically considered as a reference, we discuss herein the relative advantages of the sublingual and oral routes as alternatives to SCIT in order to elicit allergen-specific tolerance. The buccal and gut immune systems are similarly organized to favor immune tolerance to antigens/allergens, due to the presence of tolerogenic dendritic cells and macrophages promoting the differentiation of CD4⁺ regulatory T cells. Sublingual immunotherapy (SLIT) is now established as a valid treatment option, with clinical efficacy demonstrated in allergic rhinoconjunctivitis (to either grass, tree, weed pollens or mite allergens) and encouraging results obtained in the management of mild/moderate allergic asthma. While still exploratory, oral immunotherapy (OIT) has shown promising results in the desensitization of patients with food allergies. We review at both biological and clinical levels the perspectives currently pursued for those two mucosal routes.

Clinical practice recommendations for allergen-specific immunotherapy in children: the Italian consensus report

Allergen-specific immunotherapy (AIT) is currently recognized as a clinically effective treatment for allergic diseases, with a unique disease-modifying effect. AIT was introduced in clinical practice one century ago, and performed in the early years with allergenic extracts of poor quality and definition. After the mechanism of allergic reaction were recognized, the practice of AIT was refined, leading to remarkable improvement in the efficacy and safety profile of the treatment. Currently AIT is accepted and routinely prescribed worldwide for respiratory allergies and hymenoptera venom allergy. Both the subcutaneous (SCIT) and sublingual (SLIT) routes of administration are used in the pediatric population.AIT is recommended in allergic rhinitis/conjunctivitis with/without allergic asthma, with an evidence of specific IgE-sensitization towards clinically relevant inhalant allergens. Long-term studies provided evidence that AIT can also prevent the onset of asthma and of new sensitizations. The favorable response to AIT is strictly linked to adherence to treatment, that lasts 3-5 years. Therefore, several factors should be carefully evaluated before starting this intervention, including the severity of symptoms, pharmacotherapy requirements and children and caregivers' preference and compliance.In recent years, there have been increasing interest in the role of AIT for the treatment of IgE-associated food allergy and extrinsic atopic dermatitis. A growing body of evidence shows that oral immunotherapy represents a promising treatment option for IgE-associated food allergy. On the contrary, there are still controversies on the effectiveness of AIT for patients with atopic dermatitis.This consensus document was promoted by the Italian Society of Pediatric Allergy and Immunology (SIAIP) to provide evidence-based recommendations on AIT in order to implement and optimize current prescription practices of this treatment for allergic children.

Clinical considerations in the use of sublingual immunotherapy for allergic rhinitis

BACKGROUND

Allergen immunotherapy (AIT) has been in practice for more than 100 years. However, research in novel routes and delivery methods of immunotherapy to treat allergic rhinitis (AR) and conjunctivitis has only recently occurred in the United States, where the predominant form of AIT provided is largely via a subcutaneous immunotherapy (SCIT) route. AIT may prevent new sensitizations, improve symptoms, decrease medication usage, and prevent allergic asthma. Although AIT is the only potentially curative treatment for AR, access and adherence continue to be problematic. Only a fraction of eligible patients actually undergo treatment, and attrition rates are high. An obvious limitation of SCIT includes the requirement of regular injections to be provided in the physician's office due to the potential for anaphylaxis. Sublingual immunotherapy (SLIT) for home administration has been investigated as a potential alternative to address this limitation of SCIT.

METHODS

A literature review was performed including the current findings from randomized clinical trials and meta-analyses with a discussion of the most recent evidence for the efficacy, safety, and dosing of allergen SLIT.

RESULTS

The current data suggest that SLIT is effective for treatment of seasonal allergies, can potentially prevent asthma, and has a favorable safety profile. Head-to-head studies, however, are few, and comparative effectiveness still remains to be answered. Optimal treatment algorithms for SLIT have not yet been established, with wide variation in dosage selection and schedules. Similarly to SCIT, only a few allergens such as ragweed and grass pollen have been found to be effective in large clinical trials.

CONCLUSION

Recent data indicate that SLIT is an effective treatment modality for seasonal AR, improve quality of life, and can potentially prevent asthma but head-to head studies comparing SLIT to SCIT are needed.

Efficacy and safety of sublingual immunotherapy in children

Allergen immunotherapy (AIT) is currently the only available disease-modifying and aetiological treatment of IgE-mediated diseases. Sublingual allergen immunotherapy (SLIT) constitutes the preferred route of administration of AIT for respiratory allergies in Europe. Recently it has also been approved in the US. Further applications are currently under evaluation, such as IgE-mediated food allergy and IgE-mediated atopic dermatitis. The SLIT safety profile is overall favourable, although local adverse events, usually mild, are described. Most of the meta-analyses confirmed the efficacy of SLIT in reducing symptoms and medication intake in children with allergic diseases. AIT, as an immune-modulating treatment, can modify the natural history of the allergic diseases: reduction of the risk of development of asthma and bronchial hyperreactivity in patients with allergic rhinitis, and reduction of the onset of new sensitizations. A great interest is now devoted to the preventive effects of AIT and, consequently, to the optimal time of initiation.

House Dust Mite Respiratory Allergy: An Overview of Current Therapeutic Strategies

Although house dust mite (HDM) allergy is a major cause of respiratory allergic disease, specific diagnosis and effective treatment both present unresolved challenges. Guidelines for the treatment of allergic rhinitis and asthma are well supported in the literature, but specific evidence on the efficacy of pharmacotherapy treatment for known HDM-allergic patients is weaker. The standard diagnostic techniques--skin prick test and specific IgE testing--can be confounded by cross-reactivity. However, component-resolved diagnosis using purified and recombinant allergens can improve the accuracy of specific IgE testing, but availability is limited. Treatment options for HDM allergy are limited and include HDM avoidance, which is widely recommended as a strategy, although evidence for its efficacy is variable. Clinical efficacy of pharmacotherapy is well documented; however, symptom relief does not extend beyond the end of treatment. Finally, allergen immunotherapy has a poor but improving evidence base (notably on sublingual tablets) and its benefits last after treatment ends. This review identifies needs for deeper physician knowledge on the extent and impact of HDM allergy in respiratory disease, as well as further development and improved access to molecular allergy diagnosis. Furthermore, there is a need for the development of better-designed clinical trials to explore the utility of allergen-specific approaches, and uptake of data into guidance for physicians on more effective diagnosis and therapy of HDM respiratory allergy in practice.

Optimal management of allergic rhinitis

Allergic rhinitis (AR), the most common chronic disease in childhood is often ignored, misdiagnosed and/or mistreated. Undertreated AR impairs quality of life, exacerbates asthma and is a major factor in asthma development. It can involve the nose itself, as well as the organs connected with the nose manifesting a variety of symptoms. Evidence-based guidelines for AR therapy improve disease control. Recently, paediatric AR guidelines have been published by the European Academy of Allergy and Clinical Immunology and are available online, as are a patient care pathway for children with AR and asthma from the Royal College of Paediatrics and Child Health. Management involves diagnosis, followed by avoidance of relevant allergens, with additional pharmacotherapy needed for most sufferers. This ranges, according to severity, from saline sprays, through non-sedating antihistamines, oral or topical, with minimally bioavailable intranasal corticosteroids for moderate/severe disease, possibly plus additional antihistamine or antileukotriene. The concept of rhinitis control is emerging, but there is no universally accepted definition. Where pharmacotherapy fails, allergen-specific immunotherapy, which is uniquely able to alter long-term disease outcomes, should be considered. The subcutaneous form (subcutaneous immunotherapy) in children has been underused because of concerns regarding safety and acceptability of injections. Sublingual immunotherapy is both efficacious and safe for grass pollen allergy. Further studies on other allergens in children are needed. Patient, carer and practitioner education into AR and its treatment are a vital part of management.

Will sublingual immunotherapy offer benefit for asthma?

Evidence shows that sublingual immunotherapy (SLIT) is indicated in patients with allergic rhinitis (AR). In this article we discuss whether SLIT could offer benefit for children and adults with asthma.We reviewed individual trials on SLIT in asthmatic patients, but also asthma data reported in some SLIT trials conducted in AR patients. Findings were complemented with data from systematic reviews and metaanalysis on the subject since 2000 and some guidelines that mention immunotherapy for asthma treatment. In AR patients with concomitant persistent asthma, SLIT reduces medication needs while maintaining symptom control. This holds especially true for house dust mite SLIT. Data on pollen SLIT and lung symptom improvement with SLIT, however, are less convincing. Therefore, we suggest SLIT should be added as an optional add-on therapy for patients with asthma whenever a causative allergen has been demonstrated and AR is associated with asthma. For the future, SLIT should be studied in specifically designed asthma studies in allergic asthmatics without AR.

Selection of patients for sublingual versus subcutaneous immunotherapy

Allergen immunotherapy is the sole treatment for IgE-mediated allergic diseases directed at the underlying mechanism. The two widely accepted administration routes are sublingual (SLIT) and subcutaneous (SCIT). We reviewed how patients should best be selected for immunotherapy and how the optimal administration route can be defined. Before deciding SCIT or SLIT, appropriate selection of patients for allergen immunotherapy (AIT) is mandatory. To be eligible for AIT, subjects must have a clear medical history of allergic disease, with exacerbation of symptoms on exposure to one or more allergens and a corresponding positive skin or in vitro test. Then the route of administration should be based on: published evidence of clinical and immunologic efficacy (which varies per allergic disease and per allergen); mono- or multi-allergen immunotherapy, for SLIT multi-allergen immunotherapy was not effective; safety: adverse events with SLIT are more frequent, but less severe; and, costs and patient preferences, closely related to adherence issues. All these are discussed in the article.

Effect of inhaled inactivated Mycobacterium phlei in children with moderate asthma

Bacillus Calmette-Guérin and other mycobacterial vaccines are important therapeutic methods in a series of chronic inflammatory disorders characterized by Th1/Th2 imbalance in which Th2 type cells and cytokines often increase. However, few studies have investigated whether it can reduce or prevent the symptoms and attacks in children with asthma. This study evaluated the effect of inactivated Mycobacterium phlei inhaled by an atomizing device placed on asthmatic children. In this randomized, single-center, Seretide-controlled study, children aged 4-12 years with newly diagnosed, moderate, persistent asthma were treated with either inhaled inactivated M. phlei or inhaled Seretide patch. The efficacy of inhaled inactivated M. phlei was related with the alleviation of asthma symptoms, improvement of lung function and reduction of bronchial hyper-responsiveness and total serum IgE, which was similar with Seretide. These findings may have important clinical value in confirming inhaled inactivated M. phlei as a new therapeutic method in moderately asthmatic children.

Current and future directions in pediatric allergic rhinitis

BACKGROUND

Allergic rhinitis (AR) is a common pediatric problem that significantly affects sleep, learning, performance, and quality of life. In addition, it is associated with significant comorbidities and complications.

OBJECTIVE

The aim was to provide an update on the epidemiology, comorbidities, pathophysiology, current treatment, and future direction of pediatric AR.

METHODS

Literature reviews in each of these areas were conducted, and the results were incorporated.

RESULTS

The prevalence of AR is increasing in the pediatric population and is associated with significant morbidity, comorbidities, and complications. The mainstay of current treatment strategies includes allergen avoidance, pharmacotherapy, and allergen specific immunotherapy.

CONCLUSIONS

In the future, diagnosis will be improved by microarrayed recombinant allergen testing and therapy will be expanded to include emerging treatments such as sublingual immunotherapy and combination products.

Pediatric sublingual immunotherapy efficacy: evidence analysis, 2009-2012

OBJECTIVE

To perform a structured analysis of the latest scientific evidence obtained for the clinical efficacy of sublingual immunotherapy (SLIT) in children.

DATA SOURCES

PubMed, Embase, reference lists from reviews, and personal databases were reviewed for original articles on clinical trials with SLIT in patients younger than 18 years published from January 1, 2009, through December 31, 2012, using broad search and medical subject heading terms.

STUDY SELECTIONS

Clinical trials, irrespective of their design, of SLIT in the treatment of respiratory and food allergy in patients 18 years or younger were selected. Clinical outcomes (symptom scores, medication use, provocation tests, pulmonary function tests, skin prick tests, and adverse events) and immunologic changes were tabulated. Quality of each trial and total quality of compounded evidence was analyzed with the Grading of Recommendations Assessment, Development and Evaluation system.

RESULTS

Of 56 articles, 29 met the inclusion criteria. New evidence is robust for the precoseasonal tablet and drop grass pollen SLIT efficacy in allergic rhinitis and scarce for seasonal asthma. Some evidence for Alternaria SLIT efficacy is appearing. For house dust mite (HDM) SLIT in asthma, there is high-quality evidence for medication reduction while maintaining symptom control; evidence for HDM SLIT efficacy in allergic rhinitis is of moderate-low quality. There is moderate evidence for efficacy of dual grass pollen-HDM SLIT after 12 months of treatment and 1 year after discontinuation. Specific provocation test results (nasal, skin) improve with grass pollen and HDM SLIT but nonspecific bronchial provocation testing does not. Food oral immunotherapy is more promising than food SLIT. Possible new surrogate markers have been reported. No anaphylaxis was found among 2469 treated children.

CONCLUSION

Evidence for efficacy of SLIT in children with respiratory or food allergy is growing.

High-dose sublingual immunotherapy with single-dose aqueous grass pollen extract in children is effective and safe: a double-blind, placebo-controlled study

BACKGROUND

Sublingual allergen-specific immunotherapy is a viable alternative to subcutaneous immunotherapy particularly attractive for use in children.

OBJECTIVE

This study investigated efficacy and safety of high-dose sublingual immunotherapy (SLIT) in children allergic to grass pollen in a randomized, double-blind, placebo-controlled trial.

METHODS

After a baseline seasonal observation, 207 children aged 4 to 12 years with grass pollen-allergic rhinitis/rhinoconjunctivitis with/without bronchial asthma (Global Initiative for Asthma I/II) received either high-dose grass pollen SLIT or placebo daily for 1 pre-/co-seasonal period. The primary end point was the change of the area under the curve of the symptom-medication score (SMS) from the baseline season to the first season after start of treatment. Secondary outcomes were well days, responders, immunologic changes, and safety.

RESULTS

Mean changes in the area under the curve of the SMS from the baseline to the first grass pollen season after the start of treatment were -212.5 for the active group and -97.8 for the placebo group (P = .0040). Rhinoconjunctivitis SMS (P = .0020) and separated symptom and medication scores were also statistically different between the 2 groups (P = .0121 and P = .0226, respectively). The number of well days and the percentage of responders were greater in the active group. Changes in allergen-specific IgE and IgG levels indicated a significant immunologic effect. The treatment was well tolerated, and no serious treatment-related events were reported.

CONCLUSIONS

This study confirmed that this SLIT preparation significantly reduced symptoms and medication use in children with grass pollen-allergic rhinoconjunctivitis. The preparation showed significant effects on allergen-specific antibodies, was well tolerated, and appeared to be a valid therapeutic option in children allergic to grass pollen. This trial was registered at www.clinicaltrials.gov as NCT00841256.

Novel routes for allergen immunotherapy: safety, efficacy and mode of action

Allergen immunotherapy is the only curative treatment of IgE-mediated type I respiratory allergies. Subcutaneous immunotherapy (SCIT) is used as a reference therapy and has transformed allergic treatments; it improves symptoms (asthma and rhinitis) as well as the quality of life of patients. SCIT requires repetitive administration and carries the risk of severe systemic adverse effects, including anaphylaxis. Sublingual immunotherapy is now a valid noninvasive alternative to SCIT, as a safe and efficacious treatment for respiratory allergies. In this article, we compare various routes of allergen immunotherapy, including SCIT and sublingual immunotherapy, as well as more exploratory routes currently under investigation (i.e., intralymphatic, epicutaneous, intranasal and oral). We discuss their respective advantages, as well as their foreseen modes of action.

Allergic rhinitis in children

Allergic rhinitis affects up to 40% of children but is commonly undiagnosed. Careful assessment of nasal symptoms allows for the most appropriate therapeutic options to be chosen. Allergen avoidance is often difficult in practice. Antihistamines are of limited benefit in allergic rhinitis caused by house dust mite and other perennial allergens, where symptoms, predominantly nasal obstruction, are not histamine mediated. In contrast, symptoms triggered by pollen, such as nasal itch, rhinorrhoea and sneezing, are relieved by antihistamines. Intranasal steroids are the treatment of choice for persistent moderate-severe allergic rhinitis and are more effective than antihistamines for relief of nasal obstruction. Failure to respond to intranasal medications is often caused by poor compliance or inefficient use of nasal sprays. Immunotherapy may be a useful, if expensive, option, particularly where symptoms are because of a specific pollen. The benefits of immunotherapy in house dust mite-induced rhinitis and asthma remain controversial.

Sublingual immunotherapy not effective in house dust mite-allergic children in primary care

BACKGROUND

Sublingual immunotherapy (SLIT) as a therapy for the treatment of allergic rhinitis in children might be acceptable as an alternative for subcutaneous immunotherapy. However, the efficacy of SLIT with house dust mite extract is not well established.

OBJECTIVE

To investigate whether SLIT in house dust mite-allergic children recruited in primary care is effective and safe.

METHODS

Children aged 6-18 years (n = 251) recruited in primary care with a house dust mite-induced allergic rhinitis received either SLIT or placebo for 2 years. Symptoms and medication use were assessed throughout the study. Primary outcome parameter was the mean total nose symptom score (scales 0-12) during the autumn of the second treatment year. Safety was assessed by recording any adverse event.

RESULTS

Overall, the mean nose symptom score ± s.d. after 2 years of treatment showed no significant effect of SLIT (symptom score intervention group 2.26 ± 1.84 vs. placebo group, 2.02 ± 1.67; p = 0.08). There were no significant differences in secondary outcomes, nor in subgroup analyses. The number of patients reporting adverse events was comparable between both groups.

CONCLUSIONS

Sublingual immunotherapy with house dust mite allergen was not better than placebo in reducing rhinitis symptoms in house dust mite-allergic children in primary care. SLIT as administered in this study can be considered safe.

Immunological approaches for tolerance induction in allergy

Allergy is the consequence of an inappropriate inflammatory immune response generated against harmless environmental antigens. In allergic disorders such as asthma and rhinitis, the Th2 mediated phenotype is a result of loss of peripheral tolerance mechanisms. In cases such as these, approaches such as immunotherapy attempt to treat the underlying cause of allergic disease by restoring tolerance. Immunotherapy initiates many complex mechanisms within the immune system that result in initiation of innate immunity, activation of both cellular and humoral B cell immunity, as well as triggering T regulatory subsets which are major players in the establishment of peripheral tolerance. Though studies clearly demonstrate immunotherapy to be efficacious, research to improve this treatment is ongoing. Investigation of allergenicity versus immunogenicity, native versus modified allergens, and the use of adjuvant and modality of dosing are all current strategies for immunotherapy advancement that will be reviewed in this article.

Continuous apple consumption induces oral tolerance in birch-pollen-associated apple allergy

BACKGROUND

Patients with birch pollen allergy (major allergen: Bet v 1) have often an associated oral allergy syndrome (OAS) to apple, which contains the cross-reactive allergen Mal d 1. As successful birch pollen immunotherapy does not consistently improve apple related OAS symptoms, we evaluated whether regular apple consumption has an effect on OAS and immune parameters of Mal d 1 or Bet v 1 allergy.

METHODS

A total of 40 patients with a clear history of birch pollen rhinoconjunctivitis and associated OAS to apple were included in an open, randomized, controlled clinical trial: 27 patients consumed daily defined amount of apple (1-128 g), doubling the amount every two to three weeks, while 13 patients remained untreated. Primary endpoint was the proportion of patients that achieved tolerance to at least 128 g of apple at the end of the study after 8 months. Exploratory endpoints were questionnaire about cross-reactive food and pollen allergy symptoms, conjunctival provocation test with birch pollen and Bet v 1, and in vitro tests (tIgE, sIgE, and IgG4 to Mal d 1 and Bet v 1; basophil activation test with both allergens).

RESULTS

Seventeen of 27 patients in active group and none of 13 patients in control group (P = 0.0001) could tolerate a whole apple after the intervention. However, differences in endpoints reflecting systemic immune reactivity did not reach statistical significance.

CONCLUSION

In patients with OAS to apple, tolerance can be safely induced with slowly, gradually increasing consumption of apple. However, the observation of a relapse after discounting of apple consumption and absence of immunologic changes suggest that induced tolerance is only transient.

Quality of life improvement with sublingual immunotherapy: a prospective study of efficacy

Due to its excellent safety profile, ease of administration, and economic considerations, sublingual immunotherapy (SLIT) is becoming a preferred form of allergen specific immunotherapy. The efficacy of SLIT is still debated. The purpose of this act of practice trial is to evaluate quality of life outcomes in patients treated with SLIT. Fifty one patients with allergic rhinoconjunctivitis demonstrated by skin testing completed the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) at initiation, at four months and at 10-12 months of SLIT. Significant improvement (P < 0.05) on six of seven domain categories of the RQLQ questionnaire was noted. Total RQLQ scores also showed significant improvement. This study supports SLIT as a modality effective in controlling allergic symptoms.

Allergic rhinitis

Allergic rhinitis is a very common disorder that affects people of all ages, peaking in the teenage years. It is frequently ignored, underdiagnosed, misdiagnosed, and mistreated, which not only is detrimental to health but also has societal costs. Although allergic rhinitis is not a serious illness, it is clinically relevant because it underlies many complications, is a major risk factor for poor asthma control, and affects quality of life and productivity at work or school. Management of allergic rhinitis is best when directed by guidelines. A diagnostic trial of a pharmacotherapeutic agent could be started in people with clinically identified allergic rhinitis; however, to confirm the diagnosis, specific IgE reactivity needs to be recorded. Documented IgE reactivity has the added benefit of guiding implementation of environmental controls, which could substantially ameliorate symptoms of allergic rhinitis and might prevent development of asthma, especially in an occupational setting. Many classes of drug are available, effective, and safe. In meta-analyses, intranasal corticosteroids are superior to other treatments, have a good safety profile, and treat all symptoms of allergic rhinitis effectively. First-generation antihistamines are associated with sedation, psychomotor retardation, and reduced academic performance. Only immunotherapy with individually targeted allergens has the potential to alter the natural history of allergic rhinitis. Patients' education is a vital component of treatment. Even with the best pharmacotherapy, one in five affected individuals remains highly symptomatic, and further research is needed in this area.

Evidence of effect of subcutaneous immunotherapy in children: complete and updated review from 2006 onward

OBJECTIVE

To update the scientific evidence of subcutaneous immunotherapy (SCIT) in children.

DATA SOURCES

PubMed, EMBASE, and known articles.

STUDY SELECTION

All publications on SCIT in pediatric patients from January 2006 to April 2011. Study design was not a restriction. The articles were analyzed according to their outcomes and evaluated on their scientific quality using the Grading of Recommendations Assessment, Development, and Evaluation and Jadad tools. Clinical, safety, and immunologic data were gathered.

RESULTS

The scientific evidence produced by the 31 articles analyzed showed that there is high-quality evidence that grass pollen SCIT causes a reduction in the combined symptom-medication score and increases the threshold of the conjunctival provocation test, immediately and 7 years after termination of SCIT, as well as the threshold of the specific bronchial provocation test and the skin prick test reactivity. Alternaria SCIT improves medication scores, combined symptom-medication scores, and quality of life. It augments the threshold in the nasal provocation test. High-quality evidence of house dust mite SCIT shows that asthma symptom and medication scores improve and emergency department visits and skin reactivity are reduced; moderate evidence indicates improvement in pulmonary function tests. Pollen SCIT prevents asthma (moderate evidence); evidence for long-term benefit of pollen SCIT (7-12 years after termination) is low to moderate. There is inconclusive evidence for SCIT reducing new sensitizations.

CONCLUSION

There is acceptable evidence that shows that grass pollen, Alternaria, and house dust mite SCIT is beneficial in allergic children.

Sublingual immunotherapy in children with allergic rhinitis: quality of systematic reviews

Systematic reviews have gained popularity as a way to combine the increasing amount of research information. This study assessed the quality of systematic reviews and meta-analyses of sublingual immunotherapy (SLIT) for allergic rhinitis in children, published since 2000. Eligible reviews were identified by searching Medline/Pubmed, Embase, and the Cochrane Library, from 2000 through 2008. Methodological quality was assessed using the assessment of multiple systematic reviews instrument. Ten systematic reviews were included, one of which was published in the Cochrane Library. Eight reviews gave some details about the search strategy. None of the reviews included measures to avoid selection bias. In 60% of the reviews, the methodological quality of the included studies was (partly) assessed. Four reviews pooled the results of individual studies, neglecting clinical heterogeneity. Three of the 10 reviews provided information about sources of funding or grants from industry. Of the 10 reviews, the six reviews with the highest overall score scored 5-8 points, indicating moderate quality. Systematic reviews are useful to evaluate the efficacy of SLIT in children. Although more reviews have become available, the methodological quality could be improved. SLIT for children could be promising, but methodological flaws in the reviews and individual studies are too serious to draw definite conclusions.

Close collaboration between academia, industry and drug regulators is required in the development of allergen products for specific immunotherapy in children

Modification of the response to allergens at an early stage and thereby of the natural history of a respiratory allergic disease by preventing disease progression would constitute the key benefit of specific immunotherapy (SIT) in children. However, although allergen products for SIT have been on the market on a named-patient basis for many years, long-term efficacy, the optimal duration of the treatment and the optimal dosage have not been sufficiently elaborated until now. The enactment of the Therapy Allergen Ordinance in Germany mandates that allergen products for SIT of the most prevalent allergies must submit an application for marketing authorization to the German authorities. In line with the European Paediatric Regulation, decisions by the European Medicines Agency on agreed paediatric investigation plans must be included in these applications. These regulatory requirements provide a unique opportunity to fill the gap in knowledge concerning the benefits of SIT for children and to obtain the data needed to support evidence-based authorization of allergen products for immunotherapy. This goal can only be achieved through close cooperation between academia, drug regulators and industry as well as parent/patient organizations.

Sublingual immunotherapy in allergic asthma: Current evidence and needs to meet

Allergen-specific immunotherapy is aimed at modifying the natural history of allergy by inducing tolerance to the causative allergen. In its traditional, subcutaneous form, immunotherapy has complete evidence of efficacy in allergic asthma. However, subcutaneous immunotherapy (SCIT) has a major flaw in side effects, and especially in possible anaphylactic reactions, and this prompted the search for safer ways of administration of allergen extracts. Sublingual immunotherapy (SLIT) has met such need while maintaining a clinical efficacy comparable to SCIT. In fact, the safety profile, as outlined by a systematic revision of the available literature, was substantially free from serious systemic reactions. A number of meta-analyses clearly showed that SLIT is effective in allergic rhinitis by significantly reducing the clinical symptoms and the use of anti-allergic drugs, while the efficacy in allergic asthma is still debated, with some meta-analyses showing clear effectiveness but other giving contrasting results. Besides the efficacy on symptoms, the preventive activity and the cost-effectiveness are important outcomes of SLIT in asthma. The needs to meet include more data on efficacy in house dust mite asthma, optimal techniques of administration and, as previously done with SCIT, introduction of adjuvants able to enhance the immunologic response and use of recombinant allergens.

Strategies of mucosal immunotherapy for allergic diseases

Incidences of allergic disease have recently increased worldwide. Allergen-specific immunotherapy (SIT) has long been a controversial treatment for allergic diseases. Although beneficial effects on clinically relevant outcomes have been demonstrated in clinical trials by subcutaneous immunotherapy (SCIT), there remains a risk of severe and sometimes fatal anaphylaxis. Mucosal immunotherapy is one advantageous choice because of its non-injection routes of administration and lower side-effect profile. This study reviews recent progress in mucosal immunotherapy for allergic diseases. Administration routes, antigen quality and quantity, and adjuvants used are major considerations in this field. Also, direct uses of unique probiotics, or specific cytokines, have been discussed. Furthermore, some researchers have reported new therapeutic ideas that combine two or more strategies. The most important strategy for development of mucosal therapies for allergic diseases is the improvement of antigen formulation, which includes continuous searching for efficient adjuvants, collecting more information about dominant T-cell epitopes of allergens, and having the proper combination of each. In clinics, when compared to other mucosal routes, sublingual immunotherapy (SLIT) is a preferred choice for therapeutic administration, although local and systemic side effects have been reported. Additionally, not every allergen has the same beneficial effect. Further studies are needed to determine the benefits of mucosal immunotherapy for different allergic diseases after comparison of the different administration routes in children and adults. Data collected from large, well-designed, double-blind, placebo-controlled, and randomized trials, with post-treatment follow-up, can provide robust substantiation of current evidence.

Sublingual immunotherapy in asthma does not influence lymphocyte sensitivity to Fas stimulation

BACKGROUND

The resistance of T lymphocytes to Fas-mediated apoptosis is an important feature of atopic asthma. The only effective causative treatment of atopic diseases is immunotherapy. Clinical efficacy of sublingual immunotherapy (SLIT) has been already proven, but there is still limited number of studies on its influence on lymphocytes function.

OBJECTIVES

The aim of the study was to evaluate whether SLIT could restore the sensitivity of asthmatic T cells to undergo Fas-mediated apoptosis.

MATERIAL AND METHODS

Peripheral blood was collected from 12 patients aged 8 ±2 years suffering from atopic asthma and undergoing sublingual specific immunotherapy. To evaluate sensitivity to Fas-mediated apoptosis, the blood was transmitted to sterile tubes and mixed with purified monoclonal antibody anti-CD95. After incubation, leukocytes were stained with Annexin V, propidium iodide, and monoclonal antibody against CD2 conjugated with phycoerythrin-cyanin 5.1, and then analyzed with flow cytometry. The procedure was repeated for each patient after 12 months of SLIT. -

RESULTS

Stimulation with anti-CD95 of T lymphocytes from patients with atopic asthma before treatment increased the number of early apoptotic cells (from 19.5 ±16.7% before stimulation to 26.6 ±16.7% Annexin V positive cells after stimulation). After one year of SLIT anti-CD95 still caused an increase of the early apoptotic cells ratio in the lymphocyte population (from 12.4 ±7.4% before stimulation to 24.7 ±15.4% Annexin V positive T cells after CD95 stimulation). Although an increasing trend could be observed, differences between the analyzed groups were not statistically significant.

CONCLUSIONS

A year of SLIT does not change the sensitivity of T lymphocytes from peripheral blood of children suffering from atopic asthma to Fas-mediated apoptosis.

Sublingual immunotherapy in children: facts and needs

Allergen specific immunotherapy (SIT) is the practice of administering gradually increasing doses of the specific causative allergen to reduce the clinical reactivity of allergic subjects, and is the only treatment targeting the causes of hypersensitivity and not only the symptoms, as done by drugs. The traditional, subcutaneous immunotherapy (SCIT) was burdened by the problem of systemic reactions which may be sometimes severe and - though very rarely - even fatal. This was the background to develop non injections routes for SIT and particularly sublingual immunotherapy (SLIT), that emerged as a real treatment option for respiratory allergy.

A number of studies was conducted to evaluate efficacy and safety of SLIT, the first meta-analysis - including 22 placebo-controlled trials - concluded for positive results in both issues, but the number of studies on children was too low to draw definite conclusions. Since then, many other studies became available and make possible to analyze SLIT in children in its well defined aspects as well as in sides still requiring more solid data.