Safety of sublingual immunotherapy in children with asthma

Morphofunctional analysis of antigen uptake mechanisms following sublingual immunotherapy with beads in mice

Background

Recently, sublingual immunotherapy (SLIT) has been used as a safe and efficient method for the treatment of and immunization against asthma and various allergies. However, the routes of antigen/allergen (particulate antigen) uptake through the mucosa of the oral cavity remain incompletely understood, as do the roles of sex and age in the process. For this purpose, to elucidate the mechanism and efficacy of SLIT among different sexes and ages, microbeads were dripped into the sublingual region to mimic particulate antigen uptake by the sublingual mucosa.

Methods

Twenty microliters of either phosphate buffered saline (PBS) or fluorescently labelled microbeads (latex and silica beads) were placed under the tongue of both male and female C57BL/6 mice at young (3 months) and old (6 months) ages. The lower jaw was examined 30 min after administration, and beads were detected with a fluorescence stereomicroscope. Morphological observations of the mucosa of the fluorescent areas were made with a scanning electron microscope (SEM) and an all-in-one light fluorescence microscope (LM). Fluorescence intensity was compared between both sexes and ages.

Results

Stereomicroscopic observation revealed fluorescent illuminations in three compartments of the sublingual mucosa: the sublingual caruncles (SC), the oral rostral mucosa (OR) and the buccal mucosa (BM). Interestingly, the fluorescence intensity tended to be higher among females than among males in the SC region in particular. However, there were no significant age-related differences. SEM and LM revealed beads in the lumina of both mandibular ducts and sublingual ducts (Sd). Additionally, the apical cytoplasm of some Sd cells contained silica beads. However, there was no specification in the OR mucosa or BM.

Conclusions

This study reveals the major role Sd plays in local immunity via the antigen uptake mechanisms. Furthermore, our data suggest that the efficacy of SLIT in humans could be affected by sex.

Plasticity of immune system vs. memory therapy IST

BACKGROUND

Pharmacotherapy and immunotherapy are the main treatments for allergic diseases to inhalants.

OBJECTIVE

This study investigates whether to repeat short cycles of immunotherapy after 3 or 5 years the from interruption of the first therapeutic cycle, lasting 3-4 years, to maintain immune memory in individuals subjected to IST.

METHODS AND RESULTS

We have compared two groups, one of 452 patients who, after the first treatment for 3-4 years of IST, performed a cycle of four months after three and 10 years from the suspension, and a second group of 126 individuals who have performed only the IST treatment for 3-4 years. The best results were obtained in the first group.

CONCLUSIONS

These results are due to the immune system's plasticity, a very important concept in clinical practice.

Local Side Effects of Sublingual and Oral Immunotherapy

Sublingual immunotherapy (SLIT) is increasingly used worldwide, and several products have been recently registered as drugs for respiratory allergy by the European Medicine Agency and the Food and Drug Administration. Concerning inhalant allergens, the safety of SLIT is overall superior to that of subcutaneous immunotherapy in terms of systemic adverse events. No fatality has been ever reported, and episodes of anaphylaxis were described only exceptionally. Looking at the historical and recent trials, most (>90%) adverse events are "local" and confined to the site of administration. For this reason, a specific grading system has been developed by the World Allergy Organization to classify and describe local adverse events. There is an increasing amount of literature concerning oral desensitization for food allergens, referred to as oral immunotherapy. Also, in this case, local side effects are predominant, although systemic adverse events are more frequent than with inhalant allergens. We review herein the description of local side effects due to SLIT, with a special focus on large trials having a declared sample size calculation. The use of the Medical Dictionary for Regulatory Activities nomenclature for adverse events is mentioned in this context, as recommended by regulatory agencies. It is expected that a uniform classification/grading of local adverse events will improve and harmonize the surveillance and reporting on the safety of SLIT.

Sublingual Immunotherapy: A Useful Tool for the Allergist in Private Practice

This is a review of the author's experience with Sublingual Immunotherapy in a private office setting. Sublingual Immunotherapy should be considered by any allergy practitioner as a useful tool. Sublingual Immunotherapy is safe while at the same time it is effective. It enables the practitioner to treat asthmatics and young children without the concerns implicit with allergy injections.

Safety profile of sublingual immunotherapy

Sublingual immunotherapy (SLIT) was proposed for clinical practice about 20 years ago with the main aim of improving the safety and avoiding the adverse effects of traditional treatment for allergic airways disease. To date, 32 randomized controlled trials and 6 postmarketing surveys have been published that provide a robust documentation of the safety profile of the treatment.Looking at the randomized trials it emerges that the more frequent adverse event of SLIT is oral itching or swelling, followed by gastrointestinal complaints. These adverse events are invariably described as mild and easily managed by adjusting the dose. Relevant systemic adverse events (asthma, urticaria, angioedema) occur sporadically and, with the exception of oral/gastrointestinal adverse events, the incidence of adverse events seems not to differ between the placebo and active groups. The safety profile of SLIT does not differ between adults and children.The postmarketing surveys consistently show that the incidence of adverse events associated with SLIT is less than 10%, corresponding to less than 1 adverse event per 1000 doses, and is thus quite superior to the safety profile of subcutaneous immunotherapy. Of note, the most recent data show that the rate of adverse events with SLIT is not increased in children below the age of 5 years.

A review of allergoid immunotherapy: is cat allergy a suitable target?

To modify the course of allergy, different types of specific allergen immunotherapy have been developed such as sublingual immunotherapy and subcutaneous immunotherapy with native allergens or subcutaneous immunotherapy with polymerized allergoids. However, the optimal specific immunotherapy, especially for cat allergy, remains undetermined. Few studies investigating immunotherapy in cat allergy have been published, and the risk of serious adverse reactions and systemic reactions has often been an important issue. Monomeric allergoids have lower allergenic potential while their immunogenicity remains constant, resulting in excellent safety with notable efficacy. Specific immunotherapy with monomeric allergoids could, therefore, be of high value, especially in cat allergy as well as other types of allergy, and bring relief to a great community of patients.

Safety and tolerability of sublingual immunotherapy in clinical trials and real life

PURPOSE OF REVIEW

Sublingual immunotherapy (SLIT) is effective in allergic rhinitis and asthma. Apart from its efficacy, safety is crucial as this treatment is usually self-administered at home. Tolerability also plays a pivotal role, as mild local reactions, although not life-threatening, may represent a risk for treatment withdrawal and can therefore negatively affect clinical outcomes. The present study addresses this issue by reviewing double-blind, placebo-controlled, randomized trials and real-life studies.

RECENT FINDINGS

The number of life-threatening SLIT-related reactions is negligible. SLIT-related adverse events are not always consistently reported nor uniformly classified in published studies. However, systemic reactions are rare and side effects mostly consist of mild, self-limiting local reactions. No treatment-related risk factors for adverse events have been clearly defined, as far as type of allergen, dose or schedule.

SUMMARY

SLIT provides an optimal safety profile both in children and in adults. Apart from life-threatening reactions, the lack of standardization of adverse events reporting may account for the wide variability of the prevalence of side effects in clinical trials and in real-life setting. It can lead to a possible underestimation of adverse events, concerning, in particular, local reactions. Since poor tolerability may affect adherence and cause treatment discontinuation, adopting shared strategies in order to recognize, grade and manage adverse events is mandatory.

Gum pigmentation: an unusual adverse effect of sublingual immunotherapy

Sublingual immunotherapy has gained acceptance amongst the paediatric community as it is very well tolerated and is safe. The adverse effects of this therapy is minimal consisting mainly of local side effects within the oral cavity such as itching of the mouth, swelling of the lips and less frequently abdominal pain, wheezing and urticaria has been described. This report is to highlight another local side effect of sublingual immunotherapy which has been observed in 3 of our patients. This is pigmentation of the gums which can occur anytime during the course of the immunotherapy. It resolves on stopping the immunotherapy and is likely due to a local inflammatory process occurring in the gums of these children. There is no associated pain or itching with the pigmentation. It can persist as long as the child is on the immunotherapy.

Sublingual immunotherapy in preschool children: an update

Allergen immunotherapy is a subject widely debated by allergists. Currently, there are controversial discussions focused on the sublingual route. Sublingual immunotherapy (SLIT) has so far been used in Europe, Asia and Australia for the treatment of allergic respiratory diseases. The minimum age to start specific immunotherapy with inhalant allergens in children has not been clearly established, and position papers discourage its use in children younger than 5 years of age. Nevertheless, it is known that SLIT efficacy is higher when SLIT is started at an earlier age. The aim of this review is to focus on studies in preschool children evaluating SLIT safety and efficacy, in order to improve this practice at an earlier age in childhood.

Balancing efficacy against safety in sublingual immunotherapy with inhalant allergens: what is the best approach?

Over the last 20 years, studies and clinical trials have demonstrated efficacy, safety and cost-effectiveness of sublingual immunotherapy (SLIT) for respiratory allergic diseases. Nevertheless, it seems to be mostly used as a second-line therapeutic option, and adherence to treatment is not always optimal. Selective literature research was done in Medline and PubMed, including guidelines, position papers and Cochrane meta-analyses concerning SLIT in adult patients. The most recent reviews confirm SLIT as viable and efficacious treatment especially for allergic rhinitis, even if the optimal dosage, duration, schedule are not clearly established for most of the products. Despite an optimal safety profile, tolerability and patient-reported outcomes concerning SLIT have received poor attention until now. Recently, new tools have been specifically developed in order to investigate these aspects. Regular assessment of tolerability profile and SLIT-related patient-reported outcomes will allow balancing efficacy with tolerability and all the other patient-related variables that may affect treatment effectiveness beyond its efficacy.

Grading local side effects of sublingual immunotherapy for respiratory allergy: speaking the same language

Sublingual immunotherapy (SLIT) is increasingly used worldwide. Despite its safety being well ascertained, there is no universally accepted system to grade and classify its adverse events (AEs). According to the literature, it seems reasonable to classify and grade systemic side effects by using the previously published World Allergy Organization recommendations. On the other hand, local side effects are the most frequent with SLIT, sometimes leading to its discontinuation. Therefore grading of the severity of local side effects was perceived as necessary for the purpose of uniform reporting, classification, and quantification of this aspect. A World Allergy Organization Taskforce, after examining the available literature and the postmarketing surveillance data, proposed a clinically based grading of the severity of local AEs caused by SLIT. The use of the Medical Dictionary for Regulatory Activities nomenclature for AEs was also included in this context. The proposed grading system for SLIT-induced local reactions is expected to improve and harmonize surveillance and reporting of the safety of SLIT.

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.

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.

Oral macrophage-like cells play a key role in tolerance induction following sublingual immunotherapy of asthmatic mice

Sublingual allergen-specific immunotherapy (SLIT) is a safe and efficacious treatment for type 1 respiratory allergies. Herein, we investigated the key subset(s) of antigen-presenting cells (APCs) involved in antigen/allergen capture and tolerance induction during SLIT. Following sublingual administration, fluorochrome-labeled ovalbumin (OVA) is predominantly captured by oral CD11b⁺CD11c⁻ cells that migrate to cervical lymph nodes (CLNs) and present the antigen to naive CD4⁺ T cells. Conditional depletion with diphtheria toxin of CD11b⁺, but not CD11c⁺ cells, in oral tissues impairs CD4⁺ T-cell priming in CLNs. In mice with established asthma to OVA, specific targeting of the antigen to oral CD11b⁺ cells using the adenylate cyclase vector system reduces airway hyperresponsiveness (AHR), eosinophil recruitment in bronchoalveolar lavages (BALs), and specific Th2 responses in CLNs and lungs. Oral CD11b⁺CD11c⁻ cells resemble tolerogenic macrophages found in the lamina propria (LP) of the small intestine in that they express the mannose receptor CD206, as well as class-2 retinaldehyde dehydrogenase (RALDH2), and they support the differentiation of interferon-γ/interleukin-10 (IFNγ/IL-10)-producing Foxp3⁺ CD4⁺ regulatory T cells. Thus, among the various APC subsets present in oral tissues of mice, macrophage-like cells play a key role in tolerance induction following SLIT.

Undertreatment of allergy: exploring the utility of sublingual immunotherapy

Allergic syndromes are highly prevalent and are comprised of a wide variety of clinical problems, including rhinitis, conjunctivitis, atopic dermatitis and urticaria, asthma, and food allergies. Numerous studies have shown that allergic syndromes are both underdiagnosed and undertreated. This is related to many factors, including trivialization of allergic conditions by physicians and patients, failure to adhere to diagnostic and treatment guidelines, and dissatisfaction with conventional pharmacologic treatments. Immunotherapy involves the administration of allergen extracts in an attempt to induce immunologic tolerance and has been used for the treatment of allergic syndromes and the prevention of long-term complications. Conventional subcutaneous immunotherapy is effective but is also associated with a risk of serious adverse events, requires administration by a trained health care professional, and is contraindicated in certain populations. By contrast, sublingual immunotherapy has been used extensively in Europe and possesses most of the benefits of subcutaneous immunotherapy along with increased safety, tolerability, and convenience. This narrative review explores data from selected clinical studies and concludes that sublingual immunotherapy may be well suited to fill the gap posed by the undertreatment of allergic syndromes in the United States.

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.

Perception and practice of sublingual immunotherapy among practicing allergists

BACKGROUND

Currently, little information is available regarding who is using sublingual immunotherapy (SLIT) in the United States, what product they may be using, how they are dosing that product, and what perceived effect it may be having on patients.

OBJECTIVE

To gather information regarding the perception and use of SLIT among practicing allergists in the United States.

METHODS

On behalf of the American College of Allergy, Asthma and Immunology (ACAAI) Immunotherapy and Diagnostics Committee, an electronic survey was sent to all practicing allergists of the ACAAI in March 2007.

RESULTS

The survey response rate was 25.7% (828/3,217) in which 92.5% of the respondents (766/828) practiced in the United States. For 61.7% (471/763) the most cited reason for not using SLIT was lack of approval by the Food and Drug Administration (FDA). If SLIT were an FDA-approved form of immunotherapy, 65.7% would use it to treat allergic rhinitis, 45.5% would use SLIT to treat patients younger than 5 years, and 40.9% would use it to treat moderate to severe asthma. A total of 5.9% (45/766) of US allergists reported using SLIT. Most perceived SLIT to be as effective (44.7%) or more effective (10.5%) than subcutaneous immunotherapy (SCIT). Most allergists who used SLIT (65.9%) had it reimbursed by patients paying out of pocket. The most commonly used extract (79.1%) was a commercially available extract used for SCIT. Some practitioners (53.5%) required their patients to administer doses of SLIT in their office, but 81.8% only required that this be done with the first dose. Practitioners gave epinephrine injectors to 41.5% of their patients receiving SLIT.

CONCLUSIONS

Although only 5.9% of US allergists reported using SLIT, most of the 828 surveyed (766 US allergists) viewed SLIT as safe and effective and would consider using SLIT if it were an FDA-approved therapy.

Oral dendritic cells mediate antigen-specific tolerance by stimulating TH1 and regulatory CD4+ T cells

BACKGROUND

A detailed characterization of oral antigen-presenting cells is critical to improve second-generation sublingual allergy vaccines.

OBJECTIVE

To characterize oral dendritic cells (DCs) within lingual and buccal tissues from BALB/c mice with respect to their surface phenotype, distribution, and capacity to polarize CD4(+) T-cell responses.

METHODS

In situ analysis of oral DCs was performed by immunohistology. Purified DCs were tested in vitro for their capacity to capture, process, and present the ovalbumin antigen to naive CD4(+) T cells. In vivo priming of ovalbumin-specific T cells adoptively transferred to BALB/c mice was analyzed by cytofluorometry in cervical lymph nodes after sublingual administration of mucoadhesive ovalbumin.

RESULTS

Three subsets of oral DCs with a distinct tissue distribution were identified: (1) a minor subset of CD207(+) Langerhans cells located in the mucosa itself, (2) a major subpopulation of CD11b(+)CD11c(-) and CD11b(+)CD11c(+) myeloid DCs at the mucosal/submucosal interface, and (3) B220(+)120G8(+) plasmacytoid DCs found in submucosal tissues. Purified myeloid and plasmacytoid oral DCs capture and process the antigen efficiently and are programmed to elicit IFN-gamma and/or IL-10 production together with a suppressive function in naive CD4(+) T cells. Targeting the ovalbumin antigen to oral DCs in vivo by using mucoadhesive particles establishes tolerance in the absence of cell depletion through the stimulation of IFN-gamma and IL-10-producing CD4(+) regulatory T cells in cervical lymph nodes.

CONCLUSION

The oral immune system is composed of various subsets of tolerogenic DCs organized in a compartmentalized manner and programmed to induce T(H)1/regulatory T-cell responses.

Preventive effects of sublingual immunotherapy in childhood: an open randomized controlled study

BACKGROUND

Sublingual immunotherapy (SLIT) has been proved to be effective in allergic rhinitis and asthma, but there are few data on its preventive effects, especially in children.

OBJECTIVE

To evaluate the clinical and preventive effects of SLIT in children by assessing onset of persistent asthma and new sensitizations, clinical symptoms, and bronchial hyperreactivity.

METHODS

A total of 216 children with allergic rhinitis, with or without intermittent asthma, were evaluated and then randomized to receive drugs alone or drugs plus SLIT openly for 3 years. The clinical score was assessed yearly during allergen exposure. Pulmonary function testing, methacholine challenge, and skin prick testing were performed at the beginning and end of the study.

RESULTS

One hundred forty-four children received SLIT and 72 received drugs only. Dropouts were 9.7% in the SLIT group and 8.3% in the controls. New sensitizations appeared in 34.8% of controls and in 3.1% of SLIT patients (odds ratio, 16.85; 95% confidence interval, 5.73-49.13). Mild persistent asthma was less frequent in SLIT patients (odds ratio, 0.04; 95% confidence interval, 0.01-0.17). There was a significant decrease in clinical scores in the SLIT group vs the control group since the first year. The number of children with a positive methacholine challenge result decreased significantly after 3 years only in the SLIT group. Adherence was 80% or higher in 73.8% of patients. Only 1 patient reported systemic itching.

CONCLUSIONS

In everyday clinical practice, SLIT reduced the onset of new sensitizations and mild persistent asthma and decreased bronchial hyperreactivity in children with respiratory allergy.

Injection and sublingual immunotherapy in the management of allergies affecting the unified airway

The spectrum of allergic disease involves both the upper and lower airways. Immunotherapy has been shown to produce immunologic changes that can result in the improvement of allergic diseases. Numerous clinical trials have demonstrated the effectiveness of injection and sublingual immunotherapy in the treatment of rhinitis and asthma. Recent data suggest that immunotherapy may have a role in preventing the development of new sensitizations or in decreasing the progression of allergic disease from rhinitis to asthma. Models of immunotherapy may therefore transition from symptom-relieving treatments to preventive methodologies for the management of allergic disease.

Sublingual immunotherapy in children

Sublingual immunotherapy (SLIT) is a safe and patient-friendly variant of allergen immunotherapy. These characteristics may provide physicians with a therapy, perfectly suited to the treatment of allergic children. To give an overview of currently published studies on SLIT in children Pubmed was searched for randomised clinical trials (RCTs). In addition available systematic reviews and long-term observational studies were analysed. Until now, 13 RCTs on allergic rhinitis, 22 studies on asthma (including eight studies involving only children) and one study on atopic dermatis have been published. In addition, five systematic reviews on allergic rhinitis have been published and one is in press. One meta-analysis of adults and children with asthma has been reported. All studies report varying results. The effects and their magnitude differ between studies. Systematic reviews give inconsistent results. For allergic rhinitis three reviews appeared to be negative, two were positive and one analysis was inconsistent regarding children. In asthma a meta-analysis involving both adults and children concluded that SLIT is moderately effective. From observational studies effects of SLIT are suggested to persist after discontinuation. Randomised trials indicate that SLIT may prevent the onset of asthma and new sensitisations. As long as evidence for effectiveness is weak, SLIT cannot be firmly recommended in clinical practice. Nevertheless, the proven effectiveness of SLIT in adults supports the proof in principle of this therapy. In the near future immunotherapy trials in children may provide the required proof of effectiveness.

A synthetic triacylated pseudo-dipeptide molecule promotes Th1/TReg immune responses and enhances tolerance induction via the sublingual route

In this study, we tested two triacylated pseudo-dipeptidic molecules, OM-197-MP-AC and OM-294-BA-MP as candidate adjuvants for allergy vaccines. Both molecules induce human dendritic cell (h-DC) maturation and polarize naïve T cells toward the Th1 type with IFNgamma production. Only OM-294-BA-MP induces IL10 gene expression both in monocyte-derived DCs and CD4+ naïve T cells. Sublingual administration of OM-294-BA-MP plus the antigen enhances tolerance induction in BALB/c mice with established asthma to ovalbumin with an impact on both airways hyperresponsiveness and lung inflammation. Given its Th1/Treg polarizing properties, OM-294-BA-MP is a valid candidate for sublingual allergy vaccines.

New perspectives in the treatment of allergic rhinitis and asthma in children

PURPOSE OF REVIEW

Allergic rhinitis and asthma are some of the most prevalent chronic diseases in children. Meticulous evaluations of the therapeutic options and interventions are needed to control this burden. The central pathogenic mechanism is an immediate hypersensitivity reaction, followed by interventions in the allergic cascade. Once inflammation is established, potent anti-inflammatory agents or mediator antagonists could help control the phenomenon and reduce the characteristic symptoms related to severity.

RECENT FINDINGS

Monoclonal antibody against IgE has demonstrated its efficacy in reducing the symptoms of asthma and rhinitis. In difficult-to-treat asthma patients it allows a reduction in the dose of inhaled steroids, the number of exacerbations, emergency visits and hospitalizations. Its broad implementation is limited by its high cost because adverse events are not a concern. Specific sublingual immunotherapy gave promising results in clinical trials, while modifying immunoglobulins and cytokine profiles, also inducing T-cell tolerance. Safety issues of subcutaneous immunotherapy have been surpassed by the sublingual route, with equivalent efficacy. The new inhaled steroid ciclesonide is effective in established inflammation, is activated only in the respiratory system, and has negligible systemic effects.

SUMMARY

Robust evidence on the efficacy and safety of several novel therapies in rhinitis and asthma is available.

Allergic rhinitis and its impact on asthma update: allergen immunotherapy

The Allergic Rhinitis and its Impact on Asthma document was first published in 2001. Since then, new data on specific immunotherapy have appeared. This review is intended as an update to the original document. MedLine (2001 to June 2006) was searched with appropriate key words, and panelists were asked to identify further relevant articles. Randomized controlled trials were considered for the evaluation of efficacy. For the evaluation of safety and additional effects, studies with lower grades of evidence were included. The clinical efficacy of injection immunotherapy in rhinitis and asthma was confirmed, as well as the safety, provided that recommendations are followed. Studies have demonstrated the long-term efficacy and the preventive effect of immunotherapy in reducing the onset of new sensitizations. One randomized open trial demonstrated that in children with allergic rhinitis, injection immunotherapy may reduce the risk of developing asthma. There is strong evidence that sublingual immunotherapy is effective in allergic rhinitis in adults. Recent meta-analyses demonstrated its efficacy in allergic rhinitis in children and in asthma, although more definitive trials are required. Current data indicate that sublingual immunotherapy is safe and the rate of adverse reactions is not greater below 5 years of age. One randomized open trial showed that in children with allergic rhinitis, sublingual immunotherapy reduced the onset of asthma. Further studies are needed to identify the optimal maintenance dose and to elucidate the mechanism of action. Novel approaches for immunotherapy are currently under evaluation, including the use of adjuvants, peptides, and DNA-conjugated and recombinant allergens.

Sublingual immunotherapy: update 2006

PURPOSE OF REVIEW

Sublingual immunotherapy is currently accepted as a viable therapeutic option, and is widely used in many European countries. In the past 2 years, new data concerning clinical, immunological and practical aspects of sublingual immunotherapy have been published, and many critical points have been addressed.

RECENT FINDINGS

In addition to the new data on clinical efficacy, the most recent studies have shown that, similar to the injection route, sublingual immunotherapy can also prevent the onset of new sensitizations and the onset of asthma. Moreover, several postmarketing surveys have confirmed the satisfactory safety profile, even in very young children, and compliance has been measured. The good safety profile has also suggested the possibility of using sublingual immunotherapy without the updosing phase. Finally, the mechanisms of action have been systematically investigated and the biodistribution of sublingual allergens has been further clarified.

SUMMARY

More new data on sublingual immunotherapy are rapidly appearing in the international literature. These data consistently confirm the value of this treatment and show that sublingual immunotherapy is a viable and useful form of immunotherapy.

Sublingual immunotherapy: the optimism and the issues

The acceptability of sublingual immunotherapy (SLIT) in guidelines or statements has recently increased. SLIT is currently used in Europe, Asia, and Australia for the treatment of allergic respiratory diseases. Four meta-analyses have shown that SLIT is an effective tool for the treatment of patients with asthma and/or rhinitis, and only conflicting results were reported for children with allergic rhinitis. Moreover, it offers logistic advantages and is safe. However, some unmet needs are to be faced, such as the difficulty of manufacturers to achieve the homogeneity of standardized vaccines, the magnitude of their clinical efficacy, and the pivotal question of an early intervention with SLIT in young children with IgE-mediated disorders. Altogether, SLIT has already given convincing results in respiratory diseases both in adults and children. In the future, this route of administration of allergic vaccines may improve even the treatment of patients with IgE-mediated food allergy. These patients indeed deserve better than allergen avoidance. The immunomodulatory treatment of allergic diseases probably has found a new tool; however, a more balanced understanding of this form of allergen immunotherapy is needed. This aim could be achieved through: (1) the improvement of products standardization quality; (2) an attempt to modify in children the natural course of allergic diseases; and (3) new research on mechanisms of action.

Assessment of sublingual immunotherapy efficacy in children with house dust mite-induced allergic asthma optimally controlled by pharmacologic treatment and mite-avoidance measures

Although several studies have demonstrated the efficacy of subcutaneous immunotherapy in allergic asthma, few have shown the same benefit using sublingual immunotherapy (SLIT) in asthmatic patients. This study was conducted to assess the efficacy of house dust mite (HDM) SLIT in addition to allergen avoidance and standard pharmacologic treatment. A double-blind, placebo-controlled trial was performed in 111 children (aged 5-15 yr) with HDM-induced mild-to-moderate asthma. After a 4-week baseline phase, patients were randomly assigned to receive SLIT with tablets of HDM extract (n = 55) or placebo (n = 56) for 18 months. Pharmacologic treatment was adjusted every 3 months following a step-down approach. Asthma symptom scores, reduction in use of inhaled corticosteroids and inhaled beta(2)-agonists, rhinitis symptoms, lung function tests, skin sensitivity to HDM, dust mite-specific immunoglobulin (Ig) E and IgG(4), and quality of life (QoL) were assessed during the study. After 18 months of treatment, diurnal and nocturnal asthma symptoms scores did not show significant differences between SLIT and placebo groups. Inhaled corticosteroids and inhaled beta(2)-agonists use was reduced in both groups without significant differences between groups. There were no significant differences in lung function (forced expiratory volume in 1 s and peak flow rate variations) between groups. Rhinitis symptom score decreased in both groups, with no difference between the two groups. The severity dimension of QoL was significantly improved in the SLIT group (age 6-12 yr). SLIT induced a significant reduction of skin sensitivity to HDM (p < 0.01) and a significant increase in HDM-specific IgE and IgG(4) antibodies (p < 0.001) in the SLIT group compared with the placebo group. SLIT was well tolerated with mild/moderate local adverse events. No severe systemic reactions were reported. This study indicates that, when mild-moderate asthmatic children are optimally controlled by pharmacologic treatment and HDM avoidance, SLIT does not provide additional benefit, despite a significant reduction in allergic response to HDM. Under such conditions, only a complete, but ethically unfeasible, discontinuation of inhaled corticosteroid would have demonstrated a possible benefit of SLIT.

Economic evaluation of sublingual immunotherapy vs symptomatic treatment in adults with pollen-induced respiratory allergy: the Sublingual Immunotherapy Pollen Allergy Italy (SPAI) study

BACKGROUND

Few data are available on the pharmacoeconomic aspects of immunotherapy.

OBJECTIVE

To evaluate, from the health care system and societal perspectives, the costs and consequences of sublingual immunotherapy (SLIT) added to pharmacotherapy compared with drugs alone for respiratory allergy.

METHODS

This study compared costs, clinical outcomes, and cost-effectiveness ratios of 2 strategies in the management of allergic rhinitis and asthma, namely, SLIT associated with pharmacotherapy and pharmacotherapy alone (no SLIT). A decision tree was developed and populated with epidemiologic and resource utilization data concerning approximately 2,200 patients. Direct costs included visits, tests, pharmacotherapy, immunotherapy, and hospitalizations. Indirect costs and out-of-pocket drugs were also included. Outcome was calculated as the number of improved patients and asthma cases avoided at 6 years. Sensitivity analysis was performed by varying costs and epidemiologic data.

RESULTS

SLIT improved the symptoms of 399 of 1,000 patients and prevented asthma in 229 of 1,000 patients compared with drugs alone. For SLIT added to pharmacotherapy and pharmacotherapy alone, the direct cost per patient at more than 6 years was Euro2,400 and Euro3,026, whereas the indirect cost was Euro1,913 and Euro3,400.

CONCLUSION

From both perspectives and for both effectiveness end points, SLIT is less expensive and more effective than pharmacotherapy alone.

New insights in sublingual immunotherapy

Sublingual immunotherapy (SLIT) is accepted in the official documents and is currently used in many European countries. In recent years, new clinical data on efficacy and safety have been published, including meta-analyses in adults and children and surveys of safety in children younger than age 5 years. Moreover, it has been shown that, similar to the injection route, SLIT can prevent the onset of new sensitizations and the onset of asthma. Additionally, the mechanisms of action are beginning to be systematically studied. Some points need further investigation, such as the effect in asthma, the mechanisms of action, and the optimal dose to be administered.

Sublingual immunotherapy in the treatment of children

Children with controlled intermittent mild-to-moderate asthma, controlled rhinitis and a single sensitivity may be appropriate candidates for sublingual immunotherapy (SLIT). Positive effects of SLIT may depend on initiation in early childhood and a long duration of treatment. To ensure optimum compliance, sociological, economic and familial factors should also be taken in to consideration when prescribing SLIT. Evidence from recent long-term trials indicates that SLIT interfered with the atopic march and the allergic progression from rhinitis to asthma without any severe adverse side effects. Local immune response has been seen to be blunted with SLIT, which suggests that treatment has an immunomodulatory effect. In addition, it may also decrease the risk of new sensitizations. Ongoing developments in SLIT, particularly advances in dosing and new indications, such as food allergies, will increase the use of this treatment modality in children.

Clinical and immunologic effects of sublingual immunotherapy in asthmatic children sensitized to mites: a double-blind, randomized, placebo-controlled study

Immunotherapy through oral routes is thought to be a valuable therapeutic option for asthma. The clinical and immunologic effects of sublingual immunotherapy (SLIT) in children with asthma caused by mites were evaluated in a double-blind, placebo-controlled study for 6 months. Patients (aged 6-12 yr) with mild-to-moderate asthma, with single sensitization to mite allergen, received either SLIT or placebo with a standardized Dermatophagoides pteronyssinus (D.p.)/D. farinae (D.f.) 50/50 extract. The cumulative dose was around 41824 IR, equivalent to 1.7 mg of D.p. and 3.0 mg of D.f. allergen. Symptom and medication scores were assessed throughout the study. Serum total immunoglobulin (Ig)E, eosinophil count, eosinophil cationic protein, specific IgE, specific IgG4, and skin sensitivity were evaluated before starting the treatment and after the treatment period. Twenty patients completed the study. At the beginning of the treatment, no differences were observed between the groups for symptom and medication scores, skin sensitivity, or immunologic parameters. After 6 months of treatment, there was a significant difference in nighttime asthma symptom scores and specific IgG4 (p < 0.05) in the SLIT group compared with the placebo group. Daytime symptom and medication scores, total IgE, eosinophil count, forced expiratory volume in 1 s, and mean evening peak expiratory flow rate reached significant differences in the SLIT group during the treatment period (p < 0.05). No severe adverse effects were reported. Our results revealed that treatment for 6 months with SLIT is clinically effective in decreasing asthmatic symptoms and medication use in children with mild-to-moderate asthma because of mite sensitivity. The clinical usefulness of this form of immunotherapy and the mechanism underlying its immunologic effects deserve further studies.

Sublingual immunotherapy: a comprehensive review

Sublingual immunotherapy (SLIT) has been used with increasing frequency in Europe and is viewed with increasing interest by allergists in the United States. To address this interest, a Joint Task Force of the American College of Allergy, Asthma and Immunology and the American Academy of Allergy, Asthma and Immunology's Immunotherapy and Allergy Diagnostic Committees reviewed the available literature on SLIT and prepared this report. The task force concluded that despite clear evidence that SLIT is an effective treatment, many questions remained unanswered, including effective dose, treatment schedules, and overall duration of treatment. Until these have been determined, an assessment of the cost/benefit ratio of the treatment cannot be made. SLIT does appear to be associated with few serious side effects, but it has not been administered in high-risk asthmatic patients, nor in the studies reviewed has it been administered as a mixture of non-cross-reacting allergens. Furthermore, there is currently no allergy extract approved for this use in the United States, nor is there a Current Procedural Terminology code for billing purposes. All of these factors should be given careful consideration by anyone contemplating initiating SLIT treatment for their allergic patients.

Post-marketing survey on the safety of sublingual immunotherapy in children below the age of 5 years

BACKGROUND

The age below 5 years is considered a prudential limit for immunotherapy in view of the possible severity of side-effects. Sublingual immunotherapy (SLIT) seems to be safe, but no study in very young children is available. We performed a safety post-marketing surveillance study in children below 5 years.

METHODS

Children aged 3-5 years with respiratory allergy receiving SLIT were followed-up for at least 2 years. A diary card for side-effects was filled by parents at each dose given. Local and systemic side-effects were graded as: mild (no intervention, no dose adjustment), moderate (medical treatment and/or dose reduction), severe (life-threatening/hospitalization/emergency care). The comparative safety of different allergens and regimens was also assessed.

RESULTS

One hundred and twenty-six children (mean age 4.2 years, 67 male) were included. Seventy-six (60%) had rhinitis with asthma, 34 (27%) rhinitis only and 16 (13%) only asthma. Immunotherapy was prescribed for mites (62%), grasses (22.2%), Parietaria (11.9%), Alternaria (2.4%) and olive (1.5%). Eighteen children underwent an accelerated build-up. The total number of doses was about 39,000. Nine side-effects were reported in seven children (5.6% patients and 0.2/1000 doses). Two episodes of oral itching and one of abdominal pain were mild. Six gastrointestinal side-effects were controlled by reducing the dose. All side-effects occurred during up-dosing phase. No difference in terms of safety among the allergens used was observed.

CONCLUSION

SLIT is safe also in children under the age of 5 years.

Sublingual immunotherapy in pediatric patients: beyond clinical efficacy

PURPOSE OF REVIEW

Sublingual immunotherapy (SLIT) is widely used in several European countries. Many clinical trials and a meta-analysis presently support its efficacy, but limits and indications in pediatric age still need to be clarified. We review here the most recent literature on SLIT, with particular attention paid to the safety of children and to the additional clinical effects.

RECENT FINDINGS

In addition to clinical trials, post-marketing surveillance studies have confirmed the optimal safety profile of SLIT in adults and children, including those below the age of 5 years. The most recent studies have shown that SLIT, identically to the subcutaneous route, has the potential to affect the immunological response to allergens. This is testified to by the facts that SLIT can prevent the onset of new sensitizations and maintain its beneficial effect for years after discontinuation. Moreover, it has been shown that SLIT can prevent the onset of asthma in children with rhinitis.

SUMMARY

Due to its excellent safety, SLIT would be an optimal candidate for use in pediatric age groups, where the natural history of allergy can be to some extent modified. Nonetheless, formal and rigorous studies are needed to define its exact indication and dosage.

Sublingual immunotherapy for allergic rhinoconjunctivitis--the seeming and the real

BACKGROUND

Subcutaneous specific immunotherapy (SIT) has been shown to be a causal treatment with long-term efficacy for allergic rhinoconjunctivitis and asthma, and a preventive measure against the development of asthma and new sensitizations. As it is associated with several inconveniences and serious side effects, sublingual immunotherapy (SLIT) has been developed to evade these problems.

METHODS

The present review of previously published studies on allergic rhinoconjunctivitis aimed to determine the efficacy of SLIT in comparison with subcutaneous treatment and to summarize long-term results of immunotherapy and its effects on the prevention and treatment of asthma and the prevention of new sensitizations.

RESULTS

The effect of SLIT on allergic rhinoconjunctivitis is low to moderate, depends on the allergen used and is more pronounced in adults than in children, in whom a consistent effect has not been demonstrated. Direct comparison with SIT shows conflicting and inconsistent results. Detailed studies on the prevention of asthma and new sensitizations are not available. Consistent effects of asthma treatment on both symptom and medication scores and lung function have not been reported. A quantitative evaluation is not possible due to indistinct inclusion criteria and different outcome criteria. In summary, currently SLIT plays no significant role in the treatment of asthma, apart from children monosensitized to house dust mites in whom it may have low-moderate effects. Only one study deals with the long-term efficacy of SLIT, which demonstrated a persistent positive effect on asthma, whereas data on rhinoconjunctivitis are completely lacking.

CONCLUSIONS

Primary and secondary targets of specific immunotherapy have not been answered satisfactorily for the sublingual route. To date, SLIT cannot be recommended as an adequate alternative to the subcutaneous form. Questions regarding the cumulative dose, duration of therapy and immunological mechanisms have also not been answered. The indication should thus be limited to adult patients with pollen-induced rhinoconjunctivitis being unable to perform SIT, e.g. due to significant side effects.