Effect of grass pollen immunotherapy with Alutard SQ on quality of life in seasonal allergic rhinoconjunctivitis

Sublingual Tablet Immunotherapy Improves Quality of Life in Adults With Allergic Rhinoconjunctivitis

BACKGROUND

Allergic rhinitis with or without conjunctivitis can negatively impact many aspects of quality of life (QoL). The efficacy and safety of standardized quality (SQ) sublingual immunotherapy (SLIT) tablets have been confirmed across large clinical trials in adults with grass, tree, ragweed, and house dust mite (HDM) allergic rhinitis with or without conjunctivitis.

OBJECTIVE

This pooled analysis investigates whether the reduction in symptom burden found across the clinical trials is supported by improvements in QoL.

METHODS

A total of 11 phase II/III randomized placebo-controlled trials across the SQ grass, tree, ragweed, and HDM SLIT tablets (grass: N = 3179; ragweed: N = 767; tree: N = 634; HDM: N = 2221) were included. QoL was assessed using the standardized Rhinitis Quality of Life Questionnaire (RQLQ), with the exception of 3 grass trials, which used the nonstandardized version. The overall RQLQ scores were expressed as a mean of 7 domains. In the pooled analysis, treatment was used as fixed effect; and the trial, and the interaction between region/country and trial as random effects.

RESULTS

The pooled analysis showed consistent and statistically significant improvements in overall RQLQ scores across all 4 SQ SLIT tablets versus placebo (pooled estimate [95% CI], P value-grass: -0.20 [-0.28 to -0.12], P < .001; tree: -0.42 [-0.58 to -0.26], P < .001; ragweed: -0.36 [-0.55 to -0.17], P < .001; HDM: -0.28 [-0.39 to -0.17], P < .001). Furthermore, significant improvements versus placebo for all 4 SQ SLIT tablets were seen across the 7 individual domains.

CONCLUSIONS

The proven efficacy of SQ SLIT tablets to reduce symptoms across 4 of the most common respiratory allergens is supported by concurrent significant improvements in RQLQ scores overall and for all 7 domains.

Current practices and future trends in cockroach allergen immunotherapy

PURPOSE OF REVIEW

This review evaluates the current modes of allergen-specific immunotherapy for cockroach allergens, in terms of clinical outcomes and explores future trends in the research and development needed for a more targeted cockroach immunotherapy approach with the best efficacy and minimum adverse effects.

SUMMARY

Cockroach allergy is an important risk factor for allergic rhinitis in the tropics, that disproportionately affects children and young adults and those living in poor socio-economic environments. Immunotherapy would provide long-lasting improvement in quality of life, with reduced medication intake. However, the present treatment regime is long and has a risk of adverse effects. In addition, cockroach does not seem to have an immuno-dominant allergen, that has been traditionally used to treat allergies from other sources. Future trends of cockroach immunotherapy involve precision diagnosis, to correctly identify the offending allergen. Next, precision immunotherapy with standardized allergens, which have been processed in a way that maintains an immunological response without allergic reactions. This approach can be coupled with modern adjuvants and delivery systems that promote a Th1/Treg environment, thereby modulating the immune response away from the allergenic response.

The Use of Biomarkers to Predict Aero-Allergen and Food Immunotherapy Responses

The incidence of allergic conditions has continued to rise over the past several decades, with a growing body of research dedicated toward the treatment of such conditions. By driving a complex range of changes in the underlying immune response, immunotherapy is the only therapy that modulates the immune system with long-term effects and is presently utilized for the treatment of several atopic conditions. Recent efforts have focused on identifying biomarkers associated with these changes that may be of use in predicting patients with the highest likelihood of positive clinical outcomes during allergen immunotherapy (AIT), providing guidance regarding AIT discontinuation, and predicting symptomatic relapse and the need for booster AIT after therapy. The identification of such biomarkers in food allergy has the additional benefit of replacing oral food challenges, which are presently the gold standard for diagnosing food allergies. While several markers have shown early promise, research has yet to identify a marker that can invariably predict clinical response to AIT. Skin prick testing (SPT) and specific IgE have commonly been used as inclusion criteria for the initiation of AIT and prediction of reactions during subsequent allergen challenge; however, existing data suggests that changes in these markers are not always associated with clinical improvement and can be widely variable, reducing their utility in predicting clinical response. Similar findings have been described for the use of allergen-specific functional IgG4 antibodies, basophil activation and histamine release, and type 2 innate lymphoid cells. There appears to be a promising association between changes in the expression of dendritic cell-associated markers, as well as the use of DNA promoter region methylation patterns in the prediction of allergy status following therapy. The cellular and molecular changes brought about by immunotherapy are still under investigation, but major strides in our understanding are being made.

Nasal allergen-neutralizing IgG4 antibodies block IgE-mediated responses: Novel biomarker of subcutaneous grass pollen immunotherapy

BACKGROUND

Grass pollen subcutaneous immunotherapy (SCIT) is associated with induction of serum IgG₄-associated inhibitory antibodies that prevent IgE-facilitated allergen binding to B cells.

OBJECTIVE

We sought to determine whether SCIT induces nasal allergen-specific IgG₄ antibodies with inhibitory activity that correlates closely with clinical response.

METHODS

In a cross-sectional controlled study, nasal fluid and sera were collected during the grass pollen season from 10 SCIT-treated patients, 13 untreated allergic patients (with seasonal allergic rhinitis [SAR]), and 12 nonatopic control subjects. Nasal and serum IgE and IgG₄ levels to Phleum pratense components were measured by using the Immuno Solid Allergen Chip microarray. Inhibitory activity was measured by IgE-facilitated allergen binding assay. IL-10⁺ regulatory B cells were quantified in peripheral blood by using flow cytometry.

RESULTS

Nasal and serum Phl p 1- and Phl p 5-specific IgE levels were increased in patients with SAR compared to nonatopic control subjects (all, P < .001) and SCIT-treated patients (nasal, P < .001; serum Phl p 5, P = .073). Nasal IgG₄ levels were increased in the SCIT group compared to those in the SAR group (P < .001) during the pollen season compared to out of season. IgG-associated inhibitory activity in nasal fluid and serum was significantly increased in the SCIT group compared to that in the SAR (both, P < .01). The magnitude of the inhibitory activity was 93% (P < .001) in nasal fluid compared to 66% (P < .001) in serum and was reversed after depletion of IgG. Both nasal fluid (r = -0.69, P = .0005) and serum (r = -0.552, P = .0095) blocking activity correlated with global symptom improvement. IL-10⁺ regulatory B cells were increased in season compared to out of season in the SCIT group (P < .01).

CONCLUSION

For the first time, we show that nasal IgG₄-associated inhibitory activity correlates closely with the clinical response to allergen immunotherapy in patients with allergic rhinitis with or without asthma.

Adherence During Early Allergen Immunotherapy and Strategies to Motivate and Support Patients

Allergic rhinitis is one of the most common chronic inflammatory conditions, affecting up to 30% of people in Europe. Allergen immunotherapy (AIT) is the only treatment for allergic rhinitis and asthma that has a disease-modifying effect, and it is recommended in European guidelines for use in conjunction with patient education, specific allergen avoidance, and symptomatic pharmacotherapy. Reported AIT adherence rates vary widely but are often low in real-world settings. Factors known to affect adherence are patient, treatment, or physician-related, and vary between healthcare settings. Misconceptions or a lack of AIT knowledge among patients with regard to efficacy and side effects may contribute to high rates of discontinuation observed during the first year of AIT treatment. Interventions to improve patient adherence are multifaceted and should focus on patient education, particularly the provision of accurate information regarding adverse effects of AIT and when to expect an improvement in symptoms, patient-support programmes, and the use of regular eHealth reminders via a telephone call, text message, or social media. Serum-based biomarkers also have the potential to play a role in evaluating early response to AIT and in monitoring treatment adherence in clinical practice. In this review, the authors explore barriers to continuation with AIT and discuss initiatives to motivate and support patients through the challenging early months of treatment, prior to the onset of clinical effect and when side effects are most common, to encourage long-term adherence to therapy and achieve optimal patient outcomes.

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.

Proteomics for Allergy: from Proteins to the Patients

Proteomics encompasses a variety of approaches unraveling both the structural features, post-translational modifications, and abundance of proteins. As of today, proteomic studies have shed light on the primary structure of about 850 allergens, enabling the design of microarrays for improved molecular diagnosis. Proteomic methods including mass spectrometry allow as well to investigate protein-protein interactions, thus yielding precise information on critical epitopes on the surface of allergens. Mass spectrometry is now being applied to the unambiguous identification, characterization, and comprehensive quantification of allergens in a variety of matrices, as diverse as food samples and allergen immunotherapy drug products. As such, it represents a method of choice for quality testing of allergen immunotherapy products.

Update on Biomarkers to Monitor Clinical Efficacy Response During and Post Treatment in Allergen Immunotherapy

Allergen immunotherapy (AIT) is an immune modulating treatment for allergic diseases. Although highly effective, some patients do not respond to the treatment. To date there are no surrogate biomarkers that are predictive of the clinical response to AIT. More and more is known about the underlying immunological mechanism involved in AIT. Through modulation of both innate and adaptive immune responses, involving reduced ILC2 and enhanced Treg and Breg induction and functionality, along with induction of IgG4 antibody production which have the capacity to inhibit both allergen-induced basophil responsiveness and CD23-mediated IgE-facilitated allergen presentation, the result is an immune skewing towards a more balanced Type I response. So far, however there is not a clear correlation with the observed immunological changes and predictive correlates of clinical efficacy. The most promising biomarker of successful AIT is IgE-FAB as a reflection of functional IgG4. Cellular responses and cytokine analysis gives a great deal of insight into the mechanisms of AIT but may not represent useful or indeed reliable biomarkers in a clinical setting. There is a need for more research for confirmation and interpretation of the possible association with biomarkers and clinical response to AIT.

Allergen immunotherapy for birch pollen-allergic patients: recent advances

As of today, allergen immunotherapy is performed with aqueous natural allergen extracts. Recombinant allergen vaccines are not yet commercially available, although they could provide patients with well-defined and highly consistent drug substances. As Bet v 1 is the major allergen involved in birch pollen allergy, with more than 95% of patients sensitized to this allergen, pharmaceutical-grade recombinant Bet v 1-based vaccines were produced and clinically tested. Herein, we compare the clinical results and modes of action of treatments based on either a birch pollen extract or recombinant Bet v 1 expressed as hypoallergenic or natural-like molecules. We also discuss the future of allergen immunotherapy with improved drugs intended for birch pollen-allergic patients suffering from rhinoconjunctivitis.

Allergen extracts for immunotherapy: to mix or not to mix?

Allergen immunotherapy (AIT) is established as a curative treatment for allergic rhinitis, asthma, as well as insect venom allergy. AIT is based on the administration of natural allergen extracts via the subcutaneous or sublingual routes to reorient the immune system towards tolerogenic mechanisms. In this regard, since many patients are poly-allergic, mixtures of allergen extracts are often used with a potential risk to cause allergen degradation, thereby affecting treatment efficacy. Herein, we discuss the advantages and drawbacks of mixing homologous (i.e., related) or heterogeneous (i.e., unrelated) allergen extracts. We provide evidence for incompatibilities between mixes of grass pollen and house dust mite extracts containing bodies and feces, and summarize critical points to consider when mixing allergen extracts for AIT.

The efficacy assessment of a self-administered immunotherapy protocol

Background

We previously reported the safety of a self‐administered subcutaneous immunotherapy (SCIT) protocol. Here we report the results of the retrospective efficacy trial of the United Allergy Service (UAS) self‐administered SCIT protocol. We hypothesized that by utilizing a slow SCIT buildup phase, designed to attain recommended allergen concentrations on a cumulative basis, efficacious outcomes and clinical relevance would be achieved.

Methods

We enrolled 60 SCIT patients and 56 control patients. The study contrasted baseline and treatment period combined symptom plus medication scores (CSMS) as the primary outcome measure and rhinoconjunctivitis quality of life questionnaire (RQLQ) scores as the secondary study outcome measure. Changes in pollen counts were also examined with regard to effects on these efficacy parameters.

Results

The treatment group showed significantly improved CSMS (standardized mean difference [SMD]: −1.57; 95% confidence interval [CI], −1.97 to −1.18; p < 0.001) and RQLQ (SMD: −0.91; 95% CI, −1.23 to −0.59; p < 0.001). These treatment group outcome measures were respectively improved by 33% and 29% compared to baseline and greater than 40% in comparison to the control group (p < 0.0001). Significant results were also shown when examining these outcome measures with regards to either monotherapy or poly‐allergen SCIT. Furthermore, a comparison to recent meta‐analyses of SCIT studies showed equivalent efficacy and clinical relevance. Assessment of pollen counts during the baseline and treatment periods further corroborated the efficacy of the UAS SCIT protocol.

Conclusion

These efficacy results, and our previous safety results, show that a carefully designed and implemented self‐administered SCIT protocol is efficacious and safe.

Allergy immunotherapy: the future of allergy treatment

Allergic respiratory disease represents a significant and expanding health problem worldwide. Allergic symptoms, such as asthma and hay fever, cause sleep impairment and reduce school and work performance. The cost to society is substantial. Allergen avoidance and pharmacotherapy cannot control the disease. Only allergy immunotherapy has disease-modifying potential and should be included in optimal treatment strategies. Allergy immunotherapy was first administered as subcutaneous injections and has been practiced for the past 100 years or so. Recently, tablet-based sublingual allergy immunotherapy (SLIT) was introduced with comprehensive clinical documentation. SLIT tablets represent a more patient-friendly concept because they can be used for self-treatment at home.

Exploratory study of tolerability and immunological effect of a short up-dosing immunotherapy phase with a standardised allergen extract derived from pollen of Olea europaea

BACKGROUND

A new subcutaneous specific immunotherapy (SCIT) product adsorbed on aluminium hydroxide has been developed with a short and simplified up-dosing phase, containing a biologically standardized allergen pollen extract from Olea europaea.

OBJECTIVE

To assess the tolerability profile of the updosing phase and its immunological effect, in terms of specific IgG4 and IgE levels and immediate skin reactivity.

MATERIAL AND METHODS

The study was an exploratory, multi-centre, open-label, single-arm, phase II/III clinical trial. Adults with a clinical history of allergic rhinoconjunctivitis with/without asthma due to sensitization to olive pollen were selected. Five up-dosing doses (300, 600, 3000, 6000 and 15000SQ+) were administered at weekly intervals, followed by a maintenance dose (15000SQ+) after 2 weeks. Adverse events were collected during the 30 min observation period after injections, after a telephone contact 2 days after each visit, and after reviewing the subjects' diary. IgG4 and IgE levels and immediate skin reactivity were evaluated at the beginning and at the end of the trial.

RESULTS

Ninety-three subjects were included in the trial (mean age, 35.7 ± 10.3 years; women, 66.7 %). A total of 95 adverse drug reactions, all mild in intensity and non-serious, were reported during the trial: 85 local in 34.4 % subjects, 9 systemic in 4.3 % subjects and one non-specific (grade 0). Within 6 weeks, significant changes in IgG4 and IgE levels and in immediate skin reactivity to Olea europaea were accomplished.

CONCLUSION

This new SCIT derived from pollen of Olea europaea presented a good tolerability profile and induced significant immunological responses already after a 6 week treatment. However, the non-controlled design may limit the interpretation of these results.

TRIAL REGISTRATION

EudraCT no: 2011-004852-20; ClinicalTrials.gov Identifier: NCT01674595.

Development and evaluation of a sublingual tablet based on recombinant Bet v 1 in birch pollen-allergic patients

BACKGROUND

Sublingual immunotherapy (SLIT) applied to type I respiratory allergies is commonly performed with natural allergen extracts. Herein, we developed a sublingual tablet made of pharmaceutical-grade recombinant Bet v 1.0101 (rBet v 1) and investigated its clinical safety and efficacy in birch pollen (BP)-allergic patients.

METHODS

Following expression in Escherichia coli and purification, rBet v 1 was characterized using chromatography, capillary electrophoresis, circular dichroism, mass spectrometry and crystallography. Safety and efficacy of rBet v 1 formulated as a sublingual tablet were assessed in a multicentre, double-blind, placebo-controlled study conducted in 483 patients with BP-induced rhinoconjunctivitis.

RESULTS

In-depth characterization confirmed the intact product structure and high purity of GMP-grade rBet v 1. The crystal structure resolved at 1.2 Å documented the natural conformation of the molecule. Native or oxidized forms of rBet v 1 did not induce the production of any proinflammatory cytokine by blood dendritic cells or mononuclear cells. Bet v 1 tablets were well tolerated by patients, consistent with the known safety profile of SLIT. The average adjusted symptom scores were significantly decreased relative to placebo in patients receiving once daily for 5 months rBet v 1 tablets, with a mean difference of 17.0-17.7% relative to the group treated with placebo (P < 0.025), without any influence of the dose in the range (12.5-50 μg) tested.

CONCLUSION

Recombinant Bet v 1 has been produced as a well-characterized pharmaceutical-grade biological drug. Sublingual administration of rBet v 1 tablets is safe and efficacious in patients with BP allergic rhinoconjunctivitis.

Incidence and risk factors for subcutaneous immunotherapy anaphylaxis: the optimization of safety

Fatal reactions related to subcutaneous allergen immunotherapy are rare: one event in 2.5 million injections has been reported in the USA and none in Europe. The prevalence of very severe systemic reactions (systemic adverse events [SAEs]) is one in 1 million injections. Though the serious events rate is decreasing and the majority of SAEs (∼0.2% per injection) are moderate and reversible, they still represent a major concern. Uncontrolled asthma, long-term therapy with β-blockers and high degree of allergen sensitivity are generally considered risk factors. The relevance of other conditions, like previous local reactions, the use of extracts conjugated with adjuvants and accelerated build-up schedules is controversial, as well as the role of preventative strategies. A careful risk assessment of patients and optimal administration procedures may significantly decrease the risk of SAEs. However, more uniform safety data are required and an accurate safety profile should be provided for every allergen product.

Immunotherapy: what lies beyond

Allergen immunotherapy has been used to treat allergic diseases, such as asthma, allergic rhinitis, and venom allergy, since first described over a century ago. The current standard of care in the United States involves subcutaneous administration of clinically relevant allergens for several months, building up to eventual monthly injections for typically 3 to 5 years. Recent advances have improved the safety and efficacy of immunotherapy. The addition of omalizumab or Toll-like receptor agonists to standard subcutaneous immunotherapy has proved beneficial. Altering the extract itself, either through chemical manipulation producing allergoids or directly producing recombinant proteins or significant peptides, has been evaluated with promising results. The use of different administration techniques, such as sublingual immunotherapy, is common in Europe and is on the immediate horizon in the United States. Other methods of administering allergen immunotherapy have been studied, including epicutaneous, intralymphatic, intranasal, and oral immunotherapy. In this review we focus on new types and routes of immunotherapy, exploring recent human clinical trial data. The promise of better immunotherapies appears closer than ever before, but much work is still needed to develop novel immunotherapies that induce immunologic tolerance and enhanced clinical efficacy and safety over that noted for subcutaneous allergen immunotherapy.

Immunologic effect and tolerability of intra-seasonal subcutaneous immunotherapy with an 8-day up-dosing schedule to 10,000 standardized quality-units: a double-blind, randomized, placebo-controlled trial

BACKGROUND

International guidelines recommend that allergen-specific immunotherapy for pollen-induced rhinoconjunctivitis is initiated preseasonally. However, because subjects often present to physicians with allergy symptoms during the pollen season, "within-season" initiation of specific immunotherapy is of special interest.

OBJECTIVE

We evaluated the immunomodulatory effects and tolerability of subcutaneous immunotherapy (SCIT) with Standardized Quality (SQ) 6-grass mix and rye allergen extract, using an 8-day intra-seasonal up-dosing schedule to 10,000 SQ-units (SQ-U).

METHODS

In a 9-week, multicenter, randomized, double-blind, placebo-controlled trial, adults (mean age, 34.6 years; 99.3% whites) with grass pollen-induced rhinoconjunctivitis (mean disease duration, 15.1 years) were randomized 3:1 to receive SCIT or placebo. Treatment was initiated during the 2008 pollen season, with an 8-day up-dosing from 100 to 10,000 SQ-U (6 daily injections) followed by 2 maintenance injections of 10,000 SQ-U at intervals of 2 and 4 weeks, respectively. The primary end point examined immunologic effects, assessing the difference in IgE-blocking factor (serum components competing with IgE for allergen binding) between SCIT and placebo at week 9. Secondary/explorative end points included the difference in IgE-blocking factor, specific IgG(4), and specific IgE at various times. Tolerability (adverse events, local and systemic allergic reactions) of the up-dosing schedule was also evaluated.

RESULTS

Of the 148 treated subjects 144 (SCIT n = 109; placebo n = 35) were analyzed for the primary parameter. Immunologic response (significantly higher increase in IgE-blocking factor and IgG(4) levels) occurred with SCIT versus placebo at week 9 (IgE-blocking factor, P = 0.0017; IgG(4,)P = 0.0215). Significant differences were observed as early as week 3. AEs were reported in 60.7% of SCIT- and 30.6% of placebo-treated subjects, with no treatment-related serious AEs. Local allergic reactions occurred in 46.4% of SCIT and 8.3% of placebo subjects (χ(2) test, P < 0.0001). No significant difference was observed between groups in the incidence of systemic reactions (7.1% SCIT vs 5.6% placebo; χ(2) test, P = 0.7413).

CONCLUSIONS

This trial provides the first description of short (8-day) intra-seasonal up-dosing with SCIT, which induced immunologic effects after only 3 weeks, and was generally well tolerated, although it induced a marked increase in the rate of local reactions compared with placebo. ClinicalTrials.gov identifier NCT00807547; ALK trial ID SHX0562.

Subcutaneous immunotherapy for allergic rhinitis: an evidence based review of the recent literature with recommendations

BACKGROUND

Allergic rhinitis is a common allergic disease with increasing prevalence in Western Societies. Medical therapy is first line treatment, and is aimed at reducing symptoms of immunoglobulin E (IgE)-mediated inflammation of the nasal passages. In patients with disease refractory to medical therapy, subcutaneous immunotherapy is an option. The aim of this study is to update a recent Cochrane review with available level 1 evidence for seasonal and perennial allergic rhinitis.

METHODS

A systematic review of the literature was performed from 2006 to 2011 and compared with data from a 2007 Cochrane review on immunotherapy for seasonal allergic rhinitis. We included all studies of level 1 evidence. All forms of single extract immunotherapy were considered. Studies with primary asthma related end-points were excluded. Primary end-points were instruments of clinical efficacy (ie, symptom-medication scores) and adverse events.

RESULTS

We retrieved 12 level 1 studies for review. In total, 1512 patients were randomized into treatment groups, alternative study groups (alternative duration of therapy or sublingual immunotherapy [SLIT]), or placebo. Efficacy was evaluated based on reported symptom and/or medication score, validated quality of life instruments, immunological assays, challenge testing, and adverse events.

CONCLUSION

Subcutaneous immunotherapy improves symptom and/or medication scores and validated quality of life measures. In addition, associated changes in surrogate markers of immunologic protection are observed. Subcutaneous immunotherapy is safe when administered to carefully selected patients and in settings capable of responding to systemic reactions. Subcutaneous immunotherapy is recommended for patients with seasonal or perennial allergic rhinitis not responsive to conservative medical therapy, and whose symptoms significantly affect quality of life.

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

Allergen-specific immunotherapy (SIT) involves the repeated administration of allergenic extracts to atopic individuals over a period of 3 to 5 years either subcutaneously (SCIT) or sublingually (SLIT) for the treatment of allergic respiratory diseases, including asthma and allergic rhinitis (AR). In studies, SCIT and SLIT have been shown to improve existing symptoms of asthma and AR and to also have the capability to cause disease-modifying changes of the underlying atopic condition so as to prevent new allergic sensitization as well as arrest progression of AR to asthma. Recent evidence suggests that immunotherapy brings about these effects through actions that use T-regulatory cells and blocking antibodies such as IgG(4) and IgA(2,) which can then result in an "immune deviation" from a T-helper (Th) 2 cell pattern to a Th1 cell pattern. Numerous meta-analyses and studies have been performed to evaluate the existing data among these studies, with the consensus recommendation favoring the use of immunotherapy because of its potential to modify existing diseases. Significant adverse reactions can occur with immunotherapy, including anaphylaxis and, very rarely, death. A primary factor in considering SIT is its potential to provide long-lasting effects that are able to be sustained well after its discontinuation. Given the significant burden these allergic diseases impose on the health-care system, SIT appears to be a cost-effective adjunctive treatment in modifying the existing disease state.

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.

Subcutaneous versus sublingual immunotherapy for allergic rhinitis and/or asthma

Subcutaneous allergen-specific immunotherapy has long been used in allergic rhinitis and/or asthma and has been recognized to be efficacious. However, owing to the inconvenience of injection and the risk of serious side effects, alternative concepts inspiring the search for effective noninjective routes, namely sublingual administration of allergens, have emerged. Sublingual immunotherapy (SLIT) appears to be associated with a lower incidence of systemic reactions. The clinical efficacy of subcutaneous immunotherapy (SCIT) is well established for both rhinitis and asthma. Meta-analyses relating to its efficacy on asthma and rhinitis are available. SLIT has also been validated in this respect. Comparative clinical studies of SLIT versus SCIT are scarce demonstrating both routes to be clinically efficient. Knowledge of the exact mechanism of action of SLIT has been increasing in the last decade. In addition, recent studies have proved similarities of the immunological changes with the treatment of both routes. Further comparative clinical and immunological studies of SLIT versus SCIT are needed to confirm the long-term efficacy and to complete the knowledge of immunological mechanisms of both routes. Moreover, better understanding of the interaction of allergen and oral mucosal dendritic cells during SLIT may allow improved targeting of SLIT vaccines.

Occupational rhinitis in bell pepper greenhouse workers: determinants of leaving work and the effects of subsequent allergen avoidance on health-related quality of life

BACKGROUND

Avoidance of occupational allergens or reduction in exposure has been advocated as the mainstay of the management of occupational rhinitis. Sparse data to the effect of allergen avoidance are available.

OBJECTIVE

To identify factors that may lead to leaving work and to address the effect of subsequent allergen avoidance on quality of life.

METHODS

A survey to the prevalence of occupational allergy to bell pepper performed in 1999 comprised 472 employees, of which 254 had work-related rhinitis and 228 completed the Rhinitis-related Quality of Life Questionnaire. After 8-year follow-up in 2007, 91 workers with rhinitis in 1999 were available to fill out the questionnaire again and were used to evaluate the course of nasal disease in terms of perceived severity and impact on daily life.

RESULTS

Workers with rhinitis at baseline were more likely to leave their job in bell pepper cultivation for another job (OR = 1.62, 95% CI 0.95-2.75). Among the 91 workers, 58 subjects were still at work, whereas 33 subjects had left work. The subjects who left jobs reported substantial improvement in quality of life. The magnitude of the changes ranged from -0.31 to -1. The effect of quitting work on the mean quality of life score amounted -0.76 ± 0.15.

CONCLUSIONS

The current study is the first large longitudinal studies showing that leaving work and subsequent occupational allergen avoidance have a beneficial effect on rhinitis-related quality of life. The study suggests that occupational rhinitis can be a reason to leave work.

Subcutaneous specific immunotherapy for seasonal allergic rhinitis: a review of treatment practices in the US and Europe

BACKGROUND

Subcutaneous specific immunotherapy (SCIT) is claimed to be successful both in the US and Europe, yet treatment methodology differs.

METHODS

The authors review current literature surrounding guidelines and clinical trials in Europe and the US and contrast the treatment approach to SCIT for allergic rhinitis. Search methodology employs MEDLINE and PubMed, selecting articles on SCIT and allergic rhinitis, limited between 1990-2009. They focus on the safety and efficacy of vaccines, and the differences in formulations. Also mentioned are: standardization, new approaches in SCIT and sublingual immunotherapy (SLIT).

RESULTS

SCIT treatment differs in many respects regarding availability of SCIT products, regulatory controls, guidelines (e.g. multiple allergen vaccines in US, single allergen vaccines in Europe) and in location of formulation (US, clinician's office; Europe, manufacturers).

CONCLUSIONS

SCIT is an effective and safe therapy, but major evidence for efficacy is provided from European studies of single allergen extract vaccines; these vaccines may gain more acceptance because of increasing regulatory approval and lower numbers of injections. The potential impact upon public health (e.g. arrest of the 'allergic march') should not be overlooked.

Sublingual immunotherapy: what have we learnt from the 'big trials'?

PURPOSE OF REVIEW

Recent systematic reviews support the use of sublingual immunotherapy for allergic rhinoconjunctivitis in adults, whereas data in children have been less convincing. The present review evaluates three recent 'definitive' trials in adults and one in children.

RECENT FINDINGS

Two large independent randomized controlled trials of grass allergen tablets have confirmed the efficacy of sublingual immunotherapy in adults with seasonal allergic rhinoconjunctivitis. Effects were both allergen dose-dependent and time-dependent. Tablets were well tolerated and equally effective in monosensitized compared with polysensitized patients and in patients with peak seasonal asthma (patients with perennial asthma were specifically excluded). Local side effects were common but largely self-limiting and not bothersome. There were no serious treatment-related adverse events. Results were similar in magnitude to those observed in a comparable study of subcutaneous immunotherapy using an alum-based vaccine. A trial of sublingual drops in children with hayfever in a primary care setting was negative, although these results could not be generalized.

SUMMARY

Sublingual immunotherapy represents an effective and well tolerated treatment for seasonal allergic rhinoconjunctivitis in adults. Current ongoing paediatric trials and evaluation of long-term effects in adults will further define its role in therapy.

Allergen-specific immunotherapy in allergic rhinitis and asthma. Mechanisms and proof of efficacy

Appeared at the beginning of the 20th century, allergen-specific immunotherapy (SIT) has long been used in allergic rhinitis and asthma without any knowledge of its mechanisms of action or any tangible proof of its efficacy. However, from the beginning of the era of evidence-based medicine, a number of placebo-controlled studies have been published and reached a sufficient number to assess the cellular events induced by SIT and allow meta-analysis to provide guidelines based on proofs. Controlled studies and meta-analysis concerned not only subcutaneous immunotherapy but also the sublingual route, demonstrating an effect of SIT on symptoms and medication use. Most recently sublingual tablets were proposed in allergic rhinitis. This paper reviews the mechanisms of SIT, the evidence of efficacy of SIT from the injective to the sublingual route and reminds the current guidelines.

Targeting the MHC class II pathway of antigen presentation enhances immunogenicity and safety of allergen immunotherapy

BACKGROUND

Current s.c. allergen-specific immunotherapy (SIT) leads to amelioration of IgE-mediated allergy, but it requires numerous allergen injections over several years and is frequently associated with severe side-effects. The aim of this study was to test whether modified recombinant allergens can improve therapeutic efficacy in SIT while reducing allergic side-effects.

METHODS

The major cat allergen Fel d 1 was fused to a TAT-derived protein translocation domain and to a truncated invariant chain for targeting the MHC class II pathway (MAT-Fel d 1). The immunogenicity was evaluated in mice, while potential safety issues were assessed by cellular antigen stimulation test (CAST) using basophils from cat-dander-allergic patients.

RESULTS

MAT-Fel d 1 enhanced induction of Fel d 1-specific IgG2a antibody responses as well as the secretion of IFN-gamma and IL-2 from T cells. Subcutaneous allergen-specific immunotherapy of mice using the modified Fel d 1 provided stronger protection against anaphylaxis than SIT with unmodified Fel d 1, and MAT-Fel d 1 caused less degranulation of human basophils than native Fel d 1.

CONCLUSION

MAT-Fel d 1 allergen enhanced protective antibody and Th1 responses in mice, while reducing human basophil degranulation. Immunotherapy using MAT-Fel d 1 allergen therefore has the potential to enhance SIT efficacy and safety, thus, shortening SIT. This should increase patient compliance and lower treatment costs.