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

An epicutaneous therapeutic pollen-allergen extract delivery system in an allergic rhinitis mouse model: based on allergen loading on DC-specific aptamers conjugated nanogolds

BACKGROUND

Gold nanoparticles (GNPs) have previously been suggested as appropriate carriers for allergen-specific immunotherapy (AIT). In this study, we assessed efficacy of GNPs and dendritic cells (DC)-specific aptamer-modified GNPs (Apts-GNP) for epicutaneous immunotherapy (EPIT) in the case of pollen allergen extracts containing a variety of allergenic and non-allergenic components.

METHODS

BALB/c mice were sensitized to the total protein extract of Platanus orientalis pollen and epicutaneously treated in different groups either with free P. orientalis total pollen extract, naked GNPs, total extract loaded GNPs, and total extract loaded Apts-GNPs with and without skin-penetrating peptides (SPPs). Then, the specific IgE level (sIgE), total IgE concentration (tIgE) in the serum sample, IL-4, IL-17a, IFN-γ, and IL-10 cytokine concentrations in re-stimulated splenocytes with the total extract and mixture of recombinant allergens, nasopharyngeal lavage fluid (NALF) analysis, and histopathological analysis of lung tissue were evaluated.

RESULTS

This study indicated the total extract-loaded GNPs, especially Pla. ext (50 μg)-GNPs, significantly decreased sIgE, tIgE, IL-17a, and IL-4 concentrations, immune cells and eosinophils infiltration in NALF, and increased IL-10 and IFN-γ concentrations compared with the PBS-treated group. In addition, the histopathological analysis of lung tissue showed a significant decrease in allergic inflammation and histopathological damage. The DC-targeted group revealed the most significant improvement in allergic-related immune factors with no histopathological damage compared with the same dose without aptamer.

CONCLUSION

Loading total protein extract on the GNPs and the Apt-modified GNPs could be an effective approach to improve EPIT efficacy in a pollen-induced allergic mouse model.

The Hydrogel Based Allergen-Coated Gold Nanoparticles for Topical Administration: A Possible Epicutaneous Immunotherapy in Pollen-Sensitized Mice?

BACKGROUND

The rapid uptake of antigens by antigen-presenting cells (APCs) and their migration to draining lymph nodes in the initial hours after antigen administration in epicutaneous allergen specific immunotherapy (EPIT) prompted us to investigate whether the topical administration of allergens without patch application could alleviate allergy in pollen-sensitized mice. We evaluated the immunotherapeutic effect of topically administering hydrogel-based Gold nanoparticles (AuNPs) loaded with a total extract of Platanus orientalis pollen (Pla. ext (50 μg)-AuNPs) on intact skin.

METHODS

Mice sensitized to P. orientalis pollen were divided into three groups and treated with Pla. ext (50 μg)-AuNPs: 1) patch with Pla. ext (50 μg)-AuNPs, 2) patch with Pla. ext (50 μg)-AuNPs in combination with hydrogel, and 3) topical application of Pla. ext (50 μg)-AuNPs in combination with hydrogel. The immunotherapeutic effects were evaluated by measuring serum specific and total IgE antibodies, total cell and eosinophil count in nasopharyngeal lavage fluid, cytokines in the supernatants of re-stimulated splenocytes by the total extract, and histological examination of lung and nasal mucosa.

RESULTS

Topical administration of Pla. ext (50 μg)-AuNPs, like patch-based administration, significantly downregulated specific and total IgE and IL-4 production, promoted secretion of IFN-γ and IL-10, markedly reduced the number of inflammatory cells, particularly eosinophils, in nasopharyngeal lavage fluid (p < .05), and inhibited inflammation and pathological damage in lung and nasal mucosa.

CONCLUSION

Our results suggest that topical administration of AuNPs loaded with P. orientalis total pollen extract on intact skin could be a potential application for EPIT in the P. orientalis pollen -sensitized mice.

Subcutaneous immunotherapy takes more than the time in the clinic

OBJECTIVE

The aim of this study was to investigate the time use and both direct and indirect costs associated with subcutaneous immunotherapy (SCIT) for adults with allergic rhinitis (AR) and caregivers of children with AR in the US.

METHODS

We conducted a survey to assess the retrospective time use and direct costs of SCIT. The populations surveyed included adults and caregivers of children (aged 5-17) with symptomatic AR of moderate or higher severity who are currently receiving or have previously started allergy immunotherapy (AIT). The retrospectively collected, self-reported time consumption and direct costs per clinic visit when receiving SCIT were assessed as well as the productivity loss associated with SCIT. Data were analyzed using univariate descriptive statistics.

RESULTS

The study included 106 adults with AR and 191 caregivers of children with AR. We found that the median time spent per visit to the clinic was 50 min for both groups, including travel time and time at the clinic. The direct costs related to each visit included parking fees, road tolls and other costs. Adults spent $10 on parking, $9 on tolls and $10 on other costs. Finally, a median of 4 h of work was missed for both the adult patients and the adults accompanying a child.

CONCLUSIONS

We found that SCIT is associated with substantial direct patient costs and productivity loss for both adults with AR and caregivers of children with AR.

Preference for Immunotherapy with Tablets by People with Allergic Rhinitis

BACKGROUND

People with allergic rhinitis (AR) who are not controlled on conventional therapy can be treated using allergy immunotherapy (AIT) administered as tablets, injections or drops. In the US, the use of sublingual immunotherapy as tablets (SLIT-tablets) is limited in comparison to subcutaneous immunotherapy (SCIT).

OBJECTIVE

This study investigated patients' preference for SLIT-tablets vs monthly or weekly SCIT from a US patient perspective.

METHODS

We carried out a discrete choice experiment (DCE) consisting of two blocks with eight choice sets. Adults and caregivers of children with moderate-to-severe AR were included if they had not previously or were not currently receiving AIT. Three attributes were included in the design: the mode and frequency of administration, the risk of systemic reactions and the co-payment.

RESULTS

A total of 724 adults with AR and 665 caregivers of children with AR were included in the study. Both adults and caregivers had a significant preference for SLIT-tablets compared with both weekly and monthly injections and for less risk of anaphylactic shock. Caregivers were more risk-averse than adults when choosing their treatment, and the younger the child, the more risk-averse the caregiver. The preference for SLIT-tablets was found for both monoallergic and polyallergic adults and caregivers of monoallergic and polyallergic children. Respondents not wanting AIT for free were more risk-averse than those indicating that they wanted AIT for free.

CONCLUSION

Our findings suggest that SLIT-tablets is the preferred route of administration for AIT among adults and caregivers of children with AR.

Dc-specific aptamer decorated gold nanoparticles: A new attractive insight into the nanocarriers for allergy epicutaneous immunotherapy

Recently, the main goal of many allergy epicutaneous immunotherapy (EPIT) studies is to enhance the allergen delivery through the intact skin. Therefore, applying new strategies for tackling this issue are inevitable. For this purpose, ten groups of Che a 2-sensitized BALB/c mice were epicutaneously treated for a 6-week period with the rChe a 2-GNPs-Aptamer, rChe a 2-GNPs-Aptamer + skin-penetrating peptides (SPPs), rChe a 2-GNPs, rChe a 2, GNPs, and PBS. Afterward, the serum IgE and IFN-γ, TGF-β, IL-10, IL-4, IL-17a cytokine production, NALF analysis, and lung/nasal histological examinations were performed. The present study results demonstrate that, EPIT in aptamer treated groups had a significant increase of IFN-γ, TGF-β, and IL-10 concentrations and a significant decrease of IgE, IL-4, and IL-17a concentrations as well as NALF infiltrated immune cell count compared to the non-targeted ones. In addition, SPPs led to more significant improvement of immunoregulatory parameters, especially IL-10 cytokine. Accordingly, the targeted-GNPs with DC-specific aptamers could act as an efficient approach for the improvement of EPIT efficacy compared to the free allergen. Moreover, the application of SPPs might be considered as a useful tool in achieving a successful EPIT with lower doses of allergen at a shorter duration of the treatment.

State-of-the-art in marketed adjuvants and formulations in Allergen Immunotherapy: A position paper of the European Academy of Allergy and Clinical Immunology (EAACI)

Since the introduction of allergen immunotherapy (AIT) over 100 years ago, focus has been on standardization of allergen extracts, with reliable molecular composition of allergens receiving the highest attention. While adjuvants play a major role in European AIT, they have been less well studied. In this Position Paper, we summarize current unmet needs of adjuvants in AIT citing current evidence. Four adjuvants are used in products marketed in Europe: aluminium hydroxide (Al(OH)₃ ) is the most frequently used adjuvant, with microcrystalline tyrosine (MCT), monophosphoryl lipid A (MPLA) and calcium phosphate (CaP) used less frequently. Recent studies on humans, and using mouse models, have characterized in part the mechanisms of action of adjuvants on pre-existing immune responses. AIT differs from prophylactic vaccines that provoke immunity to infectious agents, as in allergy the patient is presensitized to the antigen. The intended mode of action of adjuvants is to simultaneously enhance the immunogenicity of the allergen, while precipitating the allergen at the injection site to reduce the risk of anaphylaxis. Contrasting immune effects are seen with different adjuvants. Aluminium hydroxide initially boosts Th2 responses, while the other adjuvants utilized in AIT redirect the Th2 immune response towards Th1 immunity. After varying lengths of time, each of the adjuvants supports tolerance. Further studies of the mechanisms of action of adjuvants may advise shorter treatment periods than the current three-to-five-year regimens, enhancing patient adherence. Improved lead compounds from the adjuvant pipeline are under development and are explored for their capacity to fill this unmet need.

SLIT's Prevention of the Allergic March

PURPOSE OF REVIEW

The progression of atopic disorders from atopic dermatitis in infants to allergic rhinitis and asthma in children, adolescents, and adults defines the allergy march. Allergen immunotherapy is the only causal treatment altering the immunological mechanism underlying the allergic diseases. The sublingual administration route is more acceptable than the subcutaneous one in pediatric age.

RECENT FINDINGS

Several studies show the efficacy and safety profile of sublingual immunotherapy (SLIT) for the treatment of respiratory allergy diseases, but few data are available on its effect of primary and secondary prevention of allergic disease. The purpose of this manuscript is to review the latest studies addressing the effect of SLIT on the development of new sensitizations in not sensitized or already sensitized patients and progression of the allergy march.

The atopic march: current insights into skin barrier dysfunction and epithelial cell-derived cytokines

Atopic dermatitis often precedes the development of other atopic diseases. The atopic march describes this temporal relationship in the natural history of atopic diseases. Although the pathophysiological mechanisms that underlie this relationship are poorly understood, epidemiological and genetic data have suggested that the skin might be an important route of sensitization to allergens. Animal models have begun to elucidate how skin barrier defects can lead to systemic allergen sensitization. Emerging data now suggest that epithelial cell-derived cytokines such as thymic stromal lymphopoietin (TSLP), IL-33, and IL-25 may drive the progression from atopic dermatitis to asthma and food allergy. This review focuses on current concepts of the role of skin barrier defects and epithelial cell-derived cytokines in the initiation and maintenance of allergic inflammation and the atopic march.

Satisfaction and quality of life of allergic patients following sublingual five-grass pollen tablet immunotherapy in Spain

BACKGROUND

Five-grass pollen tablet is an effective and well-tolerated therapy for patients with allergic rhinoconjunctivitis (ARC). This trial sought to determine the satisfaction and health-related quality of life (HRQoL) of patients undergoing this treatment.

METHODS

This was a cross-sectional, multicentre, observational, naturalistic study, following a discontinuous pre- and co-seasonal five-grass pollen regimen over two seasons in Spain (2012, 2013). The HRQoL of the patients was measured with the specific Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) for adults, adolescent (AdolRQLQ), or paediatric (PRQLQ) patients. Treatment satisfaction was assessed by the Satisfaction Scale for Patients Receiving Allergen Immunotherapy (ESPIA) questionnaire. Patients/investigators were surveyed on beliefs and attitudes towards the five-grass pollen tablet. ARC evolution according to allergic rhinitis and its impact on asthma (ARIA) criteria and treatment adherence were evaluated.

RESULTS

Among the 591 ARC patients included, the mean (SD) HRQoL scores were 1.40 (1.1) in adults, 1.33 (1.1) in adolescents, and 1.15 (1.1) in children, indicating low levels of impairment (scale 0-6). ESPIA answers showed high levels of satisfaction, with an average score of 69.2 (scale 0-100). According to ARIA criteria, 88.2% of patients reported improvement of ARC. Moreover, this was accompanied by a reduced use of symptomatic medication. Adherence to treatment was estimated at 96.8%. In general, both patients and specialists exhibited a positive attitude towards five-grass pollen tablet treatment.

CONCLUSION

ARC patients treated with five-grass pollen tablet showed favourable levels of HRQoL and treatment satisfaction, with concomitant improvements in ARC and symptomatic medication use, which translated into high levels of treatment adherence and a positive attitude towards five-grass pollen tablet.

Novel Delivery Routes for Allergy Immunotherapy: Intralymphatic, Epicutaneous, and Intradermal

Current allergy immunotherapy protocols suffer from two main problems: long treatment duration and systemic allergic side effects of the allergen administrations. The immunologic effects of allergen administration could be enhanced and the number of allergen administrations and treatment duration reduced by choosing a tissue for administration that contains a high density of antigen-presenting cells. Local side effects could be reduced by choosing a route characterized by a low density of mast cells, and systemic side effects could be reduced by administration to nonvascularized tissues, so that inadvertent systemic distribution of the allergen and consequent systemic allergic side effects are minimized.

Administration and Burden of Subcutaneous Immunotherapy for Allergic Rhinitis in U.S. and Canadian Clinical Practice

BACKGROUND

Allergy immunotherapy (AIT) is the only available treatment that alters the natural course of allergies and has possible disease-modifying effects. AIT is administered primarily via subcutaneous injection delivered in a physician's office. Few studies have been conducted in the United States or Canada to evaluate the costs of subcutaneous immunotherapy (SCIT).

OBJECTIVES

To (a) describe SCIT administration processes, resources, and costs and (b) characterize the patient population receiving SCIT.

METHODS

A multisite, prospective, observational time and motion study was conducted. Injection and wait times were collected by a third-party observer on 1 visit for each patient. Extract preparation processes were also observed. Site staff reported on treatment protocols, administrative time, supplies, and patient medical history. Patients responded to questionnaires on demographics, reasons for treatment, medication use, productivity, and travel time. Costs were estimated by applying unit costs to the time observations and the patient- and staff-reported data.

RESULTS

A total of 670 SCIT patients were enrolled at 6 sites in the United States and 6 sites in Canada. Average age in the United States was 41 years (SD = 18) and 44 years (15) in Canada, with 10% of the patients aged ≥ 65 years. Annual incomes were over $100,000 for 40% of U.S. patients and 30% of Canadian patients. U.S. patients had over 4 times as many different allergens in their SCIT treatments as Canadian patients, with a mean of 18 versus 4. The most common reasons reported for starting SCIT was a "desire to cure allergies once and for all" (73%) and that "symptoms are not improved by allergy medications" (60%). Percentages of patients taking allergy medications in the 4 weeks prior to observation were 86% in the United States and 66% in Canada: antihistamines 75% United States, 54% Canada; inhaled corticosteroids 32% United States, 22% Canada. The predominant comorbidity was asthma, 43% United States, 24% Canada. Site protocols for build-up treatment phases were 1 to 2 injections per week for an average of 25 weeks (range 12-52). Maintenance phases were 1 injection every 3 to 4 weeks for an average of 4 years (range 2.5-5). Eight of the sites had total mean staff times per injection visit of 7 to 22 minutes; 1 site averaged fewer minutes, and 3 sites averaged more. Total direct medical costs were an average of $30 for Canadian patients per visit and $32 per visit for U.S. patients, half accounted for by the cost of the extract. Pre- and postinjection administrative tasks were the second largest driver of direct costs. Total injection visit-related time for patients, including round-trip travel time, averaged about 80 minutes per visit in the United States and in Canada.

CONCLUSIONS

Analyses revealed substantial variation in SCIT regimens among sites, but the sites had commonalities in the injection process components. SCIT requires patient commitment to a long-term treatment regimen involving numerous clinic visits and resources for administration.

Potential of molecular based diagnostics and its impact on allergen immunotherapy

Molecular based in vitro technologies greatly changed the diagnostic approaches in allergy. At present, sensitization profiles can be dissected according to IgE subsets, which are specific for genuine or cross-reacting components and potentially dangerous or virtually harmless components. The identification of IgE in components with specific characteristics has a direct impact on the accuracy of the diagnosis (indeed, it is possible at present to not only identify the allergen derived from a given allergen source but also the family of molecules to which the patient is sensitized), on the prognosis of the patient’s allergy, and on the prevention activities to be implemented. More interestingly, during the last few years, and thanks to the tools of molecular diagnostics, the indications for Allergen Immunotherapy (AIT) have also be modified, and novel strategies for the selection of the allergens to be administered have been better defined. Indeed, protocols indicating how Molecular Based Diagnosis (MBD) can be used to identify the best AIT approach have been recently published. In this review, the rationale for the use of MBD tools is discussed, and the recent strategies for the choice of allergens to be used in AIT are reported.

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.

Allergy immunotherapy prescribing trends for grass pollen-induced allergic rhinitis in Germany: a retrospective cohort analysis

Background

Allergy immunotherapy is an effective treatment for patients with allergic rhinitis whose symptoms are unresolved with pharmacotherapy. Allergy immunotherapy for grass pollen-induced allergic rhinitis is available in three modalities: subcutaneous immunotherapy and sublingual immunotherapy as a tablet or drop. This study aimed to understand trends in allergy immunotherapy prescribing and practice patterns for grass allergies in adult and paediatric patients in Germany.

Methods

A retrospective cohort study was conducted using IMS Disease Analyzer in Germany. Patients with an allergy immunotherapy prescription for grass pollen (Anatomical Therapeutic Chemical [ATC] classification code V01AA02) from September 2005 to December 2012 were included in the study. General Practitioners (GPs), dermatologists, Ear, Nose and Throat (ENT)-specialists, paediatricians and pneumologists were included as the allergy immunotherapy prescribing physicians in the study. Descriptive analyses were conducted on patient characteristics at index and prescribing physician specialty; a test for trend was conducted for timing of initiation of first allergy immunotherapy prescription in each annual prescribing season.

Results

Eighteen thousand eight hundred fifty eligible patients were identified during the study period. The majority of patients received subcutaneous immunotherapy; however, the proportion of patients receiving sublingual immunotherapy tablets increased from 8 % in 2006/2007 to 29 % in 2011/2012 (p < 0.001). Initiation of subcutaneous immunotherapy and Oralair® generally peaked during each prescribing year in two seasons (September-October and January) while GRAZAX® prescriptions peaked in autumn (September-October). ENT-specialists and dermatologists were the largest allergy immunotherapy prescribers in adults, while paediatricians and ENT-specialists were the largest prescribers of allergy immunotherapy in paediatric patients.

Conclusions

Subcutaneous immunotherapy remained the dominant allergy immunotherapy modality for grass pollen-induced allergic rhinitis in Germany for adult and paediatric patients; however, there was a marked increase in proportion of patients receiving sublingual immunotherapy tablets from 2006/2007 to 2011/2012, after their introduction to the market in 2006. ENT-specialists, dermatologists and paediatricians were responsible for the majority of prescribing. The predominance of particular modalities within certain physician specialties likely reflects different treatment goals or needs.

Sublingual immunotherapy: the U.S. experience

PURPOSE OF REVIEW

It is likely that approval of allergen preparations for sublingual immunotherapy (SLIT) will soon occur in the United States. This article reviews experience with SLIT in this country, concentrating on the large, multicenter trials that will provide the evidence of safety and efficacy necessary to obtain that approval.

RECENT FINDINGS

Large multicenter trials have been conducted with both grass and short ragweed. In five single-season studies with sublingual grass tablets, usually starting 4 months prior to and continuing through the pollen season, the combined symptom medication score was improved 20-28% relative to placebo-treated individuals. Short ragweed tablets, initiated 4 months prior to and continued through the pollen season, reduced symptom/medication scores by 24-26%. Similar results have been reported with short ragweed aqueous extract administered sublingually. To date, there has been only one small study each with house dust mite and cat allergen extracts. All of these studies were conducted with a single allergen. One small study, comparing timothy alone to the same dose of timothy combined with nine other pollen extracts, raised still unanswered questions regarding the efficacy of SLIT with multiple allergen mixes.

SUMMARY

SLIT is coming to the United States. There will be approved allergen preparations for which the appropriate dosing for efficacy and safety has been established. It would be inappropriate to use the evidence generated by these large studies to justify off-label use of allergen extracts approved for injection or the administration of multiple allergen preparations sublingually.

Epicutaneous Immunotherapy for Aeroallergen and Food Allergy

IgE-mediated allergies today affect up to 30 % of the population in industrialized countries. Allergen immunotherapy is the only disease-modifying treatment option with a long-term effect. However, very few patients (<5 %) choose immunotherapy, due to the long treatment duration (between 3-5 years) and possible local and systemic allergic side effects of the allergen administrations. The latter occur when an allergen accidentally reaches the blood circulation. Therefore, the ideal application route for allergen immunotherapy should be characterized by two hallmarks: firstly, by a high number of potent antigen-presenting cells, which enhance efficacy and thus shorten treatment duration. Secondly, the allergen administration site is ideally non-vascularized, so that inadvertent systemic distribution of the allergen and consequent systemic allergic side effects are minimized. The epidermis contains high numbers of potent antigen-presenting Langerhans cells and, as an epithelium, is non-vascularized. Therefore, the epidermis represents an interesting administration route. Historical evidence for the clinical efficacy of epicutaneous allergy immunotherapy (EPIT) has now been strengthened by a number of recent double-blinded placebo-controlled clinical trials performed by independent groups. We review the immunological rationale, history and clinical experience with epicutaneous allergy immunotherapy.

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

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

Food allergy: management, diagnosis and treatment strategies

Food allergy is an increasing problem in western countries, with strict avoidance being the only available reliable treatment. However, accidental ingestion can occur and anaphylactic reactions still happen. In recent years, many efforts have been made to better understand the humoral and cellular mechanisms involved in food allergy, and to improve the strategies for diagnosis and treatment. This review focuses on IgE-mediated food hypersensitivity and provides an overview of the diagnostic strategies and treatment advances. Specific immunotherapy, including different routes of administration and allergen sources, such as natural, recombinant and T-cell epitopes, are analyzed in detail. Other treatments such as anti-IgE monoclonal antibody therapy, adjuvant therapy and Chinese herbs will also be described.

Transcutaneous delivery of CpG-adjuvanted allergen via laser-generated micropores

BACKGROUND

Two main shortcomings of classical allergen-specific immunotherapy are long treatment duration and low patient compliance. Utilizing the unique immunological features of the skin by transcutaneous application of antigen opens new approaches not only for painless vaccine delivery, but also for allergen-specific immunotherapy. Under certain conditions, however, barrier disruption of the skin favors T helper 2-biased immune responses, which may lead to new sensitizations.

METHODS

In a prophylactic approach, an infra-red laser device was employed, producing an array of micropores of user-defined number, density, and depth on dorsal mouse skin. The grass pollen allergen Phl p 5 was administered by patch with or without the T helper 1-promoting CpG oligodeoxynucleotide 1826 as adjuvant, or was subcutaneously injected. Protection from allergic immune responses was tested by sensitization via injection of allergen adjuvanted with alum, followed by intranasal instillation. In a therapeutic setting, pre-sensitized mice were treated either by the standard method using subcutaneous injection or via laser-generated micropores. Sera were analyzed for IgG antibody subclass distribution by ELISA and for IgE antibodies by a basophil mediator release assay. Cytokine profiles from supernatants of re-stimulated lymphocytes and from bronchoalveolar lavage fluids were assessed by flow cytometry using a bead-based assay. The cellular composition of lavage fluids was determined by flow cytometry.

RESULTS

Application of antigen via micropores induced T helper 2-biased immune responses. Addition of CpG balanced the response and prevented from allergic sensitization, i.e. IgE induction, airway inflammation, and expression of T helper 2 cytokines. Therapeutic efficacy of transcutaneous immunotherapy was equal compared to subcutaneous injection, but was superior with respect to suppression of already established IgE responses.

CONCLUSIONS

Transcutaneous immunotherapy via laser-generated micropores provides an efficient novel platform for treatment of type I allergic diseases. Furthermore, immunomodulation with T helper 1-promoting adjuvants can prevent the risk for new sensitization.

Transcutaneous immunotherapy via laser-generated micropores efficiently alleviates allergic asthma in Phl p 5-sensitized mice

Background

Specific immunotherapy via the subcutaneous or oral route is associated with local and, in some cases, systemic side effects and suffers from low patient compliance. Due to its unique immunological features, the skin represents a promising target tissue for effective and painless treatment of type I allergy. The current study was performed to compare the efficacy of transcutaneous immunotherapy via laser-generated micropores to subcutaneous injection.

Methods

BALB/c mice were sensitized by intraperitoneal injection of recombinant grass pollen allergen Phl p 5 together with alum. Subsequently, lung inflammation was induced by repeated intranasal challenge. During the treatment phase, adjuvant-free Phl p 5 was applied in solution to microporated skin or was subcutaneously injected. Lung function and cellular infiltration; Phl p 5–specific serum levels of IgG1, IgG2a, and IgE; and cytokine levels in bronchoalveolar lavage fluids as well as in supernatants of splenocyte cultures were assessed.

Results

Both therapeutic approaches reduced airway hyperresponsiveness and leukocyte infiltration into the lungs. Whereas subcutaneous immunotherapy induced a systemic increase in Th2-associated cytokine secretion, transcutaneous application revealed a general downregulation of Th1/Th2/Th17 responses. Successful therapy was associated with induction of IgG2a and an increase in FOXP3+ CD4+ T cells.

Conclusions

Transcutaneous immunotherapy via laser microporation is equally efficient compared with conventional subcutaneous treatment but avoids therapy-associated boosting of systemic Th2 immunity. Immunotherapy via laser-microporated skin combines a painless application route with the high efficacy known from subcutaneous injections and therefore represents a promising alternative to established forms of immunotherapy.

Intralymphatic immunotherapy for cat allergy induces tolerance after only 3 injections

BACKGROUND

Subcutaneous allergen-specific immunotherapy frequently causes allergic side effects and requires 30 to 80 injections over 3 to 5 years.

OBJECTIVE

We sought to improve immunotherapy by using intralymphatic allergen administration (intralymphatic immunotherapy [ILIT]) and by targeting allergen to the MHC class II pathway.

METHODS

Recombinant major cat dander allergen Fel d 1 was fused to a translocation sequence (TAT) and to part of the human invariant chain, generating a modular antigen transporter (MAT) vaccine (MAT-Fel d 1). In a randomized double-blind trial ILIT with MAT-Fel d 1 in alum was compared with ILIT with placebo (saline in alum) in allergic patients (ClinicalTrials.govNCT00718679).

RESULTS

ILIT with MAT-Fel d 1 elicited no adverse events. After 3 placebo injections within 2 months, nasal tolerance increased less than 3-fold, whereas 3 intralymphatic injections with MAT-Fel d 1 increased nasal tolerance 74-fold (P < .001 vs placebo). ILIT with MAT-Fel d 1 stimulated regulatory T-cell responses (P = .026 vs placebo) and increased cat dander-specific IgG(4) levels by 5.66-fold (P = .003). The IgG(4) response positively correlated with IL-10 production (P < .001).

CONCLUSION

In a first-in-human clinical study ILIT with MAT-Fel d 1 was safe and induced allergen tolerance after 3 injections.

Epicutaneous allergen-specific immunotherapy ameliorates grass pollen-induced rhinoconjunctivitis: A double-blind, placebo-controlled dose escalation study

BACKGROUND

Epicutaneous allergen administration using a patch may be an alternative to subcutaneous or sublingual immunotherapy.

OBJECTIVE

To optimize treatment dose and to demonstrate the efficacy and safety of epicutaneous immunotherapy.

METHODS

This monocentric, placebo-controlled, double-blind trial included 132 patients with grass pollen-induced rhinoconjunctivitis. In February 2008, patients were randomly allocated to receive placebo or 3 different doses of allergen. Before and during the pollen season 2008, patients received 6 weekly patches. Efficacy was assessed 4 to 5 months later (n = 110) and during the pollen season of the treatment-free follow-up year in 2009 (n = 93). The primary outcome was patient-reported changes in hay fever symptoms assessed by a visual analog scale. Secondary outcome measures were weekly visual analog scale symptom scores during pollen season, use of rescue medication, changes in conjunctival and skin reactivity, as well as safety.

RESULTS

Hay fever symptoms during the pollen season were reduced by more than 30% in 2008 and by 24% in 2009 in the high-dose group as compared with that in the placebo group, and the alleviation of symptoms in the follow-up year was dependent on the treatment dose. Higher allergen doses were associated with drug-related adverse events (AEs), predominantly manifested by pruritus, erythema, wheal, or eczema. Eleven systemic AEs of grades 1 to 2 required treatment and led to study exclusion. The dropout rate due to AEs was 8.3%. No drug-related serious AE was recorded.

CONCLUSION

Epicutaneous immunotherapy is safe and efficacious in a dose-dependent manner after 6 patches only.

Epicutaneous allergen administration: is this the future of allergen-specific immunotherapy?

IgE-mediated allergies, such as allergic rhinoconjunctivitis and asthma, have become highly prevalent, today affecting up to 30% of the population in industrialized countries. Allergen-specific immunotherapy (SIT) either subcutaneously or via the sublingual route is effective, but only few patients (<5%) choose immunotherapy, as treatment takes several years and because allergen administrations are associated with local and, in some cases, even systemic allergic side-effects because of allergen accidentally reaching the circulation. In order to resolve these two major drawbacks, the ideal application site of SIT should have two characteristics. First, it should contain a high number of potent antigen-presenting cells to enhance efficacy and shorten treatment duration. Secondly, it should be nonvascularized in order to minimize inadvertent systemic distribution of the allergen and therefore systemic allergic side-effects. The epidermis, a nonvascularized multilayer epithelium, that contains high numbers of potent antigen-presenting Langerhans cells (LC) could therefore be an interesting administration route. The present review will discuss the immunological rational, history and actual clinical experience with epicutaneous allergen-specific immunotherapy.