The Art of Immunotherapy.

Selection of a patient with rhinitis/conjunctivitis or asthma for allergy immunotherapy (AIT) requires several decisions. First, does the patient's sensitization, pattern of exposure to an allergen, and degree of exposure to that allergen reasonably suggest a causal relationship? Does the level and duration of symptoms warrant the cost and inconvenience of immunotherapy, or is the patient motivated by the disease-modifying potential of AIT? If AIT is selected, is the choice to be greater safety and convenience with sublingual immunotherapy (SLIT) tablets, but with treatment probably limited to 2 or 3 allergens, or for subcutaneous immunotherapy where multiple allergen therapy is the rule and efficacy may be somewhat greater, at least initially, or does the physician go off-label into the unknowns of liquid SLIT? Are there extracts of sufficient potency to achieve likely effective doses? How does the physician deal with large local or systemic reactions, with gaps in treatment, with pollen seasons, and the use of premedication or cautionary prescription of epinephrine autoinjectors? How can adherence to AIT be improved? These and other questions are addressed in this paper.

Methods for Experimental Allergen Immunotherapy: Subcutaneous and Sublingual Desensitization in Mouse Models of Allergic Asthma.

Allergic asthma is characterized by airway hyperresponsiveness, remodeling, and reversible airway obstruction. This is associated with an eosinophilic inflammation of the airways, caused by inhaled allergens such as house dust mite or grass pollen. The inhaled allergens trigger a type-2 inflammatory response with the involvement of innate lymphoid cells (ILC2) and Th2 cells, resulting in high immunoglobulin E (IgE) antibody production by B cells and mucus production by airway epithelial cells. As a consequence of the IgE production, subsequent allergen reexposure results in a classic allergic response with distinct early and late phases, both resulting in bronchoconstriction and shortness of breath. Allergen-specific immunotherapy (AIT) is the only treatment that is capable of modifying the immunological process underlying allergic responses including allergic asthma. Both subcutaneous AIT (SCIT) as well as sublingual AIT (SLIT) have shown clinical efficacy in long-term suppression of the allergic response. Although AIT treatments are very successful for rhinitis, application in asthma is hampered by variable efficacy, long duration of treatment, and risk of severe side effects. A more profound understanding of the mechanisms by which AIT induces tolerance to allergens in sensitized individuals is needed to be able to improve its efficacy. Mouse models have been very valuable in preclinical research for characterizing the mechanisms of desensitization in AIT and evaluating novel approaches to improve its efficacy. Here, we present a rapid and reproducible mouse model for allergen-specific immunotherapy. In this model, mice are sensitized with two injections of allergen adsorbed to aluminum hydroxide, followed by subcutaneous injections (SCIT) or sublingual administrations (SLIT) of allergen extracts as an immunotherapy treatment. Finally, mice are challenged by intranasal allergen administrations. We will also describe the protocols as well as the most important readout parameters for the measurements of invasive lung function, serum immunoglobulin levels, isolation of bronchoalveolar lavage fluid (BALF), and preparation of cytospin slides. Moreover, we describe how to perform ex vivo restimulation of lung single-cell suspensions with allergens, flow cytometry for identification of relevant immune cell populations, and ELISAs and Luminex assays for assessment of the cytokine concentrations in BALF and lung tissue.

Allergen immunotherapy in the current COVID-19 pandemic: A position paper of AeDA, ARIA, EAACI, DGAKI and GPA: Position paper of the German ARIA GroupA in cooperation with the Austrian ARIA GroupB, the Swiss ARIA GroupC, German Society for Applied Allergology (AEDA)D, German Society for Allergology and Clinical Immunology (DGAKI)E, Society for Pediatric Allergology (GPA)F in cooperation with AG Clinical Immunology, Allergology and Environmental Medicine of the DGHNO-KHCG and the European Academy of Allergy and Clinical Immunology (EAACI)H.

No abstract available.

Cost-effectiveness of grass pollen allergen immunotherapy in adults.

BACKGROUND: Major scientific societies, such as the EAACI or the AAAAI, do not express any suggestion on which form of allergen immunotherapy (AIT) is to be preferred (subcutaneous immunotherapy, SCIT, vs sublingual immunotherapy, SLIT). This choice could depend on their relative pharmacoeconomic value. OBJECTIVE: To assess the cost-effectiveness of AIT for grass pollen, administered as SCIT or SLIT. METHODS: We created a Markovian Model, to evaluate, in a hypothetical cohort of adult patients suffering from moderate-to-severe rhino-conjunctivitis with or without allergic asthma, the cost-effectiveness of SLIT (tablets, Grazax® and Oralair® ) or SCIT (various currently available products, plus indirect nonmedical costs, such as travel and productivity costs) in addition to pharmacological therapy, assuming a 9-year horizon to capture AIT long-term effects. The incremental cost-effectiveness ratio (ICER) was calculated assuming pharmacological therapy as the reference comparator. RESULTS: In the base case, SCIT was slightly more expensive, but more effective than SLIT, being the most cost-effective option (ICER for SCIT, €11 418; ICER for SLIT, €15 212). ICERs greater than €120 000 for both SCIT and SLIT were demonstrated in a scenario assuming that low treatment persistence rates, which are common in real-life, lead to absence of long-term AIT clinical benefit. Considering indirect nonmedical costs SLIT resulted more cost-effective than SCIT (ICER for SCIT, €17 318; ICER for SLIT, €15 212). CONCLUSION: In daily practice, AIT for grass pollens may be a cost-effective option only in patients with low discontinuation rates. SCIT, which is less affected by this limitation than SLIT, seems the most cost-effective AIT form.

Investigational new drugs for allergic rhinitis.

INTRODUCTION: Allergic rhinitis (AR) is a multifactorial disease characterized by paroxysmal symptoms of sneezing, rhinorrhea, postnasal drip and nasal congestion. For over a century, subcutaneous allergen immunotherapy (SCIT) has been recognized as the most effective therapy to date that may modify the underlying disease course and provide long-term benefits for individuals refractory to pharmacotherapy. However, over the past 25 years, there has been substantial growth in developing alternative therapies to traditional SCIT. Areas covered: This article will review the most current literature focusing on advancements of AR therapies. Novel AR therapies that are currently under investigation include: the addition of omalizumab, an anti-immunoglobulin E (IgE) monoclonal antibody (mAb), to SCIT; altering the method of delivery of allergen immunotherapy (AIT) including sublingual (SLIT), epicutaneous (EIT), intralymphatic (ILIT), intranasal (INIT) and oral mucosal immunotherapy (OMIT); use of capsaicin spray; novel H3 and H4 antihistamines; activation of the innate immune system through Toll-like receptor agonists; and the use of chemically altered allergens, allergoids, recombinant allergens and relevant T-cell epitope peptides to improve the efficacy and safety of AIT. Expert opinion: These promising novel therapies may offer more effective and/or safer treatment options for AR patients, and in some instances, induce immunologic tolerance.

Sublingual versus subcutaneous immunotherapy: patient adherence at a large German allergy center.

BACKGROUND: Many placebo-controlled studies have demonstrated that allergen immunotherapy (AIT) is an effective therapy for treating allergies. Both commonly used routes, subcutaneous (SCIT) and sublingual immunotherapy (SLIT), require high patient adherence to be successful. In the literature, numbers describing adherence vary widely; this investigation compares these two routes of therapy directly. METHODS: All data were retrieved from the patient data management system of a center for dermatology, specific allergology, and environmental medicine in Germany. All 330 patients (aged 13-89 years) included in this study had commenced AIT between 2003 and 2011, thus allowing a full 3-year AIT cycle to be considered for each investigated patient. RESULTS: In this specific center, SCIT was prescribed to 62.7% and SLIT to 37.3% of all included patients. The total dropout rate of the whole patient cohort was 34.8%. Overall, SLIT patients showed a higher dropout rate (39.0%) than did SCIT patients (32.4%); however, the difference between these groups was not significant. Also, no significant difference between the overall dropout rates for men and for women was observed. A Kaplan-Meier curve of the patient collective showed a remarkably high dropout rate for the first year of therapy. CONCLUSION: The analysis presented in this single-center study shows that most patients who discontinue AIT do so during the first year of therapy. Patients seem likely to finish the 3-year therapy cycle if they manage to adhere to treatment throughout the first year. Strategies for preventing nonadherence in AIT, therefore, need to be developed and standardized in future investigations.

Subcutaneous and Sublingual Immunotherapy in a Mouse Model of Allergic Asthma.

Allergic asthma, caused by inhaled allergens such as house dust mite or grass pollen, is characterized by reversible airway obstruction, associated with an eosinophilic inflammation of the airways, as well as airway hyper responsiveness and remodeling. The inhaled allergens trigger a type-2 inflammatory response with involvement of innate lymphoid cells (ILC2) and Th2 cells, resulting in high production of immunoglobulin E (IgE) antibodies. Consequently, renewed allergen exposure results in a classic allergic response with a distinct early and late phase, both resulting in bronchoconstriction and shortness of breath. Allergen specific immunotherapy (AIT) is the only treatment that is capable of modifying the immunological process underlying allergic responses including allergic asthma and both subcutaneous AIT (SCIT) as well as sublingual AIT (SLIT) have proven clinical efficacy in long term suppression of the allergic response. Although these treatments are very successful for rhinitis, application of AIT in asthma is hampered by variable efficacy, long duration of treatment, and the risk of severe side-effects. A more profound understanding of the mechanisms by which AIT achieves tolerance to allergens in sensitized individuals is needed to improve its efficacy. Mouse models have been very valuable as a preclinical model to characterize the mechanisms of desensitization in AIT and to evaluate novel approaches for improved efficacy. Here, we present a rapid and reproducible mouse model for allergen-specific immunotherapy. In this model, mice are sensitized with two injections of allergen absorbed to aluminum hydroxide to induce allergic sensitization, followed by subcutaneous injections (SCIT) or sublingual administrations (SLIT) of the allergen as immunotherapy treatment. Finally, mice are challenged by three intranasal allergen administrations. We will describe the protocols as well as the most important read-out parameters including measurement of invasive lung function measurements, serum immunoglobulin levels, isolation of broncho-alveolar lavage fluid (BALF), and preparation of cytospins. Moreover, we describe how to restimulate lung single cell suspensions, perform flow cytometry measurements to identify populations of relevant immune cells, and perform ELISAs and Luminex assays to measure the cytokine concentrations in BALF and lung tissue.

Analysis of aluminium in rat following administration of allergen immunotherapy using either aluminium or microcrystalline-tyrosine-based adjuvants.

BACKGROUND: Investigation into the absorption, distribution and elimination of aluminium in rat after subcutaneous aluminium adjuvant formulation administration using ICP-MS is described. METHOD & RESULTS: Assays were verified under the principles of a tiered approach. There was no evidence of systemic exposure of aluminium, in brain or in kidney. Extensive and persistent retention of aluminium at the dose site was observed for at least 180 days after administration. CONCLUSION: This is the first published work that has quantified aluminium adjuvant retention based on the quantity of aluminium delivered in a typical allergy immunotherapy course. The results indicate that the repeated administration of aluminium-containing adjuvants will likely contribute directly and significantly to an individual's body burden of aluminium.

Distinct modulation of allergic T cell responses by subcutaneous vs. sublingual allergen-specific immunotherapy.

BACKGROUND: Allergen-specific immunotherapy is the only curative treatment for type I allergy. It can be administered subcutaneously (SCIT) or sublingually (SLIT). The clinical efficacy of these two treatment modalities appears to be similar, but potential differences in the immunological mechanisms involved have not been fully explored. OBJECTIVE: To compare changes in the allergen-specific T cell response induced by subcutaneous vs. sublingual administration of allergen-specific immunotherapy (AIT). METHODS: Grass pollen-allergic patients were randomized into groups receiving either SCIT injections or SLIT tablets or neither. PBMCs were tested for Timothy grass (TG)-specific cytokine production by ELISPOT after in vitro expansion with TG-peptide pools. Phenotypic characterization of cytokine-producing cells was performed by FACS. RESULTS: In the SCIT group, decreased IL-5 production was observed starting 10 months after treatment commenced. At 24 months, T cell responses showed IL-5 levels significantly below the before-treatment baseline. No significant reduction of IL-5 was observed in the SLIT or untreated group. However, a significant transient increase in IL-10 production after 10 months of treatment compared to baseline was detected in both treatment groups. FACS analysis revealed that IL-10 production was associated with CD4(+) T cells that also produced IFNγ and therefore may be associated with an IL-10-secreting type 1 cell phenotype. CONCLUSION AND CLINICAL RELEVANCE: The most dominant immunological changes on a cellular level were a decrease in IL-5 in the SCIT group and a significant, transient increase of IL-10 observed after 10 months of treatment in both treated groups. The distinct routes of AIT administration may induce different immunomodulatory mechanisms at the cellular level.

The 6 thalamic regions: surgical approaches to thalamic cavernous malformations, operative results, and clinical outcomes.

OBJECT: The ideal surgical approach to thalamic cavernous malformations (CMs) varies according to their location within the thalamus. To standardize surgical approaches, the authors have divided the thalamus into 6 different regions and matched them with the corresponding surgical approach. METHODS: The regions were defined as Region 1 (anteroinferior), Region 2 (medial), Region 3 (lateral), Region 4 (posterosuperior), Region 5 (lateral posteroinferior), and Region 6 (medial posteroinferior). The senior author's surgical experience with 46 thalamic CMs was reviewed according to this classification. An orbitozygomatic approach was used for Region 1; anterior ipsilateral transcallosal for Region 2; anterior contralateral transcallosal for Region 3; posterior transcallosal for Region 4; parietooccipital transventricularfor Region 5; and supracerebellar-infratentorial for Region 6. RESULTS: Region 3 was the most common location (17 [37%]). There were 5 CMs in Region 1 (11%), 9 in Region 2 (20%), 17 in Region 3 (37%), 3 in Region 4 (6%), 4 in Region 5 (9%), and 8 in Region 6 (17%). Complete resection was achieved in all patients except for 2, who required a second-stage operation. The mean follow-up period was 1.7 years (range 6 months-9 years). At the last clinical follow-up, 40 patients (87%) had an excellent or good outcome (modified Rankin Scale [mRS] scores 0-2) and 6 (13%) had poor outcome (mRS scores 3-4). Relative to their preoperative condition, 42 patients (91%) were unchanged or improved, and 4 (9%) were worse. CONCLUSIONS: The authors have presented the largest series reported to date of surgically treated thalamic CMs, achieving excellent results using this methodology. In the authors' experience, conceptually dividing the thalamus into 6 different regions aids in the selection of the ideal surgical approach fora specific region.

A Phase I clinical trial with subcutaneous immunotherapy vaccine of Timothy grass pollen extract according to EMA guidelines.

AIM: A double-blind placebo-controlled study was conducted according to EMA guidelines, to evaluate safety, tolerability and short-term treatment effects of three up-dosing regimens of Phleum pratense subcutaneous immunotherapy. MATERIALS & METHODS: Forty-two patients were randomized to groups: A (6 weekly doses), B (8 weekly doses) or C (eight doses, two clustered increasing doses over 3 weeks). RESULTS: The most frequent adverse events were local reactions. No serious adverse events were found. Higher number and more severe systemic reactions were reported in group C. A decrease in cutaneous responses and an increase of specific antibodies was shown in all active groups even at very short-term. CONCLUSION: Phleum pratense subcutaneous immunotherapy in depot presentation exhibited good safety and tolerability. Group A seemed to show the best profile.

Current opinion and review on peanut oral immunotherapy.

In the last decade, peanut oral immunotherapy research has shown promise as an alternative treatment to avoidance in peanut-allergic patients. Research has not only focused on desensitization, but also on immunologic changes and sustained-tolerance. This article reviews the current literature and the historical background of oral immunotherapy as well as immune mechanisms in oral immunotherapy and other therapies being explored in food allergic individuals.

Oral/sublingual Phleum pretense grass tablet (Grazax/Grastek) to treat allergic rhinitis in the USA.

With the approval of two grass tablets and one ragweed tablet for sublingual immunotherapy (SLIT) by the US FDA in April 2014, the practice of allergy immunotherapy (AIT) in the USA has dramatically changed. Until this time, there were no approved allergen extracts for sublingual administration and physicians who prescribed SLIT for their patients did so without full knowledge of proper dosing or assurance of its safety. Now sublingual allergen tablets are available that have proven safe and effective doses. This article describes, in detail, the studies that have been conducted with a timothy grass SLIT tablet and draws some comparisons to the alternative 5-grass SLIT tablet. It also attempts to predict what will be the impact of the introduction of these tablets on the practice of AIT in the USA over the next few years.

Real-life compliance and persistence among users of subcutaneous and sublingual allergen immunotherapy.

BACKGROUND: Subcutaneous allergen immunotherapy (SCIT) and sublingual allergen immunotherapy (SLIT) are safe and effective treatments of allergic rhinitis, but high levels of compliance and persistence are crucial to achieving the desired clinical effects. OBJECTIVE: Our objective was to assess levels and predictors of compliance and persistence among grass pollen, tree pollen, and house dust mite immunotherapy users in real life and to estimate the costs of premature discontinuation. METHODS: We performed a retrospective analysis of a community pharmacy database from The Netherlands containing data from 6486 patients starting immunotherapy for 1 or more of the allergens of interest between 1994 and 2009. Two thousand seven hundred ninety-six patients received SCIT, and 3690 received SLIT. Time to treatment discontinuation was analyzed and included Cox proportional hazard models with time-dependent covariates, where appropriate. RESULTS: Overall, only 18% of users reached the minimally required duration of treatment of 3 years (SCIT, 23%; SLIT, 7%). Median durations for SCIT and SLIT users were 1.7 and 0.6 years, respectively (P < .001). Other independent predictors of premature discontinuation were prescriber, with patients of general practitioners demonstrating longer persistence than those of allergologists and other medical specialists; single-allergen immunotherapy, lower socioeconomic status; and younger age. Of the persistent patients, 56% were never late in picking up their medication from the pharmacy. Direct medication costs per nonpersistent patient discontinuing in the third year of treatment were €3800, an amount that was largely misspent. CONCLUSION: Real-life persistence is better in SCIT users than in SLIT users, although it is low overall. There is an urgent need for further identification of potential barriers and measures that will enhance persistence and compliance.

Pollinex Quattro: an innovative four injections immunotherapy in allergic rhinitis.

The prevalence of seasonal allergic rhinitis in the western world is high and increasing. Besides considerably affecting physical and psychosocial aspects of patients' lives, allergic rhinitis is often associated with allergic asthma and may aggravate this condition over time. Specific immunotherapy is currently the only approved therapy that can modify the underlying disease process and induce long-term tolerance to allergens. Pollinex Quattro is a subcutaneous four injections immunotherapy consisting of tyrosine-absorbed specific allergoids and enhanced with the adjuvant monophosphoryl lipid A (MPL(®)). MPL(®) induces a significant Th 1-type immune response, characterized by an increase of allergen-specific IgG antibody levels and dampening of the IgE response during allergen exposure. Due to this dual action of stimulating the immune system, Pollinex Quattro is clinically effective after only four injections given pre-seasonally. A large clinical program has demonstrated efficacy and tolerability of Pollinex Quattro in children, adolescents and adults with grass and tree pollen allergy. A health economics study concluded that an immunotherapy with only 4 injections might be more cost-beneficial than other application forms of immunotherapy.

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.