Allergen immunotherapy practice in the United States: guidelines, measures, and outcomes

Clinical Practice Guideline: Immunotherapy for Inhalant Allergy

OBJECTIVE

Allergen immunotherapy (AIT) is the therapeutic exposure to an allergen or allergens selected by clinical assessment and allergy testing to decrease allergic symptoms and induce immunologic tolerance. Inhalant AIT is administered to millions of patients for allergic rhinitis (AR) and allergic asthma (AA) and is most commonly delivered as subcutaneous immunotherapy (SCIT) or sublingual immunotherapy (SLIT). Despite its widespread use, there is variability in the initiation and delivery of safe and effective immunotherapy, and there are opportunities for evidence-based recommendations for improved patient care.

PURPOSE

The purpose of this clinical practice guideline (CPG) is to identify quality improvement opportunities and provide clinicians trustworthy, evidence-based recommendations regarding the management of inhaled allergies with immunotherapy. Specific goals of the guideline are to optimize patient care, promote safe and effective therapy, reduce unjustified variations in care, and reduce the risk of harm. The target patients for the guideline are any individuals aged 5 years and older with AR, with or without AA, who are either candidates for immunotherapy or treated with immunotherapy for their inhalant allergies. The target audience is all clinicians involved in the administration of immunotherapy. This guideline is intended to focus on evidence-based quality improvement opportunities judged most important by the guideline development group (GDG). It is not intended to be a comprehensive, general guide regarding the management of inhaled allergies with immunotherapy. The statements in this guideline are not intended to limit or restrict care provided by clinicians based on their experience and assessment of individual patients.

ACTION STATEMENTS

The GDG made a strong recommendation that (Key Action Statement [KAS] 10) the clinician performing allergy skin testing or administering AIT must be able to diagnose and manage anaphylaxis. The GDG made recommendations for the following KASs: (KAS 1) Clinicians should offer or refer to a clinician who can offer immunotherapy for patients with AR with or without AA if their patients' symptoms are inadequately controlled with medical therapy, allergen avoidance, or both, or have a preference for immunomodulation. (KAS 2A) Clinicians should not initiate AIT for patients who are pregnant, have uncontrolled asthma, or are unable to tolerate injectable epinephrine. (KAS 3) Clinicians should evaluate the patient or refer the patient to a clinician who can evaluate for signs and symptoms of asthma before initiating AIT and for signs and symptoms of uncontrolled asthma before administering subsequent AIT. (KAS 4) Clinicians should educate patients who are immunotherapy candidates regarding the differences between SCIT and SLIT (aqueous and tablet) including risks, benefits, convenience, and costs. (KAS 5) Clinicians should educate patients about the potential benefits of AIT in (1) preventing new allergen sensitizations, (2) reducing the risk of developing AA, and (3) altering the natural history of the disease with continued benefit after discontinuation of therapy. (KAS 6) Clinicians who administer SLIT to patients with seasonal AR should offer pre- and co-seasonal immunotherapy. (KAS 7) Clinicians prescribing AIT should limit treatment to only those clinically relevant allergens that correlate with the patient's history and are confirmed by testing. (KAS 9) Clinicians administering AIT should continue escalation or maintenance dosing when patients have local reactions (LRs) to AIT. (KAS 11) Clinicians should avoid repeat allergy testing as an assessment of the efficacy of ongoing AIT unless there is a change in environmental exposures or a loss of control of symptoms. (KAS 12) For patients who are experiencing symptomatic control from AIT, clinicians should treat for a minimum duration of 3 years, with ongoing treatment duration based on patient response to treatment. The GDG offered the following KASs as options: (KAS 2B) Clinicians may choose not to initiate AIT for patients who use concomitant beta-blockers, have a history of anaphylaxis, have systemic immunosuppression, or have eosinophilic esophagitis (SLIT only). (KAS 8) Clinicians may treat polysensitized patients with a limited number of allergens.

The Art of Dosing for Subcutaneous Immunotherapy in North America

Subcutaneous immunotherapy (SCIT) is a long-established treatment option for allergic rhinoconjunctivitis. Proper dosing of the allergens is critical for the efficacy and safety of SCIT. Of the hundreds of liquid allergen extracts in the United States, effective and well-tolerated SCIT dosing has only been established for a small number. Thus, SCIT dosing remains largely empiric and continues to be, by necessity, an art. To highlight the complexity of SCIT dosing, this review summarizes the historical and current landscape of U.S. allergen extracts, differences among U.S. and European allergen extracts, allergen selection for SCIT, considerations for compounding of allergen extract mixtures, and recommended dosing. As of 2021, 18 standardized allergen extracts are available in the United States; all other extracts remain unstandardized without characterization of allergen content or potency. U.S. allergen extracts differ from European extracts in formulation and potency characterization. There is no standardized methodology for SCIT allergen selection, and interpretation of allergen sensitization is not straightforward. Compounding of SCIT mixtures requires consideration of potential dilution effects, allergen cross-reactivity, proteolytic activity, and additives. Probable effective dose ranges for SCIT are recommended in U.S. allergy immunotherapy practice parameters, although there are few studies using U.S. extracts supporting these doses as therapeutic. In contrast, optimized doses of sublingual immunotherapy tablets have been confirmed in North American phase 3 trials. The SCIT dosing for each patient remains an art that requires clinical experience and consideration of polysensitization, tolerability, compounding of allergen extract mixtures, and the range of recommended doses within the context of extract potency variability.

Recent Updates of Immunotherapy for Allergic Rhinitis in Children

Purpose of Review

Allergen immunotherapy (AIT) is a novel treatment approach with disease-modifying and preventative benefits that are not shared with other strategies for treating allergic illnesses. It has been demonstrated to be safe and effective in children. This review provides the most recent information on AIT in children as well as any pertinent updates.

Recent Findings

Although there is not a standard way to begin AIT, there are clear indications for AIT. Each case needs to be evaluated on its own by weighing the pros and downsides. AIT has been proven to significantly improve symptoms and quality of life in children with allergic illness, reduce medication use, stop the development of new allergen sensitizations, and stop the progression of allergic rhinitis to asthma. Novel approaches are under investigation to overcome some known AIT disadvantages.

Summary

This review provides a thorough summary of the most recent research and updates on AIT in children.

Essentials of allergen immunotherapy: A primer for the practitioner

It has been more than a decade since the most recent allergen immunotherapy (AIT) practice parameter was published and 5 years since a focused practice parameter on sublingual immunotherapy (SLIT) was issued. There is an unmet need, therefore, for a more up-to-date, concise summary of AIT to be published to provide allergy/immunology practitioners, allergy/immunology fellows-in-training, medical students, residents, and other health-care practitioners with the most current information available on AIT. The Allergen Immunotherapy Primer (AITP) is not intended to define a standard of care or to be inclusive of all proper methods of care, nor is it intended to replace or supplant established AIT practice parameters; rather, the goal of this AITP is to supplement the established practice parameters and to serve primarily as an updated tool for the practicing allergist/immunologist, allergy/immunology trainees, and health-care professionals seeking practical and concise information with regard to AIT. Primer topics include the history of AIT; descriptions of the mechanisms and biomarkers of subcutaneous immunotherapy (SCIT) and SLIT; the efficacy and safety of SCIT; the efficacy and safety of SLIT, pediatric SLIT, and SCIT; the long-term efficacy of SLIT and SCIT; long-term adherence strategies for AIT; the implications of real-world data for AIT; the role of AIT for asthma; patterns of cross-allergenicity among pollens; a practical implementation guide for optimized construction of AIT vaccines; standardization of allergen extracts; updated information on federal regulations about the United States Pharmacopeia and the compounding of allergenic extracts; an update on AIT venom immunotherapy; the advantages and disadvantages of accelerated immunotherapy regimens; the important role of shared decision-making in AIT and how it can be incorporated into the informed consent process; and a forecast of future directions in allergen immunotherapy.

Allergen Immunotherapy in Pediatric Respiratory Allergy

Purpose of Review

Atopic diseases such as asthma and allergic rhinitis are highly prevalent in children. Common triggers include tree and grass pollens, house dust mites, molds, and animal dander. These diseases are most often treated symptomatically; however, many patients show partial or poor response and require long-term medication use. Allergen immunotherapy (AIT) stands as the only treatment modality that can alter the underlying disease process and potentially offer a cure. In this review article, we discuss the merits of AIT with particular emphasis on its efficacy and safety in pediatric patients. We also discuss the challenges for AIT implementation and present an overview of current research that aims at improving its applicability for the treatment of allergic diseases.

Recent Findings

Subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) are both safe and efficacious treatment options in children with allergic rhinitis and allergic asthma. Additionally, AIT has efficacy in preventing the development of asthma in children. Although there are clear advantages with AIT, there are challenges to overcome to optimize treatment. Solutions include improved diagnostics with pre-treatment biomarkers and molecular multiplex assays, biomarkers for prediction of response (e.g., basophil activation markers), improved allergen immunogenicity with the use of recombinant AIT, adjuvants, and allergoids, and lastly improved safety with the concurrent use of omalizumab.

Summary

AIT has shown safety and efficacy in major clinical trials for the treatment of allergic rhinitis and allergic asthma in children. AIT provides a curative treatment option for atopic disorders and should be considered in children with allergic rhinitis and allergic asthma. There are many continued advances being made in the field of allergy to further improve the safety and efficacy profile and shorten the duration of AIT treatment.

Risk factors for fatal and nonfatal reactions to immunotherapy (2008-2018): postinjection monitoring and severe asthma

BACKGROUND

Subcutaneous allergen immunotherapy (SCIT) is highly effective but risks exist.

OBJECTIVE

To identify practices that influence systemic allergic reactions (SRs) to SCIT and SCIT-associated infections.

METHODS

Members of the American College of Allergy, Asthma and Immunology and the American Academy of Allergy, Asthma and Immunology completed an annual survey of SCIT-related SRs of varying severity (2008-2018). Injection-related infections were queried (2014-2018). Strategies to enforce postinjection waiting times and to reduce risks from asthma/severe asthma were queried (2016-2018).

RESULTS

Data were gathered on 64.5 million injection visits. Ten confirmed fatalities occurred since 2008, including 3 new fatalities since 2017. One fatal reaction occurred per 7.2 million injection visits (2008-2018). No infections occurred. Practices that tracked the time after injections, and required checking out with office personnel, had significantly lower total (P < .001), grade 3 (severe) (P < .001), and grade 4 (very severe) SRs (P < .001). Having more individuals with asthma on SCIT was associated with more grade 3 SRs (P < .02). Not prescribing SCIT in individuals with uncontrolled asthma was associated with fewer grade 3 SRs (P = .02). Having individuals with more severe asthma on SCIT was associated with more total, grade 1, and grade 2 SRs (P < .001); 50% of grade 3 and 4 SRs occurred in individuals with severe asthma.

CONCLUSION

SCIT-related fatalities have declined since 2008, with a slight increase in recent years. SCIT is not associated with an increased risk of infections. Tracking the time after injections and checking out with office staff confer significantly lower risks of severe SRs. Asthma, especially severe asthma, is a major risk factor for severe and fatal SRs. Strategies that reduce risks for individuals with asthma, such as not prescribing SCIT to patients with uncontrolled asthma, may lower the risks.

Perceptions and Management of Allergic Rhinitis Among Ecuadorian Otorhinolaryngologists: A Survey-Based Study

Objective

Allergic rhinitis (AR) represents a large burden to the healthcare system due to its high prevalence and impact on patients’ lives. Despite the existence of evidence-based guidelines, some studies have found that physicians do not always follow the latest recommendations. The aim of our study was to determine how Ecuadorian otorhinolaryngologists (ENTs) perceive some epidemiological aspects related to AR, as well as their preferences for managing the disease.

Methods

We conducted an observational, survey-based cross-sectional study, among 116 Ecuadorian ENTs. The survey used was adapted from a previous publication and consisted of 30 multiple choice questions, concerning several topics of AR. Descriptive statistics (frequency, and standard deviation) were performed for clinical and demographic variables.

Results

A total of 116 Ecuadorian ENTs completed the survey. Of them, 62.9% were male, with an average age of 42 years (SD ± 11.58). Computed tomography (CT) scan and nasal cytology were selected as the main diagnostic tests for AR by 62/91 (68.1%) and 45/91 (49.5%) of participants, respectively. Moreover, only 12/116 (10.3%) of participants performed skin prick tests (SPT). Allergen immunotherapy (AIT) was performed by 37/107 (36.4%) of participants.

Conclusion

In general, most participants agreed that the prevalence of AR appears to be increasing, with increased exposure to allergens, irritants, and pollutants as the main probable cause. Children and adolescents were accounted as the group most affected by AR, with sinusitis and asthma identified as the most frequent comorbidities. Finally, we found unmet needs in the diagnostic and management of AR that should be addressed among Ecuadorian ENTs, in particular the high use of CT scans as part of routine evaluations, as well as the low use of allergen immunotherapy.

Measurement of German cockroach allergens and their isoforms in allergen extracts with mass spectrometry

BACKGROUND

Allergen extracts are the primary tool for diagnosis and treatment of allergic diseases. In the United States, most allergen extracts are non-standardized. More sophisticated analytical approaches are needed to characterize these products and enable manufacturers and regulators to better determine potency.

OBJECTIVE

To expand the multiple reaction monitoring (MRM) assay for an in-depth characterization of German cockroach (GCr; Blattella germanica) allergen extracts.

METHODS

We applied advanced liquid chromatography (LC) and mass spectrometry (MS) techniques including MRM. The expanded LC/MRM-MS method was optimized to measure known GCr allergens and their isoforms/variants in commercial extracts and environmental samples. We performed isoform-specific allergen measurements in multiple extracts from four commercial sources and extracts prepared using environmental samples from urban homes. To investigate causes of heterogeneity, we examined over 30 extraction process variables.

RESULTS

Evaluation of the commercial extracts confirmed the variability of production lots and commercial sources. Commonly used defatting and extraction protocols yielded extracts with comparable allergen profiles and content. However, the identity and quality of source materials was a major contributor to variability. In comparing commercial GCr extracts to environmental samples, relative quantities of Bla g 1, Bla g 2, Bla g 3, Bla g 4 and Bla g 11 were similar, while Bla g 5, Bla g 6, Bla g 7 and Bla g 8 were present in the environmental samples but largely absent for the commercial extracts.

CONCLUSIONS AND CLINICAL RELEVANCE

LC/MRM-MS can be used to measure all known GCr allergens in commercial allergen extracts and environmental samples. Significant differences exist between allergen profiles of commercial extracts and the profiles of environmental samples from dwellings. This analytical platform can serve as a template to achieve better product characterization of similarly complex products.

EAACI Guidelines on Allergen Immunotherapy: House dust mite-driven allergic asthma

Allergen immunotherapy (AIT) has been in use for the treatment of allergic disease for more than 100 years. Asthma treatment relies mainly on corticosteroids and other controllers recommended to achieve and maintain asthma control, prevent exacerbations, and improve quality of life. AIT is underused in asthma, both in children and in adults. Notably, patients with allergic asthma not adequately controlled on pharmacotherapy (including biologics) represent an unmet health need. The European Academy of Allergy and Clinical Immunology has developed a clinical practice guideline providing evidence-based recommendations for the use of house dust mites (HDM) AIT as add-on treatment for HDM-driven allergic asthma. This guideline was developed by a multi-disciplinary working group using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. HDM AIT was separately evaluated by route of administration and children and adults: subcutaneous (SCIT) and sublingual AIT (SLIT), drops, and tablets. Recommendations were formulated for each. The important prerequisites for successful treatment with HDM AIT are (a) selection of patients most likely to respond to AIT and (b) use of allergen extracts and desensitization protocols of proven efficacy. To date, only AIT with HDM SLIT-tablet has demonstrated a robust effect in adults for critical end points (exacerbations, asthma control, and safety). Thus, it is recommended as an add-on to regular asthma therapy for adults with controlled or partially controlled HDM-driven allergic asthma (conditional recommendation, moderate-quality evidence). HDM SCIT is recommended for adults and children, and SLIT drops are recommended for children with controlled HDM-driven allergic asthma as the add-on to regular asthma therapy to decrease symptoms and medication needs (conditional recommendation, low-quality evidence).

Immunotherapy of house dust mite allergy

House dust mite (HDM) is a predominant source of indoor aeroallergen worldwide, which induces allergic diseases including allergic rhinoconjunctivitis, allergic asthma, atopic eczema and other allergic skin diseases. Allergen specific immunotherapy (AIT) is the only potential disease-modifying treatment of HDM allergic subjects. However, AIT remains underused due to no universally accepted allergen standardization and a shortage of rigorous clinical studies to confirm safety and efficacy. With the effort of doctors and researchers in allergy field, efficacy, safety, standardization and strategy of AIT are being continuously developed. This review presents the updated research based on recently published trials and meta-analyses.

Evolving patterns in the diagnosis and management of allergy-mediated disorders

BACKGROUND

This analysis explores the increasing heterogeneity of trends in allergy management under the premise that the practice of allergy has undergone significant changes in national economics, healthcare delivery, and treatment options from 2007 to 2016.

METHODS

Centers for Medicare and Medicaid Services (CMS) data were obtained for: (1) temporal trends in allergy immunotherapy injection (Current Procedural Terminology [CPT] codes 95115, 95117) and testing (CPT 95004, 95024) from 2007 to 2016; (2) geographic trends; and (3) practitioners administering immunotherapy. Although there are no sublingual immunotherapy (SLIT) CPT codes, billing for unlisted allergy/immunologic services (CPT 95199) were obtained.

RESULTS

Since 2007, there were 99.5 million allergy tests and 33.5 million immunotherapy injections billed to Medicare beneficiaries. Increases in testing have outpaced rising immunotherapy administration (49.7% vs 19.6% increase). Significant regional variation in testing rates was noted, with the greatest ratio of testing to immunotherapy in the South (0.35) and smallest ratio in the Northeast (0.18). The maximum unlisted allergy services billed was 594 (of which includes SLIT), compared to annual subcutaneous immunotherapy (SCIT) totals in the millions. The majority of immunotherapy in 2016 was administered by allergists/immunologists (51.6%) followed by otolaryngologists (31.2%), trends that have remained consistent since 2012.

CONCLUSION

Physicians have been more aggressive in the workup of allergy-mediated disorders in recent years. Although differences in allergen load exist, there is tremendous geographic variation in the ratio of testing to immunotherapy. While the role otolaryngologists play in immunotherapy remains stable, allergists manage the majority of patients, reinforcing the importance of interdisciplinary cooperation and outreach. SLIT does not appear to play a significant role in this population.

Long-term effect of monophosphoryl lipid A adjuvanted specific immunotherapy in patients with grass pollen allergy

BACKGROUND

Ultra-short course pollen immunotherapy adjuvanted with monophosphoryl lipid A (MPL) is attractive to conventional allergen-specific immunotherapy (AIT). Long term efficacy of MPL-AIT has not been evaluated.

METHODS

68 patients (age 16.75 ± 5.3 years) with allergic rhinitis to grass pollen were investigated. Group 1: 21 controls; Group 2: 19 after complete AIT, and Group 3: 28 with AIT and treatment cessation: 4 years range 3-6 years ago.

RESULTS

The clinical symptoms (running nose, sneezing, conjunctivitis and the weekly overall score) were significantly reduced in patients group 2 and 3 compared with controls without AIT p < 0.0001. T-regulatory cells and TH1/TH2 cytokine pattern did not differ between patient groups.

CONCLUSION

The patients in our trial with grass pollen allergy exhibited significant and long-lasting improvements after MPL-AIT, however larger trials are needed to support this finding.

Allergen immunotherapy for the treatment of respiratory allergies in the elderly

PURPOSE OF REVIEW

Respiratory allergies, including asthma and allergic rhinitis can also occur in the elderly. Allergen immunotherapy for allergic diseases is the only disease-modifying treatment for patients with allergies available thus far. Here, we review current evidence supporting the use of allergen immunotherapy in the elderly and discuss its efficacy and utility for the treatment of respiratory allergic diseases in this setting.

RECENT FINDINGS

Subcutaneous and/or sublingual immunotherapy are effective therapeutic options in not only young but also older patients. Allergen immunotherapy reduces medication and symptom scores in the elderly and can thus be safely prescribed in this population.

SUMMARY

Elderly individuals with proven, clinically relevant immunoglobulin E sensitization to inhalant allergens may benefit from allergen immunotherapy for respiratory allergic diseases. Older patients without contraindications should therefore be considered for treatment, with the additional benefit of reduced medication and symptom scores.

Safety considerations in providing allergen immunotherapy in the office

PURPOSE OF REVIEW

This review highlights the risks of allergy immunotherapy, methods to improve the quality and safety of allergy treatment, the current status of allergy quality metrics, and the future of quality measurement. In the current healthcare environment, the emphasis on outcomes measurement is increasing, and providers must be better equipped in the development, measurement, and reporting of safety and quality measures.

RECENT FINDINGS

Immunotherapy offers the only potential cure for allergic disease and asthma. Although well tolerated and effective, immunotherapy can be associated with serious consequence, including anaphylaxis and death. Many predisposing factors and errors that lead to serious systemic reactions are preventable, and the evaluation and implementation of quality measures are crucial to developing a safe immunotherapy practice. Although quality metrics for immunotherapy are in their infancy, they will become increasingly sophisticated, and providers will face increased pressure to deliver safe, high-quality, patient-centered, evidence-based, and efficient allergy care.

SUMMARY

The establishment of safety in the allergy office involves recognition of potential risk factors for anaphylaxis, the development and measurement of quality metrics, and changing systems-wide practices if needed. Quality improvement is a continuous process, and although national allergy-specific quality metrics do not yet exist, they are in development.

Molecular diagnosis and immunotherapy

PURPOSE OF REVIEW

To describe recent insights into how molecular diagnosis can improve indication and selection of suitable allergens for specific immunotherapy and increase the safety of this therapy.

RECENT FINDINGS

As specific allergen immunotherapy targets specific allergens, identification of the disease-eliciting allergen is a prerequisite for accurate prescription of treatment. In areas of complex sensitization to aeroallergens or in cases of hymenoptera venom allergy, the use of molecular diagnosis has demonstrated that it may lead to a change in indication and selection of allergens for immunotherapy in a large proportion of patients when compared with diagnosis based on skin prick testing and/or specific IgE determination with commercial extracts. These changes in immunotherapy prescription aided by molecular diagnosis have been demonstrated to be cost-effective in some scenarios. Certain patterns of sensitization to grass or olive pollen and bee allergens may identify patients with higher risk of adverse reaction during immunotherapy.

SUMMARY

Molecular diagnosis, when used with other tools and patients' clinical records, can help clinicians better to select the most appropriate patients and allergens for specific immunotherapy and, in some cases, predict the risk of adverse reactions. The pattern of sensitization to allergens could potentially predict the efficacy of allergen immunotherapy provided that these immunotherapy products contain a sufficient amount of these allergens. Nevertheless, multiplex assay remains a third-level approach, not to be used as screening method in current practice.

Changes in skin reactivity and associated factors in patients sensitized to house dust mites after 1 year of allergen-specific immunotherapy

Background

Allergen-specific immunotherapy (SIT) can significantly improve symptoms and reduce the need for symptomatic medication.

Objective

The aim of this study was to investigate changes in skin reactivity to house dust mites (HDMs) as an immunologic response and associated factors after 1 year of immunotherapy.

Methods

A total of 80 patients with allergic airway diseases who received subcutaneous SIT with HDMs from 2009 to 2014 were evaluated. The investigated parameters were basic demographic characteristics, skin reactivity and specific IgE for HDM, serum total IgE level, blood eosinophil counts, and medication score.

Results

The mean levels of skin reactivity to HDMs, blood eosinophil counts, and medication scores after 1 year were significantly reduced from baseline. In univariate comparison of the changes in skin reactivity to HDMs, age ≤30 years, HDMs only as target of immunotherapy, and high initial skin reactivity (≥2) to HDMs were significantly associated with the reduction in skin test reactivity. In multivariate analysis, high initial skin reactivity and HDMs only as target allergens were significantly associated with changes in skin reactivity to HDMs. In the receiver operating characteristic curve of the initial mean skin reactivity to HDMs for more than 50% reduction, the optimal cutoff value was 2.14.

Conclusion

This study showed significant reductions in allergen skin reactivity to HDMs after 1 year of immunotherapy in patients sensitized to HDMs. The extent of initial allergen skin reactivity and only HDMs as target allergen were important predictive factors for changes in skin reactivity.

Different Responses in Induction of Allergen Specific Immunoglobulin G4 and IgE-Blocking Factors for Three Mite Subcutaneous Immunotherapy Products

PURPOSE

Specific immunoglobulin G4 (sIgG4) and immunoglobulin E (IgE)-blocking factors produced by subcutaneous immunotherapy (SCIT) play a critical role in the induction of allergen tolerance. However, comparative studies of available SCIT reagents on the induction of sIgG4 are limited. We compared increases in sIgG4 for three different house dust mite (HDM) SCIT reagents.

MATERIALS AND METHODS

Seventy-two HDM sensitized allergic patients were enrolled and classified into four groups: 1) control (n=27), 2) SCIT with Hollister-Stier® (n=19), 3) Tyrosine S® (n=16), and 4) Novo-Helisen® (n=10). Levels of specific IgE (sIgE), sIgG4, and IgE blocking factor to Dermatophagoides farinae (D. farinae) were measured using ImmunoCAP (sIgE, sIgG4) and enzyme-linked immunosorbent assay (ELISA) (IgE-blocking factors). Levels were measured before and 13.9±6.6 months after the SCIT. The allergen specificity and the induction levels of sIgE and sIgG4 were confirmed by immunoblot analysis.

RESULTS

After SCIT, sIgG4 levels to D. farinae increased significantly; however, the increases differed significantly among the SCIT groups (p<0.001). Specific IgG4 levels to D. farinae were highest in Hollister-Stier® (3.7±4.1 mg/L), followed by Novo-Helisen® (2.2±2.3 mg/L) and Tyrosine S® (0.7±0.5 mg/L). In addition, patients who were administered using Hollister-Stier® showed the most significant decrease in IgE/IgG4 ratio (p<0.001) and increase in blocking factor (p=0.009). Finally, according to IgE immunoblot results, the Hollister-Stier® group showed the most significant attenuation of IgE binding patterns among others.

CONCLUSION

Currently available SCIT reagents induce different levels of specific IgG4, IgE/IgG4 ratio, and IgE-blocking factor.

Generation and purification of monoclonal antibodies against Der f 2, a major allergen from Dermatophagoides farinae

Monoclonal antibodies (mAbs) are needed for the quantitation of environmental allergens for precise diagnosis and immunotherapy. In this study, we produced and purified monoclonal antibodies against Der f 2, one of the major allergens of the house dust mite Dermatophagoides farina, in order to develop an assay for the detection of this allergen. BALB/c mice were immunized four times with the protein Der f 2 together with an adjuvant after which splenocytes were collected and fused with SP2/0 (myeloma cells) in the presence of polyethylene glycol (PEG). The fused cells were selected in the presence of Hypoxanthine-Aminopterin-Thymidine (HAT) and then Hypoxanthine-Thymidine (HT) medium. Positive cells were screened with ELISA and subcloned by limited dilution at least three times to achieve stable mAb-producing clones. Four stable mAb-producing clones were obtained. One clone with IgG1 isotype and another with IgG2b isotype were chosen to produce large amounts of mAb by inoculation of the cells into the abdominal cavity of mice. Ascites were collected and the mAbs were purified using protein A affinity chromatography. Testing of the ascites by ELISA showed the titration of IgG1 and IgG2b to be higher than 1/10(6) dilution. The specificity of both antibodies was confirmed by immunoblotting. Thus, we produced two mAb clones against Der f 2 that can be used to create a precise quantitative method to identify allergen components in dust samples and facilitate further study in Der f 2 component-resolved diagnosis (CRD).

Diagnosis and treatment of allergic diseases in Zhejiang Province: a cross-sectional survey

BACKGROUND

The specialty of allergy developed quickly in western countries because of the rapid increase of allergic diseases, whereas it developed relatively slowly in China. The prevalence of allergen sensitization and allergic diseases in Zhejiang Province of China is high and improving the medical services for these diseases is critically needed.

OBJECTIVE

To investigate the working status of the diagnosis and treatment of allergic diseases, including doctor resources, diagnostic methods, and allergen-specific immunotherapy in patients of Zhejiang Province, and to provide instructions for the strategic development of subspecialties of allergic diseases.

METHODS

First we defined the doctors who treat allergic diseases, and designed a comprehensive questionnaire to collect personal and hospital information for these doctors. The questionnaires were distributed to hospitals with different ranks and from different areas in the province. The general condition of doctor's resources, carryout of diagnostic methods, and allergen-specific immunotherapy were described and variations in the different specialties, hospitals, and areas were further analyzed.

RESULTS

Doctors in their thirties with bachelor's degrees were the mainstream for diagnosing and treating allergic diseases. The main specialties of the doctor resources were the specialties of Ear, Nose and Throat (ENT), Respirology, Pediatrics, and Dermatology. The Pediatrics specialty had a more reasonable infrastructure of doctor resources with more young doctors working in this subspecialty. The development of allergy subspecialty varied within hospitals at different levels or from different areas. The carryout of the skin prick test (SPT), serum specific IgE (ssIgE), and subcutaneous immunotherapy (SCIT) was best performed in provincial hospitals, while sublingual immunotherapy (SLIT) was prescribed most commonly in municipal hospitals. The performance of SPT and ssIgE in Hangzhou, Jiaxing, and Wenzhou areas was much better than that in other places. The performance of SCIT and SLIT was best in Wenzhou.

CONCLUSIONS

Our survey revealed a very initial and unbalanced development for the allergy subspecialty in Zhejiang Province. Doctor resources for allergic diseases were mainly from the specialties of ENT, Respirology, and Pediatrics, and the performance of diagnosis and treatment was mainly focused on provincial and municipal hospitals. Continuous education of allergies could be extended to primary healthcare centers and more efforts should be directed to those areas with poor medical resources.

Math-free guides for glycerin and allergens at variable subcutaneous injection volumes: How's my dosing? Update

BACKGROUND

Current summaries of effective maintenance dose ranges for subcutaneous immunotherapy (SCIT) are based on administration of 0.5-mL volumes. Extract formulations delivering equivalent dose ranges for practices using different injection volumes have not been reported, and calculation of the final glycerin concentrations in these solutions remains an inconvenient and repetitive process.

OBJECTIVE

To create math-free guides for allergen doses and glycerin concentrations that identify the extract concentrate volumes required to deliver doses within the ranges cited in the 2011 immunotherapy practice parameters for clinicians using 5.0-mL maintenance vials and injection volumes ranging from 0.2 to 1.0 mL.

METHODS

Algebraic calculations were performed to determine the specific combinations of extract concentrate strengths, volumes of these products in patient vaccines, and injection volumes needed for administration of target allergen doses spanning the current SCIT practice parameter recommendations.

RESULTS

For each product or group (nonstandardized extracts), tables were constructed to define the allergen doses provided by various combinations of extract concentrate volumes and injection volumes. The values within the effective dose ranges for each product were highlighted to facilitate comparisons of specific conditions relevant to allergy specialists. Glycerin tables were also created to permit convenient assessments of the final concentrations of this stabilizer in patient prescriptions.

CONCLUSION

SCIT dosing and glycerin tables are useful tools to assist allergists with practice decisions that involve variable patient formulas and injection volumes and can help identify suitable conditions for treatment of patients presenting with diverse allergen sensitivities and specificity profiles.

Pollen used to produce allergen extracts

OBJECTIVE

To review the use of pollen for the production of allergen extracts to diagnose and treat allergic diseases, examine the associated regulations, and highlight candidate areas for improvement.

DATA SOURCES

A PubMed search was performed using focused keywords combined with a review of regulatory documents and industry guidelines.

STUDY SELECTIONS

The information obtained through literature, documents, and industry was scrutinized and used with personal experience and expertise to write this article.

RESULTS

Both genetic and environmental factors affect the allergenic composition of pollen because it is a biologically active pharmaceutical ingredient obtained from nature. The potential effect of airborne contaminants in pollen requires major attention but can be properly addressed through careful collection practices, combined with a proper interpretation of the data on purity obtained for each pollen lot. The regulations associated with pollen used to manufacture allergen extracts in the United States and Europe and the numbers of pollen allergen extracts commercially available in both areas of the world differ. A critical parameter to select the appropriate extracts for diagnosis and allergen immunotherapy is to understand the phenomenon of cross-reactivity among pollen families, genera, and species.

CONCLUSION

Physicians should be aware of the factors responsible for the qualitative and quantitative composition of pollen allergen extracts and the associated regulations to produce suitable extracts to diagnose and treat allergic diseases. Collaboration and cooperation among allergen manufacturing companies and regulatory agencies are necessary.

Allergen stabilities and compatibilities in immunotherapy mixtures that contain cat, dog, dust mite, and cockroach extracts

BACKGROUND

Indoor allergen mixtures that contain cat, dog, dust mite, and cockroach extracts are commonly used in allergy clinics for subcutaneous immunotherapy, but product-specific stabilities and mixing compatibilities in these complex patient formulas have not been determined.

OBJECTIVES

To assess the recoveries of cat, dog epithelia, dog dander, dust mite Dermatophagoides farinae, and cockroach mix allergen activities in 5 component mixtures and 1:10 (vol/vol) dilutions stored for up to 12 months.

METHODS

Concentrated stock mixtures, 10-fold dilutions of these mixtures in human serum albumin-saline diluent, and analogous single-extract controls were analyzed for major allergen concentrations (cat Fel d 1, dog dander Can f 1) and multiallergen IgE-binding potencies (dog epithelia, D farinae, cockroach mix) after storage for 3, 6, 9, and 12 months at 2°C to 8°C.

RESULTS

The selected immunoassays were specific for individual target extracts in the 5-component mixtures and exhibited analytical sensitivities sufficient for evaluation of both the concentrated and diluted indoor allergen formulas. All control samples except diluted cockroach extract had near-complete stabilities during refrigerated storage. Mixtures that contained cat, dog epithelia, dog dander, and D farinae extracts exhibited favorable mixing compatibilities in 1:1 (vol/vol) concentrates (47.5% glycerin) and 1:10 (vol/vol) dilutions (4.75% glycerin), relative to corresponding control sample reactivities. Cockroach allergens in both 1:1 (vol/vol) and 1:10 (vol/vol) concentrations were stabilized significantly by mixing with the other 4 indoor allergen extracts.

CONCLUSION

Extracts in mixtures that contained 5 common sources of indoor allergens possess favorable stabilities and mixing compatibilities and support the practice of combining these products in the same patient treatment formulations for subcutaneous immunotherapy.

Immediate-type hypersensitivity drug reactions

Hypersensitivity reactions including anaphylaxis have been reported for nearly all classes of therapeutic reagents and these reactions can occur within minutes to hours of exposure. These reactions are unpredictable, not directly related to dose or the pharmacological action of the drug and have a relatively high mortality risk. This review will focus on the clinical presentation, immune mechanisms, diagnosis and prevention of the most serious form of immediate onset drug hypersensitivity reaction, anaphylaxis. The incidence of drug-induced anaphylaxis deaths appears to be increasing and our understanding of the multiple and complex reasons for the unpredictable nature of anaphylaxis to drugs is also expanding. This review highlights the importance of enhancing our understanding of the biology of the patient (i.e. immune response, genetics) as well as the pharmacology and chemistry of the drug when investigating, diagnosing and treating drug hypersensitivity. Misdiagnosis of drug hypersensitivity leads to substantial patient risk and cost. Although oral provocation is often considered the gold standard of diagnosis, it can pose a potential risk to the patient. There is an urgent need to improve and standardize diagnostic testing and desensitization protocols as other diagnostic tests currently available for assessment of immediate drug allergy are not highly predictive.

Current developments for improving efficacy of allergy vaccines

Allergic diseases are prevalent worldwide. Allergen immunotherapy (AIT) is a current treatment for allergy, leading to modification of the natural course of disease. Mechanisms of efficacy include Treg through release of IL-10 and TGF-β and specific IgG4 blocking antibodies. Subcutaneous and sublingual routes are popular, but uptake is limited by inconvenience and safety concerns. Inclusion criteria limit application to a small proportion of allergic patients. New forms of immunotherapy are being investigated for more efficacious, convenient and safer options with promising advances in recent years. The rationale of reducing vaccine allergenicity to increase safety while improving immunogenicity led to investigation of T-cell epitope-based peptides and recombinant allergen derivatives. Additionally, different routes of administration and adjuvants and adjunct therapies are being explored. This review discusses the current status of AIT and recent advances to improve clinical efficacy, safety and long-term immune tolerance.

Practical clinical approaches to the allergic rhinitis patient

BACKGROUND

Numerous treatment strategies are available for the treatment of allergic rhinitis (AR), including environmental controls, pharmacotherapy, immunotherapy, and surgery in appropriately selected patients. A stepwise algorithmic approach based on disease severity and persistence of symptoms is often advocated to effectively manage patients with AR.

METHODS

A review is provided of current evidence and guidelines for the management of AR. Practical clinical strategies to improve patient adherence to therapy and outcome are described.

RESULTS

Algorithms to manage AR are based on the severity and persistence of disease. A tailored strategy geared toward addressing symptoms that are most troublesome to the patient is beneficial, as is the assessment of comorbid conditions such as rhinosinusitis, asthma, and laryngopharyngeal reflux. Allergen-specific immunotherapy (AIT) is an underused treatment modality and patients with persistent AR should be considered candidates for desensitization, if appropriate. Assessment of patient outcome is important and the use of validated symptom surveys can provide an objective measure of quality of life.

CONCLUSION

A large armamentarium of treatment options is available to the otolaryngologist treating the patient with AR. A step-wise and tailored approach with equal attention dedicated to patient education and assessment of patient outcome can be helpful to improve efficacy of treatment.

Adherence with allergen immunotherapy labeling guidelines

BACKGROUND

Little is known about the adherence rate to allergen immunotherapy (AIT) labeling guidelines.

OBJECTIVE

To assess adherence to labeling guidelines of AIT Practice Parameter 2011 at University of Michigan Health Service.

METHODS

AIT vials of 320 patients who received their care at the University of Michigan Health Service were reviewed. Data collected looked at patient identifiers (PI), concentrations in volume/volume (v/v) format, color coding, allergen content, expiration date and instructions about AIT dosing, and systemic reaction treatment. Data were analyzed by using χ(2) test and the Fisher exact test and logistic regression.

RESULTS

Of 238 non-university formulated labels, 65% had 2 PIs, 62% had a v/v concentration, 41% had color coding, 71% had the content listed, and 100% had a recorded expiration date. Only 21% had all 5 recommended components. All 82 University vials had 5 components. Labels with 2 PIs were more likely to have a v/v concentration with its corresponding color coding (odds ratio [OR] 3.84 [95% CI, 1.9-7.7]; P < .001). Labels that specified the extract's content were more likely to be color coded or to have a v/v concentration listed (OR 6.3 [95% CI, 3.4-11.8]; P < .001). For all AIT vials, complete labels were significantly more likely to have a clear buildup schedule (OR 9.6 [95% CI, 4.2-23.2]; P < .001), dosing adjustment after a missed dose (OR 8.2 [95% CI, 3.4-19.8]; P < .001) or after a reaction (OR 13.7 [95% CI, 7.8-2.1]; P < .001), and clear systemic reaction treatment instructions (OR 9.7 [95% CI, 7.8-24.1]; P < .001).

CONCLUSION

Fewer than 25% of the nonuniversity prescribers adhered to AIT practice parameters 5 years after publication. Recording 2 PIs, the v/v concentration, or the color coding increased the likelihood of having a complete label. Complete label contents were associated with clear instructions about AIT dosing and reaction treatment and/or dose adjustments.

The safety of self-administered allergen immunotherapy during the buildup and maintenance phases

BACKGROUND

Self-administered allergen immunotherapy is considered controversial. We believe the implementation of a self-administration protocol characterized by patient preselection and a slow buildup phase is safe.

METHODS

We analyzed 23,614 patient records and associated immunotherapy injections for systemic reactions (SR) during a 1-year period (2011 to 2012). SRs were graded in accordance with the World Allergy Organization (WAO) criteria.

RESULTS

Thirty-seven SRs were reported for 23,614 patients who self-administered 2,021,600 injections yielding an annual SR rate of 0.16% (per patient) or 0.002% (per injection). Only 9 of 4643 pediatric (0.19%) and 28 of 18,971 adult patients (0.15%) experienced 1 or more SRs. No deaths (grade V SR) occurred. From 2009 through early 2014, over 90,000 patients received more than 10 million injections in accordance with the United Allergy Services (UAS) protocol without fatalities.

CONCLUSION

We believe this safety profile is due to a preselection of patients to exclude those with a high risk for adverse reactions and a slow immunotherapy buildup phase. In contrast, previous studies documented office-based SRs ranging from approximately 3% to greater than 14%. Thus, the UAS home-immunotherapy SR rate is significantly lower than office-based immunotherapy SR rates (p < 0.0001). The enhanced safety of this protocol results in a decreased frequency and severity of SRs. This safety report, derived from analyses of one of the largest patient cohorts studied, corroborates and expands the observations of previous studies of self-administered subcutaneous immunotherapy in a low-risk patient population by assessing self-administered allergen immunotherapy during the buildup and maintenance phases.

Mixing compatibilities of Aspergillus and American cockroach allergens with other high-protease fungal and insect extracts

BACKGROUND

Recent studies have shown that Alternaria and German cockroach allergens can be degraded by endogenous proteases from other insect and fungal extracts when combined for immunotherapy, but data supporting the compatibilities of other high-protease products in comparable mixtures have not been reported.

OBJECTIVE

To assess the stabilities and compatibilities of Aspergillus fumigatus and American cockroach allergens after mixing with protease-rich extracts from other insects or fungi at concentrations similar to those recommended for subcutaneous immunotherapy.

METHODS

Mixtures containing A fumigatus, American cockroach, and other fungal or insect extracts were evaluated by quantitative (enzyme-linked immunosorbent assays) and qualitative (immunoblotting) methods. Test mixtures and control samples at 10% to 50% glycerin concentrations were analyzed after storage for up to 12 months at 2°C to 8°C.

RESULTS

Moderate to high recoveries of Aspergillus extract activities were retained in control samples and extract mixtures under all conditions examined. American cockroach extract controls were partly degraded at 10% to 25% glycerin, and cockroach allergen compatibilities were decreased significantly in mixtures with several fungal extracts at 25% glycerin. Mixing with other insects did not compromise the stability of American cockroach allergens at 25% to 50% glycerin.

CONCLUSION

Aspergillus extracts exhibited favorable stabilities after mixing with other high-protease products. American cockroach extract potencies were unstable in less than 50% glycerin, even in the absence of other protease-containing allergens, and were destabilized in mixtures with several fungal extracts. Addition of fungal and insect extracts to separate treatment vials or preparation of fungal-insect mixtures at elevated glycerin concentrations might be necessary to produce compatible patient formulations for allergen immunotherapy injections.

In vitro evaluation of allergen potencies of commercial house dust mite sublingual immunotherapy reagents

Purpose

The clinical efficacy of allergen-immunotherapy is known to be dose dependent. However, optimal maintenance dosage has not yet been determined for sublingual immunotherapy (SLIT). Furthermore, since companies adopt their own units for expression of allergenicity, the allergen concentrations of individual reagents cannot be compared easily. We sought to measure and compare the allergenicities of 3 commercially available house dust mite (HDM) SLIT regents and a subcutaneous immunotherapy reagent.

Methods

We measured the HDM allergenic potency of the maintenance dosages of three SLIT reagents: Staloral® (300 index of reactivity [IR] /mL, recommended maintenance dosage [MD]: 120 IR), SLITone® (1,000 standard therapeutic unit [STU]/mL, recommended MD: 200 STU), Wolwopharma® (100 µg/mL, recommended MD: 20 µg), and subcutaneous immunotherapy regents of Hollister-Stier (10,000 allergy unit [AU] /mL). The allergenic potency was assessed by measuring the total protein concentrations, mite group 1 and 2 allergens using 2-site ELISA, and an inhibition test against IgE specific to Dermatophagoides farinae and Dermatophagoides pteronyssinus.

Results

The protein content of the Wolwopharma® reagent was 1.5-261.4 times higher than that of the other 2 SLIT reagents. The concentration of group 1 major allergens in Staloral® (132.03 µg/mL) was 33- to 44.5-fold higher than in SLITone® (4.00 µg/mL) and Wolwopharma® (2.97 µg/mL). The concentration of group 2 major allergen was also 8.9- to 10.5-fold higher in Staloral® (15.7 µg/mL) than in SLITone® (1.8 µg/mL) or Wolwopharma® (1.5 µg/mL). An ELISA inhibition study against HDM-specific IgE showed that the allergen potency of Staloral® reagent is 8.5-fold and 21-fold higher than that of SLITone® or Wolwopharma®, respectively. The differences between the maintenance dosages are further exaggerated by the differences in the recommended volumes of SLIT reagents.

Conclusions

The allergen potencies of commercially available HDM SLIT reagents are markedly different. Consensus regarding the optimal allergen concentration for SLIT reagents used to treat HDM respiratory allergies is needed.

[Personalised medicine for the diagnosis and treatment of allergic diseases]

Immunoglobulin E (IgE) mediated allergic diseases are characterised by heterogeneous clinical phenotypes and a large variety of different sensitisation patterns. Apart from genetic predisposition several environmental factors play a role in sensitisation and elicitation of symptoms. Since the majority of clinically relevant allergens are now available as purified recombinant allergens component-resolved in vitro diagnosis allows the sensitization profile of allergic patients to be determined at the molecular level. Such data may allow physicians to draw conclusions on the severity and persistence of a given allergic disease and to predict the outcome of allergen-specific immunotherapy (SIT) However, the potential of this approach needs to be demonstrated in controlled clinical trials. Moreover, in the context of atopic dermatitis, allergic rhinitis, allergic bronchial asthma as well as the atopic march several screening-biomarkers, diagnostic and prognostic biomarkers, biomarkers of severity and predictive biomarkers are presented and discussed in this article. Traditionally a relevant proportion of allergen-specific immunotherapies is performed in a personalised manner using named patient products manufactured on the basis of an individual prescription. Such named patient products are often mixtures containing several allergen extracts from different sources. However, there is no proven evidence for the safety and efficacy of this approach. In Germany the Therapy Allergen Ordinance ("Therapieallergene-Verordnung", TAV) regulates that in the future allergen products for SIT of insect venom allergies, allergies to pollen of early flowering trees and grass pollen and house dust mite allergies cannot be marketed as named patient products, but always require a marketing authorisation. Thus personalised SIT with named patient products is restricted to the treatment of less prevalent allergies, for which the generation of state-of-the-art clinical data is more difficult. Several recombinant allergens are currently evaluated in phase III clinical trials. In contrast to allergen extracts recombinant allergens offer the possibility to treat patients with a precisely adjusted mixture of the disease-eliciting allergen molecules. However, the implementation of this personalised approach to SIT within the given regulatory framework represents a challenge to regulators.

Defining quality metrics and improving safety and outcome in allergy care

BACKGROUND

The delivery of allergy immunotherapy in the otolaryngology office is variable and lacks standardization. Quality metrics encompasses the measurement of factors associated with good patient-centered care. These factors have yet to be defined in the delivery of allergy immunotherapy. We developed and applied quality metrics to 6 allergy practices affiliated with an academic otolaryngic allergy center.

METHODS

This work was conducted at a tertiary academic center providing care to over 1500 patients. We evaluated methods and variability between 6 sites. Tracking of errors and anaphylaxis was initiated across all sites. A nationwide survey of academic and private allergists was used to collect data on current practice and use of quality metrics.

RESULTS

The most common types of errors recorded were patient identification errors (n = 4), followed by vial mixing errors (n = 3), and dosing errors (n = 2). There were 7 episodes of anaphylaxis of which 2 were secondary to dosing errors for a rate of 0.01% or 1 in every 10,000 injection visits/year. Site visits showed that 86% of key safety measures were followed. Analysis of nationwide survey responses revealed that quality metrics are still not well defined by either medical or otolaryngic allergy practices. Academic practices were statistically more likely to use quality metrics (p = 0.021) and perform systems reviews and audits in comparison to private practices (p = 0.005).

CONCLUSION

Quality metrics in allergy delivery can help improve safety and quality care. These metrics need to be further defined by otolaryngic allergists in the changing health care environment.

Allergen-specific immunotherapy in asthmatic children: from the basis to clinical applications

Atopic asthma in childhood with the tendency to persist into adult life is an important issue in pediatrics. Allergen-specific immunotherapy (SIT) is the only curative treatment option for these children, being directed to the causes of the disease. The Th2 phenotype is a predominant immunological pattern in atopic asthma and SIT leads to apoptosis/anergy of T cells and induces immune-regulatory responses and immune deviation towards Th1. Many factors can affect the safety and efficacy of SIT, such as pattern of sensitization, allergy vaccine (allergen extracts, adjuvants and conjugated molecules), route of administration (subcutaneous or sublingual) and different treatment schedules. Overall, asthma symptoms and medication scores usually decrease following a SIT course and the most common observed side effects are restricted to local swelling, erythema and pruritus. Compared with conventional pharmacotherapy, SIT may be more cost effective, providing a benefit after discontinuation and a steroid-sparing effect. In addition, it can prevent new sensitizations in monosensitized asthmatic children. Microbial supplements such as probiotics, immunomodulatory substances like anti-IgE/leukotrienes, antibodies and newer allergen preparations such as recombinant forms have been tested to improve the efficacy and safety of SIT with inconclusive results. In conclusion, SIT provides an appropriate solution for childhood asthma that should be employed more often in clinical practice. Further studies are awaited to improve current knowledge regarding the mechanisms behind SIT and determine the most appropriate materials and schedule of immunotherapy for children with asthma.

Immunotherapy preparation guidelines, rules, and regulation

Allergen immunotherapy has been used to treat allergic diseases for more than 100 years. In the U.S., the preparation of diagnostic and therapeutic extracts requires the cooperation of the extract manufacturer, who provides the individual allergen concentrates, and the practicing physician who formulates, dilutes, and administers the final patient-specific treatment extract. The guidelines, rules, and regulations for these activities have been established and continue to be developed as progress is made. The molecular characterization and standardization of allergenic extracts has allowed for improvements in defining the potency of these products. In turn, these advances have led to improved dosing regimens and formulation practices. This review will describe in detail some of these interactions and will identify issues that require more attention.

Allergen immunotherapy extract treatment set preparation: making a safer and higher quality product for patients

The best possible allergen immunotherapy clinical outcomes require the provision of high quality and safe allergen immunotherapy extract preparations. Evolving national guidelines and regulatory bodies have devoted special attention to the safe compounding of sterile products, including allergen extracts. It is incumbent upon allergists preparing extract treatment sets for patients to be familiar with and adopt training, procedures and safety measures that lead to standardized high quality products. Preparers and supervisors must maintain ongoing competency in aseptic technique and prescribing principles, such as probable effective dose ranges, allergen cross-reactivity, and separation of high protease-containing extracts from susceptible extracts. Accordingly, knowledge and application of vial labeling, diluent selection, standard operating procedures, mixing log documentation, and mixing condition principles are a necessity. Although there have been no instances of infectious complications from allergen immunotherapy in a century of clinical practice, continued vigilance in the use of measures that ensure extract sterility is paramount. A review of allergen immunotherapy preparation recommendations and best practices based on published national guidelines is presented. Further study of preparation measures and prescribing principles will continue to advance the practice of allergen immunotherapy and offer opportunities for refinement of current recommendations.

Cross-reaction and co-sensitization among related and unrelated allergens in canine intradermal tests

BACKGROUND

Intradermal tests are used to identify allergens for avoidance and immunotherapy in atopic dogs.

HYPOTHESIS/OBJECTIVES

To evaluate cross-reaction or co-sensitization among 53 intradermal test allergens.

ANIMALS

Six hundred and fifty-one client-owned dogs with atopic dermatitis.

METHODS

Intradermal tests were performed with 53 house dust/storage mite, epidermal, insect, tree, weed and grass pollen and mould allergens. Pairwise comparisons were used to calculate the odds ratios (ORs), 95% confidence intervals (CIs) and statistical significance for the results of each allergen pair, with significance at P < 0.0006 (Holm-Bonferroni correction to reduce the false-detection rate).

RESULTS

Apart from cotton, cockroach, red clover, grain smut and Penicillium, the results for the allergens within each group were statistically associated [ORs from 4.7 (CI 2.5-8.9) to 1229.4 (CI 166.5-1795.1); P = 0.0005 to P < 0.0001]. Excluding red clover and cotton, 94% of results between tree, weed and grass pollens were also statistically associated [ORs from 8.3 (CI 3.6-24.7) to 117 (CI 29.1-341); P = 0.0005 to P < 0.0001]. In contrast, few allergens from unrelated groups were statistically associated [ORs from 0.12 (CI 0.03-1.1) to 27.7 (CI 0.2-93); P = 1.0 to P < 0.0001]. The mean (SD) of the log e transformed ORs for the related and statistically associated allergens [5.3 (1.3)] was significantly greater than those for related but nonstatistically associated [1.7 (1.6)] or unrelated allergens [1.4 (1.4); P < 0.0001].

CONCLUSIONS AND CLINICAL IMPORTANCE

This suggests that there is cross-reaction or co-sensitization between related allergens. This could have implications for allergen selection in testing and immunotherapy, but further studies are required to differentiate cross-reaction from co-sensitization.

Assessment of specific immunotherapy efficacy using a novel placebo score-based method

BACKGROUND

In trials of allergen immunotherapy, allergen exposure is typically assessed by pollen counts, but these may misrepresent exposure if performed remotely from multiple study centers.

OBJECTIVE

To assess whether symptomatology in placebo-treated patients is a better measure of local allergen burden at individual centers in such trials.

METHODS

Data from a multicenter, placebo-controlled trial of preseasonal grass pollen immunotherapy were reanalyzed to identify the 4 weeks at each center in which the placebo-treated subjects had the highest combined symptom/medication scores (CSMS). The difference in CSMS between active and placebo groups was compared during the 4 peak placebo score weeks (PlSW) and the 4 peak pollen count weeks (PoCW).

RESULTS

The benefit of immunotherapy over placebo in the PlSW analysis (18.5%) was greater than in the PoCW analysis (13.6%), with increased statistical significance (P = .0001, .0038, respectively). Similar improved discrimination was observed when analyzing benefits in subgroups of patients with severe symptoms, a high disease burden, and in different geographical locations.

CONCLUSION

This novel PlSW analysis results in better discrimination of the effects of allergen immunotherapy compared with placebo and may be widely applicable in similar studies, both prospectively and retrospectively.

Correlation of Der p 2 T-cell responses with clinical characteristics of children allergic to house dust mite

BACKGROUND

An understanding of the mechanisms responsible for the development and maintenance of allergic inflammation and their clinical implications is needed to develop specific and successful treatment for allergy.

OBJECTIVES

To characterize in vitro T-cell responses to Der p 2, one of the major allergens of house dust mite (HDM), and investigate potential correlations between clinical and laboratory parameters.

METHODS

Forty-two patients monosensitized to HDM and 10 age-matched, healthy children were studied. Dendritic cells pulsed with Der p 2 were used to stimulate autologous CD14(-) cells. Der p 2-specific T-cell activation markers, proliferation, and cytokine production profiles were examined.

RESULTS

Der p 2-specific T-cell activation markers, proliferation, and T(H)2 cytokine production were significantly higher in HDM patients compared with healthy controls. Moreover, a significant correlation between proliferation and T(H)2 cytokine production was observed. Within the allergic group, skin reaction to HDM was significantly stronger in patients with a Der p 2-specific T-cell response. Levels of HDM-specific IgE directly correlated with interleukin 5 and interleukin 13 levels and with skin prick test results and, ultimately, with the patient's family history of allergy. Furthermore, the presence of atopic march correlated with T-cell proliferation.

CONCLUSION

We found that, in HDM patients, Der p 2-specific T(H)2 responses, promoted by autologous dendritic cells in vitro, correlate with clinical parameters.