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We review the history of the classification and coding changes for anaphylaxis and provide current and perspective information in the field. In 2012, an analysis of Brazilian data demonstrated undernotification of anaphylaxis-related deaths because of the difficulties of coding using the International Classification of Diseases, 10th Revision. This work triggered strategic international actions supported by the Joint Allergy Academies and the International Classification of Diseases World Health Organization (WHO) leadership to update the classification of allergic disorders for the International Classification of Diseases, 11th Revision (ICD-11), which resulted in construction of the pioneer "Allergic and hypersensitivity conditions" chapter. The usability of the new framework has been tested by evaluating the same data published in 2012 from the ICD-11 perspective. Coding accuracy was much improved, reaching 95% for definite anaphylaxis. As the results were provided to the WHO Mortality Reference Group, coding rules have been changed, allowing anaphylaxis to be recorded as an underlying cause of death in official mortality statistics. The mandatory use of ICD-11 from January 2022 for documenting cause of death could have 2 immediate consequences: (1) the reported number of anaphylaxis-related deaths might increase because of more appropriate coding and (2) the cross-sectional and longitudinal mortality data generated might ultimately lead to a better understanding of anaphylaxis epidemiology and improved health policies directed at reducing anaphylaxis-related mortality., (Copyright © 2019 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Background: Food allergy is an important public health problem because it affects children and adults, can be severe and even life-threatening, and may be increasing in prevalence. Beginning in 2008, the National Institute of Allergy and Infectious Diseases, working with other organizations and advocacy groups, led the development of the first clinical guidelines for the diagnosis and management of food allergy. A recent landmark clinical trial and other emerging data suggest that peanut allergy can be prevented through introduction of peanut-containing foods beginning in infancy., Objectives: Prompted by these findings, along with 25 professional organizations, federal agencies, and patient advocacy groups, the National Institute of Allergy and Infectious Diseases facilitated development of addendum guidelines to specifically address the prevention of peanut allergy., Results: The addendum provides 3 separate guidelines for infants at various risk levels for the development of peanut allergy and is intended for use by a wide variety of health care providers. Topics addressed include the definition of risk categories, appropriate use of testing (specific IgE measurement, skin prick tests, and oral food challenges), and the timing and approaches for introduction of peanut-containing foods in the health care provider's office or at home. The addendum guidelines provide the background, rationale, and strength of evidence for each recommendation., Conclusions: Guidelines have been developed for early introduction of peanut-containing foods into the diets of infants at various risk levels for peanut allergy., (Published by Elsevier Inc.)

Background: Hypereosinophilic syndromes (HESs) are chronic disorders that require long-term therapy to suppress eosinophilia and clinical manifestations. Corticosteroids are usually effective, yet many patients become corticosteroid refractory or develop corticosteroid toxicity. Mepolizumab, a humanized monoclonal anti-IL-5 antibody, showed corticosteroid-sparing effects in a double-blind, placebo-controlled study of FIP1L1/PDGFRA-negative, corticosteroid-responsive subjects with HESs., Objective: We evaluated long-term safety and efficacy of mepolizumab (750 mg) in HES., Methods: MHE100901 is an open-label extension study. The primary end point was the frequency of adverse events (AEs). Optimal dosing frequency, corticosteroid-sparing effect of mepolizumab, and development of antimepolizumab antibodies were also explored., Results: Seventy-eight subjects received 1 to 66 mepolizumab infusions each (including mepolizumab infusions received in the placebo-controlled trial). Mean exposure was 251 weeks (range, 4-302 weeks). The most common dosing interval was 9 to 12 weeks. The incidence of AEs was 932 events per 100 subject-years in the first year, declining to 461 events per 100 subject-years after 48 months. Serious AEs, including 1 death, were reported by the investigator as possibly due to mepolizumab in 3 subjects. The median daily prednisone dose decreased from 20.0 to 0 mg in the first 24 weeks. The median average daily dose for all subjects over the course of the study was 1.8 mg. Sixty-two percent of subjects were prednisone free without other HES medications for ≥ 12 consecutive weeks. No neutralizing antibodies were detected. Twenty-four subjects withdrew before study completion for death (n = 4), lack of efficacy (n = 6), or other reasons., Conclusion: Mepolizumab was well tolerated and effective as a long-term corticosteroid-sparing agent in PDGFRA-negative HES., (Published by Mosby, Inc.)

Because of advances in our understanding of the hypereosinophilic syndrome (HES) and the availability of novel therapeutic agents, the original criteria defining these disorders are becoming increasingly problematic. Here, we discuss shortcomings with the current definition of HES and recent developments in the classification of these disorders. Despite significant progress in our understanding of the pathogenesis of some forms of HES, the current state of knowledge is still insufficient to formulate a new comprehensive etiologic definition of HESs. Nevertheless, we suggest a new working definition that overcomes some of the most obvious limitations with the original definition.

Background: Although inhaled corticosteroids (ICSs) generally protect against severe exacerbations in asthma, they may result in elevated IgE levels, which are associated with exacerbations., Objective: To determine whether variation in the low-affinity IgE receptor gene, FCER2, is associated with severe exacerbations defined as emergency department visits and/or hospitalizations in patients with asthma on ICSs., Methods: We resequenced, then genotyped 10 FCER2 single nucleotide polymorphisms (SNPs) in 311 children randomized to inhaled budesonide as part of the Childhood Asthma Management Program. We evaluated the association of FCER2 variants with IgE levels and presence or absence of severe exacerbations over the 4-year clinical trial. We also evaluated differences in cellular expression of the novel FCER2 SNP, T2206C., Results: In white subjects, 3 FCER2 SNPs were significantly associated (P < .05) with elevated 4-year IgE level; each was also associated with increased severe exacerbations. Final multivariable models demonstrated associations between T2206C and severe exacerbations in both white and African American children (hazard ratio, 3.95; 95% CI, 1.64-9.51; and hazard ratio, 3.08; 95% CI, 1.00-9.47), despite ICS use. Interaction models supported a true gene-environment effect in white subjects (interaction P = .004). T2206C was also associated with decreased FCER2 expression (P = .02)., Conclusion: FCER2 predicts the likelihood of treatment protocol success in asthma. The associations of T2206C with IgE level, severe exacerbations, and FCER2 expression may provide a mechanistic basis for the observed findings., Clinical Implications: Genetic variation in FCER2 may help form a prognostic model for ICS response in asthma.

Risk assessment of individuals with anaphylaxis is currently hampered by lack of (1) an optimal and readily available laboratory test to confirm the clinical diagnosis of an anaphylaxis episode and (2) an optimal method of distinguishing allergen-sensitized individuals who are clinically tolerant from those at risk for anaphylaxis episodes after exposure to the relevant allergen. Our objectives were to review the effector mechanisms involved in the pathophysiology of anaphylaxis; to explore the possibility of developing an optimal laboratory test to confirm the diagnosis of an anaphylaxis episode, and the possibility of improving methods to distinguish allergen sensitization from clinical reactivity; and to develop a research agenda for risk assessment in anaphylaxis. Researchers from the American Academy of Allergy, Asthma & Immunology and the European Academy of Allergology and Clinical Immunology held a PRACTALL (Practical Allergy) meeting to discuss these objectives. New approaches being investigated to support the clinical diagnosis of anaphylaxis include serial measurements of total tryptase in serum during an anaphylaxis episode, and measurement of baseline total tryptase levels after the episode. Greater availability of the test for mature beta-tryptase, a more specific mast cell activation marker for anaphylaxis than total tryptase, is needed. Measurement of chymase, mast cell carboxypeptidase A3, platelet-activating factor, and other mast cell products may prove to be useful. Consideration should be given to measuring a panel of mediators from mast cells and basophils. New approaches being investigated to help distinguish sensitized individuals at minimum or no risk from those at increased risk of developing anaphylaxis include measurement of the ratio of allergen-specific IgE to total IgE, determination of IgE directed at specific allergenic epitopes, measurement of basophil activation markers by using flow cytometry, and assessment of allergen-specific cytokine responses. Algorithms have been developed for risk assessment of individuals with anaphylaxis, along with a research agenda for studies that could lead to an improved ability to confirm the clinical diagnosis of anaphylaxis and to identify allergen-sensitized individuals who are at increased risk of anaphylaxis.

Background: Placebos are hypothesized to exert positive effects on medical conditions by enhancing patient expectancies. Recent reviews suggest that placebo benefits are restricted to subjective responses, like pain, but might be ineffective for objective physiologic outcomes. Nevertheless, mind-body links and placebo responsivity in asthma are widely believed to exist., Objective: We carried out a randomized, double-blind investigation to (1) determine whether placebo can suppress airway hyperreactivity in asthmatic subjects, (2) quantify the placebo effect, (3) identify predictors of the placebo response, and (4) determine whether physician interventions modify the placebo response., Methods: In a double-blind, crossover design investigation, 55 subjects with mild intermittent and persistent asthma with stable airway hyperreactivity were randomized to placebo or salmeterol before serial methacholine challenges. Subjects were additionally randomized to physician interactions that communicated either positive or neutral expectancies regarding drug effect., Results: Placebo bronchodilator administration significantly reduced bronchial hyperreactivity compared with baseline (the calculated concentration of methacholine required to induce a 20% decrease in FEV(1) nearly doubled); 18% of subjects were placebo responders by using conservative definitions. Experimental manipulation of physician behavior altered perceptions of the physician but not the magnitude or frequency of the placebo response., Conclusions: Objective placebo effects exist in asthma. These responses are of significant magnitude and likely to be meaningful clinically. The placebo response was not modulated by alterations in physician behavior in this study., Clinical Implications: The placebo response in patients with asthma is important in understanding the limitations of clinical research studies and in maximizing safe and effective therapies. This article confirms the existence of a strong placebo response in an objective and clinically relevant measure of disease activity.

Background: CD23 plays a role in the regulation of IgE production and allergy-induced immune and inflammatory responses. A novel anti-CD23 monoclonal antibody, lumiliximab, is a potential therapeutic antibody recently demonstrated to be safe in human beings., Objective: This study investigated the effects of lumiliximab on allergen-induced immune responses from atopic subjects compared with blocking HLA-DR and costimulatory molecules, CD80 and CD86., Methods: Allergen-stimulated PBMCs from atopic subjects were pretreated with lumiliximab or antibodies to CD80, CD86, and HLA-DR. Cultures were analyzed for cell proliferation and IL-1beta, TNF-alpha, and IL-5 cytokine secretion. An allergen-specific T-cell line was developed and analyzed for lymphocyte proliferation in response to allergen with or without lumiliximab. Lumiliximab's effect on CD86 expression was evaluated by flow cytometry in the U937 monocytic cell line., Results: Lumiliximab reduced allergen-induced PBMC proliferation by 50% (n = 6; P = .006). In addition, cultures pretreated with lumiliximab had a reduction in the proinflammatory cytokines IL-1beta (P < .003) and TNF-alpha (P = .05) and the T(H)2 cytokine IL-5 (P = .002). Blocking CD86 resulted in greater reduction in proliferation than lumiliximab (P = .003) but similar effects in cytokine secretion. The anti-CD80 blocking antibody had no effect on cytokine production but did reduce proliferation. Furthermore, the addition of lumiliximab to cytokine stimulated U937 cells reduced surface expression of CD86 (P = .012)., Conclusion: These results indicate that the anti-CD23 mAb, lumiliximab, may be involved in modulating antigen presenting cells and reducing TH2-type immune responses. The use of this antibody may provide clinical benefit for treating allergic diseases.

Background: The immunologic response to allergen immunotherapy with 3 serial 5-fold doses of cat extract has been studied after approximately 5 weeks of immunotherapy. The highest dose containing 15 mug of Fel d 1 produced the most consistent and favorable response. It is unknown whether the comparative response on reaching a maintenance dose is maintained with long-term maintenance therapy., Objective: The purpose of this investigation was to evaluate the immunologic responses with these 3 serial doses of cat hair and dander extract at baseline, after reaching the maintenance dose (approximately 5 weeks), and after 1 year of maintenance immunotherapy., Methods: Twenty-eight patients with cat allergy randomized in a double-blind study were assigned to one of 4 treatment groups: placebo or cat hair and dander extract containing 0.6 mug of Fel d 1, 3 mug of Fel d 1, and 15 mug of Fel d 1 at maintenance. Studies included skin prick tests and late cutaneous reactions with cat hair and dander extract, titrated nasal challenges with the extract, serum cat allergen-specific IgG4 and IgE measurement, and flow cytometric and ELISA analysis of whole blood and intranasal cytokines (TGF-beta, IL-10, IFN-gamma, IL-4, and IL-5)., Results: Twenty-six subjects completed the study. After both 5 weeks and 1 year, significant and dose-dependent differences were seen with total symptom scores on nasal challenge ( P < .0001), with titrated skin prick testing with cat dander extract at 5 weeks ( P = .014) and 1 year ( P < .0001), and with cat-specific IgG4 measurement at 5 weeks ( P = .004) and 1 year ( P = .003). At 1 year, neither flow cytometry of whole blood nor ELISA evaluation of nasal cytokines demonstrated any significant differences among the treatment groups., Conclusion: The response to titrated nasal allergen challenge, titrated skin prick testing, and allergen-specific IgG4 measurement to cat immunotherapy at 5 weeks is predictive of the response at 1 year.

Background: Beta-blocker therapy postmyocardial infarction is generally recommended because it reduces mortality. However, beta-blockers may increase anaphylaxis mortality in the growing population of patients with peanut-induced anaphylaxis., Objective: We sought to assess the risks and benefits of beta-blocker therapy among patients with peanut allergy and heart disease., Methods: We created a Markov model for patients with heart disease at risk for peanut-induced anaphylaxis to compare life expectancy with the following strategies: (1) beta-blocker and (2) no beta-blocker. Meta-analysis and a literature review were used to estimate model parameters. We performed sensitivity analysis to explore parameter uncertainty., Results: For peanut-allergic patients who are postmyocardial infarction or who have congestive heart failure, the heart disease benefit of beta-blockers outweighs the increased likelihood of dying from anaphylaxis, increasing life expectancy by 9.4 and 17.4 months, respectively. Beta-blocker was preferred unless (1) the annual rate of moderate to severe anaphylaxis exceeded 6.0% for postmyocardial infarction and 15% for congestive heart failure patients; (2) beta-blocker therapy increased the incidence of moderate to severe anaphylaxis >2.5-fold for postmyocardial infarction and >5.8-fold for congestive heart failure patients; (3) anaphylaxis case fatality exceeded 6.5% postmyocardial infarction; or (4) beta-blocker therapy increased anaphylaxis case fatality >25-fold postmyocardial infarction., Conclusion: Our results suggest that for patients postmyocardial infarction or with congestive heart failure who are at risk for peanut-induced anaphylaxis, beta-blocker use should still improve survival. However, the epidemiology of anaphylaxis and effects of beta-blocker therapy on anaphylaxis incidence and mortality require further study.

Background: CD23, a cell-surface molecule, is involved in a variety of pathways likely to influence IgE production and inflammation in allergic disorders, such as allergic rhinitis and allergic asthma., Objective: This study investigated the safety, clinical activity, and pharmacokinetic profile of IDEC-152, an IgG1 anti-CD23 antibody, in patients with mild-to-moderate persistent allergic asthma., Methods: This single-dose, dose-escalating, placebo-controlled study involved 30 patients. Cohorts of 3 to 6 patients received single intravenous infusions of either placebo or IDEC-152 (0.05, 0.25, 1.0, 4.0, 10.0, or 15.0 mg/kg) on study day 1. Safety, clinical activity, and pharmacokinetics were assessed for 12 weeks after treatment., Results: IDEC-152 was well tolerated. Adverse events (AEs) were mild, no grade 4 or serious AEs were reported, and no relationships were apparent between the dose of IDEC-152 and the frequency, severity, or type of event. The most common AEs in the IDEC-152 group included ecchymosis at the injection site, sinusitis, headache, arthralgia, cold syndrome, infection, throat irritation, and dysmenorrhea. Commonly reported AEs in the placebo group included headache, abdominal pain, and infection. Sustained and dose-dependent decreases in mean IgE concentrations were noted. The mean maximum concentration and area under the curve of IDEC-152 were proportional to the dose administered for the dose range 4.0 to 15.0 mg/kg. The serum half-life of the IDEC-152 antibody increased from 2 to 10 days with increasing doses. After single-dose administration of IDEC-152, no dose-dependent change in FEV(1) was observed, and most changes in peak expiratory flow rate were within 10% of baseline values., Conclusion: These data suggest that IDEC-152 is safe and has the potential for clinical activity in allergic asthma.

Airway inflammation is a key factor in the mechanisms of asthma. Articles published in the Journal of Allergy and Clinical Immunology this past year have highlighted the utility of investigative bronchoscopy with segmental antigen challenge and induced sputum analyses to evaluate features of airway inflammation in relationship to asthma severity. Peripheral blood cell generation of cytokines IFN-gamma (T(H)1) and IL-5 (T(H)2) was used to evaluate the relationship of the balance of T(H)1/T(H)2 cytokines to asthma persistence and severity in a 42-year, longitudinal study. Chemokines, including thymus and activation-regulated chemokine, are important to the regulation of inflammation and IgE synthesis. Their potential role in asthma has also been evaluated. Finally, albuterol (R)- and (S)-enantiomers may have distinct effects on airway relaxation and regulation of inflammation, suggesting the possibility that monoisomeric therapy has therapeutic advantages. The potential contribution of genetic factors and mechanisms to airway inflammation and remodeling also continues to be an area of intense investigation. During the past year a number of articles published in the Journal of Allergy and Clinical Immunology have identified and clarified potential genetic mechanisms in asthma. The contribution of genetics to asthma has been examined in a wide variety of studies, ranging from epidemiologic association and twin studies all the way to molecular analysis through microarray gene expression experiments.

Genetics provides the basis for the host response to a variety of environmental factors that can play a role in the generation of complex genetic diseases, such as asthma and atopy. An understanding of the genetic bases for these conditions is therefore essential to understand their pathophysiology. Studies of the genetics of asthma and atopy have suffered from several daunting challenges. These include the recognition that these are conditions caused by numerous genes, with each gene assuming variable roles in different individuals. In addition, each gene presumably contributes only a small percentage to a given individual's genetic risk of asthma. This has led to the current situation, in which studies often demonstrate a lack of replication that can be explained by their being insufficiently powered. Furthermore, the pathophysiologies of asthma and atopy are incompletely understood, and the lack of clearly defined phenotypes also contributes to the inadequacies of the current literature. Nonetheless, regions of the human genome have been reproducibly associated with asthma and atopy. These regions have undergone intense study, and many genetic variants within them have been implicated as asthma and allergy genes. In addition, through candidate gene approaches, several genetic polymorphisms have been convincingly linked to increased risks for the development of asthma and atopy. Many of these genes are associated with alterations in responsiveness to therapeutic agents used in the treatment of these conditions. These genetic studies have an exciting potential for individually tailoring the therapeutic regimen to a given subject's genotype. It is to be hoped that they will also define new targets for the next generation of asthma and allergy therapeutic agents.

The pulmonary vasculitides are a group of rare but serious disorders that require early recognition, accurate diagnosis, and effective therapy. Churg-Strauss syndrome (CSS) is classified as small vessel vasculitis. Four different definitions for the diagnosis of CSS have been developed: (1) the pathologic criteria put forth by Churg and Strauss, (2) the criteria based on clinical grounds from Lanham and colleagues, (3) the criteria based on clinical grounds from the American College of Rheumatology, and (4) the criteria from the Chapel Hill Consensus Conference, which closely concur with the Churg and Strauss definition. It is apparent that cessation, diminution, or even a switch from low-dose systemic to inhaled corticosteroid therapy can precipitate the appearance of CSS. The term forme fruste has been used to indicate that the signs and symptoms of CSS were (inadvertently) suppressed by cortico-steroids. The clinical risk factors for CSS are moderately severe or severe asthma, chronic sinusitis, or reductions in systemic corticosteroid therapy. Differential diagnosis, treatment, and ongoing monitoring of CSS therapeutic responses are reviewed. The introduction of leukotriene modifiers and high-potency inhaled corticosteroids have allowed control of asthma symptoms, which results in avoidance or reduction in oral corticosteroid use. The advent of these agents has been associated with reports of CSS appearing in patients with asthma. The available data regarding the association of CSS and antiasthma agents are most consistent with the unmasking of a previously contained pathologic condition (forme-fruste CSS) or disease that progresses because systemic corticosteroids were avoided. Early recognition and immunosuppressive therapy are the keystones of successful treatment of this rare disorder.