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Peanut allergy can result in severe, sometimes fatal hypersensitivity reactions that place a considerable burden on the lives of patients. This article reviews the first approved immunotherapy for the mitigation of allergic reactions following accidental peanut exposure, peanut (This article highlights the unmet need for patients with peanut allergy, describes the therapeutic landscape, and reviews the development of and clinical data for PTAH.PTAH offers a standardized preparation of peanut allergen, with a tolerability and efficacy profile clearly defined through its robust clinical development and trial program. In children 4-17 years old, PTAH provides a standardized, approved product that many clinicians sought prior to initiating oral immunotherapy. PTAH reduced the likelihood of more severe reactions following exposure to peanut protein; although peanut avoidance remains essential, PTAH will enable more individuals with peanut allergy to participate in activities of daily life with less anxiety.Peanut allergy is a serious, potentially fatal condition. It often starts in childhood, and the only treatment used to be emergency medicine after contact with peanuts. Children are recommended to avoid any contact with peanuts or products made with peanuts, which can be difficult and stressful, especially in social situations such as school.A treatment called oral immunotherapy, based on very small amounts of protein from peanut, was developed to help the body get used to coming into contact with peanuts without a dangerous reaction. PTAH (Peanut [

BACKGROUND: Rhinovirus frequently causes asthma exacerbations among children and young adults who are allergic. The interaction between allergen and rhinovirus-induced symptoms and inflammation over time is unclear. OBJECTIVE: Our aim was to compare the response to an experimental inoculation with rhinovirus-16 in allergic asthmatics with the response in healthy controls and to evaluate the effects of administrating omalizumab before and during the infection. METHODS: Two clinical trials were run in parallel. In one of these trials, the response to an experimental inoculation with rhinovirus-16 among asthmatics with high levels of total IgE was compared to the response in healthy controls. The other trial compared the effects of administering omalizumab versus placebo to asthmatics in a randomized, double-blind placebo-controlled investigation. The primary outcome for both trials compared lower respiratory tract symptoms (LRTSs) between study groups over the first 4 days of infection. RESULTS: Frequent comparisons of symptoms, lung function, and blood eosinophil counts revealed differences that were more pronounced among allergic asthmatics than among controls by days 2 and 3 after virus inoculation. Additionally, an augmentation of upper respiratory tract symptom scores and LRTS scores occurred among the atopic asthmatics versus the controls during the resolution of symptoms (P < .01 for upper respiratory symptom tract scores and P < .001 for LRTS scores). The beneficial effects of administering omalizumab on reducing LRTSs and improving lung function were strongest over the first 4 days. CONCLUSIONS: LRTSs and blood eosinophil counts were augmented and lung function was reduced among allergic asthmatics early after rhinovirus inoculation but increased late in the infection during symptom resolution. The effect of administering omalizumab on the response to rhinovirus was most pronounced during the early/innate phase of the infection.

Background Relative enlargement of the pulmonary artery (PA) on chest CT imaging is associated with respiratory exacerbations in patients with COPD or cystic fibrosis. We sought to determine whether similar findings were present in patients with asthma and whether these findings were explained by differences in ventricular size. Methods We measured the PA and aorta diameters in 233 individuals from the Severe Asthma Research Program III cohort. We also estimated right, left, and total epicardial cardiac ventricular volume indices (eERVVI, eELVVI, and eETVVI, respectively). Associations between the cardiac and PA measures (PA-to-aorta [PA/A] ratio, eERVVI-to-eELVVI [eRV/eLV] ratio, eERVVI, eELVVI, eETVVI) and clinical measures of asthma severity were assessed by Pearson correlation, and associations with asthma severity and exacerbation rate were evaluated by multivariable linear and zero-inflated negative binomial regression. Results Asthma severity was associated with smaller ventricular volumes. For example, those with severe asthma had 36.1 mL/m2 smaller eETVVI than healthy control subjects (P = .003) and 14.1 mL/m2 smaller eETVVI than those with mild/moderate disease (P = .011). Smaller ventricular volumes were also associated with a higher rate of asthma exacerbations, both retrospectively and prospectively. For example, those with an eETVVI less than the median had a 57% higher rate of exacerbations during follow-up than those with eETVVI greater than the median (P = .020). Neither PA/A nor eRV/eLV was associated with asthma severity or exacerbations. Conclusions In patients with asthma, smaller cardiac ventricular size may be associated with more severe disease and a higher rate of asthma exacerbations. Trial Registry ClinicalTrials.gov; No.: NCT01761630; URL: www.clinicaltrials.gov

Regulator of G protein signaling (RGS) 2 terminates bronchoconstrictive Gαq signaling; murine RGS2 knockout demonstrate airway hyperresponsiveness. While RGS2 promoter variants rs2746071 and rs2746072 associate with a clinical mild asthma phenotype, their impact on human airway smooth muscle (HASM) contractility and asthma severity outcomes is unknown.We sought to determine whether reductions in RGS2 expression seen with these 2 RGS2 promoter variants augment HASM contractility and associate with an asthma severity phenotype.We transfected HASM with a range of RGS2-specific small interfering RNA (siRNA) concentrations and determined RGS2 protein expression by Western blot analysis and intracellular calcium flux induced by histamine (a Gαq-coupled H1 receptor bronchoconstrictive agonist). We conducted regression-based genotype association analyses of RGS2 variants from 611 patients from the National Heart, Lung, and Blood Institute Severe Asthma Research Program 3.RGS2-specific siRNA caused dose-dependent increases in histamine-stimulated bronchoconstrictive intracellular calcium signaling (2-way ANOVA, P .0001) with a concomitant decrease in RGS2 protein expression. RGS2-specific siRNA did not affect Gαq-independent ionomycin-induced intracellular calcium signaling (P = .42). The minor allele frequency of rs2746071 and rs2746072 was 0.46 and 0.28 among African American/non-Hispanic Black patients and was 0.28 and 0.27 among non-Hispanic White patients, among whom these single nucleotide polymorphisms were in stronger linkage disequilibrium (rRGS2 promoter variation associates with a molecular and clinical phenotype characterized by enhanced bronchoconstrictive stimulation in vitro and higher asthma exacerbations rates in non-Hispanic White patients.

Background Although pre-puberty asthma is more prevalent in males, after puberty through middle-age, asthma is more prevalent in females. The surge of sex hormones with puberty might explain this gender switch. Methods To examine the effects of sex hormones on lung function and symptoms with puberty, Tanner stage was assessed in 187 children 6–18 years of age (59% severe) enrolled in the NIH/NHLBI Severe Asthma Research Program (SARP). The effects of circulating sex hormones (n = 68; testosterone, dehydroepiandrosterone sulfate (DHEA-S), estrogen, and progesterone) on lung function and 4 week symptom control (ACQ6) in cross-section were tested by linear regression. Results From pre−/early to late puberty, lung function did not change significantly but ACQ6 scores improved in males with severe asthma. By contrast females had lower post-BD FEV1% and FVC% and worse ACQ6 scores with late puberty assessed by breast development. In males log DHEA-S levels, which increased by Tanner stage, associated positively with pre- and post-BD FEV1%, pre-BD FVC %, and negatively (improved) with ACQ6. Patients treated with high-dose inhaled corticosteroids had similar levels of circulating DHEA-S. In females, estradiol levels increased by Tanner stage, and associated negatively with pre-BD FEV1% and FVC %. Conclusions These results support beneficial effects of androgens on lung function and symptom control and weak deleterious effects of estradiol on lung function in children with asthma. Longitudinal data are necessary to confirm these cross-sectional findings and to further elucidate hormonal mechanisms informing sex differences in asthma features with puberty. Trial registration ClinicalTrials.gov registration number: NCT01748175. Electronic supplementary material The online version of this article (10.1186/s12890-018-0612-x) contains supplementary material, which is available to authorized users.

This article presents an overview of future uses for biologic therapies in the treatment of immunologic and allergic conditions. Discussion is centered on the use of existing therapies outside of their current indication or on new therapies that are close to approval. This information may help familiarize practicing allergists and immunologists with therapies they may soon encounter in their practice as well as help identify conditions and treatments that will require further study in the near future.

Background The effect of age on asthma severity is poorly understood. Objectives The objective of this study was to compare the baseline features of severe and nonsevere asthma in the Severe Asthma Research Program (SARP) III cohort, and examine in cross section the effects of age on those features. Methods SARP III is a National Institutes of Health/National Heart Lung Blood Institute multisite 3-year cohort study conducted to investigate mechanisms of severe asthma. The sample included 188 children (111 severe, 77 nonsevere) and 526 adults (313 severe, 213 nonsevere) characterized for demographic features, symptoms, health care utilization, lung function, and inflammatory markers compared by age and severity. Results Compared with children with nonsevere asthma, children with severe asthma had more symptoms and more historical exacerbations, but no difference in body weight, post-bronchodilator lung function, or inflammatory markers. After childhood, and increasing with age, the cohort had a higher proportion of women, less allergen sensitization, and overall fewer blood eosinophils. Enrollment of participants with severe asthma was highest in middle-aged adults, who were older, more obese, with greater airflow limitation and higher blood eosinophils, but less allergen sensitization than adults with nonsevere asthma. Conclusions The phenotypic features of asthma differ by severity and with advancing age. With advancing age, patients with severe asthma are more obese, have greater airflow limitation, less allergen sensitization, and variable type 2 inflammation. Novel mechanisms besides type 2 inflammatory pathways may inform the severe asthma phenotype with advancing age.

In this review, we examine the current understanding of the pathogenesis, clinical presentations, diagnostic tools, and treatment options of pediatric mastocytosis as well as the natural history of the disease. We discuss the emerging concept of mast cell activation syndrome. Mastocytosis in children presents most commonly as isolated cutaneous lesions and is a relatively rare occurrence with excellent prognosis and spontaneous regression often occurring by adolescence. Systemic mastocytosis with organ system involvement is a more serious condition and is likely to persist into adulthood.

It has been shown recently that MCs are required for differential regulation of the immune response by granulocytic versus monocytic MDSCs. Granulocytic MDSCs promoted parasite clearance, whereas monocytic MDSCs enhanced tumor progression; both activities were abrogated in MC-deficient mice. Herein, we demonstrate that the lack of MCs also influences MDSC trafficking. Preferential trafficking to the liver was not seen in MC-deficient mice. In addition, evidence that the MC mediator histamine was important in MDSC trafficking and activation is also shown. MDSCs express HR1–3. Blockade of these receptors by HR1 or HR2 antagonists reversed the histamine enhancement of MDSC survival and proliferation observed in cell culture. In addition, histamine differentially influenced Arg1 and iNOS gene expression in MDSCs and greatly enhanced IL-4 and IL-13 message, especially in granulocytic MDSCs. Evidence that histamine influenced activity seen in vitro translated to in vivo when HR1 and HR2 antagonists blocked the effect of MDSCs on parasite expulsion and tumor metastasis. All of these data support the MDSC-mediated promotion of Th2 immunity, leading to the suggestion that allergic-prone individuals would have elevated MDSC levels. This was directly demonstrated by looking at the relative MDSC levels in allergic versus control patients. Monocytic MDSCs trended higher, whereas granulocytic MDSCs were increased significantly in allergic patients. Taken together, our studies indicate that MCs and MC-released histamine are critical for MDSC-mediated immune regulation, and this interaction should be taken into consideration for therapeutic interventions that target MDSCs.

S Lee, A Peterson, CM Lohse, EP Hess, RL Campbell. J Allergy Clin Immunol Pract. 2017;5(5):1295–1301 To evaluate variables to help in the identification of patients who are at an increased risk for biphasic anaphylactic reactions in the emergency department (ED). The study included 807 patients in the ED with a total of 872 ED visits for anaphylaxis. The median age was 34 years, with 58% female patients and 26% pediatric subjects

Reducing asthma exacerbation frequency is an important criterion for approval of asthma therapies, but the clinical features of exacerbation-prone asthma (EPA) remain incompletely defined.To describe the clinical, physiologic, inflammatory, and comorbidity factors associated with EPA.Baseline data from the NHLBI Severe Asthma Research Program (SARP)-3 were analyzed. An exacerbation was defined as a burst of systemic corticosteroids lasting 3 days or more. Patients were classified by their number of exacerbations in the past year: none, few (one to two), or exacerbation prone (≥3). Replication of a multivariable model was performed with data from the SARP-1 + 2 cohort.Of 709 subjects in the SARP-3 cohort, 294 (41%) had no exacerbations and 173 (24%) were exacerbation prone in the prior year. Several factors normally associated with severity (asthma duration, age, sex, race, and socioeconomic status) did not associate with exacerbation frequency in SARP-3; bronchodilator responsiveness also discriminated exacerbation proneness from asthma severity. In the SARP-3 multivariable model, blood eosinophils, body mass index, and bronchodilator responsiveness were positively associated with exacerbation frequency (rate ratios [95% confidence interval], 1.6 [1.2-2.1] for every log unit of eosinophils, 1.3 [1.1-1.4] for every 10 body mass index units, and 1.2 [1.1-1.4] for every 10% increase in bronchodilatory responsiveness). Chronic sinusitis and gastroesophageal reflux were also associated with exacerbation frequency (1.7 [1.4-2.1] and 1.6 [1.3-2.0]), even after adjustment for multiple factors. These effects were replicated in the SARP-1 + 2 multivariable model.EPA may be a distinct susceptibility phenotype with implications for the targeting of exacerbation prevention strategies. Clinical trial registered with www.clinicaltrials.gov (NCT 01760915).

RS Gupta, MM Walkner, M Greenhawt. J Allergy Clin Immunol Pract. 2016;4(5):956–962 To determine the prevalence of food sensitization and clinical food allergy among siblings of food-allergic children. Children were enrolled as part of the Chicago Family Cohort Food Allergy study. Eligible families had 1 index child with confirmed food allergy and at least 1 sibling participating in the study. There were 478 food-allergic children and 642 siblings. Of index children, 63.6% were male, and 50% were between the ages of 2 and 5 years. Of siblings, 66.5% were younger than the index child. A structured questionnaire-based interview was performed with each parent. Serum IgE (sIgE) values for 9 common food allergens …

SM van Dijk, H Gardarsdottir, M Wassenburg. J Allergy Clin Immunol Pract. 2016;4(5):926–931 To assess the impact of a diagnosis of penicillin allergy in hospitalized patients. The study included all patients (children and adults) admitted at the University Medical Center in Utrecht, the Netherlands, over a 1-year period who underwent a standardized pharmacotherapeutic interview. There were 997 patients with documentation of penicillin allergy (Pen-A) and 2939 patients without documentation of penicillin allergy (non–Pen-A). This was a prospective, matched cohort study. Patients were registered as having penicillin allergy if the history demonstrated either an evaluation by …

Pediatric asthma remains a significant burden upon patients, families, and the healthcare system. Despite the availability of evidence-based best practice asthma management guidelines for over a decade, published studies suggest that many primary care physicians do not follow them. This article describes the Provider Quality Improvement (PQI) intervention with six diverse community-based practices. A pediatrician and a nurse practitioner conducted the year-long intervention, which was part of a larger CDC-funded project, using problem-based learning within an academic detailing model. Process and outcome assessments included (1) pre- and post-intervention chart reviews to assess eight indicators of quality care, (2) post-intervention staff questionnaires to assess contact with the intervention team and awareness of practice changes, and (3) individual semi-structured interviews with physician and nurse champions in five of the six practices. The chart review indicated that all six practices met predefined performance improvement criteria for at least four of eight indicators of quality care, with two practices meeting improvement criteria for all eight indicators. The response rate for the staff questionnaires was high (72%) and generally consistent across practices, demonstrating high staff awareness of the intervention team, the practice "asthma champions," and changes in practice patterns. In the semi-structured interviews, several respondents attributed the intervention's acceptability and success to the expertise of the PQI team and expressed the belief that sustaining changes would be critically dependent on continued contact with the team. Despite significant limitations, this study demonstrated that interventions that are responsive to individual practice cultures can successfully change practice patterns.

Mast cells have long been recognized for their role in immediate hypersensitivity reactions, by virtue of the presence of high affinity receptors for IgE (FcepsilonRI) on their surface. More recently, mast cells have been postulated to be involved in a variety of chronic inflammatory disorders as numerous mediators released by activated mast cells are characterized. This article summarizes current information on mast cell mediators, heterogeneity, and differentiation, and it reviews studies of mast cells in the normal eye and various ocular disorders.

Anaphylaxis prevalence has increased within the last few years. This may be due to a marked increase in allergic sensitization to foods especially in the pediatric population, as well as to an increase in outdoor recreational habits and the availability of new biologic medications. Furthermore, guidelines for the diagnosis of anaphylaxis have been published, thus facilitating the recognition of this disorder. Diagnosis of anaphylaxis is mainly based on history and clinical criteria of organ system involvement. The serum tryptase assay is now commercially available and may be a helpful diagnostic tool in certain clinical situations involving hypotension, but not in the context of food-induced anaphylaxis. Treatment of anaphylaxis mainly involves the use of epinephrine as a first line medication for severe manifestations followed by symptomatic management of specific symptoms, such as antihistamines for urticaria and albuterol for wheezing. Although commonly practiced, treatment with systemic corticosteroids is not supported by evidence-based literature. Observation in a medical facility for 4-6 hours is recommended to monitor for late phase reactions, although these rarely occur. Education is an essential component of management of a patient with a previous history of anaphylaxis, emphasizing early use of epinephrine and providing a written action plan. Referral to a board-certified allergist/immunologist is recommended to determine the cause of the anaphylaxis as well as to rule out other potential conditions. In this review, our main focus will be on the treatment and prevention of anaphylaxis while providing our readers with a brief introduction to the diagnosis of anaphylaxis, its prevalence and its most common causes.

Anaphylaxis prevalence has increased within the last few years. This may be due to a marked increase in allergic sensitization to foods especially in the pediatric population, as well as to an increase in outdoor recreational habits and the availability of new biologic medications. Furthermore, guidelines for the diagnosis of anaphylaxis have been published, thus facilitating the recognition of this disorder. Diagnosis of anaphylaxis is mainly based on history and clinical criteria of organ system involvement. The serum tryptase assay is now commercially available and may be a helpful diagnostic tool in certain clinical situations involving hypotension, but not in the context of food-induced anaphylaxis. Treatment of anaphylaxis mainly involves the use of epinephrine as a first line medication for severe manifestations followed by symptomatic management of specific symptoms, such as antihistamines for urticaria and albuterol for wheezing. Although commonly practiced, treatment with systemic corticosteroids is not supported by evidence-based literature. Observation in a medical facility for 4-6 hours is recommended to monitor for late phase reactions, although these rarely occur. Education is an essential component of management of a patient with a previous history of anaphylaxis, emphasizing early use of epinephrine and providing a written action plan. Referral to a board-certified allergist/immunologist is recommended to determine the cause of the anaphylaxis as well as to rule out other potential conditions. In this review, our main focus will be on the treatment and prevention of anaphylaxis while providing our readers with a brief introduction to the diagnosis of anaphylaxis, its prevalence and its most common causes.

Objective To characterize uterine mast cells and investigate uterine muscle strips contractile responses to challenge with an allergen in nonpregnant and pregnant women. Study design A double-antibody labeling technique was used to identify tryptase positive or chymase-tryptase–positive mast cells in uterine samples from term pregnant and nonpregnant women. Longitudinal myometrial strips were prepared from biopsies of hysterectomy specimens from patients undergoing procedures for benign indications and women who had elective cesarean sections. Responses to ragweed antigen were compared in uterine tissues from allergic and nonallergic patients and with passively sensitized tissues in the absence or presence of H 1 receptor antagonist and a cyclooxygenase inhibitor. Results Tryptase-chymase–positive mast cells were predominant in nonpregnant myometrium, whereas tryptase-positive cells were dominant in pregnant myometrium. Mast cell density was significantly higher in tissue from pregnant women than those of nonpregnant women. Studies in tissues from patients with known allergy to ragweed, as well as in passively sensitized tissues, showed an immediate and substantial increase in the frequency and force of myometrial contraction after a challenge with ragweed antigen. A similar response was observed to histamine. There was no contractile response to antigen challenge in tissues from nonallergic patients. An H 1 receptor antagonist partially inhibited the response to antigen, whereas a cyclooxygenase inhibitor had no effect. Conclusion Sensitized isolated pregnant and nonpregnant human uterine tissue is capable of responding to antigen challenge with strong myometrial contractions. This ability, along with the increased density of mast cells in pregnant tissues as compared with nonpregnant tissues, indicates a possible role for mast cells in mediating uterine contractility in pregnancy.

Uncontrolled asthma in children can result in significant morbidity, activity limitations, and financial burden. Current National Asthma Education and Prevention Program asthma management guidelines recommend that all children with persistent asthma receive longterm inhaled corticosteroids (ICSs) controller therapy. Other controller medications, such as cromolyn and nedocromil, are less effective alternatives to ICSs in children with persistent asthma. Although comparative studies need to be conducted in children, the results of several adult studies suggest that ICSs are more effective than leukotriene modifiers as longterm controller monotherapy in patients with moderate to severe persistent asthma. Early ICS intervention is important in children with persistent asthma, as the greatest losses in lung function typically occur in the early stage of disease. Once initiated, ICS therapy should be administered on a regular basis, because discontinuing ICS use may result in increased asthma symptoms, asthma e...

Objective To review the current data and treatment options for mild persistent asthma. Data Sources A MEDLINE search was performed for relevant articles. Study Selection The expert opinion of the author was used to select studies for inclusion in this review. Results Current data suggest that asthma severity is determined early in life and that disease progression may not occur outside early childhood. Furthermore, no therapy has been demonstrated to clearly prevent or reverse structural airway changes in patients with persistent asthma. Thus, the primary goal of asthma therapy is to prevent disease exacerbations rather than to halt disease progress, at least in patients past early childhood. Published reports of severe exacerbations in patients with reported mild asthma may actually reflect inclusion of patients with more severe forms of the disease who were inappropriately classified in terms of asthma severity. Conclusion Unlike the case for moderate and severe asthma, where regular therapy with inhaled corticosteroids is clearly the treatment of choice, clear guidelines for treating patients with mild persistent asthma have not been established. Patients with mild disease without severe exacerbations may require only the minimum therapy necessary for disease control.

Background The initial 12-week, double-blind phases of three studies demonstrated that budesonide inhalation suspension (BIS) is effective and well tolerated in infants and young children (6 months to 8 years of age) with persistent asthma. Objective Open-label, 52-week extensions to these studies were conducted to evaluate long-term safety of BIS, including effects of treatment with the lowest effective dose of BIS on hypothalamic-pituitary-adrenal (HPA)-axis function, as compared with conventional asthma therapy (CAT). Complete results of the earlier phases of the studies and of long-term safety are reported elsewhere; only results pertaining to HPA-axis function are summarized here. Methods Patients eligible for the open-label phases of the three trials were randomized to treatment with nebulized BIS (n = 447) or CAT (n = 223). CAT included short-acting oral or inhaled β 2 -agonists, methylxanthines, or cromolyn sodium; in two of the studies, CAT could have included other inhaled corticosteroids. HPA-axis function, which had been evaluated during the 12-week double-blind studies, was again evaluated at the beginning and end of the 52-week study period using basal plasma cortisol concentrations and response to stimulation with a 250-μg dose of adrenocorticotropic hormone. Results There was no evidence of altered HPA-axis function attributable to BIS treatment. No clinically or statistically significant differences in basal or adrenocorticotropic hormone-stimulated plasma cortisol concentrations were observed between BIS and CAT in either the 12-week, double-blind or 52-week, open-label phases of the three studies. Conclusions The results indicate that treatment with BIS does not result in clinically significant suppression of HPA-axis function in infants and young children.

JL Friedlander, WJ Sheehan, SN Baxi. J Allergy Clin Immunol Pract. 2013;1(5):479–484 The goal of this study was to investigate the relation between food allergy and asthma morbidity in inner-city students with asthma. A total of 300 elementary school students with physician-diagnosed asthma were enrolled over a period of 6 years in the School Inner-City Asthma Study in the northeastern United States. Subjects were eligible if they had wheezing, used controller medications, or had unscheduled health care visits for asthma in the previous 12 months. This population was primarily a nonwhite (>95%), impoverished cohort …

Background: Disialoganglioside GD3 is expressed on the surface of selected cell types. Anti-GD3 mAb administered to human subjects with malignant melanoma produces signs and symptoms of immediate hypersensitivity reactions. Objective: The expression of GD3 by human mast cells was assessed during mast cell development in vitro and in samples of lung and skin. Methods: GD3 on tissue- and in vitro–derived mast cells was analyzed after double labeling of cells for tryptase (G3 mAb) or Kit (YB5.B8 mAb) and GD3 (R24 mAb). Glycolipids in extracts of fetal liver–derived mast cells were examined by using high-performance thin-layer chromatography. Results: Flow cytometry showed that the percentage of GD3 + cells increased in parallel to Kit + cells during the recombinant human stem cell factor–dependent development of fetal liver–derived mast cells. Double-labeling experiments showed that GD3 + cells were also surface Kit + and granule tryptase positive, identifying them as mast cells in preparations of lung-, skin-, fetal liver–, and cord blood–derived cells. The major acidic glycolipid detected was NeuAcα2-8NeuAcα2-3Galβ1-4Glcβ1-1′Cer (GD3). Among peripheral blood leukocytes, only basophils and about 10% of the T cells were labeled with anti-GD3 mAb. Anti-GD3 mAb–conjugated magnetic beads were used to purify mast cells to greater than 90% purity from dispersed skin cells enriched to approximately 12% purity by means of density-dependent sedimentation but were less proficient for dispersed human lung mast cells, most likely because of other cell types that express GD3. Conclusion: GD3 is expressed on the surface of developing human mast cells in parallel to tryptase in secretory granules and, like Kit, can serve as a target for their enrichment by immunoaffinity techniques. (J Allergy Clin Immunol 2001;107:322-30.)

P Amin, L Levin, T Epstein J Allergy Clin Immunol Pract. 2014;2(6):709–715 To determine whether the University of Cincinnati’s Asthma Predictive Index (ucAPI) and/or persistent wheezing by the age of 3 years are able to predict asthma at the age of 7 years, as confirmed by objective measures. Five hundred eighty-nine children were recruited from the Cincinnati Childhood Allergy and Air Pollution Study, a prospective birth cohort of children with at least 1 atopic parent; 54.8% were boys, 21.2% were African American, and 16.7% were from a household with yearly income

AC Wu, L Li, V Fung. J Allergy Clin Immunol Pract. 2014;2(5):607–613 To assess the risk of asthma exacerbation in children with asthma treated with various controller medications, including inhaled corticosteroids (ICS), leukotriene antagonists (LTRA), and ICS/long-acting β-agonist combinations (ICS-LABA). The study subjects included 26 191 controller-naive asthmatic children aged 4 to 17 years with uncontrolled asthma defined as at least 1 previous asthma exacerbation in the preceding year requiring an ED visit, hospitalization, or a short course of oral corticosteroids. Subjects were recruited from the databases of 6 private health plans (59%) and from the Tennessee Medicaid population (41%). This was a retrospective cohort study of …

Background: Human basophils are difficult to detect with classic histochemical stains at sites of allergic inflammation. The 2D7+ anti-basophil monoclonal antibody was used to identify basophils in skin during the late-phase response to a cutaneous allergen challenge. Methods: The 2D7+ monoclonal antibody was used on protease-digested sections of skin biopsy specimens obtained 6 and 24 hours after an allergen or buffer challenge. The skin chamber technique was used to compare buffer- and allergen-challenged sites at 6 hours, and intradermal injection of allergen was used to compare allergen-challenged sites at 6 and 24 hours. Results: Dramatic increases in the numbers of 2D7+ cells and in tissue staining by 2D7+ were observed 6 hours after allergen challenge compared with buffer challenge. Histamine levels in skin chamber fluid varied with 2D7+ cell concentrations. By 24 hours, 2D7+ cells and tissue staining appeared to diminish but were still detectable in the allergen-challenged sites. Basophils localized primarily in and around blood vessels, whereas mast cells remained mostly in the superficial dermis. Mast cells were 2D7− in both the allergen- and buffer-challenged skin. Metachromatic staining of 2D7 basophils with toluidine blue was absent in these tissue sections. Conclusions: The 2D7 monoclonal antibody provides a more sensitive and precise marker than histochemical staining for human basophil involvement during the late-phase response to an allergen challenge. Basophil infiltration was observed at 6 hours only after allergen challenge and persisted at similar levels by 24 hours. (J Allergy Clin Immunol 1998;101:354-62.)

Human fetal livers contain progenitor cells that become mast cells after 4 weeks of culture with recombinant human stem cell factor. Expression of cell surface CD29 (beta 1), CD18 (beta 2), CD61 (beta 3), and beta 5 integrins was investigated on such cells by flow cytometry and adhesion measurements. High surface expression of CD49e, CD51, and CD61 along with kit was apparent by 4 weeks of culture, whereas expression of each at day 0 was low to undetectable. CD29 and CD49d were detected on cells from day 0 to 4 weeks of culture; CD49b, CD49c, CD49f, CD18, and CD54 expression was negligible. The fetal liver- derived mast cells spontaneously adhered to vitronectin. No evidence for degranulation was found during vitronectin-dependent adhesion. Adhesion occurred in part through the CD61/CD51 receptor. No evidence for adhesion to vitronectin through CD29 and beta 5 integrins was obtained. Almost all of the vitronectin-adherent cells expressed CD51, CD61, kit, and tryptase, and exhibited metachromasia with toluidine blue. Thus, among the fetal liver-derived cells, developing mast cells were selectively adherent to vitronectin. These mast cells and the other cell types present also adhere spontaneously to fibronectin and to laminin, this adhesion being partially inhibited by antibodies against CD61 and CD29 integrins. In conclusion, human mast cells acquire functional vitronectin receptors as they develop from fetal liver progenitors under the influence of rhSCF. This may be important for the recruitment, localization, and retention of developing mast cells.

Galectin-3 is an endogenous soluble lectin within the family called galectins that bind beta-galactosides. Homologs of the protein isolated from different sources were previously designated as IgE-binding protein (epsilon BP), CBP35, CPB30, Mac-2, RL-29, RLL, L-29, and HL-29. All are now renamed galectin-3. This lectin is widely distributed in cells and tissues of mice, rats, dogs, hamsters, and humans. Light microscopic immunohistochemistry and ultrastructural immunogold labeling methods were used to determine the distribution of galectin-3 in human mast cells of several organs, in mast cells developed in vitro from human fetal liver cells, and in human peripheral blood basophils. Immunolabeling for the protein was observed in mast cells from all sources and in basophils. The lectin was detected in the nucleus and/or the cytoplasm. The nuclear labeling was over heterochromatin whereas euchromatin was unlabeled. Cytoplasmic labeling was concentrated over secretory granules. The intensity of staining generally was greater in mast cells of skin when compared with that of mast cells in other locations and with that of basophils. Studies have indicated that in mast cells galectin-3 may be involved in promoting their adhesion to basal laminae. In this study the localization of galectin-3 in the secretory granules of human mast cells and basophils suggests that these cells may release this lectin when activated to degranulate.

Biomarkers of disease activity have come into wide use in the study of mechanisms of human disease and in clinical medicine to both diagnose and predict disease course; as well as to monitor response to therapeutic intervention. Here we review biomarkers of the involvement of mast cells, basophils, and eosinophils in human allergic inflammation. Included are surface markers of cell activation as well as specific products of these inflammatory cells that implicate specific cell types in the inflammatory process and are of possible value in clinical research as well as within decisions made in the practice of allergy-immunology.

Although interleukin-4 (IL-4) in mice is known to augment the proliferation of mast cells and to modulate the expression of certain mast cell protease transcripts, its effect on human mast cells is less well understood. The current study examined the effects of recombinant human IL-4 (rhuIL-4) on stem cell factor (SCF)-dependent fetal liver- derived human mast cells in liquid culture. In no case did rhuIL-4 augment proliferation of mast cells. rhuIL-4 selectively inhibited certain aspects of the development of mast cells in cultures of fetal liver cells with rhuSCF. These include lower numbers and percentages of cells expressing tryptase and surface Kit, smaller cells, and lower contents of cells for tryptase, histamine, and Kit. Development of metachromasia was not attenuated. The downregulation of Kit, the surface receptor for SCF, is probably a critical factor, because cells lacking this molecule would not be able to respond to SCF. In contrast to mast cell progenitors, mast cells already developed in vitro from fetal liver cells are relatively resistant to rhuIL-4, but are still dependent for survival on the presence of rhuSCF.

We examined the cellular distribution of rat tryptase in rat skin, lung, small intestine, and peritoneal lavage cells by immunohistochemical techniques. Tryptase purified to apparent homogeneity from rat skin was used to generate a goat polyclonal anti-rat tryptase antibody. Tryptase-containing cells were detected in lung, skin, and peritoneal lavage cells. Small intestine mucosa, on the other hand, showed few if any tryptase-positive cells. Sequential staining with Alcian blue and anti-tryptase antibody showed that tryptase is located only in mast cells. Sequential staining with safranin to identify the connective tissue type of mast cell and anti-tryptase antibody showed that tryptase resides only in this mast cell type. However, only a subpopulation of the safranin-stained mast cells contained tryptase. In lung, 53% of the mast cells stained with safranin; 94% contained tryptase. In skin, 80% stained with safranin; only 6% contained tryptase. In peritoneal cells, more than 95% of the mast cells were stained with safranin; 20% contained tryptase. In the bowel mucosa, where few cells are stained by safranin, no cells with tryptase were detected. The percentages of cells with chymase I that also contained tryptase were 80% and 84% for lung, 4% and 7% for skin, and 15% and 13% for peritoneal cells by respective simultaneous and sequential double labeling with anti-tryptase and anti-chymase I antibodies. This study suggests that the rat connective tissue type of mast cell is subdivided into two forms on the basis of the presence or absence of tryptase, whereas rat mucosal mast cells lack this enzyme. These results contrast with those in humans, in which tryptase is present in all mast cells, but are similar to mice, in which tryptase mRNA has been detected only in the connective tissue type.

We have previously shown the development in vitro of tryptase+ human mast cells from fetal liver cells cocultured with murine 3T3 fibroblasts. In this study, recombinant human stem cell factor (rhuSCF), the ligand for the c-kit proto-oncogene product called Kit, stimulated the growth and differentiation primarily of mast cells from dispersed fetal liver cells, whereas recombinant human interleukin-3 (rhuIL-3) stimulated the differentiation of basophils along with other cell types. Cultures of fetal liver cells were initiated and maintained in the presence of rhuSCF or rhuIL-3 for up to 6 weeks. Metachromatic cells in cytospins were identified as mast cells primarily on the basis of tryptase expression, and as MCT or MCTC by immunohistochemistry using monoclonal antibodies against tryptase and chymase, whereas basophils were metachromatic, polymorphonuclear, and lacked these proteases. Levels of tryptase and histamine were measured by radioimmunoassay, tryptase and chymase activities by peptide hydrolysis, and cell surface Kit by flow cytometry with the monoclonal antibody YB5.B8. The predominant presence of mast cells occurred only in the cultures supplemented with rhuSCF. The percentage and total number of mast cells increased over time with increasing concentrations of rhuSCF and reached a plateau at 55 ng/mL. At this concentration of rhuSCF, mast cells first appeared by day 7; by day 42, 106% of the starting number of cells were present and 85% of these were tryptase+, 31% being weakly chymase+. These mast cells appeared immature by ultrastructural criteria; most cells were mononuclear, but some had nuclei with deeply divided lobes. DNA synthesis in tryptase+ mast cells at days 21 and 28 of culture with rhuSCF was demonstrated by incorporation of bromodeoxyuridine. Calculated levels of histamine (1.2 pg/mast cell) and tryptase (0.9 pg/mast cell) were similar to those determined previously in coculture experiments with murine 3T3 fibroblasts. Chymase activity was undetectable in most cell extracts. On day 0, 4% to 20% of fetal liver cells expressed cell surface Kit. In the presence of rhuSCF, the percentages and total numbers of Kit+ cells and the apparent concentration of Kit per cell increased along with the number of tryptase+ cells. In the presence of rhuIL-3, toluidine blue+, tryptase- cells first and maximally appeared at day 14 (11% +/- 2.5%). The percentage of these toluidine blue+ cells then declined to about 6% by days 21 and 35, while the total number of positive cells declined over 10-fold. Kit+ cells in the presence of rhuIL-3 declined from 9% on day 3 to 2% on day 35.(ABSTRACT TRUNCATED AT 400 WORDS)

Allelic variants at codons 16 and 27 of the beta(2)-adrenergic receptor gene (ADRB2) have shown clinical and pharmacological implications in asthma, hypertension, ischemic heart failure, diabetes, obesity, and cystic fibrosis. We have developed a simultaneous genotyping assay for the c.46AG and c.79CG allelic variants using hybridization probes and melting curve analysis. The assay was optimized on a panel of 30 DNA samples of known ADRB2 genotype as determined by sequencing with 100% concordance between the two techniques. Melting temperature (Tm) ranges for the different genotypes were obtained using data from three independent experiments. Single peaks for p.Arg16Arg (Tm = 57.76 degrees C +/- 0.10 degrees C) and p.Gly16Gly (Tm = 66.73 degrees C +/- 0.18 degrees C) and two melting peaks for p.Arg16Gly were obtained. Similarly, single peaks for p.Gln27Gln (Tm = 53.98 degrees C +/- 0.19 degrees C) and p.Glu27Glu (Tm = 64.93 degrees C +/- 0.16 degrees C) and two peaks for p.Gln27Glu were detected. Independent operators easily assigned genotypes in a sample set of 385 asthmatic patients. Haplotype and allele frequencies were in concordance with previously published data: Arg allele frequencies in children/adults were 0.34/0.30 in Caucasians and 0.45/0.52 in African Americans, and Gln allele frequencies were 0.58/0.52 in Caucasians and 0.82/0.84 in African Americans. Thus, the ADRB2 genotyping assay represents a highly reliable and rapid technique for routine clinical use in the simultaneous detection of ADRB2 variants.

Lesional (n = 15) and non-lesional (n = 10) skin of subjects with mastocytosis was analysed for the distribution and concentration of trypase positive, chymase negative mast cells (MCT) and tryptase positive, chymase positive mast cells (MCTC) cells and compared to normal skin (n = 23) and non-lesional skin of subjects with unexplained anaphylaxis or flushing episodes (n = 6). Skin biopsies were fixed in Carnoy's fluid and subjected to double immunohistochemical staining with biotinylated mouse monoclonal anti-chymase antibody followed by alkaline phosphatase-conjugated mouse monoclonal anti-tryptase antibody. MCTC cells were the only type of mast cells seen in all specimens analysed and in each case were more numerous in superficial compared to deep regions of dermis. The concentration (mean +/- s.d.) of mast cells in the superficial dermis of mastocytosis lesions (40 985 +/- 21 772 mast cells/mm3) was significantly increased over that in corresponding areas of non-lesional skin from subjects with mastocytosis (7178 +/- 3607 mast cells/mm3), skin from subjects with idiopathic anaphylaxis or flushing episodes (6974 +/- 3873 mast cells/mm3) and normal skin (7347 +/- 2973 mast cells/mm3). The exclusive presence of MCTC cells in skin lesions of mastocytosis which are characterized by non-malignant hyperplasia of mast cells suggests involvement of local tissue factors in mast cell recruitment and differentiation.

D Colson, N Kalach, P Soulaines. J Allergy Clin Immunol Pract. 2014;2(5):587–593 The purpose of this study was to evaluate the impact of various elimination diets on the nutritional status of children with eosinophilic esophagitis (EoE). The study included 59 children consecutively referred to the pediatric gastroenterology department at the hospital Necker-Enfants Malades in Paris, France, who had nutritional assessment before and after a 2-month dietary therapy period without oral or topical corticosteroids. There were 37 boys and 22 girls ranging in age from 9 months to 15 years. Children with EoE were treated with a modified 6 …

Objective To compare the safety of budesonide inhalation suspension (BIS) with placebo in infants 6 to 12 months of age with mild to moderate persistent asthma or recurrent wheeze. Study design In this multicenter, randomized, double-blinded, parallel-group, placebo-controlled study, 141 patients received 0.5 mg BIS (n = 48), 1.0 mg BIS (n = 44), or placebo (n = 49) once daily for 12 weeks. The primary variable was adrenal function, based on cosyntropin-stimulated plasma cortisol levels. Spontaneous adverse events and clinical laboratory findings also were monitored. Results Overall, the types and frequencies of adverse events reported during the study were comparable across treatment groups. The response to cosyntropin stimulation was similar across treatment groups, with no significant difference between BIS treatment and placebo. Conclusions The safety profile of BIS was similar to that of placebo, with no suppressive effect on adrenal function in patients 6 to 12 months of age with mild to moderate persistent asthma or recurrent wheeze.

Background Because of potential toxicities of inhaled corticosteroid (ICS) use in pediatric asthma, alternative or steroid-sparing therapy is desirable. There are no previous studies evaluating montelukast's steroid-sparing effects in children with asthma. Objective To evaluate whether (1) montelukast as add-on therapy improves asthma symptom control and (2) montelukast provides steroid-sparing effects in children with asthma treated with low to moderate doses of ICS therapy. Methods In a double-blind, placebo-controlled trial, 36 children ages 6 to 14 years with symptomatic asthma maintained on a stable low to moderate dose of ICSs were randomly assigned to receive montelukast or matching placebo for 24 weeks after a run-in period of 2 weeks (period I). During the trial, subjects kept daily asthma diary cards and monthly spirometry was performed. After a 4 week add-on period (period II), the subjects completed a 20-week (period III) ICS tapering period based on a predetermined protocol. Results In period II, the difference in the number of rescue-free days was significantly higher in the montelukast group ( P = 0.0001), and the number of rescue-free days per week was also significantly higher in montelukast-treated subjects compared with placebo subjects ( P = 0.002). In period III, the percentage reduction in ICS dose was not significant between montelukast and placebo ( P = 0.10), but the montelukast group experienced an average 17% decrease in ICS dose and the control group experienced an average 64% increase in ICS dose. Conclusions Montelukast treatment significantly increased the number of rescue-free days in symptomatic children with asthma.

To investigate the role of mast cells in treatment-associated adverse reactions in patients with onchocerciasis, changes in plasma tryptase levels and skin mast cell counts were examined in 2 groups of Onchocerca volvulus-infected subjects after ivermectin treatment. After treatment, an increase in tryptase levels was observed concurrent with the onset of blood eosinopenia and preceding the appearance of plasma eosinophil-derived neurotoxin (EDN) and interleukin-5. Tryptase levels were correlated with development of peripheral eosinopenia and markers of eosinophil activation and degranulation. Dermal mast cell numbers increased transiently at 24 h after treatment, preceding the onset of dermal eosinophil infiltration and the development of clinically apparent inflammation. Local reactions were strongly correlated with levels of plasma tryptase and EDN, and the severity of systemic reactions was correlated with levels of tryptase, EDN, and interleukin-5. The data indicate that mast cells play a role in initiation of tissue inflammatory reactions after ivermectin treatment of onchocerciasis.

WD Arroyave, FA Rabito, JC Carlson. J Allergy Clin Immunol Practice. 2013;1(5):501–508 The goal of this study was to examine the relationship between specific IgE (sIgE) to indoor allergens and asthma outcomes as defined according to emergency department (ED) visits and wheeze. Subjects included all participants in the 2005–2006 National Health and Nutrition Examination Survey who reported having current asthma. There were 351 children

The in vitro development of human mast cells from fetal liver cells with recombinant human stem cell factor in serum-containing RPMI was compared to that in AIM-V media with and without serum. Compared to serum-containing media, AIM-V medium caused mast cells to develop earlier and in greater numbers. By 2 weeks, about 60% of cells in serum-free AIM-V medium were phenotypic mast cells, approximately 2 times the percentages in serum-containing media. By 6 weeks the percentages of mast cells wereor =80% under all conditions, but the number of mast cells was 3-4-fold greater in serum-free AIM-V medium than in serum-supplemented media. Mast cells obtained in serum-free AIM-V medium exhibited rounded nuclei, like tissue-derived mast cells; mast cells obtained in serum-supplemented media had segmented nuclei. By 10-12 weeks of culture about 40% of the AIM-V-derived cells showed strong chymase immunocytochemical staining, a pattern observed for only 14% of the cells in serum-containing media. AIM-V medium is a suitable medium for the development of human mast cells in vitro, and permits an earlier, more selective and greater expansion of mast cells than serum-containing media.

Mast cell neutral proteases are the most precise markers of heterogeneity among human mast cells. Two types of human mast cells have been recognized. MCTC cells contain tryptase together with chymase, cathepsin-G like protease, and mast cell carboxypeptidase; MCT cells contain tryptase, but lack the other neutral proteases present in MCTC cells. All mast cells develop from hemopoietic stem cells. In vitro procedures for studying mast cell growth have been developed, using the major human mast cell growth factor, stem cell factor (SCF, also called Kit-ligand). Cultures of hemopoietic progenitor cells in the presence of SCF alone result in selective differentiation to mast cells. The same progenitor cells can be induced to differentiate into other lineages when SCF is used with various lineage-specific colony-stimulating factors such as erythropoietin for erythrocytes. Mast cell development from hematopoietic progenitors may represent a "default pathway," occurring optimally in a permissive microenvironment such as skin, bowel, and lung. The presence or absence of certain cytokines in blood and bone marrow may create a non-permissive environment, thus the absence of granulated mast cells in such locations.