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Diagnostic Exercise Challenge Testing

Abstract  
This article reviews the diagnostic challenge methods—both exercise and surrogate—for diagnosis of exercise-induced bronchoconstriction (EIB) and EIB with known asthma. Indirect challenges that release the entire repertoire of mediators representative of EIB and asthma are more specific for diagnosis and are recommended over direct challenges such as methacholine challenge, which are sensitive but nonspecific. Self-reported history and empiric therapeutic trials are not adequate for diagnosis of EIB with or without known asthma. Objective pulmonary function documentation with bronchodilator reversibility or exercise or surrogate challenge are optimal for diagnosis of EIB or EIB with known asthma. Such objective pulmonary function documentation is optimal for the proper management and healthy lifestyle of the exercising athlete or individual.
  • Content Type Journal Article
  • Category Pediatric Allergy and Immunology (Jay M. Portnoy and Christina E. Ciaccio, Section Editors)
  • Pages 1-9
  • DOI 10.1007/s11882-011-0225-4
  • Authors
    • Christopher Randolph, Department of Pediatrics/Medicine, Division of Allergy/Immunology Center for Allergy, Asthma, and Immunology, Yale University, 1389 West Main Street, Suite 205, Waterbury, CT 06708, USA

Overview of Serological-Specific IgE Antibody Testing in Children

Abstract  
Allergic diseases are among the most common chronic conditions in the pediatric population. Allergy diagnostic testing is an important part of the evaluation/management of allergic patients because the history may not be precise enough to identify the specific allergen sensitivity. In addition to providing information about specific sensitivities, allergy diagnostic tests have some predictive value in terms of future risk of developing an allergic condition and the severity/persistence of the allergic disease. The two most commonly used methods of confirming allergen sensitization are skin testing and measurement of serum-specific IgE. Both methods have similar diagnostic value in terms of sensitivity and specificity, with both parameters varying with the clinical scenario and allergen tested. Currently, there are three US Food and Drug Administration–cleared, serum-specific IgE assays used in the United States. The three assays report comparable analytic sensitivity, with the coefficients of variation of the precision, reproducibility, and linearity being less than 15%. However, comparative studies have demonstrated significant inter-assay variability, suggesting that they detect different populations of IgE antibody in human sera or do not measure the same antibodies with the same efficiency. Current specific IgE assays utilize allergen extract reagents. Testing with these reagents may identify sensitivity to clinically irrelevant allergens. This diagnostic limitation has spurred the development of molecular diagnostic tests, also referred to as component-resolved diagnostics, which utilize purified native or recombinant allergens to detect IgE sensitivity to individual allergen molecules. These advancements in serum IgE testing may enhance the precision of allergy diagnostic testing, which may decrease the need for oral food challenges and improve the specificity of allergen immunotherapy.
  • Content Type Journal Article
  • Category Pediatric Allergy and Immunology (Jay M. Portnoy and Christina E. Ciaccio, Section Editors)
  • Pages 1-7
  • DOI 10.1007/s11882-011-0226-3
  • Authors
    • Linda Cox, Nova Southeastern University, 5333 North Dixie Highway, Fort Lauderdale, FL 33335, USA

Mast cells are critically involved in serum-mediated vascular leakage in chronic urticaria beyond high-affinity IgE receptor stimulation

To cite this article: Bossi F, Frossi B, Radillo O, Cugno M, Tedeschi A, Riboldi P, Asero R, Tedesco F, Pucillo C. Mast cells are critically involved in serum-mediated vascular leakage in chronic urticaria beyond high-affinity IgE receptor stimulation. Allergy 2011; DOI: 10.1111/j.1398-9995.2011.02704.x.AbstractBackground:  Chronic urticaria (CU) is one of the most common skin disorders whose pathogenic mechanisms are not fully clarified. Autoimmune aetiology can be ascribed to 45% of patients with CU, and basophil histamine release is positive in 40% of cases. Our aim was to use a novel approach to evaluate the serum permeabilizing effect to identify the mediators of endothelial cell (EC) leakage and to define the role of mast cells (MCs) in the process.Methods:  Permeabilizing activity of sera from 19 patients with CU and 11 healthy blood donors was evaluated by measuring serum-induced degranulation of two MC lines, expressing (LAD2) or lacking (HMC-1) the IgE receptor. Mast cell supernatant (SN) was then incubated with an EC monolayer, and endothelial permeability was evaluated by Fluorescein isothiocyanate–bovine serum albumin leakage in a transwell system.Results:  All 19 patient sera failed to induce direct EC leakage, but 15/19 and 17/19 promoted degranulation of HMC-1 and LAD2, respectively. Interestingly, 85% of autologous serum skin test-negative sera were able to cause MC degranulation. Also, 17/19 SNs from HMC-1 and all SNs from LAD2 incubated with CU sera increased endothelial permeability. Endothelial cell leakage remained unchanged after Ig depletion and was prevented by antihistamine, platelet-activating factor or leukotriene antagonist.Conclusions:  Our study shows that CU sera are able to degranulate MCs through an IgE- and IgG-independent mechanism. The nature of histamine-releasing factors involved is still unclear, but our finding opens new ways to the understanding of the pathogenesis of CU, particularly in patients not showing circulating autoantibodies to FcεRI or IgE.

Asthma, allergy and respiratory infections: the vitamin D hypothesis

To cite this article: Bozzetto S, Carraro S, Giordano G, Boner A, Baraldi E. Asthma, allergy, and respiratory infections: the vitamin D hypothesis. Allergy 2011; DOI: 10.1111/j.1398-9995.2011.02711.x.AbstractThe recent discovery that every tissue in the human body has vitamin D receptors and that vitamin D has pleiotropic effects has prompted an increased interest in this hormone. Vitamin D deficiency is widespread and on the increase. There is no consensus on the serum vitamin D levels to consider appropriate for global health, the cutoffs for its deficiency, or the doses to use for its supplementation. Vitamin D seems to correlate closely with host reactions against various respiratory infections. Epidemiological studies have shown that low serum 25-hydroxyvitamin D levels are associated with a higher risk of upper and lower respiratory infections in children and a shortage of vitamin D may contribute to asthmatic patients’ symptoms and morbidity rates. There are studies highlighting associations between childhood asthma, fetal lung and/or immune development, and maternal vitamin D intake. An insufficiency of this vitamin also seems to be implicated in the onset of childhood atopy and food allergies. The hypothesis is that vitamin D could have a central role in these pathological situations and that it may represent a novel preventive and/or therapeutic strategy. This article reviews and discusses published data on the relationship between vitamin D and asthma and allergy, emphasizing the need for controlled, prospective studies on vitamin D supplementation to clarify whether it has a role in the prevention of and treatment for asthma and allergic conditions.

Markers of autoreactivity, coagulation and angiogenesis in patients with nonallergic asthma

To cite this article: Asero R., Tedeschi A., Cugno M. Markers of autoreactivity, coagulation and angiogenesis in patients with nonallergic asthma. Allergy 2011; 66: 1339–1344.AbstractBackground:  Patients with nonallergic asthma frequently show autoreactivity as do subjects with chronic urticaria (CU). Activation of the coagulation cascade and hyper-expression of vascular endothelial growth factor (VEGF) were recently found in CU, and there is sparse evidence that the same may occur in asthma.Objective:  To investigate autoreactivity, activation of the coagulation cascade, and expression of VEGF in patients with nonallergic asthma.Methods:  Twenty-one adults with nonallergic asthma underwent autologous plasma skin test (APST) and the measurement of plasma levels of the prothrombin fragment F1+2, D-dimer, VEGF, and the inflammatory marker C-reactive protein (CRP). Twenty-one healthy sex- and age-matched subjects served as normal controls.Results:  The APST scored positive in 19 of 21 (90%) patients vs 0 controls. Mean fragment F1+2 plasma levels were significantly higher in patients with asthma (267 ± 243 pM) than in controls (150 ± 51 pM; P = 0.0001). Similarly, plasma levels of both D-dimer and VEGF were significantly higher in patients than in controls (D-dimer: 2364 ± 1467 vs 1301 ± 525 pM; P = 0.0001; VEGF: 1721 ± 2566 vs 76 ± 375 fM; P = 0.0001). A trend toward increased levels of F1+2, D-dimer, VEGF, and CRP was found in patients with a more severe disease according to GINA classification.Conclusion:  Nonallergic asthma is characterized by autoreactivity as well as increased coagulation and angiogenesis markers, which are known to enhance vascular permeability. The presence of circulating vasoactive factors may be relevant to understand the disease pathophysiology and to detect novel therapeutic strategies in nonallergic asthma.

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