Margaretha A. Faber

Cor a 14: Missing Link in the Molecular Diagnosis of Hazelnut Allergy?

Background: Hazelnut allergy shows distinct clinical patterns that can be predicted through component-resolved diagnosis. However, identification of sensitization profiles remains incomplete. Methods: Sera of 75 patients allergic to hazelnuts, 14 infants with atopic dermatitis (AD) sensitized to hazelnuts, 15 hazelnut-tolerant individuals with specific IgE (sIgE) to hazelnuts and 15 healthy control individuals were tested for sIgE reactivity to rCor a 1.04, rCor a 8, nCor a 9, nCor a 11, rCor a 14, rBet v 1, rBet v 2 and cross-reactive carbohydrate determinants (CCDs). Results: Sensitization to Cor a 14 was observed in 18 out of 20 preschool children, 8 out of 10 school-aged children and 2 out of 7 adults with generalized reactions and in 3 out of 14 infants with AD. Only 2 out of 38 patients with an oral allergy syndrome (OAS) were sensitized to Cor a 14. No sensitization to Cor a 14 was observed in the group of hazelnut-tolerant and healthy control individuals. Sensitization to Cor a 1.04 was seen in 36 out of 38 OAS patients and in 14 out of 37 patients with generalized reactions. However, only 3 patients with generalized reactions were monosensitized to Cor a 1.04. Sensitization to Cor a 9 was observed in 26 out of 37 patients with generalized reactions and in 4 out of 14 infants with AD. Sensitization to Cor a 11, Cor a 8, rBet v 2 and CCDs was rare. Conclusions: Sensitization to Cor a 14 can have early onset and shows age-related variations. Together with Cor a 9, Cor a 14 enables us to correctly identify almost 90% of children with generalized reactions to hazelnut.

Basophil activation tests: time for a reconsideration

Challenges in in vitro allergy diagnostics lie in the development of accessible and reliable assays allowing identification of all offending allergens and cross-reactive structures. Flow-assisted analysis and quantification of in vitro activated basophils serves as a diagnostic instrument with increasing applications developed over the years. From the earliest days it was clear that the test could constitute a diagnostic asset in basophil-mediated hypersensitivity. However, utility of the basophil activation test should be reassessed regarding difficulties with preparation, characterization and validation of allergen extracts; availability and the potential of more accessible diagnostics. Today, the added value mainly lies in diagnosis of immediate drug hypersensitivity. Other potential indications are monitoring venom-immunotherapy and follow-up of natural history of food allergies. However, results in these nondiagnostic applications are preliminary. We review the most relevant clinical applications of the basophil activation test. Some personal comments and views about perspectives and challenges about flow-assisted allergy diagnosis are made.

Shellfish allergens: tropomyosin and beyond

IgE‐mediated shellfish allergy constitutes an important cause of food‐related adverse reactions. Shellfish are classified into mollusks and crustaceans, the latter belonging to the class of arthropoda. Among crustaceans, shrimps are the most predominant cause of allergic reactions and thus more extensively studied. Several major and minor allergens have been identified and cloned. Among them, invertebrate tropomyosin, arginine kinase, myosin light chain, sarcoplasmic calcium‐binding protein, and hemocyanin are the most relevant. This review summarizes our current knowledge about these allergens.

Cannabis Allergy: What do We Know Anno 2015

For about a decade, IgE-mediated cannabis (marihuana) allergy seems to be on the rise. Both active and passive exposure to cannabis allergens may lead to a cannabis sensitization and/or allergy. The clinical manifestations of a cannabis allergy can vary from mild to life-threatening reactions, often depending on the route of exposure. In addition, sensitization to cannabis allergens can trigger various secondary cross-allergies, mostly for plant-derived food. This clinical entity, which we have designated as the “cannabis-fruit/vegetable syndrome” might also imply cross-reactivity with tobacco, latex and plant-food derived alcoholic beverages. These secondary cross-allergies are mainly described in Europe and appear to result from cross-reactivity between non-specific lipid transfer proteins or thaumatin-like proteins present in Cannabis sativa and their homologues that are ubiquitously distributed throughout plant kingdom. At present, diagnosis of cannabis-related allergies rests upon a thorough history completed with skin testing using native extracts from buds and leaves. However, quantification of specific IgE antibodies and basophil activation tests can also be helpful to establish correct diagnosis. In the absence of a cure, treatment comprises absolute avoidance measures including a stop of any further cannabis (ab)use.

Influence of IL‐6, IL‐33, and TNF‐α on Human Mast Cell Activation: Lessons from Single Cell Analysis by Flow Cytometry

Mechanisms that govern priming and degranulation of human mast cells (MCs) remain elusive. Besides, most of our knowledge is based on experiments from which data only reflect an average of all stimulated cells. This study aims at investigating the effects of proinflammatory cytokines IL‐6, IL‐33, and TNF‐α on IgE‐dependent and IgE‐independent activation of individual MCs.

Phenotypic and functional characterization of in vitro cultured human mast cells.

Mast cell progenitor cells, derived from CD34+ hematopoietic stem cells, enter the circulation and subsequently mucosal or connective tissues where they mature to mast cells. Upon activation, mast cells increase the expression of activation markers, e.g. CD63, and release histamine amongst other mediators. Traditionally, release of these mediators is quantified using assays measuring their extracellular concentration in the supernatant of stimulated cells.

Sensitization profiles to peanut allergens in Belgium; cracking the code in infants, children and adults

Objectives: Peanut allergy shows distinct clinical patterns that can be predicted by component resolved diagnosis. However, data about peanut sensitization profiles in populations with a broad age stratification are scarce. Methods: Sera of 89 peanut allergic patients (age 1–70 years), 21 infants (<1 year) with atopic dermatitis (AD) sensitized to peanut, 24 age matched peanut-tolerant individuals with positive specific IgE (sIgE) to peanut and 15 healthy individuals were tested for sIgE reactivity to rAra h 1, rAra h 2, rAra h 3, rAra h 8, rAra h 9 and rBet v 1 (FEIA ImmunoCAP, Thermo Fisher Scientific). Results: In infants with AD, Ara h 1, Ara h 2 and Ara h 3 enabled to explain 14/21 (67%) of peanut sensitizations. No sensitization to Ara h 8 or Bet v 1 was observed. Patients with generalized reactions were more frequently sensitized to Ara h 1, Ara h 2 and Ara h 3 compared to patients with an oral allergy syndrome (OAS) and peanut-tolerant patients. Sensitization to Ara h 8 was significantly more observed in patients with an OAS. Ara h 2 showed to be the best marker to distinguish patients with generalized reactions from patients with an OAS and/or peanut sensitized patients but tolerating the legume. Conclusion: Sensitization to Ara h 1, Ara h 2 and Ara h 3 can have an early onset and is predominantly associated with a more severe outcome. Ara h 2 is the best marker of a generalized peanut allergy.

Measuring histamine content and release at single-cell level during venom allergy immunotherapy

From the Division of Allergy, Department of Medical Subspecialties, National Center for Child Health and Development, Clinical Research Center, National Center for Child Health and Development, and the Department of Allergy and Immunology, National Research Institute for Child Health and Development, Tokyo, Japan. E-mail: saito-hr@ ncchd.go.jp. Disclosure of potential conflict of interest: K. Horimukai is employed by the National Center for Child Health and Development (NCCHD) and the Jikei University Katsushika Medical Center; has received research support from the Ministry of Health, Labour and Welfare (the grant no. of MHLW is henceforth H22-Men’eki-Ippan-002 and H25-Nanchito-Ippan-001, unless otherwise specified); and has received payment for lectures from Maruho Co Ltd and GlaxoSmithKline KK. K. Morita is employed by the NCCHD; has received research support from Shiseido Co, Ltd, and the Ministry of Health, Labour and Welfare. E. Inoue has consultant arrangements with Tokyo Women’s Medical University and Stagen Co, Ltd; is employed by the NCCHD; has received research support from theMinistry of Health, Labour andWelfare and theMinistry of Education, Culture, Sports, Science, and Technology; and has received payment for lectures from Takeda Pharmaceutical Co, Ltd, Chugai Pharmaceutical Co Ltd, and Japan Clinical Cancer Research Organization. H. Saito is employed by the NCCHD; has received research support from the Ministry of Health, Labour and Welfare and Japan Society for the Promotion of Science (21390303 & 23390262); has received payment for lectures from Teijin Pharma Ltd, Shiseido Co Ltd, Merck Sharp and Dohme KK, Taiho Pharmaceutical Co Ltd, Nippon Boehringer-Ingelheim Co Ltd, Ono Pharmaceutical Co Ltd, GlaxoSmithKline KK, Pfizer Japan, Inc, Novartis Pharma KK, Kyowa Hakko Kirin Co Ltd, Kyorin Pharmaceutical Co Ltd, and Daiichi Sankyo Co Ltd; has received payment for manuscript preparation from Taiho Pharmaceutical Co Ltd; has received payment for the development of educational presentations from Shimane University and Toho University; and has received travel support from Shimane University Japanese Society of Allergology, Japanese Society of Pediatric Allergy & Clinical Immunology, and Pfizer Japan, Inc. Y. Ohya is employed by the NCCHD; has received research support from the Ministry of Health, Labour and Welfare, the NCCHD, the Environmental Restoration & Conservation Agency, Shiseido Co Ltd, Maruho Co Ltd, and the National Institute for Environmental Studies; has received payment for lectures from Merck Sharp and Dohme, GlaxoSmithKline KK, Malho Co Ltd, Teijin Pharma Ltd, Shiseido Co Ltd, Abbott Japan Co Ltd, Sanofi KK, Simens AG, Kyowa Hakko Kirin Co Ltd, and Nikkei Radio Broadcasting Co; has received payment for manuscript preparation from the University of Tokyo Press, Tokyo Igakusha, and the Asahi Shinbun; has received payment for the development of educational presentations from the Japan Allergy Foundation, the Japan Pharmacists Education Center, NHK Educational Co, and the Korean Pediatric Society; and has received travel support from the Japanese Society of Child Health, the Japanese Society of Pediatric Dermatology, Tokyo metropolitan government, the National Institute for Environmental Studies, the Ministry of Environment, and the Cabinet Office.

Cross-reactive aeroallergens: which need to cross our mind in food allergy diagnosis?

Secondary food allergies due to cross-reactivity between inhalant and food allergens are a significant and increasing global health issue. Cross-reactive food allergies predominantly involve plant-derived foods resulting from a prior sensitization to cross-reactive components present in pollen (grass, tree, weeds) and natural rubber latex. Also, primary sensitization to allergens present in fungi, insects, and both nonmammalian and mammalian meat might induce cross-reactive food allergic syndromes. Correct diagnosis of these associated food allergies is not always straightforward and can pose a difficult challenge. As a matter of fact, cross-reactive allergens might hamper food allergy diagnosis, as they can cause clinically irrelevant positive tests to cross-reacting foods that are safely consumed. This review summarizes the most relevant cross-reactivity syndromes between inhalant and food allergens. Particular focus is paid to the potential and limitations of confirmatory testing such as skin testing, specific IgE assays, molecular diagnosis, and basophil activation test.

Rocuronium hypersensitivity: Does off-target occupation of the MRGPRX2 receptor play a role?

BACKGROUND The neuromuscular blocking agent (NMBA) rocuronium is a relevant cause of perioperative hypersensitivity (POH) with a significant risk of diagnostic error. Recently, it has been suggested to reclassify hypersensitivity to NMBA as type A reactions resulting from off-target occupation of the nonimmune MRGPRX2 receptor. OBJECTIVE To investigate whether basophil activation experiments can benefit diagnosis and add to the insights in the pathomechanisms of rocuronium hypersensitivity. METHODS A total of 140 patients with a suspected POH to rocuronium in whom peak tryptase was available had complete diagnostic workup for all potential culprits including triple confirmatory testing with skin tests, basophil activation test (BAT), and quantification of specific IgE (sIgE) antibodies to rocuronium and morphine. To further analyze the clinical relevance of sIgE antibodies, quantitative basophil inhibition experiments were performed by coincubation of the cells with rocuronium and morphine, an opiate known to harbor a substituted ammonium structure. RESULTS Diagnosis of rocuronium hypersensitivity was established in 72 of 140 patients (51.4%), of whom 65 (90.3%) demonstrated mast cell activation. Of the 72 patients, 64 displayed a positive skin test, 8 (11.1%) had their diagnosis documented only by BAT. Coincubation of morphine and rocuronium induced a dose-dependent inhibition of BAT with rocuronium that was restricted to 4 of 6 patients with IgE reactivity to rocuronium and/or morphine. CONCLUSIONS BAT can benefit diagnosis of rocuronium hypersensitivity. As basophils barely express MRGPRX2 and BAT rocuronium can be inhibited by morphine, we believe that hypersensitivity to rocuronium still mainly results from IgE/high-affinity receptor for sIgE (FcεRI)-dependent effector cell activation. However, it cannot be excluded that in a few patients rocuronium hypersensitivity results from off-target occupation of the MRGPRX2 receptor.