The basophil activation test (BAT) has become a pervasive test for allergic response through the development of flow cytometry, discovery of activation markers such as CD63 and unique markers identifying basophil granulocytes. Basophil activation test measures basophil response to allergen cross-linking IgE on between 150 and 2000 basophil granulocytes in <0.1 ml fresh blood. Dichotomous activation is assessed as the fraction of reacting basophils. In addition to clinical history, skin prick test, and specific IgE determination, BAT can be a part of the diagnostic evaluation of patients with food-, insect venom-, and drug allergy and chronic urticaria. It may be helpful in determining the clinically relevant allergen. Basophil sensitivity may be used to monitor patients on allergen immunotherapy, anti-IgE treatment or in the natural resolution of allergy. Basophil activation test may use fewer resources and be more reproducible than challenge testing. As it is less stressful for the patient and avoids severe allergic reactions, BAT ought to precede challenge testing. An important next step is to standardize BAT and make it available in diagnostic laboratories. The nature of basophil activation as an ex vivo challenge makes it a multifaceted and promising tool for the allergist. In this EAACI task force position paper, we provide an overview of the practical and technical details as well as the clinical utility of BAT in diagnosis and management of allergic diseases.

Suspected perioperative allergic reactions are rare but can be life-threatening. The diagnosis is difficult to make in the perioperative setting, but prompt recognition and correct treatment is necessary to ensure a good outcome. A group of 26 international experts in perioperative allergy (anaesthesiologists, allergists, and immunologists) contributed to a modified Delphi consensus process, which covered areas such as differential diagnosis, management during and after anaphylaxis, allergy investigations, and plans for a subsequent anaesthetic. They were asked to rank the appropriateness of statements related to the immediate management of suspected perioperative allergic reactions. Statements were selected to represent areas where there is a lack of consensus in existing guidelines, such as dosing of epinephrine and fluids, the management of impending cardiac arrest, and reactions refractory to standard treatment. The results of the modified Delphi consensus process have been included in the recommendations on the management of suspected perioperative allergic reactions. This paper provides anaesthetists with an overview of relevant knowledge on the immediate and postoperative management of suspected perioperative allergic reactions based on current literature and expert opinion. In addition, it provides practical advice and recommendations in areas where consensus has been lacking in existing guidelines.

Background-The WHO classification separates mastocytosis into distinct variants, but prognostication remains a clinical challenge. The aim of this study was to improve prognostication for patients with mastocytosis. Methods-We analysed data of the registry of the European Competence Network on Mastocytosis including 1639 patients (age 17-90 years) diagnosed with mastocytosis according to Sperr et al.

Despite their low frequency, drug hypersensitivity reactions (DHRs) can be serious and result in lifelong sequelae. The diagnosis is critical to avert future reactions and should identify the culprit drug or drugs and safe alternatives. However, making the diagnosis can be complex and challenging. Reliable in vitro tests can offer the potential to improve a diagnosis of DHR and influence medical decision making. Importantly, in vitro testing is frequently not performed as a test in isolation but rather as a component of a diagnostic algorithm along with additional tests. There are several in vitro approaches for the different endotypes of DHRs. However, only few are available for routine diagnosis, and many are restricted to research laboratories. In vitro tests exhibit varying sensitivity and specificity depending on the drug involved and the clinical phenotype. In vitro tests can complement skin tests, especially in patients with negative or equivocal skin test responses inconsistent with the clinical presentation and in severe reactions in which drug provocation tests are contraindicated. The main unmet need for many in vitro tests for the diagnosis of DHRs is validation in larger studies with standardized controls that could harmonize diagnostic management between the United States, European Union, and other regions of the world.

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 calciumbinding protein, and hemocyanin are the most relevant. This review summarizes our current knowledge about these allergens.IgE-mediated shellfish allergy constitutes an important and increasing health issue in both children and adults (1, 2). During the last two decades, significant progress in biochemistry and molecular biology enabled the characterization, cloning, and recombinant production of various shellfish allergen components and epitope-emulating peptides that might become available for quantification of specific IgE (sIgE) antibodies, namely molecular diagnosis. This review intends to summarize our current knowledge about shellfish allergens and their cross-reactivity as this might be the key to optimize diagnosis (3, 4). Table 1 summarizes the most relevant shellfish allergens that have currently been characterized. Tropomyosin is considered to be the major allergen in shellfish allergy. Actually, already in the early 1980s Hoffman et al. (5) identified a heat-stable IgE-binding allergen in shrimps that was later identified as tropomyosin in brown shrimp (Penaeus aztecus) reacting with 28/ 34 (82%) of shrimp-sensitive individuals (6). Moreover, tropomyosin has been identified as a panallergen of many invertebrate species including other crustaceans (lobster, crab), mollusks (mussels, oysters, scallops, octopus, squids, snails, abalones, whelk, clams, razor shell), cockroaches, and mites (7-18). Tropomyosins are present in both muscle and nonmuscle cells. In striated muscle, they mediate the interaction of troponin-actin complex to regulate contraction. Note that tropomyosins from crustaceans share a high homology (up to 98%), whereas the amino acid sequence identity between (3,(19)(20)(21)(22)(23)(24)(25). Children were once reported to recognize a greater epitope repertoire than adults and thus suggested that shrimp sensitization could decrease over age (22). However, more recent studies with challenged patients could not reproduce this observation with the same epitope mapping (3, 24). About one decade ago, a recombinant tropomyosin from Penaeus aztecus, rPen a 1, became commercially available for molecular diagnostic testing, with improved results as a diagnostic tool in comparison with the whole-shrimp extract (26,27). In addition to tropomyosin, several other allergenic components have been identified in shellfish. In 2003, Yu et al. identified a novel allergen in Penaeus monodon (black tiger shrimp) (28), designated as Pen m 2, with arginine kinase activity. Similar to tropomyosin, arginine kinase is highly abundant i...

Suspected perioperative hypersensitivity reactions are rare but contribute significantly to the morbidity and mortality of surgical procedures. Recent publications have highlighted the differences between countries concerning the respective risk of different drugs, and changes in patterns of causal agents and the emergence of new allergens. This review summarises recent information on the epidemiology of perioperative hypersensitivity reactions, with specific consideration of differences between geographic areas for the most frequently involved offending agents.

Perioperative hypersensitivity reactions (POH) constitute a clinical and diagnostic challenge, a consequence of heterogeneous clinical presentations, and multiple underlying pathomechanisms. POH do not necessarily involve an allergen-specific immune response with cross-linking of specific immunoglobulin E (sIgE) antibodies on mast cells and basophils. POH can also result from alternative specific and non-specific effector cell activation/degranulation such as complement-derived anaphylatoxins and off-target occupancy of mast cell, basophil, or both surface receptors. Moreover, POH and anaphylaxis can occur independent from mast cell and basophil degranulation.The manifestations of POH primarily affect the cardiovascular, respiratory, and integumentary systems. POH present within the context of surgical or procedural pathology and the effects of surgical and anaesthetic techniques on pre-existing physiological reserve. The majority of cases of appropriately-treated intraoperative anaphylaxis can be considered a compensated cardiovascular anaphylaxis. With increasing severity of anaphylaxis, maldistribution and hypovolaemia lead to reduced venous return and circulatory failure. Treatment with a combination of epinephrine and i.v. fluid is critical for successful resuscitation, although the excessive use of epinephrine without adequate volume expansion may be deleterious. Neural control of the airways is important in the pathophysiology of bronchospasm. Anticholinergic drug premedication is beneficial in patients with hyperreactive airways. Pulmonary oedema can result from a combination of pulmonary capillary hypertension, incompetence of the alveolocapillary membrane, or both. Angioedema can be distinguished mechanistically into histaminergic and non-histaminergic (e.g. bradykinin-mediated). An understanding of the molecular mechanisms and pathophysiology of POH are essential for the immediate management and subsequent investigation of these cases.

Background. The final response that leads to basophil degranulation results from a cross-talk between activatory and inhibitory signals. However, in the context of basophil biology, the inhibitory mechanisms that control these processes are still poorly understood.Aim. To investigate the expression and function of the inhibitory receptor CD300a in human basophils. Methods. Peripheral blood of 20 patients with birch pollen allergy and 10 healthy control individuals were assessed for CD300a expression before and after activation. To study the function of CD300a, basophils were pre-incubated with anti-human CD300a/c monoclonal antibodies and analyzed for the upregulation of the activation marker CD203c and appearance of the degranulation marker CD63 following IgE-dependent and IgE-independent triggering.Results. Basophils from allergic individuals constitutively expressed significantly less CD300a than non-allergics (P 5 0.001). However, after cross-linking with either anti-IgE or recombinant major birch pollen allergen (rBet v 1), basophils from allergic patients demonstrated a significant and rapid (3 min) up-regulation of CD300a expression in all activated basophils that persisted for over 2 h (P < 0.05). Moreover, CD300a expression was significantly higher in the CD203c bright1 CD63 bright1 subpopulation than in CD203c bright1 CD63 2 cells (P < 0.05). In both patients and controls, pre-incubation with antiCD300a/c significantly inhibited IgE-mediated CD63 expression (P < 0.05), though it did not affect CD203c. In contrast, IgE-independent basophil activation was not inhibited by CD300a/c engagement.Conclusion. CD300a is expressed on human peripheral blood basophils and rapidly up-regulated upon cross-linking of IgE/FceRI and suppresses anaphylactic degranulation. V C 2011 International Clinical Cytometry Society