Patients monoallergic to NRL or birch pollen showed no sensitization to bromelain-type CCD or profilin. Sensitization to profilin and/or bromelain-type CCD, caused by pollen (timothy grass, mugwort) or hymenoptera venom allergens, can elicit false-positive IgE antibodies against NRL and apple.

Background: Correct identification of the culprit venom is a prerequisite for specific venom immunotherapy (VIT). Despite the efficacy of VIT, issues as how to monitor treatment and when to discontinue maintenance therapy remain to be established.Methods: To evaluate diagnostic performances of the basophil activation test (BAT) in wasp venom allergy, 80 patients with a definite history of wasp venom anaphylaxis (systemic reactors) and 14 waspstung asymptomatic controls (stung controls) were enrolled. Venom-induced basophil activation was analyzed flow cytometrically by double-labeling with anti-IgE and anti-CD63. Results were compared to wasp IgE levels and results of a venom skin test (VST). To establish whether the BAT constitutes a candidate marker to monitor VIT, the BAT was repeated in 22 patients on the 5th day of a build-up course and after 6 months of maintenance VIT. Whether the BAT could contribute in the decision of discontinuing VIT was assessed in a cross-sectional analysis in 30 patients receiving treatment for 3 years.Results: Comparison between systemic reactors and stung controls revealed a sensitivity of 86.4% and specificity of 100% for venom IgE, and sensitivity of 81.8% for VST, respectively. In contrast to stung controls, patients demonstrated dose-dependent venom-induced basophil activation. The BAT attained a sensitivity of 83.8% and specificity of 100%. At the end of the build-up course, no effect of VIT on the BAT was demonstrable. When the BAT was repeated after 6 months of treatment, submaximal stimulation of the cells demonstrated a significant decreased CD63 expression (P < 0.04). Patients having VIT for 3 years also demonstrated significantly lower venom-induced CD63 expression (P < 0.001). After 3 years, 60% of the patients had a negative BAT for submaximal stimulation of the cells whereas only 17.9% of the patients had negativation of wasp IgE.Conclusions: The BAT is a reliable instrument for the diagnosis of wasp venom anaphylaxis and might constitute an instrument to monitor wasp VIT. q

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...

During the last 5 years, an increasing number of studies have demonstrated that flow cytometric quantification of in vitro basophil activation can be a quite performant and reliable tool to measure IgE-dependent allergen-specific responses in allergic patients. So far, most assays have used CD63 as a basophil activation marker and native allergen extracts for stimulation. However, other basophil markers and recombinant allergens have recently been introduced. The technique has been applied for the diagnosis of allergy to pollen, house dust mite, food, natural rubber latex, hymenoptera venom and drugs. In addition, the technique has proven to be useful in non-IgE-mediated reactions such as hypersensitivity to drugs as well as detection of auto-antibodies in chronic urticaria. This review will focus on some specific issues: (1) principles of flow cytometric analysis of in vitro-activated basophils, (2) general technical aspects of the technique (including passive sensitization), (3) clinical applications and (4) recommendations for further development and evaluation of the technique.