Bacground: The identification of the disease-causing insect in venom allergy is often difficult. Objective: To establish recombinant allergen-based IgE tests to diagnose bee and yellow jacket wasp allergy. Methods: Sera from patients with bee and/or wasp allergy (n = 43) and patients with pollen allergy with false-positive IgE serology to venom extracts were tested for IgEreactivity in allergen extract-based tests or with purified allergens, including nonglycosylated Escherichia coli-expressed recombinant (r) Api m 1, rApi m 2, rVes v 5, and insect cell-expressed, glycosylated rApi m 2 as well as 2 natural plant glycoproteins (Phl p 4, bromelain). Results: The patients with venom allergy could be diagnosed with a combination of E coli-expressed rApi m 1, rApi m 2, and rVes v 5 whereas patients with pollen allergy remainednegative. For a group of 29 patients for whom the sensitizing venom could not be identified with natural allergen extracts, testing with nonglycosylated allergens allowed identification of the sensitizing venom. Recombinant nonglycosylated allergens also allowed definition of the sensitizing venom for those 14 patients who had reacted either with bee or wasp venom extracts. By IgE inhibition studies, it is shown that glycosylated Api m 2 contains carbohydrate epitopes that cross-react with natural Api m 1, Ves v 2, natural Phl p 4, and bromelain, thus identifying cross-reactive structures responsible for serologic false-positive test results or double-positivity to bee and wasp extracts. Conclusions: Nonglycosylated recombinant bee and wasp venom allergens allow the identification of patients with bee and wasp allergy and should facilitate accurate prescription of venomimmunotherapy.
COBISS.SI-ID: 27138521
Background: There is no in vitro test to predict the induction of long-term tolerance in patients treated with venom immunotherapy (VIT). The aim of this study was to investigate whether immunotherapy-induced changes in basophil responsiveness reflect a state of protection and the induction of a tolerance.Methods: Twenty-three patients with allergic reaction after Hymenoptera sting (11 wasp and 12 honeybee) were treated with VIT. In all patients, a CD63 basophil activation test was performed before the beginning of immunotherapy, after 1 year and after completing 4-6.5 years of immunotherapy (approximately 1 year after stopping). The tolerance was then evaluated by a sting challenge test. The basophil activation test was repeated3-6 months after the challenge. Results: Twenty-two subjects showed a negative sting challenge, and one subject, a positive sting challenge. Allergen-specific basophil response remained unchanged after 1 year of immunotherapy. However, after immunotherapy, a significant and approximately fourfold decrease was demonstrated in all tolerant subjects mainly in response to submaximal 0.1 mug/ml allergen concentration. This depression wassustained and did not change with the sting challenge test. In a nontolerant patient with a positive sting challenge, basophil response did notchange. Conclusions: Our results suggest that the depression of allergen-specific basophil response seems to be associated with the induction of a tolerance after completing a course of VIT.
COBISS.SI-ID: 29842393
Background The mechanisms responsible for the difference between clinically irrelevant IgE-sensitization and allergic rhinitis are not fully understood. Objective We evaluated the humoral and cellular mechanisms that may be associated with the presence of allergic rhinitis symptoms. Methods We selected 26 subjects with positive grass pollen skin tests and IgE antibodies to Timothy (g6) and the major grass allergens rPhl p 1, 5b. Fourteen of those patients reported a history of allergic rhinitis. During winter, we performed a grass pollen CD63 basophile activation test using four log allergen concentrations, followed by a grass nasal provocation test (NPT). We obtained symptom scores in the subsequent pollination season. Results We showed that subjects with a positive NPT have significantly higher CD63 basophile grass pollen responsiveness than NPT-negative subjects, preferably at submaximal allergen concentrations, which represent cellular sensitivity. Moreover, basophile sensitivity positively correlated with the size of the grass-specific IgE fraction in relation to total IgE, and it was highly predictive of allergic rhinitis symptoms in the following pollination season. Conclusion and Clinical Relevance Allergic rhinitis symptoms are significantlyassociated with allergen-specific basophile sensitivity. In vitroevaluation of basophile sensitivity should prove useful for distinguishing clinical phenotype of allergic sensitization.
COBISS.SI-ID: 28743129
Background: Airway angiogenesis may be an important part of structural remodelling in the pathogenesis of asthma. The development of asthma is frequently preceded by rhinitis. Objective: We sought to determine whether thelevels of angiogenesis-related factors are elevated in airways of patients with rhinitis or controlled asthma. Methods: We analysed the induced sputum of18 rhinitis patients, 16 asthmatic patients, and 15 healthy controls. The concentrations of angiogenin, vascular endothelial growth factor (VEGF), IL-8,fibroblast growth factor (bFGF), and TNF-alpha were measured by cytometric bead arrays. Results: We found significantly increased angiogenin and VEGF concentrations in the induced sputum supernatant of both rhinitis andasthma patients compared with that of the healthy control group (P( or =0.0005). With the exception of TNF-alpha, there was no difference in the other angiogenic factors; TNF-alpha levels were higher in the rhinitis group than in the control group (P=0.02). Conclusion: These in vivo results suggest increased airway angiogenesis in patients with rhinitis without asthma as wellas in corticosteroid-treated and well-controlled asthma patients.
COBISS.SI-ID: 25417689
Background: Current guidelines do not adequately address the question of how best to manage patients with a convincing history of insect allergy, but negative venom-specific IgE and skin test results. Methods: Forty-seven patients out of a total of 1219 (4%), with a positive history of sting allergy, were recruited over a period of 4.5 years. All recruited patients hada convincing history of a severe or a life-threatening anaphylactic reaction of Mueller grade II-IV (median grade III) after Hymenoptera sting, but negative venom-specific IgE and skin prick test results. Diagnostic work-up was prospectively followed by the CD63 basophil activation test and byintradermal skin testing. A control group of 25 subjects was also assessed. Results: Thirty-five out of 47 (75%) patients demonstrated a positive basophilCD63 response after stimulation with bee and/or wasp venom. Intradermal venom skin tests were performed for 37 patients, 17 (46%) of whom showed positive results. Out of 20 patients who demonstrated negative intradermal test results, 12 patients showed a positive CD63 response (60%). In contrast, out of 9 patients who showed a negative CD63 response, only one was detected by intradermal testing (11%). In the control group, only two out of 25 (4%) subjects displayed a positive basophil response and/or intradermal test. Conclusion: Here we show that, in complex cases with inconclusive diagnostic results, the CD63 activation test could be particularly useful and more sensitive than intradermal skin testing.
COBISS.SI-ID: 26253785