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Background: We sought to determine whether basophil-allergen sensitivity could be transferred to donor basophils by passive IgE sensitisation in allergic rhinitis and anaphylactic Hymenoptera venom hypersensitivity., Methods: We studied 15 wasp venom-, 19 grass pollen- and 2 house dust mite-allergic patients, 2 healthy donors, and 8 wasp venom-allergic donors. In all subjects, we first evaluated the initial basophil response to wasp venom, grass pollen, or house dust mite allergen. Donor basophils were then stripped, sensitised with the different patients' serum IgE, and challenged with the corresponding allergen. The CD63 response of donor basophils was then compared with initial basophil responses., Results: In wasp venom-allergic subjects, the IgE transfer did not reflect the initial basophil-allergen sensitivity, because the venom IgE of subjects with high or low basophil sensitivity induced comparable responsiveness in healthy donor basophils. Furthermore, vice versa, when we sensitised the donor basophils of wasp venom-allergic individuals with different wasp venom or house dust mite IgE, we demonstrated that their response was predictable by their initial basophil allergen sensitivity. In the rhinitis allergy model, the IgE transfer correlated with the patients' initial basophil responsiveness because the grass pollen IgE of the subjects with high basophil allergen sensitivity induced significantly higher responsiveness of donor basophils than the IgE of subjects with initially low basophil allergen sensitivity., Conclusions: Our results suggest that basophil allergen sensitivity evaluated by flow-cytometric CD63 analysis depends on two distinct contribution factors. In anaphylactic Hymenoptera allergy, the major factor was intrinsic cellular sensitivity, whereas in pollen allergy, the major factor was allergen-specific IgE on the cell surface., (© 2016 S. Karger AG, Basel.)

Background: Peanut sensitization is common in children. However, it is difficult to assess which children will react mildly and which severely. This study evaluated the relevance of basophil allergen sensitivity testing to distinguish the severity of peanut allergy in children., Methods: Twenty-seven peanut-sensitized children with symptoms varying from mild symptoms to severe anaphylaxis underwent peanut CD63 dose-response curve analysis with the inclusion of basophil allergen sensitivity calculation (CD-sens) and peanut component immunoglobulin E (IgE) testing., Results: Eleven children who had experienced anaphylaxis to peanuts showed a markedly higher peanut CD63 response at submaximal allergen concentrations and CD-sens (median 1,667 vs. 0.5; p < 0.0001) than 16 children who experienced a milder reaction. Furthermore, a negative or low CD-sens to peanuts unambiguously excluded anaphylactic peanut allergy. Children with anaphylaxis have higher levels of Ara h 1, 2, 3 and 9 IgE, but comparable levels of IgE to Ara h 8 and whole-peanut extract. The diagnostic specificity calculated with a receiver operating characteristic analysis reached 100% for CD-sens and 73% for Ara h 2., Conclusions: We demonstrated that severe peanut allergy is significantly associated with higher basophil allergen sensitivity. This cellular test should facilitate a more accurate diagnosis of peanut allergy., (© 2013 S. Karger AG, Basel.)

Upon first exposure to cetuximab, hypersensitivity reactions can occur. We aimed to assess the utility of the basophil activation test (BAT) to alpha-gal and cetuximab for predicting severe reactions. We prospectively recruited 38 patients and evaluated sIgE to alpha-gal in all patients before the first application of cetuximab. In all alpha-gal-sensitized patients, we evaluated skin tests to meat extracts, gelatine, and cetuximab and performed BAT with alpha-gal and cetuximab. In 24% (9/38) of patients, sIgE to alpha-gal was >0.10 kUA/L, and 8/9 reacted to the cetuximab. Basophil activation tests with alpha-gal were positive in all sensitized patients and were higher in those with severe reactions (18.3% in grade 4 [n = 4] vs. 1.8% in grade 2 [n = 3] or no reaction [n = 1] at 3.3 ng/mL of alpha-gal; p = 0.03). All patients with severe grade 4 reactions had a positive CD63 BAT response to cetuximab compared to patients with moderate or no reaction, who all had negative BAT (57.7% vs. 0.9% at 500 µg/mL, 63.2% vs. 4.1% at 100 µg/mL, 58.2% vs. 2.7% at 10 µg/mL, and 32.1% vs. 3.3% at 1 µg/mL of cetuximab, respectively; p ≤ 0.001). In summary, before initiating cetuximab treatment, sIgE to alpha-gal should be assessed in all patients. To predict the severity of the reaction and to assess the risk of cetuximab-induced anaphylaxis, we should perform BATs with alpha-gal or more discriminative BATs with cetuximab. [ABSTRACT FROM AUTHOR]

Background: Anaphylaxis is an acute life-threatening allergic reaction and a concern at a global level; therefore, further progress in understanding the underlying mechanisms and more effective strategies for diagnosis, prevention and management are needed. Objective: We sought to identify the global architecture of blood transcriptomic features of anaphylaxis by integrating expression data from human patients and mouse model of anaphylaxis. Methods: Bulk RNA-sequencings of peripheral whole blood were performed in: i) 14 emergency department (ED) patients with acute anaphylaxis, predominantly to Hymenoptera venom, ii) 11 patients with peanut allergy undergoing double-blind, placebo-controlled food challenge (DBPCFC) to peanut, iii) murine model of IgE-mediated anaphylaxis. Integrative characterisation of differential gene expression, immune cell-type-specific gene expression profiles, and functional and pathway analysis was undertaken. Results: 1023 genes were commonly and significantly dysregulated during anaphylaxis in ED and DBPCFC patients; of those genes, 29 were also dysregulated in the mouse model. Cell-type-specific gene expression profiles showed a rapid downregulation of blood basophil and upregulation of neutrophil signature in ED and DBPCFC patients and the mouse model, but no consistent and/or significant differences were found for other blood cells. Functional and pathway analysis demonstrated that human and mouse blood transcriptomic signatures of anaphylaxis follow trajectories of upregulation of cell movement, migration and neuroinflammatory signalling, and downregulation of lipid activating nuclear receptors signalling. Conclusion: Our study highlights the matched and extensive blood transcriptomic changes and suggests the involvement of discrete cellular components and upregulation of migration and neuroinflammatory pathways during anaphylaxis. [ABSTRACT FROM AUTHOR]

The proposed mechanism is that omalizumab changes the behaviour of basophils by lowering the densities of Fc RIs and IgEs on basophils, possibly affecting their migration.2,9 Therefore, a subgroup of CSU patients, characterized by very low number of circulating basophils, autoimmune basophil response and autoreactive serum are less likely to respond to omalizumab treatment. Keywords: basophils; chronic spontaneous urticaria; Fc RI; gene expression; omalizumab EN basophils chronic spontaneous urticaria Fc RI gene expression omalizumab 1254 1257 4 04/14/21 20210401 NES 210401 Chronic spontaneous urticaria (CSU) is characterized by the spontaneous appearance of wheals, angioedema or both for more than 6 weeks.1 CSU signs and symptoms, albeit not life-threatening, markedly affect patients' quality of life.1 Mast cell activation and degranulation with subsequent release of inflammatory mediators play a key role in CSU symptom development; however, several points of evidence suggest that basophils also contribute to the disease.1,2 Omalizumab, a recombinant humanized monoclonal anti-IgE antibody, represents an effective treatment of CSU and is often used in patients unresponsive to high doses of H1 antihistamines.1 However, the response to treatment is variable, as some CSU patients respond to treatment within days of their first omalizumab injection, others respond within weeks, and a subgroup of patients do not respond to omalizumab at all.1,2 The aim of this study was to evaluate the predictive value of basophil-associated markers, measured before starting omalizumab treatment, for the response to omalizumab in patients with CSU. [Extracted from the article]

Background: We recently showed a desensitization of FcεRI-mediated basophil response after short-term VIT. Our aim was to evaluate the allergen specificity of this desensitization. Methods: In 11 Hymenoptera-venom double positive subjects, basophil threshold sensitivity (CD-sens) to anti-FcεRI, honeybee, and Vespula venom was assessed at the beginning and just before the first maintenance dose (MD) of single ultra-rush VIT. In some patients we also monitored CD-sens to rApi m 1 and/or rVes v 5 or other co-sensitizations (i.e., grass pollen). In additional 7 patients, basophils were stripped and sensitized with house dust mite (HDM) IgEs at the same time points. Results: We demonstrated a marked reduction of CD-sens to anti-FcεRI and VIT-specific venom before the first MD in all 18 subjects included. Furthermore, in 10 out of 11 double positive subjects, a significant and comparable decrease before the first MD was also evident for non-VIT venom; this nonspecific decrease was further supported by the opposite recombinant species-specific major allergen. In one subject with additional grass pollen allergy, a decrease of CD-sens to grass allergen was also demonstrated. Similarly, in 7 cases of patients with passively HDM-sensitized basophils, a significant reduction of CD-sens was also evident to de novo sensitized HDM allergen. Conclusions: Short-term VIT induced basophil desensitization to VIT-specific as well as to VIT-nonspecific venom. As opposed to long-term VIT, which induces venom-specific changes, the effect of short-term VIT seems to be venom-nonspecific. [ABSTRACT FROM AUTHOR]

Background: Previous reports suggest the usefulness of basophil activation testing (BAT) in Hymenoptera-allergic patients with negative venom-specific IgE antibodies. We sought to evaluate the diagnostic utility of this testing in a routine clinical laboratory setting. Materials and Methods: Twenty-one patients with anaphylactic reactions to Hymenoptera sting (median grade III) and negative venom-specific IgE were routinely and prospectively tested with BAT. Results: We were able to diagnose 81% (17 of 21) of patients with BAT and 57% (12 of 21) with intradermal skin testing. Three wasp venom-allergic patients showed IgE positivity to rVes v 5. Four patients (19%) were negative for all tests. In the case of double-positive BAT, the culprit insect correlated with the venom that induced a significantly higher basophil response. Conclusions: BAT allows the identification of severe Hymenoptera-allergic patients with negative specific IgE and skin tests. The routine use of this cellular test should facilitate prescription of venom immunotherapy in complex cases with inconclusive diagnostic results. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

To cite this article:Žitnik SEK, Vesel T, Avčin T, Šilar M, Košnik M, Korošec P. Monitoring honeybee venom immunotherapy in children with the basophil activation test. Pediatr Allergy Immunol 2011 Doi: 10.1111/j.1399-3038.2011.01233.x Abstract Background: New in vitro methods are essential for developing better follow-up criteria for venom immunotherapy (VIT). Methods: Thirty-one children with a history of honeybee venom-induced systemic anaphylaxis were included in this prospective, single-blinded study. The basophil CD63 activation test (BAT) was assessed before starting VIT, at the end of the build-up phase (day 5), 6 months later, and after 2-4 yr of VIT. Results: Basophil CD63 activation test allowed identification of the culprit insect in 74% of honeybee venom-allergic children. In comparison, IgE reactivity was single positive in only 52% of children. Five days after starting VIT, BAT was highly comparable to before VIT. However, after 6 months and further after 2-4 yr of VIT, a significant and approximately fourfold decrease was demonstrated in CD63 response at sub-maximal 0.1 μg/ml allergen concentration, which mainly represents cellular sensitivity. No such differences were found at a higher 1 μg/ml of allergen concentration. Person-to-person analyses showed that after 2-4 yr of VIT, a marked CD63 decrease was evident in 85% of children. In addition, elevated basophil sensitivity measured before VIT was associated with the appearance of side effects observed during the build-up phase of VIT. Conclusion: Basophil CD63 allergen-specific sensitivity seems to be a promising tool for monitoring protective immune response in honeybee VIT. [ABSTRACT FROM AUTHOR]

Cytokines released from T lymphocytes regulate antibody production by B lymphocytes and releasability of mast cells and basophils. Immune tolerance an specific allergen (Ag) immunotherapy (SIT) might be a consequence of decreased Th2 or increased Th1 response of Ag specific T lymphocytes. We compared function of T lymphocytes in II patients with Hymenoptera venom allergy and in 7 healthy volunteers. We followed function of I lymphocytes in 6 patients during SIT. We measured released IL-2, IFN-γ, IL-4 and IL-5 from Ag and mitogens (either with phorbol-miristate-acetate (PMA) and ionomycine or anti-CD3 antibodies) stimulated peripheral blood mononuclear cells (PBMC). After stimulation with Ag PBMC of patients released 86 ± 133 pg/ml IFN-γ and 19.7 ± 20.1 pg/ml IL-4 (Th2 response), PBMCs of healthy controls released 184 ± 116 pg/ml IFN-γ and 4.8 ± 8 pg/ml IL-4 (Th1 response). Spontaneous release of IFN-γ in cultures of PBMC of patients increased after rush SIT (before: 25 ± 31 pg/ml, after 241 ± 281 pg/ml, p<0.05). After 6 months of SIT response of PBMCs of patients became similar to response of PBMCs of healthy controls. Time pattern of cytokines secreted from PBMCs after stimulation with PMA and ionomycine was different than after stimulation through T-cell receptor/CD3 complex. [ABSTRACT FROM AUTHOR]