Background: No study has assessed the diagnostic sensitivity of rApi m1 and rVes v5 on Immulite testing system. OBJECTIVE: To compare the diagnostic sensitivity of commercially available venom recombinant allergens between the currently available immunoassays (ImmunoCAP [CAP] and Immulite [LITE]), and establish their correlation with the severity of the sting reaction. Methods: This study evaluated 95 bee venom and 110 yellow-jacket venom allergic subjects. We measured the levels of sIgE to rApi m1, rVes v5 (LITE and CAP), rApi m2 (LITE), rVes v1 (CAP) and tIgE (CAP). Forty-nine healthy subjects served as controls. Results: The diagnostic sensitivity of rApi m1 and rVes v5 was significantly higher with the LITE than with the CAP system (71% vs. 88% and 82% vs. 93%). The specificity of both assays for both allergens was between 94% and 98%. Twenty-nine patients that tested negative for rApi m1 or rVes v5 with CAP were positive with LITE, but none of the patients that tested negative with LITE were positive with CAP. The positive values of rApi m1 and rVes v5 were on average 2.7 and 2.3 times higher, with the LITE than with the CAP system. The combination of rApi m1 and rApi m2 (LITE) and the combination of rVes v5 (LITE) and rVes v1 (CAP) almost matched the sensitivity of native venoms (95% and 97%, respectively), whereas the diagnostic sensitivity of the combination of rVes v5 and rVes v1 (CAP) did not reach the sensitivity of rVes v5 (LITE) alone (90% vs. 93%). IgE levels to venom recombinants and total IgE did not correlate with the severity of sting reaction. Conclusions & clinical relevance: The use of rApi m1 and rVes v5 with the LITE system significantly enhanced diagnostic utility of venom recombinants and should improve the dissection of bee and yellow-jacket venom allergy. This article is protected by copyright. All rights reserved.
COBISS.SI-ID: 38055685
Background: An important advantage of allergen immunotherapy as compared to pharmacotherapy for allergic rhinitis is the long-term effect that persists after completing immunotherapy. The mechanism of the sustained effect of allergen immunotherapy is not completely understood. Methods: We conducted a 7-year study of monitoring allergen-specific basophil response and serological markers in 20 subjects with moderate-to-severe grass pollen-allergic rhinitis just before beginning and after up-dosing of subcutaneous grass pollen immunotherapy, before the first pollen season, and 1–2 years after completion of 3–5 years of treatment. Comparable untreated rhinitis subjects were followed at the same time points. Clinical outcomes included assessment of symptoms, use of rescue medication, and quality of life. The basophil response was also monitored after removal of IgG antibodies. Results: Basophil response assessed as area under the curve (AUC) halved during initiation of SCIT and was 55% lower 1–2 years after completing SCIT. In the untreated group, the basophil response remained comparable. Although immunotherapy-induced grass pollen-specific IgG4 levels decreased to near pre-immunotherapy levels after completing SCIT, the removal of IgG antibodies resulted in an increase in basophil response almost to the pre-immunotherapy levels. In untreated subjects, removal of IgG did not have any effect on basophil response. Conclusions: Grass pollen immunotherapy induces sustained suppression of the allergen-specific basophil response that persists after completion of treatment and could account for long-term clinical tolerance. It also seems to be associated with persistent blocking activity of IgG antibodies.
COBISS.SI-ID: 37928453
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.
COBISS.SI-ID: 37979653