Background Basophil activation tests (BATs) have promise for research and for clinical monitoring of patients with allergies. However, BAT protocols vary in blood anticoagulant used and temperature ...and time of storage before testing, complicating comparisons of results from various studies. Objective We attempted to establish a BAT protocol that would permit analysis of blood within 24 hours of obtaining the sample. Methods Blood from 46 healthy donors and 120 patients with peanut allergy was collected into EDTA or heparin tubes, and samples were stored at 4°C or room temperature for 4 or 24 hours before performing BATs. Results Stimulation with anti-IgE or IL-3 resulted in strong upregulation of basophil CD203c in samples collected in EDTA or heparin, stored at 4°C, and analyzed 24 hours after sample collection. However, a CD63hi population of basophils was not observed in any conditions in EDTA-treated samples unless exogenous calcium/magnesium was added at the time of anti-IgE stimulation. By contrast, blood samples collected in heparin tubes were adequate for quantification of upregulation of basophil CD203c and identification of a population of CD63hi basophils, irrespective of whether the specimens were analyzed by means of conventional flow cytometry or cytometry by time-of-flight mass spectrometry, and such tests could be performed after blood was stored for 24 hours at 4°C. Conclusion BATs to measure upregulation of basophil CD203c and induction of a CD63hi basophil population can be conducted with blood obtained in heparin tubes and stored at 4°C for 24 hours.
Background Studies with c- kit mutant mast cell (MC)–deficient mice and antibody-mediated depletion of basophils suggest that both MCs and basophils can contribute to peanut-induced anaphylaxis ...(PIA). However, interpretation of data obtained by using such approaches is complicated because c- kit mutant mice have several phenotypic abnormalities in addition to MC deficiency and because basophil-depleting antibodies can also react with MCs. Objective We analyzed (1) the changes in the features of PIA in mice after the selective and inducible ablation of MCs or basophils and (2) the possible importance of effector cells other than MCs and basophils in the PIA response. Methods Wild-type and various mutant mice were orally sensitized with peanut extract and cholera toxin weekly for 4 weeks and challenged intraperitoneally with peanut extract 2 weeks later. Results Peanut-challenged, MC-deficient Kit W-sh/W-sh mice had reduced immediate hypothermia, as well as a late-phase decrease in body temperature that was abrogated by antibody-mediated depletion of neutrophils. Diphtheria toxin–mediated selective depletion of MCs or basophils in Mcpt5-Cre ; iDTR and Mcpt8 DTR mice, respectively, and treatment of wild-type mice with the basophil-depleting antibody Ba103 significantly reduced peanut-induced hypothermia. Non–c- kit mutant MC- and basophil-deficient Cpa3-Cre;Mcl-1 fl/fl mice had reduced but still significant responses to peanut. Conclusion Inducible and selective ablation of MCs or basophils in non–c- kit mutant mice can significantly reduce PIA, but partial responses to peanut can still be observed in the virtual absence of both cell types. The neutrophilia in Kit W-sh/W-sh mice might influence the responses of these mice in this PIA model.
We report herein a simple new fluorescent-avidin-based method to detect activated basophils in the whole blood of normal or allergic subjects, and compare this method to a basophil activation test ...based on detection of CD63.
Abstract Purpose Selexipag is a new orally available nonprostanoid prostacyclin receptor agonist for the treatment of pulmonary arterial hypertension. Warfarin is commonly used in patients with ...pulmonary arterial hypertension. Possible pharmacodynamic and pharmacokinetic interactions between selexipag and warfarin in healthy individuals were investigated. Methods This was a double-blind, 2-way, 2-treatment crossover, Phase I study. Nineteen healthy men received a single dose of selexipag 400 μg or placebo on day 1, followed by selexipag 400 μg or placebo BID on days 2 to 12. A concomitant single dose of warfarin 20 mg was administered in the morning of day 8. Findings Both treatments were well tolerated. The most frequently reported adverse event was headache in both treatments. Geometric mean ratios and 90% CIs of the maximum international normalized ratio (geometric mean ratio = 0.96; 90% CI, 0.90–1.03) and international normalized ratio AUC0–144h (geometric mean ratio = 0.98; 90% CI, 0.96–1.00) during treatment with warfarin and selexipag versus treatment with only warfarin were inside the reference limits of 0.80 to 1.25. The 90% CIs of the geometric mean ratios of AUC and Cmax for R- and S-warfarin during treatment with warfarin and selexipag versus treatment with warfarin alone were inside the reference range of 0.80 to 1.25. After repeated-dose administration of 400 μg selexipag, the AUC of selexipag and its active metabolite, ACT-333679, at steady state were not affected by a single dose of 20 mg warfarin. Implications Steady-state levels of selexipag and ACT-333679 after repeated doses of 400 μg selexipag had no influence on the warfarin pharmacodynamic variables. There was no pharmacokinetic interaction between selexipag and warfarin.
Methods Blood from healthy donors and peanut allergic patients was collected into ethylenediaminetetraacetic acid (EDTA) or heparin tubes, and samples were stored at 4°C or room temperature for 4 or ...24 hours before analysis.
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