Flow cytometric analysis of basophil activation in the diagnosis of yellowjacket venom allergy

Diagnosis of yellow jacket venom allergy is based on medical history, speci fic IgE antibodies and skin testing. Other in vitro tests like histamine re lease assay, basophil degranulation test, sulfidoleukotriene-ELISA, immunob lotting or inhibition tests are not used routinely, but may provide further information without being of prognostic value. The aim of the present stud y was to evaluate the efficiency of a novel in vitro technique for measurin g the activation of blood basophils (Basotest, Orpegen Pharma, Heidelberg, FRG) in patients with yellow jacket venom allergy. Activated basophils were detected by monoclonal antibodies against IgE and against the activation m arker gp53 (CD63) and subsequent flow cytometric analysis. 10 patients with untreated yellow yacket venom allergy, 10 patients treated with specific i mmunotherapy (SIT) and 12 healthy controls were investigated by means of Ba sotest, CAP PAST FEIA, and CAP IgE FEIA. Negative controls showed no signif icant basophil activation after stimulation with yellow jacket venom in com parison to stimulation with PBS-washing buffer. In the control group cut of f values (mean + 3 standard deviations) were defined for different allergen concentrations. Using these cut off values every patient without actual SI T was detected after stimulation with 400 ng/ml and 4 mug/ml yellow jacket venom. Patients could be identified even after a long interval to the relev ant sting reaction and despite a low CAP class. Patients receiving SIT show ed lower basophil activation than patients without SIT (not significant). T here was no correlation between basophil activation and total IgE, but baso phil activation increased with allergen concentration used for stimulation. In summary, although the number of investigated patients was small and CAP negative patients were not included, the measurement of basophil activatio n seems to be a highly sensitive and specific diagnostic technique for diag nosis of yellow jacket venom allergy. This technique is simple to perform, and results can be obtained within two hours.