Flow cytochemical analysis of atopic reactions

The technicon H-6000 has the unique ability among automated hematology systems to discriminate basophils from other hematopoietic cells on the basis of astra blue positivity of heparin-containing granules. We therefore examined the ability of this flow cytochemistry system to predict allergic diathesis in vitro by examining the number of basophils detected before and after incubation with a variety of allergens. One hundred subjects with documented atopic reactions to known allergens were examined and compared to 13 patients who had undergone successful desensitization and 12 normal subjects who had no history of atopy. One subject who had a previous anaphylactic response to penicillin but was skin-test negative to the major antigenic determinant demonstrated 55% degranulation after incubation with penicillin G. Finally, the basophil degranulation as assessed by the Technicon H-6000 was compared to a histamine release assay to determine the sensitivity of the automated system. The results suggest that flow cytochemistry may prove a valuable tool in predicting the success of desensitization therapy for common allergens and may have the potential to screen atopic reaction in the routine hematology laboratory.