Automated histamine analysis for in vitro allergy testing. I. A method utilizing allergen-induced histamine release from whole blood.

A sensitive, automated, histamine assay system has been developed and applied for in vitro allergy testing. Nine common pollen and environmental allergens were used at three log dilutions for in vivo studies utilizing small volumes of blood (15-20 ml). The clinical evaluation was correlated with the results of the histamine release. two different procedures were utilized. The first is the commonly used histamine release from washed leukocytes. There was excellent correlation between the clinical evaluation and the results of histamine release from washed leukocytes in 17 different individuals. The second and simpler method utilized whole heparinized blood which might better reflect the immunologic reaction which occurs in vivo. Aliquots of blood and allergen were incubated for 1 hr at 37 degrees C and each supernatant was then analyzed for histamine release. There was excellent correlation between the two tests in 29 patients tested by both the whole blood and washed leukocyte methods. There was also good correlation between the clinical evaluation of the patients amd the intro tests. The precision, accuracy, and sensitivity of the automated histamine assay make feasible its routine application in the clinical study of allergic patients.