In vitro measurement of lymphocyte steroid sensitivity: Lack of agreement between whole blood culture and separated lymphocyte culture

The use of a whole blood culture to measure steroid sensitivity has previou sly been compared to the use of a separated lymphocyte assay. Good correlat ion between the two methods was reported. However the number of subjects st udied appears to have been small and no patients with steroid resistance we re studied. We have studied a large number of subjects and compared steroid sensitivity measured by a whole blood culture with an established separate d lymphocyte assay. Proliferation was stimulated with phytohaemagglutinin a nd inhibited by dexamethasone. A wide range of steroid sensitivity was foun d between individuals. In steroid sensitive subjects, good agreement was se en between the two assays. However in individuals identified as steroid res istant by the separated lymphocyte assay, steroid resistance was not seen u sing the whole blood assay. This is important because in vitro lymphocyte s teroid resistance as measured by the separated lymphocyte assay has been sh own to predict a poor in vivo response to steroid therapy. Using the whole blood culture this steroid resistance would not be demonstrated. Hence the use of a whole blood assay can not be recommended.