Flow cytometric method to detect lymphocyte transformation in drug-allergic hepatic injury

Flow cytometric methods for the analysis of incorporated bromodeoxyuridine are extremely rapid and simple. We investigated whether these methods were useful for detecting drug-allergic hepatic injury in 18 patients with drug-allergic hepatic injury, 18 healthy controls, and 9 nonallergic patients receiving drugs. Peripheral blood mononuclear cells were stimulated with drug solutions. Incorporation of bromodeoxyuridine was detected after labeling with FITC, and S-phase cells were counted by flow cytometry. Percentages of S-phase cells in drug-stimulated culture minus those in spontaneous cultures were less than 1% in both healthy controls and nonallergic patients receiving drugs. Taking 1% as the upper limit, 13 patients (72%) were judged as positive. After the in vitro addition of interleukin-2, two patients among five who had been judged as negative were judged as positive. Lymphocyte transformation test by flow cytometry may be useful in the diagnosis of drug-allergic hepatic injury.