Disopyramide-induced pneumonitis, diagnosed by lymphocyte stimulation testusing bronchoalveolar lavage fluid

A 72-year-old man was admitted to our hospital with fever and cough. He had been on disopyramide treatment for nine days to control cardiac arrhythmia . On admission, chest X-ray examination revealed reticulonodular opacities in both lungs, and impending respiratory failure was evident. A differentia l cell count of the bronchoalveolar lavage fluid (BALF) showed a marked inc rease of lymphocytes. A lymphocyte stimulation test (LST) for disopyramide using BALF was positive, although the test using peripheral blood was negat ive. This case suggests that LST using BALF is useful for the diagnosis of drug-induced pneumonitis.