Increased in vitro release of interferon-gamma from ampicillin-stimulated peripheral blood mononuclear cells in Stevens-Johnson syndrome.

Stevens–Johnson syndrome (SJS) was diagnosed in a 39-year-old woman, treated with ampicillin (4000—8000 mg daily), phenytoin (250 mg daily), and furosemide (20—40 mg daily) for 25, 21, and 20 d, respectively, before the appearance of the eruption. The lymphocyte stimulation test with the MTT [3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide] assay on ampicillin, phenytoin, and furosemide showed a low value of stimulation index, which indicated negative reactivity. An in vitro IFN-γ release test was conducted on the patient with SJS and on two healthy controls. IFN-γ release increased by 52% following the in vitro challenge of the patient's peripheral blood mononuclear cells (PBMCs) with 15 μg/ml of ampicillin, but not with phenytoin or furosemide. Neither of the controls experienced increased IFN-γ release. In the present case, increased in vitro IFN-γ release was observed on ampicillin-stimulated PBMCs, which may indicate the role of ampicillin as the drug responsible for the induction of SJS, and may imply the role of IFN-γ in the pathogenesis of SJS.