The diagnostic role of the in vitro drug-induced interferon-gamma release test in Stevens-Johnson syndrome

Background Drug-related T-cell activity in cutaneous drug reactions may be assessed by in vitro cytokine release tests. The diagnostic role of in vitr o drug-induced interferon-gamma (IFN-gamma) release was evaluated in a pati ent with Stevens-Johnson syndrome. Case report Stevens-Johnson syndrome was diagnosed in a 58-year-old man, tr eated with colchicine (1 mg daily for 39 days) and allopurinol (300 mg dail y for 13 days). Based on a clinical-epidemiologic score, allopurinol was mo re likely to be the causative agent. In vitro drug-induced IFN-gamma releas e test was conducted on this patient and on two controls, using an enzyme-l inked immunoabsorbent assay (ELISA) technique. Increased IFN-gamma release was observed following an in vitro challenge of the patient's lymphocytes w ith allopurinol, but not following in vitro challenge with colchicine. An i n vitro challenge with allopurinol in two control patients, treated with al lopurinol without adverse drug reactions, did not induce a significant incr ease in IFN-gamma release. Conclusions The role of allopurinol as the drug responsible for the inducti on of Stevens-Johnson syndrome in our patient was confirmed by in vitro all opurinol-induced IFN-gamma release, which may indicate a drug-specific immu ne response.