Abstract: Objective To investigate the diagnostic role of IFN-γ release test in drug eruption.Methods Lymphocytes from heparinized venous blood were separated by gradient centrifugation,cultured in test tubes at 37℃ in 5% CO₂ with each tested drug,or with medium alone.After 24 hours of incubation,these test tubes were centrifuged,supematants were collected and stored in -70℃until the detection of human IFN-γ by ELISA in these samples was performed.The increase percentage of IFN-γ release in the supernatants of peripheral blood lymphocytes was calculated according to a formula in which the increase percentage obtained from a drug test was subtracted by that obtained from the blank control test;if the result was more than 20%,the IFN-γ release test was defined as positive.Results The positivity rate of IFN-γ release test was higher in patients with drug eruption than in the control group [80% (8/10) vs 11% (1/9),P<0.005].The sensitivity and specificity of the IFN-γ test were 88.9% and 80% respectively.According to the suspected sensitizing drugs,13 IFN-γ tests were performed for the l0 patients.Of the 13 tests,9 were positive with a positivity rate of 69.2%,which was much higher than that in the control group (P<0.05).Conclusion The positivity rate and sensitivity of the test were both higher than those of other previous in vitro tests for drug eruption,which suggests that IFN-γ release test plays a role in the confirmation of diagnosis of drug eruption,and in the investigation of sensitizing drugs.

Key words: Drug eruptions, IFN-γ release test