干扰素γ释放试验诊断药疹的作用

Diagnostic role of interferon-γrelease test in drug eruption

目的探讨干扰素γ(IFN-γ)释放试验在诊断药疹及寻找可疑致敏药物中的作用。方法取患者静脉血约5mL,肝素抗凝后梯度离心分离出淋巴细胞,加入受试药物,在37℃、5%CO_2条件下孵育24h后离心收集上清液,-70℃保存,最后用ELISA方法测定上清液中的IFN-γ含量。经公式计算出IFN-γ释放增加百分数,与不加药物的空白对照相比,增加20%以上为阳性结果。结果试验组10例药疹患者,IFN-γ释放试验结果阳性8例,阳性率80．0%；对照组9例,阳性1例,两组比较,P＜0．005,差异有统计学意义。试验的敏感性和特异性分别为88．9%和80%。试验组10例根据可疑致敏药物的不同共进行了13种可疑药物试验,阳性9种,阳性率为69．2%,与对照组(1/9)相比,P＜0．05,差异有统计学意义。试验的敏感性和特异性分别为90%和66．7%。结论本试验的阳性率、敏感性均高于以往报道的其他药疹体外实验,提示IFN-γ释放试验对于明确药疹的诊断及探讨致敏药物有着一定的作用。

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 supematants 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 10 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 1FN-γ release test plays a role in the confirmation of diagnosis of drug eruption, and in the investigation of sensitizing drugs.