T细胞免疫检测在肺结核鉴别诊断中的应用

Application of T-cell immunodetection in the differential diagnosis of pulmonary tuberculosis

目的评估结核感染T细胞免疫检测（IGRA/ELISA法）用于在肺部感染患者中鉴别诊断结核病的效能。方法选取肺部感染患者106例,根据结核诊断标准确诊30例为结核感染,76例为非结核感染。用IGRA/ELISA法检测患者血液中经结核特异性抗原刺激后的淋巴细胞释放的IFN-γ含量,比较两组IFN-γ含量的差异;绘制ROC曲线并分析AUC和最佳截断值及最佳界点处的敏感度、特异度和约登指数。结果结核组IFN-γ浓度均值为（329.72±31.03）pg/mL,非肺结核组为（52.77±12.08）pg/mL,t=8.318,P〈0.001。ROC曲线下面积AUC=0.934（95%CI,0.890~0.978）,当界点为59.70pg/mL时,灵敏度为100.0%,特异度为78.9%,约登指数为0.789;当界点为108.25pg/mL时,灵敏度为90.0%,特异度为84.2%,约登指数为0.742;当界点为404.00pg/mL时,灵敏度为33.3%,特异度为100.0%,约登指数为0.333。结论以IGRA/ELISA法检测IFN-γ浓度,以59.70pg/mL,108.25pg/mL,404.00pg/mL三个界点辅助临床对肺部感染鉴别诊断结核病有较好应用价值。

Objective To assess the value of IGRA/ELISA （Interferon-＇/release assay/Enzyme-linked immunosor- bent assay） for differential diagnosis of tuberculosis in patients with pulmonary infection. Methods According to the TB diagnostic criteria, 106 patients with lung infection were divided into the TB infection group （30 cases） or non-tuberculosis infection group （76 cases） . IGRA/ELISA was used to detect the content of inter- feron-γ （IFN-γ） released by the lymphocytes stimulated with TB-specific antigens in the blood of patients. Then the differences of IFN-γ content were compared between the two groups. The receiver operation curve （ROC） was drawn, and the area under the curve （AUC） of ROC, the optimal cut-off value as well as the sensitivity, specificity and Youden Index were analyzed. Results The average content of IFN-γin TB group was （329.72 ±31.03） pg/mL, while that in non-pulmonary tuberculosis group was （52.77±12.08） pg/mL （t=8. 318, P〈0. 001） . The AUC=0. 934 （95%CI, 0. 890 - 0. 978） . When the cut-off point was 59.70 pg/mL, the sensitivity was 100.0%, specificity was 78.9%, and Youden Index was 0. 789% When it came to 108.25 pg/mL, the sensitivity turned to 90.0%, specificity raised to 84.2%, and Youden Index was 0. 742; When it reached to 404.00 pg/mL, the sensitivity dropped to 33.3%, but specificity went up to 100.0 %, and Youden index became 0. 333. Conclusion When IGRA/ELISA assay is used for detection of IFNgamma to help making differential diagnosis of tuberculosis in patients with pulmonary infection, these three cut-off values （59.70 pg/mL, 108. 25 pg/mL and 404. 00 pg/mL） were very significant.