肺结核患者痰和血浆IFN—γ含量检测的临床意义探讨

Detection and Clinical Significance of IFN- γ Level in Sputum and Plasma of Pulmonary Tuberculosis Patients

目的探讨肺结核患者痰和血浆中γ-干扰素（interferon．gamma，IFN-γ）水平在结核病诊断、鉴别诊断中的意义。方法用酶联免疫吸附剂测定法（ELISA）分别检测44例活动性肺结核患者（PTB）、36例正常对照者、18例肺癌患者痰和血浆中IFN—γ含量。结果结核分枝杆菌潜伏感染者（LTBI）痰和血浆IFN—γ含量与健康人相接近（P〉0．05）；肺结核患者血浆IFN—γ含量显著高于正常对照及肺癌患者（P值均〈0．05），肺结核患者痰中IFN-γ含量显著低于正常对照及肺癌患者（尸值均〈0．01）；肺结核患者痰IFN—γ含量低于血浆IFN-γ含量；痰及血浆中IFN—γ的ROC曲线下面积（AUC）分别为0．90和0．91，当痰中IFN-γ诊断临界值为21．40pg／ml时，敏感度85．71％、特异性82．35％：当血浆IFN—γ诊断临界值为27．91pg／ml时，敏感度71．43％、特异性94．12％。结论痰和，或血浆中IFN—γ可以作为肺结核诊断（尤其是菌阴肺结核）、鉴别诊断的重要辅助指标之一。

Objective To estimate the clinical significance of the diagnosis and the differential diagnosis in patients with pulmonary tuberculosis （PTB） by investigating levels of IFN- γ in the sputum and plasma of the patients. Methods Levels of IFN- γ in sputum and plasma was detected in 44 cases of PTB, 36 cases of controls and 18 cases of lung cancer by using enzyme linked immunosorbent assay （ELISA）. Results The sputum and plasma IFN-γ levels were quite close in the latent Mycobacterium tuberculosis infection （LTBI） and healthy controls （P〉0.05）. The plasma levels of IFN-γ were significantly higher in PTB patients when compared with the control and lung cancer groups, respectively （P〈0.05）. Levels of IFN- γ in sputum of patients with PTB was significantly lower than in controls and lung cancer patients, respectively （P〈0.01）. Sputum levels of IFN- γ in patients with PTB were lower than those in plasma.The receiver operator characteristic （ROC） curve for sputum and plasma IFN-gamma showed an area under the curve （AUC） value of 0.90 and 0.91, respectively, accompanied the best cutoff value 27.91 pg/ml and 21.40 pg/ml respectively.Using the cutoff value for IFN- γ levels in sputum and plasma for the diagnosis of PTB, the sensitivity and specificity were found to be 85.71%, 82.35% and 71.43%, 94.12%, respectively. Conclusions Levels of IFN- γ in sputum or/and plasma can be used as one of the important supplementary target for diagnosis and differential diagnosis of PTB （especially in smear and culture negative pulmonary tuberculosis）.