酶联免疫斑点检测和结核菌素试验在初治肺结核中的辅助诊断价值

Role of Enzyme-linked Immunospot Assay and Tuberculin Skin Test in the Auxiliary Diagnosis of Initial Pulmonary Tuberculosis

目的比较酶联免疫斑点检测(ELISPOT)和结核菌素试验(TST),探讨ELISPOT在初治肺结核中的辅助诊断价值。方法选取初治肺结核123例和非结核疾病病例102例作为结核组和对照组,应用6kD早期分泌靶向抗原/10kD培养滤过蛋白融合蛋白(ESAT-6/CFP-10)作为抗原对受试者外周血单个核细胞进行ELISPOT(即ESAT-6/CFP-10-ELISPOT),检测斑点形成细胞(SFCs)的数量;同时对受试者行TST。结果结核组ESAT-6/CFP-10-ELISPOT形成的SFCs数显著高于对照组(P=0.000)。结核组中ESAT-6/CFP-10-ELISPOT的敏感度91.1%(111/123)、特异度80.4%(82/102)、阳性似然比4.60、阴性似然比0.12、阳性预测值0.85、阴性预测值0.87,TST的敏感度65.6%(59/90)、特异度45.1%(46/102)、阳性似然比1.31、阴性似然比0.76、阳性预测值0.51、阴性预测值0.60。ESAT-6/CFP-10-ELIS-POT的敏感度和特异度显著高于TST(均P=0.000)。菌阳肺结核组和菌阴肺结核组间ESAT-6/CFP-10-ELISPOT形成SFCs数量差异无显著性(P=0.166),两组ESAT-6/CFP-10-ELISPOT的敏感度分别为91.8%(67/73)和88.0%(44/50),二者比较差异无显著性(P=0.448)。结论ESAT-6/CFP-10-ELISPOT有可能作为辅助诊断初治肺结核的较为准确方法,并为菌阴肺结核提供一定的诊断依据,但诊断的特异度可能受结核潜伏感染影响。TST对初治肺结核的诊断价值较小。

Objective To compare enzyme-linked immunospot assay （ELISPOT） and tuberculin skin test （TST） and explore their roles in the auxiliary diagnosis of initial pulmonary tuberculosis. Methods Totally 123 patients with initial pulmonary tuberculosis （tuberculosis group） and 102 patients with non-tuberculosis pulmonary disease （control group） were enrolled. The peripheral blood mononuclear cells of all participants were co-cultured with early secretiny antigen target-6/culture filtrate protein-10 fusion protein （ESAT-6/CFP-10 ）, and spot forming cells （SFCs） were enumerated by ELISPOT （ESAT-6/CFP-10-ELISPOT）. TST was also performed simultaneously. Results ESAT-6/CFP-10-ELISPOT showed significantly higher numbers of SFCs after stimulation in tuberculosis group than in control group （P = 0. 000）. The sensitivity, specificity,positive likelihood ratio, negative likelihood ratio, positive predictive value, and negative predictive value of ESAT-6/CFP-10-ELISPOT were 91.1% （111/123）, 81.4% （82/102）, 4.60, 0. 12, 0. 85, and0. 87 respeetively, while the above values of TST were 65.6% （59/90）, 45. 1% （46/102） , 1.31, 0. 76, 0.51, and 0.60, respectively. The sensitivity and specificity of ESAT-6/CFP-10-ELISPOT were significantly higher than those of TST （ all P = 0. 000）. The number of SFCs were not significantly different between smear-positive tuberculosis subgroup and smear-negative tuberculosis subgroup （P = 0. 166）. The sensitivities were 91.8% （67/73） and88.0% （44/50） in these two subgroups, respectively, （P=0.448）. Conclusions ESAT- 6/CFP-10-ELISPOT may be a more accurate approach for the auxiliary diagnosis of initial pulmonary tubereu]osis; meanwhile, it offers certain diagnostic evidences for smear-negative tuberculosis. However, its specificity may be affected by latent tuberculosis infection. On the contrary, TST has poor value in the auxiliary diagnosis of initial pulmonary tuberculosis.