结核特异性抗原与CD4^(+)T细胞计数比值对AIDS合并肺结核的辅助诊断价值

The value of the ratio of tuberculosis specific antigen to CD4^(+)T cell count in the auxiliary diagnosis of AIDS complicated with pulmonary tuberculosis

目的:评价结核特异性抗原(TBAg)与CD4^(+)T淋巴细胞(简称“CD4”)计数的比值(TBAg/CD4)对AIDS合并活动性肺结核(PTB)的辅助诊断价值。方法:采用前瞻性研究的方法,参照入组标准纳入2018年1月至2020年12月苏州市第五人民医院收治的262例疑似活动性PTB的AIDS患者,并将患者分为AIDS+PTB组(152例)和AIDS组(110例)。采集患者入院次日清晨静脉血进行干扰素体外释放酶联免疫法(TB-IGRA)、血常规、CD4检测,比较两组间TBAg水平和TBAg/CD4比值的差异。以临床诊断为参考标准,评价TB-IGRA检测AIDS合并PTB的效能,并以受试者工作特征曲线(ROC曲线)下面积(AUC)确定诊断效能最佳的检测指标。结果:以临床诊断为参考标准,TB-IGRA检测AIDS合并活动性PTB的敏感度和特异度分别为53.95%(82/152)和75.45%(83/110)。TB-IGRA检测AIDS+PTB组的TBAg、TBAg/CD4水平[分别为92.51(-68.20,906.10)pg/ml和1.01(0.00,10.12)]均明显高于AIDS组[分别为85.20(-33.80,801.30)pg/ml和0.11(0.00,2.07)],对照培养管抗原浓度[529.50(12.50,1160.50)pg/ml]明显低于AIDS组[694.50(29.90,990.00)pg/ml],差异均有统计学意义(Z=-3.481、-9.557、3.289,P值均<0.001)。ROC曲线分析显示,对照培养管抗原浓度、TBAg、TBAg/CD4对诊断AIDS合并活动性PTB的AUC值分别为0.718、0.637和0.842;当TBAg/CD4的临界值为0.592时,约登指数最大,其敏感度为88.10%,特异度为77.10%。结论:相较于AIDS患者,AIDS合并PTB患者的TBAg和TBAg/CD4水平均明显升高,尤以TBAg/CD4诊断价值高,结合患者免疫状态的影响,认为TBAg/CD4对AIDS合并PTB患者具有一定辅助诊断价值。

Objective:To evaluate the value of the ratio of tuberculosis specific antigen(TBAg)to CD4^(+)T lymphocyte(CD4)count(TBAg/CD4)in the auxiliary diagnosis of AIDS complicated with active pulmonary tuberculosis(PTB).Methods:Basing on the inclusion criteria,a prospective study was conducted in 262 AIDS patients complicated with active PTB from the Fifth People’s Hospital of Suzhou from January 2018 to December 2020.The patients were divided into AIDS+PTB group(n=152)and AIDS group(n=110).The venous blood of patients in the morning of the next day after admission was collected for interferon in vitro release enzyme-linked immunosorbent assay(TB-IGRA),blood routine examination and CD4 detection.The differences of TBAg level and TBAg/CD4 ratio between the two groups were compared.Based on the clinical diagnosis,the efficacy of TB-IGRA in detecting AIDS complicated with PTB was evaluated,and the area under the receiver operating curve(ROC curve)(AUC)was used to determine the best detection index of diagnostic efficacy.Results:Based on the clinical diagnosis,the sensitivity and specificity of TB-IGRA in detecting AIDS complicated with active PTB were 53.95%(82/152)and 75.45%(83/110),respectively.TBAg and TBAg/CD4 levels in the AIDS+PTB group(92.51(-68.20,906.10)pg/ml and 1.01(0.00,10.12))were significantly higher than those in the AIDS group(85.20(-33.80,801.30)pg/ml and 0.11(0.00,2.07),respectively),and the antigen concentrations of control culture tube(529.50(12.50,1160.50)pg/ml)was significantly lower than that of AIDS group(694.50(29.90,990.00)pg/ml)(Z=-3.481,-9.557,3.289,all P<0.001).ROC curve analysis showed that the AUC values of TBAg and TBAg/CD4 for the diagnosis of AIDS complicated with active PTB were 0.718,0.637 and 0.842,respectively;when the critical value of TBAg/CD4 was 0.592,the Youden index was the largest,with a sensitivity of 88.10%and a specificity of 77.10%.Conclusion:Compared with AIDS patients,the levels of TBAg and TBAg/CD4 in AIDS patients complicate with PTB were significantly increased,and the diagnostic value of TBAg/CD4 was especially high.Combined with the influence of patients’immune status,it was considered that TBAg/CD4 had certain auxiliary diagnostic value for AIDS patients with PTB.