卡介苗缺失免疫显性抗原在结核病血清学检测中的作用

目的 探讨卡介苗( BCG)缺失免疫显性抗原在结核病血清学检测中的作用.方法 选取主流结核病血清学检测抗原的4种不同组合试剂A(结核分枝杆菌抗体IgG检测试剂)、B(结核分枝杆菌抗体检测试剂)、C(结核杆菌特异性抗体检测试剂)、D(活动性结核抗体检测ELISA系统),通过免疫印迹、胶体金和酶联免疫吸附等免疫学方法检测109例活动性结核患者和97名健康人群[分为结核菌素纯蛋白衍生物试验(PPD)阳性和阴性组]的结核抗体,应用贝叶斯概率统计学方法,综合分析不同抗原组合对结核病检测准确率的影响.结果 试剂A、B、C、D对活动性结核病IgG检出率分别是80.0％、66.7％、80.7％、56.0％,明显高于健康人群的23.9％、8.9％、6.6％、1.0％,差异均有统计学意义(x2值分别为47.53,51.59,90.48,69.68,均P＜0.01).其中试剂A、B对健康人群结核抗体检出率随PPD阳性反应强度而增高(x2值分别为2.124,2.220,均P＜0.05),试剂C、D对健康人群结核抗体检出率与PPD反应强度无相关性(x2值分别为0.122,0.479,均P＞0.05),试剂D的准确率最高,其对活动性肺结核患者IgM检出率为2.1％.结论 IgG检出的敏感性与抗原的选择及组合数量呈正相关,高的检测敏感性常伴随特异性的损失,选择BCG缺失抗原可显著提高检测特异性.

Role of BCG-depleted immunodominant antigens derived from M. tuberculosis in serological test for tuberculosis

Objective To explore the roles of BCG-depleted immunodominant antigens derived from M.tuberculosis in serological tests for tuberculosis(TB).Methods Four different combinations of current mainstream antigens used for serological diagnosis of TB were selected:Reagent A [ Mycobacterium TB immunoglobulin G (IgG) antibody assay kit]; Reagent B (Mycobacterium TB detection kit); Reagent C (M.tuberculosis-specific antibody detection kit) ; Reagent D [ Active TB antibody detection enzyme-linked immunosorbent assay (ELISA) system].Immunological methods of Western blot,colloidal gold and ELISA were developed to test the antibodies in 109 patients with active tuberculosis (TB) and 97 healthy populations.They were divided into purified protein derivative of tuberculin (PPD) positive and negative groups.Bayesian statistical analysis was used to analyze the influences of variable combinations of different antigens on the detection accuracy of TB.Results For Reagent A,B,C,D,the detection rates of IgG antibodies in the patients with active TB were 80.0％,66.7％,80.7％,56.0％ versus 23.9％,8.9％,6.6％ and 1.0％ respectively in healthy populations.The TB antibody detection rates in four TB patient populations were all higher than that in healthy populations ( x2 =47.53,51.59,90.48,69.68,all P ＜0.01 ).The TB antibody detection rates of Reagents A and B increased with the intensity of positive reaction to PPD in healthy populations (x2 =2.124,2.220,all P ＜0.05 ) while those of Reagents C,D in healthy populations were irrelevant to PPD reaction.( x2 =0.122,0.479,all P ＞0.05 ).Reagent D has the highest accuracy.The immunoglobulin M ( lgM ) antibody detection rate of Reagent D was only 2.1 ％ in the patients with active TB.Conclusions The detecting sensitivity of TB IgG antibodies is associated with antigen selection.And it is also positively correlated with the number of combined antigens. High-sensitivity detection is often accompanied by a loss of specificity.With the BCG-depleted antigens derived from M.tuberculosis,the specificity of serological test for TB may significantly improve.