Abstract: Background Tuberculous meningitis (TBM) is a worldwide central nervous system infectious disease and is seriously harmful to human beings. The traditional normal assay of cerebrospinal fluid (CSF) and radiological examination always delay the clinical treatment because of low sensitivity and specificity. Therefore, a more sensitive method for the clinical diagnosis of TBM is badly in need. This article uses T lymphocytes enzyme-linked immunospot assay (ELISPOT) to detect mononuclear cells in peripheral blood (PB) and CSF of TBM patients, and compares the sensitivity and specificity in the diagnosis of TBM between the two methods, for the purpose of providing effective examination method for the early diagnosis of TBM. Methods PB and CSF samples were collected from 30 cases of TBM (case group) and 30 cases of non-TBM (control group) respectively, and mononuclear cells were separated and extracted through cryopreservation and rapid thawing. A spot test using T lymphocytes infected with tubercle bacillus (T-SPOT.TB) was applied to check T lymphocytes secreted by interferon-γ in PB and CSF, so that the sensitivity and specificity for diagnosing TBM by this method were evaluated. Results CSF mononuclear cells ELISPOT assay showed that 28 cases in the case group were diagnosed as TBM and other 2 cases were diagnosed as non-TBM, with the positive rate being 93.33% (28/30) ; as for control group, 1 case was diagnosed as TBM, and 29 cases were diagnosed as non-TBM, with the positive rate being 3.33% (1/30). In CSF mononuclear cells ELISPOT assay, the sensitivity and specificity were 93.33% and 96.67%; false positive rate was 3.33%; false negative rate was 6.67%; positive likelihood ratio was 28.33; negative likelihood ratio was 0.07. PB mononuclear cells ELISPOT assay showed that 23 cases in the case group were diagnosed as TBM and 7 cases were diagnosed as non-TBM, with the positive rate being 76.67% (23 /30); as for control group, 4 cases were diagnosed as TBM, and 26 cases were diagnosed as non-TBM, with the positive rate being 13.33% (4/30). In PB mononuclear cells ELISPOT assay, the sensitivity and specificity were 76.67%and 86.67%; false positive rate was 13.33%; false negative rate was 23.33%; positive likelihood ratio was 5.79; negative likelihood ratio was 0.15. Fisher exact probability test showed the difference between the TBM positive rate of PB and CSF ELISPOT assay was not statistically significant ( P = 0.254). Conclusion PB and CSF mononuclear cells ELISPOT assay can be effectively favorable for the current diagnosis of TBM as an auxiliary diagnostic method. Besides, CSF mononuclear cells ELISPOT assay is more efficient than PB assay.

Key words: Tuberculosis, meningeal, Cerebrospinal fluid, Sensitivity and specificity, Enzyme-linked immunosorbent assay, Mononuclear cells

摘要： 研究背景 结核性脑膜炎为严重危害人类健康的中枢神经系统感染性疾病，传统的脑脊液分析和放射学检查方法敏感性和特异性较低，延误治疗时机，因此临床急需敏感性更高的快速检查方法用于结核性脑膜炎的诊断。本文采用T 细胞酶联免疫斑点试验（ELISPOT）检测结核性脑膜炎患者外周血和脑脊液单个核细胞，比较两种检查方法诊断结核性脑膜炎的敏感性和特异性，以为结核性脑膜炎的早期诊断提供有效检查方法。方法 分别收集结核性脑膜炎（30例）和非结核性脑膜炎（30例）患者外周血和脑脊液，分离提取单个核细胞，经冻存和复苏后采用结核杆菌感染T 细胞斑点试验（T-SPOT.TB）检测外周血和脑脊液中干扰素-γ 分泌的T 细胞数目，分别计算其诊断结核性脑膜炎的敏感性和特异性。结果 脑脊液ELISPOT试验显示，结核性脑膜炎组阳性检出率为93.33%（28/30）、非结核性颅内感染组为3 .33%（1/30）；检测灵敏度93.33%、特异度96.67%，假阳性率3.33% 、假阴性率6.67% ，阳性似然比28.33、阴性似然比0.07 。外周血ELISPOT试验显示，结核性脑膜炎组阳性检出率为76.67%（23/30）、非结核性颅内感染组为13.33%（4/30），检测灵敏度76.67%、特异度86.67%，假阳性率13.33%、假阴性率23.33%，阳性似然比5.79 、阴性似然比0.15 。外周血ELISPOT试验阳性检出率与脑脊液阳性检出率比较，差异无统计学意义（Fisher 确切概率法：P = 0.254）。 结论 采用ELISPOT试验检测外周血和脑脊液单个核细胞结核杆菌感染率有助于提高结核性脑膜炎的诊断率，而且脑脊液单个核细胞ELISPOT试验检测效率呈高于外周血检测效率之趋势。

关键词: 结核, 脑膜, 脑脊髓液, 敏感性与特异性, 酶联免疫吸附测定, 单个核细胞