结核病患者外周血γ干扰素释放试验假阴性的相关因素分析

目的 分析影响结核病患者外周血γ干扰素释放试验(interferon-gamma release assay,IGRA)检测假阴性的影响因素。方法 回顾性分析2018年1月至2020年3月解放军总医院第八医学中心结核四科收治的资料完整、外周血IGRA检测阴性和阳性的结核病患者,分别作为IGRA假阴性组(38例)和IGRA阳性组(119例),收集其一般情况、病史特点、血清生化指标和外周血淋巴细胞亚群,采用单因素和多因素logistic回归分析导致IGRA检测结果假阴性的影响因素。结果 IGRA假阴性组淋巴细胞计数、T细胞计数、CD4⁺T细胞计数、CD8⁺T细胞计数、NKT细胞计数M(Q₁,Q₃)分别为1.15(0.77,1.58)×10⁹个/L、867.50(508.75,1135.50)个/μl、493.00(256.00,673.75)个/μl、254.50(170.25,429.25)个/μl、38.50(16.50,88.25)个/μl,均明显低于IGRA阳性组分别为1.46(0.99,1.88)×10⁹个/L、1013.00(667.00,1394.00)个/μl、590.00(386.00,850.00)个/μl、335.00(232.00,561.00)个/μl、57.00(30.00,121.00)个/μl,差异均有统计学意义(Z值分别为-2.512、-2.143、-2.092、-2.303、-2.338,P值分别为0.012、0.032、0.036、0.021、0.019)。logistic回归分析结果显示,NKT细胞计数低于正常值(<40个/μl)的患者,IGRA检测出现假阴性的风险是NKT细胞计数正常者的2.440倍(95%CI:1.159~5.134)。结论 NKT细胞计数的减少可能导致外周血IGRA出现假阴性。

Analysis of risk factors associated with false negative results of interferon-gamma release assays on peripheral blood from tuberculosis patients

Objective To analyse the risk factors associated with false negative results of interferon-gamma release assays (IGRA) of peripheral blood from tuberculosis patients. Methods We performed a retrospective analysis using data from tuberculosis patients at TB Department 4 of the 8th Medical Center of the Chinese People’s Liberation Army General Hospital from January 2018 to March 2020 who had peripheral blood IGRA assay results. They were divided into IGRA negative (38 patients) and IGRA positive (119 patients) groups. General information, medical history, serum biochemical indexes and peripheral T lymphocyte subpopulation data were collected. Single factor analysis and multivariate logistic regression analysis were performed to analyze risk factors associated with false negative IGRA results in tuberculosis patients. Results The M(Q₁,Q₃) of lymphocyte count, T cell count, CD4 ⁺ T cell count, CD8⁺ T cell count and NKT cell count for the negative group were 1.15 (0.77, 1.58)×10⁹ cells/L, 867.50 (508.75, 1135.50) cells/μl, 493.00 (256.00, 673.75) cells/μl, 254.50 (170.25, 429.25) cells/μl and 38.50 (16.50, 88.25) cells/μl respectively, and were significantly lower than that of the positive group: 1.46 (0.99, 1.88)×10⁹ cells/L, 1013.00 (667.00, 1394.00) cells/μl, 590.00 (386.00, 850.00) cells/μl, 335.00 (232.00, 561.00) cells/μl and 57.00 (30.00, 121.00) cells/μl (the Z values were -2.512, -2.143, -2.092, -2.303 and -2.338, and the P values were 0.012, 0.032, 0.036, 0.021 and 0.019 respectively). Logistic regression analysis indicated that patients with NKT cell counts that were lower than normal (<40 cells/μl) had a 2.440 times higher risk (95%CI: 1.159-5.134) than those with a normal NKT cell count of having a false negative IGRA result. Conclusion Lowered NKT cell counts may be a contributing factor leading to false negative peripheral blood IGRA results.