Center for Vaccines and Immunology, National Institute for Communicable Diseases, a division of the National Health Laboratory Service, Johannesburg, South Africa.
Department of Chemical Pathology, School of Pathology, Faculty of Health Sciences, University of The Witwatersrand and National Health Laboratory Service, Johannesburg, South Africa.
Clin Infect Dis. 2021 Sep 15;73(6):1027-1036. doi: 10.1093/cid/ciab232.
For pregnant women living with human immunodeficiency virus (HIV), concurrent active tuberculosis (TB) disease increases the risk of maternal mortality and poor pregnancy outcomes. Plasma indoleamine 2,3-dioxygenase (IDO) activity measured by kynurenine-to-tryptophan (K/T) ratio has been proposed as a blood-based TB biomarker. We investigated whether plasma K/T ratio could be used to diagnose active TB among pregnant women with HIV.
Using an enzyme-linked immunosorbent assay (ELISA), we measured K/T ratio in 72 pregnant women with and active TB and compared them to 117 pregnant women with HIB but without TB, matched by age and gestational age.
Plasma K/T ratio was significantly elevated during pregnancy compared to sampling done after pregnancy (P < .0001). Pregnant women who had received isoniazid preventive therapy (IPT) before enrollment had decreased plasma K/T ratio compared to those who had not received IPT (P = .0174). Plasma K/T ratio was elevated in women with active TB at time of diagnosis compared to those without TB (P < .0001). Using a cutoff of 0.100, plasma K/T ratio gave a diagnostic sensitivity of 94% (95% confidence interval [CI]: 82-95), specificity of 90% (95% CI: 80-91), positive predictive value (PPV) 85% and negative predictive value (NPV) 98%. A receiver operating characteristic curve (ROC) gave an area under the curve of 0.95 (95% CI: .92-.97, P < .0001).In conclusion, plasma K/T ratio is a sensitive blood-based diagnostic test for active TB disease in pregnant women living with HIV. Plasma K/T ratio should be further evaluated as an initial TB diagnostic test to determine its impact on patient care.
对于感染人类免疫缺陷病毒（HIV）的孕妇，同时患有活动性结核病（TB）会增加产妇死亡率和不良妊娠结局的风险。通过色氨酸到犬尿氨酸（K/T）比值来衡量血浆吲哚胺 2,3-双加氧酶（IDO）的活性，已被提出作为一种基于血液的 TB 生物标志物。我们研究了在感染 HIV 的孕妇中，血浆 K/T 比值是否可用于诊断活动性 TB。
我们使用酶联免疫吸附测定（ELISA）测量了 72 例活动性 TB 孕妇和 117 例 HIV 孕妇的 K/T 比值，并按年龄和妊娠龄与后者进行匹配。
与产后采样相比，妊娠期间血浆 K/T 比值显著升高（P<0.0001）。与未接受异烟肼预防治疗（IPT）的孕妇相比，在入组前接受 IPT 的孕妇的血浆 K/T 比值降低（P=0.0174）。与无 TB 的孕妇相比，在诊断时患有活动性 TB 的孕妇的血浆 K/T 比值升高（P<0.0001）。使用 0.100 的截止值，血浆 K/T 比值的诊断敏感性为 94%（95%置信区间[CI]：82-95），特异性为 90%（95% CI：80-91），阳性预测值（PPV）为 85%，阴性预测值（NPV）为 98%。受试者工作特征曲线（ROC）的曲线下面积为 0.95（95% CI：0.92-0.97，P<0.0001）。
血浆 K/T 比值是一种敏感的血液诊断试验，可用于诊断感染 HIV 的孕妇中的活动性 TB 疾病。应进一步评估血浆 K/T 比值作为初始 TB 诊断试验，以确定其对患者治疗的影响。
