Dogra Sandeep, Narang Pratibha, Mendiratta Deepak K, Chaturvedi Pushpa, Reingold Arthur L, Colford John M, Riley Lee W, Pai Madhukar
Mahatma Gandhi Institute of Medical Sciences, Sevagram 442102, India.
J Infect. 2007 Mar;54(3):267-76. doi: 10.1016/j.jinf.2006.04.007. Epub 2006 Jun 2.
In vitro interferon-gamma (IFN-gamma) assays have emerged as novel alternatives to the tuberculin skin test (TST) for the diagnosis of latent tuberculosis (TB) infection. These assays have been evaluated in low incidence countries, mainly in adults, and have been shown to be more specific than TST. Because few studies have been done in high incidence countries, and because paediatric data are limited, we compared a whole-blood IFN-gamma assay with TST among hospitalized Indian children.
Between July 2004 and June 2005, a total of 105 consecutively admitted children (median age 6 years; 82% had BCG scars) in whom TB was suspected or had history of contact with an index case were recruited at a rural hospital in India. All children underwent TST, and the QuantiFERON-TB-Gold In Tube (QFT) assay.
The overall prevalence of TB infection was similar with both tests. With a TST cut-off point of > or =10mm, 10 of 105 (9.5%; 95% CI 3.8, 15.2) children were TST positive. With a cut-off point of IFN-gamma> or =0.35IU/ml, 11 of 105 (10.5%; 95% CI 4.5, 16.4) were QFT positive. The concordance between TST and QFT was substantial (agreement 95.2%; kappa [kappa] 0.73; 95% CI for kappa 0.53, 0.92). Agreement between TST and QFT results was 100% (kappa 1.0) in BCG scar-negative children as compared to 94% (kappa 0.63) in scar-positive children. BCG was not associated with the results of either TST or QFT (P>0.05 for both tests). The number of children with bacteriologically confirmed active TB was too small to permit the estimation of sensitivity of the tests.
In a rural, predominantly BCG-vaccinated paediatric population in India, the TST and QFT assay produced comparable results. BCG vaccination did not significantly affect either TST or QFT results. Larger studies are needed to compare the sensitivity of the IFN-gamma assay with that of the TST in children with bacteriologically and/or clinically confirmed TB.
体外干扰素-γ（IFN-γ）检测已成为诊断潜伏性结核（TB）感染的结核菌素皮肤试验（TST）的新型替代方法。这些检测方法已在低发病率国家进行了评估，主要针对成年人，且已证明比TST更具特异性。由于在高发病率国家开展的研究较少，且儿科数据有限，我们在印度住院儿童中比较了全血IFN-γ检测和TST。
在2004年7月至2005年6月期间，在印度一家农村医院招募了105名连续入院的儿童（中位年龄6岁；82%有卡介苗疤痕），这些儿童疑似患有TB或有与索引病例接触史。所有儿童均接受了TST和结核感染T细胞检测（QFT）。
两种检测方法的TB感染总体患病率相似。TST切点≥10mm时，105名儿童中有10名（9.5%；95%可信区间3.8，15.2）TST呈阳性。IFN-γ切点≥0.35IU/ml时，105名儿童中有11名（10.5%；95%可信区间4.5，16.4）QFT呈阳性。TST和QFT之间的一致性很高（一致性95.2%；kappa值0.73；kappa值的95%可信区间0.53，0.92）。卡介苗疤痕阴性儿童中TST和QFT结果的一致性为100%（kappa值1.0），而疤痕阳性儿童中为94%（kappa值0.
