Anibarro Luis, Trigo Matilde, Villaverde Carlos, Pena Alberto, González-Fernández Africa
Tuberculosis Unit, Department of Infectious Diseases and Internal Medicine, Pontevedra Hospital Complex, Pontevedra, Spain.
Scand J Infect Dis. 2011 Jul;43(6-7):424-9. doi: 10.3109/00365548.2011.558912. Epub 2011 Feb 18.
T-cell interferon-gamma release assays (IGRAs) have been shown to be effective tools for the detection of Mycobacterium tuberculosis infection, offering an enhanced specificity compared to the tuberculin skin test (TST). Most tuberculosis (TB) contact studies have shown a better correlation of IGRA with the intensity of M. tuberculosis exposure than that obtained using the TST. However, the correlation between tests performed before and after the tuberculin 'window period' (time between infection and when the immunological response becomes measurable) remains to be studied.
A longitudinal prospective analysis was performed in TB contacts. We analyzed the correlation between a commercially available IGRA (QuantiFERON®-TB Gold in-Tube, QFT) and the TST before and after the tuberculin window period (2 months). Concordance between both tests was assessed using the Kappa coefficient (κ). Correlation of both tests with the degree of TB exposure was also analyzed.
One hundred and fifty-two TB contacts were included in the study. Agreement between the TST and IGRA was better after the window period (κ = 0.60 at the first visit and κ = 0.73 after 2 months), especially for non-BCG vaccinated subjects (κ = 0.81). Both a positive TST and QFT were correlated, after the window period, with the size of place of contact (the smaller the place of contact, the higher the probability of having a positive test) (p = 0.022 and p = 0.02, respectively) and with the total numbers of hours spent with the index case (p = 0.006 for TST and p = 0.007 for QFT).
IGRAs are a good alternative to the TST in contact tracing studies, especially after the tuberculin window period.
T 细胞干扰素-γ释放试验（IGRAs）已被证明是检测结核分枝杆菌感染的有效工具，与结核菌素皮肤试验（TST）相比，其特异性更高。大多数结核病（TB）接触者研究表明，与 TST 相比，IGRA 与结核分枝杆菌暴露强度的相关性更好。然而，在结核菌素“窗口期”（感染与免疫反应可检测到之间的时间）之前和之后进行的检测之间的相关性仍有待研究。
对结核病接触者进行纵向前瞻性分析。我们分析了一种市售 IGRA（全血干扰素γ释放试验，QFT）与结核菌素窗口期（2 个月）前后的 TST 之间的相关性。使用 Kappa 系数（κ）评估两种检测方法之间的一致性。还分析了两种检测方法与结核暴露程度的相关性。
152 名结核病接触者纳入研究。窗口期后 TST 和 IGRA 之间的一致性更好（首次就诊时κ = 0.60，2 个月后κ = 0.73），尤其是未接种卡介苗的受试者（κ = 0.81）。窗口期后，TST 和 QFT 呈阳性均与接触地点的规模相关（接触地点越小，检测呈阳性的概率越高）（分别为 p = 0.022 和 p = 0.02），并与与索引病例共处的总时长相关（TST 为 p = 0.006，QFT 为 p = 0.007）。
在接触者追踪研究中，尤其是在结核菌素窗口期之后，IGRAs 是 TST 的良好替代方法。
