Soysal Ahmet, Türel Ozden, Toprak Demet, Bakir Mustafa
Department of Pediatrics, Marmara University School of Medicine, Istanbul, Turkey.
Jpn J Infect Dis. 2008 May;61(3):192-5.
A false-positive tuberculin skin test (TST) may be a result of T-cell sensitivity due to Bacille Calmette-Guerin (BCG) vaccination or exposure to non-tuberculous mycobacteria, thus leading to unnecessary isoniazid preventive therapy, especially in low-risk populations. Unlike TST, T-SPOT.TB is not confounded by BCG vaccination or exposure to most of the other non-tuberculous mycobacteria, because this assay is based on enumeration of interferon-gamma-secreting T cells in response to Mycobacterium tuberculosis-specific antigens. We compared the TST with T-SPOT.TB with respect to different TST cut-off points in healthy unexposed BCG-vaccinated schoolchildren. A total of 209 children between 6 and 10 years of age with a TST induration of 0 (n = 50), 10 - 14 (n = 45), 15 - 19 (n = 95) and > or =20 mm (n = 19) were enrolled. Among TST-positive subjects, only 26 (23%) were positive with T-SPOT.TB, and T-SPOT.TB was positive in 4, 7, 20 and 42% of children with TST indurations of 0, 10 - 14, 15 - 19 and > or =20 mm, respectively. We suggest that confirmation of a positive TST by the interferon-gamma-based test would reduce unnecessary preventive therapy significantly in healthy unexposed BCG-vaccinated children.
结核菌素皮肤试验（TST）假阳性可能是由于接种卡介苗（BCG）或接触非结核分枝杆菌导致T细胞敏感所致，从而导致不必要的异烟肼预防性治疗，尤其是在低风险人群中。与TST不同，T-SPOT.TB不受BCG疫苗接种或大多数其他非结核分枝杆菌接触的影响，因为该检测基于对结核分枝杆菌特异性抗原作出反应的分泌γ干扰素的T细胞计数。我们在未接触过BCG的健康学龄儿童中，就不同的TST临界值比较了TST和T-SPOT.TB。共纳入209名6至10岁儿童，其TST硬结分别为0（n = 50）、10 - 14（n = 45）、15 - 19（n = 95）和≥20 mm（n = 19）。在TST阳性受试者中，只有26名（23%）T-SPOT.TB呈阳性，TST硬结为0、10 - 14、15 - 19和≥20 mm的儿童中，T-SPOT.TB阳性率分别为4%、7%、20%和42%。我们建议，基于γ干扰素的检测对TST阳性结果进行确认，将显著减少未接触过BCG的健康儿童中不必要的预防性治疗。
