Diel Roland, Loddenkemper Robert, Meywald-Walter Karen, Niemann Stefan, Nienhaus Albert
School of Public Health c/o Institute of Medical Sociology, University of Düsseldorf, Postbox 101007, 40001 Düsseldorf, Germany.
Am J Respir Crit Care Med. 2008 May 15;177(10):1164-70. doi: 10.1164/rccm.200711-1613OC. Epub 2008 Feb 14.
Numerous studies have been published on the new Mycobacterium tuberculosis (MTB)-specific IFN-gamma release assays. However, their prognostic value for progression from latent tuberculosis infection (LTBI) to active TB has yet to be established.
To compare the QuantiFERON-TB Gold In-Tube assay (QFT) with the tuberculin skin test (TST) in recently exposed close contacts of active TB cases with respect to their development of TB disease within 2 years.
Close contacts (n = 601) of MTB-positive source cases underwent both TST and QFT testing and were subsequently observed for 103 (+/-13.5) weeks. Risk factors for MTB infection were evaluated by multivariate analysis.
For the TST, 40.4% (243/601) of contacts were positive at a 5-mm cutoff, whereas only 66 (11%) were QFT positive. QFT positivity, but not TST, was associated with exposure time (P < 0.0001). Six contacts progressed to TB disease within the 2-year follow-up. All were QFT positive and had declined preventive treatment, equating to a progression rate of 14.6% (6/41) among those who were QFT positive. The progression rate for untreated TST-positive subjects was significantly lower (P < 0.003), at 2.3% (5 of 219), and one subject who progressed was TST negative.
Results suggest that QFT is a more accurate indicator of the presence of LTBI than the TST and provides at least the same sensitivity for detecting those who will progress to active TB. The high rate of progression to active TB of those who are QFT positive (14.6%), which is far greater than the 2.3% found for those who are TST positive, has health and economic implications for enhanced TB control, particularly if this higher progression rate is seen in studies of other at-risk populations.
关于新型结核分枝杆菌（MTB）特异性γ-干扰素释放试验已有大量研究发表。然而，其对于潜伏性结核感染（LTBI）进展为活动性结核病的预后价值尚未确定。
比较结核菌素皮肤试验（TST）与全血γ-干扰素释放试验（QFT）在近期接触活动性结核病病例的密切接触者中，观察其在2年内发生结核病的情况。
对MTB阳性传染源的601名密切接触者进行了TST和QFT检测，并随后观察了103（±13.5）周。通过多变量分析评估MTB感染的危险因素。
对于TST，在5mm硬结直径的标准下，40.4%（243/601）的接触者呈阳性，而QFT阳性者仅66例（11%）。QFT阳性与接触时间相关（P<0.0001），而TST则不然。在2年随访期内，有6名接触者进展为结核病。所有进展者QFT均为阳性且拒绝预防性治疗，在QFT阳性者中进展率为14.6%（6/41）。未治疗的TST阳性者进展率显著较低（P<0.003），为2.3%（219例中有5例），且有1例进展者TST为阴性。
结果表明，QFT比TST更能准确指示LTBI的存在，并且在检测将进展为活动性结核病的患者方面至少具有相同的敏感性。QFT阳性者进展为活动性结核病的高发生率（14.6%），远高于TST阳性者的2.3%，这对加强结核病控制具有健康和经济方面的影响，特别是如果在其他高危人群的研究中也观察到这种较高的进展率。
