Greveson Kay
Inflammatory Bowel Disease, Royal Free Hospital NHS Trust, London.
Br J Nurs. 2009;18(20):1248-54. doi: 10.12968/bjon.2009.18.20.45120.
Screening and treatment of latent tuberculosis infection (LTBI) prior to anti-tumour necrosis factor alpha (anti-TNF-alpha) therapy has been shown to decrease the incidence of active tuberculosis (TB) by more than 80%, and is recommended by the British Thoracic Society. In the absence of a gold standard test for LTBI, conventional screening currently involves taking a clinical history of risk factors, a chest X-ray and a tuberculin skin test (TST) which can be difficult to interpret in immunosuppressed patients. Alternative cellular immune-based screening tests have been developed to detect Mycobacterium tuberculosis.
To examine, evaluate and summarize the quality of evidence on the use of interferon gamma release assay (the ELISpot test) in the diagnosis of latent tuberculosis prior to initiation of anti-TNF-alpha and examine the agreement with the tuberculin skin test.
Ovid Medline, Embase and the Cochrane library were searched using search terms that included tuberculosis, each of the current anti-TNF-alpha biological agents, TST and interferon-gamma release assay. Terms were searched using MeSH (medical subject headings) terms and/or free text where relevant.
Discordance between tuberculin skin test and ELISpot is greater in individuals who have had the bacillus Calmette-Guérin (BCG) vaccination and are taking corticosteroids. ELISpot technique using CFP-10 and ESAT-6 antigens is more sensitive than TST in detecting M. tuberculosis infection in patients taking corticosteroids. ELISpot avoids cross-reaction with BCG, making it a more specific test in this group of patients. Agreement between the tests was found to be fair (72.8% kappa value=0.38).
Tuberculosis resulting from reactivation of latent tuberculosis following treatment with anti-TNF is a continuing problem. Screening reduces the risk but does not eliminate it. Further studies are needed into the cost-effectiveness and sensitivity of ELISpot and the tuberculin skin test in routine clinical practice.
在抗肿瘤坏死因子α（抗TNF-α）治疗前对潜伏性结核感染（LTBI）进行筛查和治疗已被证明可使活动性结核病（TB）的发病率降低80%以上，英国胸科学会也推荐这样做。由于缺乏用于LTBI的金标准检测方法，目前的常规筛查包括了解危险因素的临床病史、进行胸部X光检查和结核菌素皮肤试验（TST），而这在免疫抑制患者中可能难以解释。已开发出基于细胞免疫的替代筛查试验来检测结核分枝杆菌。
检查、评估和总结在开始抗TNF-α治疗前使用干扰素γ释放试验（ELISpot试验）诊断潜伏性结核的证据质量，并检查其与结核菌素皮肤试验的一致性。
使用包括结核病、每种当前的抗TNF-α生物制剂、TST和干扰素-γ释放试验等检索词在Ovid Medline、Embase和Cochrane图书馆进行检索。在相关情况下使用医学主题词（MeSH）和/或自由文本进行检索。
在接种过卡介苗（BCG）且正在服用皮质类固醇的个体中，结核菌素皮肤试验和ELISpot之间的不一致性更大。使用CFP-10和ESAT-6抗原的ELISpot技术在检测服用皮质类固醇患者的结核分枝杆菌感染方面比TST更敏感。ELISpot避免了与BCG的交叉反应，使其在这类患者中成为更具特异性的检测方法。发现两种检测方法之间的一致性为中等（kappa值=0.38，一致性为72.8%）。
抗TNF治疗后潜伏性结核重新激活导致的结核病仍然是一个问题。筛查可降低风险但不能消除风险。需要进一步研究ELISpot和结核菌素皮肤试验在常规临床实践中的成本效益和敏感性。
