Center for Infectious Diseases, Division of Epidemiology and Disease Control, School of Public Health, University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
Tuberculosis (Edinb). 2009 Dec;89 Suppl 1:S41-5. doi: 10.1016/S1472-9792(09)70010-1.
Interferon-gamma release assays (IGRAs) need be evaluated for effectiveness as screening tests for tuberculosis (TB) infection in drug users. These tests have demonstrated improved sensitivity and specificity, but have not been studied in drug users. These one step blood tests are intended to replace the tuberculin skin test (TST), which is difficult to use and requires 48 hour follow-up, so they are expected to be particularly suitable for risk groups, like drug users, in whom follow-up is problematic. Drug users have traditionally been identified as being at increased risk for acquiring TB disease. The results of our pilot study using the TST and simpler and more sensitive interferon-gamma release assays showed that about 45% of current drug users in Houston tested have at least one test positive for latent tuberculosis infection (LTBI). These preliminary data suggest that there is an important reservoir of LTBI in drug using populations, and the risk of progression to active TB disease with other infections is great. However, LTBI in drug using populations has not been studied in depth and deserves further investigation. We need to evaluate the validity of IGRAs for detection of latent TB infection, the factors associated with LTBI, the incidence and risk for developing active TB disease in drug users and the effectiveness of early treatment of LTBI. We believe that using better tuberculosis screening tools will allow us to more accurately measure the prevalence of latent TB infection and incidence of active TB disease in drug using populations and develop more effective TB prevention and treatment interventions in the community.
干扰素释放试验（IGRAs）需要评估其作为药物使用者结核病（TB）感染筛查试验的有效性。这些试验已证明具有更高的敏感性和特异性，但尚未在药物使用者中进行研究。这些一步式血液检测旨在替代结核菌素皮肤试验（TST），后者使用困难，需要 48 小时随访，因此预计它们特别适合药物使用者等风险群体，因为在这些群体中进行随访存在问题。药物使用者历来被认为是感染结核病的风险增加。我们使用 TST 和更简单、更敏感的干扰素释放试验进行的初步研究结果表明，休斯顿约有 45%的当前药物使用者至少有一种潜伏性结核感染（LTBI）检测呈阳性。这些初步数据表明，药物使用者群体中存在大量 LTBI 储存库，与其他感染相关的进展为活动性结核病疾病的风险很大。然而，药物使用者中的 LTBI 尚未得到深入研究，值得进一步调查。我们需要评估 IGRAs 检测潜伏性结核感染的有效性、与 LTBI 相关的因素、药物使用者中活动性结核病疾病的发生率和风险，以及早期治疗 LTBI 的效果。我们相信，使用更好的结核病筛查工具将使我们能够更准确地衡量药物使用者群体中潜伏性结核感染的流行率和活动性结核病疾病的发生率，并在社区中制定更有效的结核病预防和治疗干预措施。
