Zwerling Alice, Joshi Rajnish, Kalantri S P, Dakshinamoorthy Gajalakshmi, Reddy Maryada Venkatarama, Benedetti Andrea, Schwartzman Kevin, Menzies Dick, Pai Madhukar
Department of Epidemiology and Biostatistics, McGill University, Montreal, Canada.
J Epidemiol Glob Health. 2013 Jun;3(2):105-17. doi: 10.1016/j.jegh.2013.03.003. Epub 2013 Apr 10.
Interferon gamma release assays (IGRAs) have been shown to be highly dynamic tests when used in serial testing for TB infection. However, there is little information demonstrating a clear association between TB exposure and IGRA responses over time, particularly in high TB incidence settings.
To assess whether QuantiFERON-TB Gold In-Tube (QFT) responses are associated with occupational TB exposures in a cohort of young health care trainees in India.
All medical and nursing students at Mahatma Gandhi Institute of Medical Sciences were approached. Participants were followed up for 18 months; QFT was performed 4 times, once every 6 months. Various modeling approaches were used to define IFN-gamma trajectories and correlations with TB exposure.
Among 270 medical and nursing trainees, high rates of conversions (6.3-20.9%) and reversions (20.0-26.2%) were found depending on the definitions used. Stable converters were more likely to have had TB exposure in hospital pre-study. Recent occupational exposures were not consistently associated with QFT responses over time.
IFN-gamma responses and rates of change could not be explained by occupational exposure investigated. High conversion and subsequent reversion rates suggest many health care workers (HCWs) would revert in the absence of treatment, either by clearing the infection naturally or due to fluctuations in the underlying immunological response and/or poor assay reproducibility. QFT may not be an ideal diagnostic test for repeated screening of HCWs in a high TB incidence setting.
干扰素γ释放试验（IGRAs）在用于结核病感染的系列检测时已被证明是高度动态的检测方法。然而，几乎没有信息表明随着时间推移结核病暴露与IGRAs反应之间存在明确关联，尤其是在结核病高发病率地区。
评估在印度一组年轻医护学员队列中，全血γ干扰素释放试验（QFT）反应是否与职业性结核病暴露相关。
研究人员联系了甘地医学科学研究所的所有医学和护理专业学生。对参与者进行了18个月的随访；QFT检测进行了4次，每6个月检测一次。使用了各种建模方法来定义干扰素γ轨迹以及与结核病暴露的相关性。
在270名医学和护理学员中，根据所使用的定义，发现了较高的血清转化（6.3 - 20.9%）和血清逆转（20.0 - 26.2%）率。稳定的血清转化者在研究前更有可能在医院接触过结核病。随着时间推移，近期职业暴露与QFT反应之间没有始终如一的关联。
所调查的职业暴露无法解释干扰素γ反应及其变化率。高血清转化率和随后的血清逆转率表明，许多医护人员在未接受治疗的情况下会出现血清逆转，要么是自然清除感染，要么是由于潜在免疫反应的波动和/或检测重复性差。在结核病高发病率地区，QFT可能不是用于反复筛查医护人员的理想诊断检测方法。
