Department of Pulmonary and Critical Care Medicine, Hallym University Medical Center, Gangwondo, South Korea.
Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, South Korea.
Front Cell Infect Microbiol. 2021 Mar 18;11:599386. doi: 10.3389/fcimb.2021.599386. eCollection 2021.
The Beijing strain of () has been most frequently isolated from TB patients in South Korea, and the hyper-virulent Beijing/K genotype is associated with TB outbreaks. To examine the diagnostic potential of Beijing/K-specific peptides, we performed IFN-γ release assays (IGRA) using a MTBK antigen tube containing Beijing/K MTBK_24800, ESAT-6, and CFP-10 peptides in a cohort studied during a school TB outbreak.
A total of 758 contacts were investigated for infection, and 43 contacts with latent TB infection (LTBI) and 25 active TB patients were enrolled based on serial screening with QuantiFERON-TB Gold In-Tube tests followed by clinical examinations. Blood collected in MTBK antigen tubes was utilized for IGRA and multiplex cytokine bead arrays. Immune responses were retested in 24 patients after TB treatment, and disease progression was investigated in subjects with LTBI.
Total proportions of active disease and LTBI during the outbreak were 3.7% (28/758) and 9.2% (70/758), respectively. All clinical isolates had a Beijing/K genotype. IFN-γ responses to the MTBK antigen identified infection and distinguished between active disease and LTBI. After anti-TB treatment, IFN-γ responses to the MTBK antigen were significantly reduced, and strong TNF-α responses at diagnosis were dramatically decreased.
MTBK antigen-specific IFN-γ has diagnostic potential for differentiating infection from healthy controls, and between active TB and LTBI as well. In addition, TNF-α is a promising marker for monitoring therapeutic responses. These data provide informative readouts for TB diagnostics and vaccine studies in regions where the Beijing/K strain is endemic.
韩国分离的结核分枝杆菌（）中，以北京株最为常见，而高毒力的北京/K 基因型与结核病爆发有关。为了研究北京/K 型特异性肽的诊断潜力，我们对在学校结核病爆发期间研究的队列进行了 IFN-γ 释放试验（IGRA），使用含有北京/K MTBK_24800、ESAT-6 和 CFP-10 肽的 MTBK 抗原管。
对 758 名接触者进行了 感染调查，根据 QuantiFERON-TB Gold In-Tube 检测后进行的临床检查，选择了 43 名潜伏性结核感染（LTBI）和 25 名活动性结核病患者作为研究对象。MTBK 抗原管采集的血液用于 IGRA 和多因子 bead 阵列检测。24 名结核病患者治疗后进行了免疫反应复测，LTBI 患者进行了疾病进展调查。
暴发期间活动性疾病和 LTBI 的总比例分别为 3.7%（28/758）和 9.2%（70/758）。所有临床分离株均为北京/K 基因型。MTBK 抗原的 IFN-γ 反应可识别 感染，并区分活动性疾病和 LTBI。抗结核治疗后，MTBK 抗原的 IFN-γ 反应明显降低，而诊断时的 TNF-α 反应显著降低。
MTBK 抗原特异性 IFN-γ 具有区分健康对照与 感染、活动性结核病与 LTBI 的诊断潜力。此外，TNF-α 是监测治疗反应的一个有前途的标志物。这些数据为北京/K 株流行地区的结核病诊断和疫苗研究提供了有价值的指标。
