• 대한의생명과학회지
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• 제24권2호
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• pp.138-142
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• 2018

The incidence of tuberculosis (TB) in the Republic of Korea remains high when compared to the incidence in other Organization for Economic Cooperation and Development (OECD) countries. The prompt diagnosis and effective treatment of latent TB infection (LTBI) are very important in terms of controlling the burden of TB. The tuberculin skin test (TST) has long been the "gold standard" assay for the diagnosis of LTBI. However, it can show false positive results due to Bacille Calmette-$Gu{\acute{e}}rin$ (BCG) vaccination and infection with many environmental nontuberculous mycobacteria (NTM). The interferon gamma release assay (IGRA) using Mycobacterium tuberculosis (MTB)-specific antigens, was developed for the detection of LTBI. The QuantiFERON-TB Gold In-Tube assay is one of the most commonly used forms of the IGRA. In order to compare the diagnostic efficacy of the TST and IGRA in relation to LTBI among BCG-vaccinated healthy donors, whole blood samples were collected from 51 participants, and the results of the TST and IGRA were compared. Of the 51 cases, 18 cases (35.3%) were positive and 33 cases (64.7%) were negative when using the TST, while four cases (7.8%) were positive and 47 cases (92.2%) negative when using the IGRA. There was no correlation between the size of the induration in the TST and the $IFN-{\gamma}$ protein level. In conclusion, the TST showed higher cross-reactivity among the BCG-vaccinated healthy participants, therefore, the IGRA might be the most suitable assay for the rapid screening of LTBI in BCG-vaccinated healthy population, or for TB contact investigation.

• Clinical and Experimental Pediatrics
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• 제52권5호
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• pp.519-528
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• 2009

결핵은 아직도 전세계적으로 소아에서 높은 유병률과 사망률을 보이는 질환이다. 아쉽게도 결핵에 대한 새로운 진단법, 치료법, 예방법에 대한 과학적 혹은 임상 연구는 주로 성인에 초점을 맞추어 왔으며 소아 결핵은 상대적으로 등한시되어 왔다. 그러나 특히 소아 결핵은 감염 후 중한 질환으로 진행되기 쉬우며 이는 사망을 초래하기도 한다. 또한 소아청소년기의 잠복결핵 감염은 후일 결핵균의 재활성으로 인하여 미래의 감염원으로 작용한다. 따라서 미래의 결핵 발생을 줄이기 위해서는 잠복결핵 감염에 대한 특징, 진단, 치료에 대해 이해하는 것이 매우 중요한다. 그러나 우리나라의 국가 결핵관리정책에는 이러한 개념들이 완전히 적용되지 않았으므로, 가능한 빨리 포함되고 시행되어져야 한다.

• Tuberculosis and Respiratory Diseases
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• 제60권5호
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• pp.497-509
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• 2006

Until recently, the tuberculin skin test (TST) has been the only tool available for diagnosing a latent TB infection. However, the development of new diagnostic tools, using the Mycobacterium tuberculosis (MTB)-specific early secreted antigenic target 6 (ESAT-6) and culture filtrate protein 10 (CFP-10) antigens, should improve the control of tuberculosis (TB) by allowing a more accurate identification of a latent TB infection (LTBI). Antigen-specific interferon-gamma ($IFN-{\gamma}$) assays have greater specificity in BCG-vaccinated individuals, and as less biased by nontuberculous mycobacterial infections. Many comparative studies have suggested that those assays have a higher specificity than the TST, and the sensitivity of these assays are expected to remarkably improved if more MTB-specific antigens can become available. Nevertheless, the major obstacle to the widespread use of these tests is the limited financial resources. Similar to other diagnostic tests, the predictive value of $IFN-{\gamma}$ assays depends on the prevalence of a MTB infection in the population being tested. Therefore, prospective studies will be meeded to establish the applicability of these new assays at multiple geographic locations among patients of different ethnicities, and to determine if the $IFN-{\gamma}$ responses can indicate those with a high risk of progressing to active TB.

• Tuberculosis and Respiratory Diseases
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• 제75권1호
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• pp.18-24
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• 2013

Background: We investigated the prevalence of latent tuberculosis infection (LTBI) among the health care workers (HCWs) and analyzed its risk factors in South Korea. Methods: A standard questionnaire regarding the baseline demographics and risk factors for LTBI was given to each participant and tuberculin skin test (TST), QuantiFERON-TB GOLD In-Tube (QFT-GIT) assay, and chest radiography were performed. Results: A total of 493 participants, 152 (30.8%) doctors and 341 (69.2%) nurses were enrolled in eight tertiary referral hospitals. The mean age of the subjects was 30.6 years old, and 383 (77.7%) were female. Of the 152 doctors, 63 (41.4%) and 36 (23.7%) were positive by TST and by QTF-GIT, respectively, and among the 341 nurses, 119 (34.9%) and 49 (14.4%) had positive TST and QFT-GIT results, respectively. Overall, the agreement between the two tests was 0.22 by the chance corrected proportional agreement rate (kappa coefficient) in 493 subjects. Experience of working in tuberculosis (TB)-related departments was significantly associated with positive LTBI test results by QFT-GIT assay, not by TST. In multivariate analysis, only age was independently associated with increased risk of a positive TST result, while age and experience of working in TB-related departments (odds ratio, 2.29; 95% confidence interval, 1.01-5.12) were independently associated with increased risk of a positive QFT-GIT result. Conclusion: A high prevalence of LTBI was found among South Korean HCWs. Considering the association between the experience of working in TB-related departments and high risk of LTBI, QFT-GIT may be a better diagnostic test for LTBI than TST in HCWs.

• 한국산업보건학회지
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• 제29권3호
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• pp.289-297
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• 2019

Objectives: To identify the positive rate of and the risk factors associated with latent tuberculosis infection(LTBI) in mine workers, the objectives of the present study evaluated those among former mine workers. Methods: Between January 2015 and May 2017, former male mine workers who had been subjects for epidemiology research for work-related chronic obstructive pulmonary disease(COPD) and had received QuantiFERON-$TB^{(R)}$ Gold In-Tube(QFT-GIT) from the Institute of Occupation and Environment(IOE) under Korea Workers' Compensation and Welfare Service(KCOMWEL) were selected as the study subjects. To identify significant variables for increased risk of LTBI, logistic regression analysis was performed. Results: A total of 736 male former mine workers were selected as study subjects. The positive rate of LTBI among subjects was 69.2%(509/736). The current smoking[odds ratio(OR), 2.3; 95% confidence interval(CI), 1.1-4.9], COPD(OR, 1.4; 95% CI, 0.9-2.3), department loading(OR, 1.8; 95% CI, 0.9-3.4) and mining(OR, 1.5; 95% CI, 0.9-2.5), and working duration of over 20(OR, 1.6; 95% CI, 0.9-3.1) and over 30 years(OR, 2.2; 95% CI, 0.9-4.9) were associated with increased risk of LTBI. The interferon-gamma(IFN-${\gamma}$) level after stimulation with Mycobacterium tuberculosis(MTB)-specific antigens showed a significantly negative correlation with age(r=-0.126). Conclusions: The present study determined that the high positive rate of LTBI among mine workers was associated with not only the host factors but also the occupational exposure to mine dust.

• 대한의생명과학회지
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• 제19권2호
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• pp.90-97
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• 2013

The tuberculin skin test (TST) and interferon gamma (IFN-${\gamma}$) release assay (IGRA) have been widely used for diagnosis of latent tuberculosis infection (LTBI). In order to overcome limitations of current LTBI diagnostic methods, the development of a novel molecular assay which is able to measure the IFN-${\gamma}$ messenger RNA (mRNA) expression level after stimulation with Mycobacterium tuberculosis (MTB) specific antigen was recently developed. The ability of a molecular assay to detect MTB infection was similar to commercial IGRA however, the optimal incubation time for stimulating IFN-${\gamma}$ was not yet established. Therefore, in this study the direct comparisons of MTB Ag stimulation times (4 and 24 hrs) were performed for diagnosis of MTB infection. Data showed that the coincident rate between QFT-GIT IFN-${\gamma}$ ELISA and IFN-${\gamma}$ RT-PCR (4 hrs) was 88.35% and that of QFT-GIT and IFN-${\gamma}$ RT-PCR (24 hrs) was 70.85%. Based on a receiver operating characteristic (ROC) curve, the 4 hrs-MTB specific Ag stimulation time for IFN-${\gamma}$ RT-PCR had the significant P value, 95% CI value, and AUC (P < 0.0001, 95% CI=0.82 to 1.02, and AUC=0.9214) in comparison with 24 hrs-MTB specific Ag stimulation time (P = 0.009, 95% CI=0.06 to 0.94, and AUC=0.7711). These results show that 4-hr was the most optimal MTB Ag stimulation time for performing IFN-${\gamma}$ RT-PCR. Although semi-quantitative RT-PCR had a few analytical limitations, it might be useful as an alternative molecular diagnostic method for detecting MTB infection.

• Pediatric Infection and Vaccine
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• 제15권1호
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• pp.52-58
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• 2008

목 적 : 잠복 결핵 감염 진단 시 사용되는 고전적인 방법인 투베르쿨린 피부 반응 검사(TST) 외 전혈에서 인터페론 감마의 분비능을 측정하는 검사가 개발된 이후 많은 연구들이 그 유용성을 입증하였으나, 소아에서는 그러한 평가가 제한되어 있다. 본 연구는 결핵에 노출된 소아의 잠복 결핵 감염 진단에 있어 QuantiFERON-TB Gold 검사의 유용성을 알아보고자 하였다. 방 법 : 2006년 1월부터 2007년 12월까지 분당 서울 대학교 병원에 결핵 환자와 접촉하여 내원한 소아를 대상으로 흉부 방사선 사진, TST 및 QuantiFERON-TB Gold 검사를 시행하였다. 초기 TST가 음성인 경우, 3개월 뒤 추적 검사를 시행하였다. TST 결과에 따라 초기 TST가 양성인 경우 감염 여부는 확실치 않으나 잠복 감염의 가능성이 있는 군, 초기 TST는 음성이었으나 3개월 뒤 검사에서 양성 전환된 경우는 잠복 결핵 감염군, 처음과 3개월 뒤 TST가 모두 음성인 경우는 감염되지 않은 군으로 정의하였다. 초기 TST가 음성이었으나 추적검사를 하지 않은 경우는 분석에서 제외시켰다. 결 과 : 대상군은 총 49명(남자 22명, 여자 27명) 이었으며, 중앙 연령은 75세(범위; 3개월-14.7세)이었다. QuantiFERON-TB Gold 검사 양성을 보인 소아는 총 5명으로, 감염 여부는 확실치 않으나 잠복 감염의 가능성이 있는 13명 중 3례(23.1%), 잠복 결핵 감염으로 진단된 8명 중 1례(13%), 그리고 감염되지 않은 21명 중 1례(5%)가 포함되었다. QuantiFERON-TB Gold와 TST의 일치도는 0.72이었다(${\kappa}=0.101$). TST와 비교하였을 때 QuantiFERON-TB Gold의 민감도는 12.5%(1/8), 특이도는 95.2%(20/ 21)으로 나타났다. 결 론 : 결핵에 노출된 소아의 잠복결핵감염의 진단에 있어서 QuantiFERON-TB Gold 검사는 TST에 비하여 민감도가 매우 낮아서 임상적 유용성이 불확실하며 더 많은 연구가 필요하다.

• Tuberculosis and Respiratory Diseases
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• 제82권4호
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• pp.298-305
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• 2019

Background: Tuberculosis (TB) causes substantial health burden to the Korean military. This study aims to assess the impact of infectious TB cases on close and casual contacts in the Korean Army settings based on contact investigation data. Methods: Six Army units with infectious TB cases from September 2012 to May 2013 were enrolled in the study. We analyzed the clinical data from close and casual contacts screened using the tuberculin skin test (TST) and QuantiFERON-TB Gold In-Tube to identify latent tuberculosis infection (LTBI) cases. For the control group, 286 military conscripts with no reported TB exposure were tested by TST only. Results: Of the 667 contacts of index cases, LTBI cases identified were as follows: 21.8% of close contacts of smearpositive cases (71/326), 8.5% of casual contacts of smear-positive cases (26/305), and 2.8% of close contacts of smearnegative cases (1/36). In the control group, 16.8% showed positivity in TST. In a multivariate analysis, having stayed in the same room or next room with TB patients was identified as a risk factor of LTBI. Conclusion: Using the data from TB contact investigations in the Korean Army units, we found an overall LTBI rate of 14.7% among the contacts screened. This study demonstrates that contacts living in the same building, especially the same room or next room, with TB patients are at a high risk of acquiring LTBI, serving as additional evidence for defining close and casual contacts of a TB patient with regard to Army barrack settings.

• Pediatric Infection and Vaccine
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• 제26권1호
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• pp.32-41
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• 2019

목적: 결핵 전파를 조기에 차단하기 위해서는, 활동성 결핵 환자와 접촉한 사람들을 조사하여 결핵 질환 및 잠복결핵감염을 진단하고 치료하는 것이 매우 중요하며, 국내에서는 민간-공공협력 결핵관리사업을 통해 적극적인 접촉자 조사 활동을 지원하고있다. 본연구에서는최근 3년간단일기관에서이루어진소아청소년연령에서의접촉자검진과소아잠복결핵감염치료 현황에 대해 조사하였다. 방법: 2014년 7월 1일부터 2017년 6월 30일까지 충남대학교병원에서 활동성 결핵 환자로 진단받은 환자들을 대상으로 가족 내 소아청소년 접촉자에 대한 검진을 시행하여 접촉자 검진 완료율 및 결과를 분석하였고, 이와 함께 동일 기간 동안 잠복결핵감염으로 치료 받은 소아청소년 환자들의 치료 현황을 후향적으로 검토하였다. 결과: 연구 기간 동안 본 기관에서 활동성 결핵 환자는 총 1,002명 진단되었고, 그 중 소아청소년 가족접촉자가 있는 환자는 171명이었다. 소아청소년 접촉자 269명 중 20명(7.4%)은 검진을 전혀 받지 않았다. 1차 검진을 받은 249명 중 폐결핵이 1명(0.4%) 진단되었고, 7명(2.8%)은 과거의 결핵 감염 병력이 있었으며, 42명(16.9%)이 잠복결핵감염으로 진단되었다. 2차 검진 시 29명(11.6%)이 추가로 잠복결핵감염으로 진단되었으며, 2차 검진까지 필요하였으나 검진을 완료하지 않은 사람이 61명으로 총 접촉자 269명 중 188명(69.9%)만이 필요한 검진을 완료하였다. 잠복결핵감염으로 치료받은 소아청소년 환자는 90명이었으며 83명(92.2%)이 치료를 완료하였고, 이 중 18명이 발진(8명), 피로(5명), 위장장애(5명) 등의 부작용을 호소하였으나 치료 중단이 필요한 심각한 부작용은 없었다. 결론: 민간-공공협력 결핵관리사업 도입 및 보편화 후에도 소아청소년 연령에서의 결핵 접촉자 검진 완료율은 낮았으며, 잠복결핵감염으로 진단받은 소아의 항결핵제 치료 시 심각한 부작용의 발생 없이 투약 완료율이 높게 나타났다. 향후 결핵 전파의 예방 및 관리를 위해 더욱 적극적인 민관 협동 노력 및 환자, 보호자 교육이 필요하겠다.

• Tuberculosis and Respiratory Diseases
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• 제73권4호
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• pp.219-223
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• 2012

Background: We investigated the prevalence of latent tuberculosis infection (LTBI) among medical students in South Korea. Methods: Students from one medical school, who were in second- or third-year classes before clerkship course, were enrolled for three consecutive years in the study. A standard questionnaire was given to each participant, and tuberculin skin test (TST), QuantiFERON-TB GOLD In-Tube (QFT-GIT) assay, and chest radiography were performed. Results: A total of 153 participants were enrolled in the study. The mean age of the subjects was $21.9{\pm}0.9$ years, 105 (68.6%) were male, and 132 (86.3%) had been vaccinated with Bacille Calmette-Gu$\acute{e}$rin (BCG). Four students (2.6%) had a history of contact with tuberculosis (TB) patients during medical practice. No abnormal chest radiograph findings were found for any of the subjects. Of the 153 subjects, 23 (15.0%) tested positive for the TST, and 8 (5.2%) tested positive for the QFT-GIT. The agreement between the two tests was determined to be 0.34 using kappa coefficients. Of the four students who had a history of contact with TB patients, only one subject tested positive for both tests, and the other three students tested negative for both tests. Conclusion: A low prevalence of LTBI was found among medical students before clerkship course in South Korea.