• Tuberculosis and Respiratory Diseases
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• v.86 no.2
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• pp.94-101
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• 2023

A recent understanding of the dynamic continuous spectrum of Mycobacterium tuberculosis infection has led to the recognition of incipient tuberculosis, which refers to the latent infection state that has begun to progress to active tuberculosis. The importance of early detection of these individuals with a high-risk of progression to active tuberculosis is emphasized to efficiently implement targeted tuberculosis preventive therapy. However, the tuberculin skin test or interferon-γ release assay, which is currently used for the diagnosis of latent tuberculosis infection, does not aid in the prediction of the risk of progression to active tuberculosis. Thus, a novel test is urgently needed. Recently, simultaneous and systematic analysis of differentially expressed genes using a high-throughput platform has enabled the discovery of key genes that may serve potential biomarkers for the diagnosis or prognosis of diseases. This host transcriptional investigation has been extended to the field of tuberculosis, providing promising results. The present review focuses on recent progress and challenges in the field of blood transcriptional signatures to predict progression to active tuberculosis.

• Clinical and Experimental Pediatrics
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• v.57 no.9
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• pp.420-424
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• 2014

The Epstein-Barr virus (EBV) is oncogenic and can transform B cells from a benign to a malignant phenotype. EBV infection is also associated with lymphoid interstitial pneumonia (LIP). Here, we report the case of a 14-year-old boy who was diagnosed with a latent EBV infection and underlying LIP, without any associated immunodeficiency. He had been EBV-seropositive for 8 years. The first clinical presentations were chronic respiratory symptoms and recurrent pneumonia. The symptoms worsened in the following 2 years. The results of in situ hybridization were positive for EBV, which led to a diagnosis of LIP. The diagnosis was confirmed by the results of a thoracoscopic lung biopsy. The EBV titer of the bronchoalveolar lavage specimens obtained after acyclovir treatment was found to be fluctuating. The patient had latent EBV infection for 8 years, until presented at the hospital with intermittent abdominal pain and distension. Physical examination and pelvic computed tomography revealed a large mesenteric mass. A biopsy of the excised mass led to a diagnosis of Burkitt's lymphoma (BL). The patient received combination chemotherapy for 4 months, consisting of vincristine, methotrexate, cyclophosphamide, doxorubicin, and prednisolone. He is now tumor-free, with the LIP under control, and is being followed-up at the outpatient clinic. This is the first report of a Korean case of chronic latent EBV infection that developed into LIP and BL in a nonimmunocompromised child.

• Tuberculosis and Respiratory Diseases
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• v.78 no.2
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• pp.56-63
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• 2015

A small number of viable tuberculosis bacilli can reside in an individual with latent tuberculosis infection (LTBI) without obvious clinical symptoms or abnormal chest radiographs. Diagnosis and treatment for LTBI are important for tuberculosis (TB) control in public and private health, especially in high-risk populations. The updated 2014 Korean guidelines for TB recommend that tuberculin skin tests, interferon-gamma release assays, or a combination of the two can be used for LTBI diagnosis according to age and immune status of the host as well as TB contact history. The regimens for LTBI treatment include isoniazid, rifampicin, or isoniazid/rifampicin. However, results of drug susceptibility test from the index case must be considered in selecting the appropriate drug for recent contacts. Standardized LTBI diagnosis and treatment based on the new 2014 guidelines will contribute to the effective TB control in Korea as well as to the establishment of updated guidelines.

• Journal of Preventive Medicine and Public Health
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• v.52 no.4
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• pp.272-275
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• 2019

The 2018 National Guideline for Tuberculosis Control, which was published by the Korea Centers for Diseases Prevention and Control (KCDC), mandates conducting an epidemiological survey among close contacts of active tuberculosis patients at public institutions such as schools. In the procedure for these surveys, the tuberculin skin test (TST) is mandated as the screening test for latent tuberculosis infection in elementary school students. However, several guidelines recommend using the interferon-gamma releasing assay (IGRA) for contacts aged over 5 years with a Bacillus Calmette-$Gu{\acute{e}}rin$ vaccination history. The main reason for this is that IGRA has a higher specificity and lower false positive rate than TST. In addition, IGRA requires only a single visit to draw blood and the results are available within 24 hours. These advantages could promote cooperation from both parents and students in conducting these surveys. Thus, these findings regarding the benefits of IGRA for surveys of close contacts at elementary schools should be incorporated into the KCDC guideline.

• Pediatric Infection and Vaccine
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• v.22 no.1
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• pp.7-15
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• 2015

Purpose: The purpose of this study is to investigate secondary infections within the households of newly diagnosed tuberculosis patients. Methods: We collected data on household infections of tuberculosis patients by retrospective review of medical records and telephone surveys. Results: Out of 321 newly diagnosed tuberculosis cases, a total of 253 patients who received telephone surveys were enrolled in this study. Less than 50% of the patients had household contacts screened for tuberculosis infection, and most of the patients were not aware of the necessity of testing. Out of 562 household contacts, there were 8 cases of secondary tuberculosis (1.4%, 8/562) in 7 households. There were 15 cases of latent infection (2.7%, 15/562) in 13 households. Out of 110 child and adolescent household contacts, there were no cases of secondary tuberculosis, and there were 8 cases of latent infection (7.3%) in 7 households, which was 20.5% among child and adolescent contacts screened for tuberculosis infection. In 3 of the cases (13.0%) that had secondary tuberculosis or latent infection in their households, the source of infection was extrapulmonary tuberculosis. There was no correlation between the frequency of household infections and the presence of pulmonary cavities, sputum AFB smear results, and microbiologically confirmed results. Conclusions: For effective investigation of tuberculosis contacts, it is necessary to raise general awareness on the necessity of investigating household contacts, and there should also be a continued assessment on tuberculosis contact investigation since government-supported programs.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.3
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• pp.238-244
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• 2017

Objectives: The major objective of this study was to investigate the prevalence of and risk factors for latent tuberculosis infection (LTBI) among employees at a workers' compensation hospital. Methods: Among the 394 employees at Incheon Hospital, 362 were enrolled in the study. An interferon-gamma release assay(IGRA) for diagnosis of LTBI was performed using QuantiFERON$^{(R)}$ TB Gold In-Tube(QFT-IT). Risk factors for LTBI were analyzed using logistic regression analysis. Results: The overall prevalence of LTBI was 32.0%(116/362). The non-medical departments have a significantly high prevalence compared to medical departments(39.7% vs 23.2%). In multivariate logistic regression analysis, experience working in the pneumoconiosis hospital(OR, 3.6; 95% CI, 1.3-10.3) was associated with development of LTBI. Conclusions: Korean guidelines for the management of tuberculosis recommend annual regular health examinations for TB and LTBI for health care workers(HCWs). Considering the high prevalence of and risk factors for LTBI among non-HCWs, it suggests a need for annual regular health examinations for TB and LTBI for all employees at workers' compensation hospitals, including pneumoconiosis hospitals.

• Journal of muscle and joint health
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• v.26 no.2
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• pp.120-130
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• 2019

Purpose: The purpose of this study was to investigate the predictors of tuberculosis (TB) drugs in health care workers diagnosed with latent tuberculosis Infection (LTBI). Methods: This study was a descriptive correlation study. Data were collected by using a self-report questionnaire. The collected data were analyzed by -test, t-test, and logistic regression analysis. Results: There were involved 160 participants, 35 (21.9%) who took the TB drugs, and 125 (73.8%) who did not take the TB drugs. The predictors on taking TB drugs in health care workers with LTBI were subjective norms (OR=3.33, p<.001), perceived sensitivity (OR=2.67, p=.026), perceived barrier (OR=0.14, p=.014), and unmarried (OR=4.69, p=.006) than married, health care worker category 2 group (OR=5.84, p=.015) and 1 group (OR=4.25, p=.022) than 3, 4 group, sleep over 7 hours (OR=4.11, p=.022) than less 7 hours sleep. Conclusion: In order to promote the use of TB drugs in health care workers with LTBI, it is necessary that take intervention strategies to increase the subjective norms and perceived sensitivity and to decrease the perceived barriers.

• Pediatric Infection and Vaccine
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• v.16 no.2
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• pp.107-114
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• 2009

Tuberculosis is a disease with high morbidity and mortality in children worldwide. Despite significant improvements in diagnostic methods, scientific researches and clinical trials for new regimens of treatment or prevention in adult tuberculosis, childhood tuberculosis has been relatively neglected. Children are at high risk of severe disease, and reactivation of latent infection in adulthood perpetuates the epidemic. Therefore, a policy of tuberculosis control in childhood should be emphasized to improve control in the total population. To understand the new view of childhood tuberculosis, this article describes changes in the disease's national epidemiology, new diagnostic tools and treatment strategies, and multi-drug resistance.

• Korean Journal of Clinical Laboratory Science
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• v.48 no.3
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• pp.225-229
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• 2016

Tuberculosis (TB) is caused by a chronic infectious agent known as Mycobacterium tuberculosis. It is transmitted in airborne particles, called droplet nuclei which was generated by cough, sneeze, shout, or sing of persons who have TB disease. Most infections of TB do not have symptoms, well known as latent tuberculosis infection (LTBI). However, about 10% of LTBI progress to active disease a one or two years after infection. To investigate the LTBI rate of college students who were in contacted with TB patients, we performed chest X-ray, tuberculin skin test (TST) and Interferon-gamma release assay (IGRA) to 74 college students. At a results, 65 students were showed negative and 9 students positive results at chest X-ray and 1st TST test. When confirmed the 65 students who were showed negative by 2st TST, the results showed correctly. But, 9 students who were showed positive results on chest X-ray and 1st TST by IGRA, the only 3 students (4.05%) showed positive results. In conclusion, the LTBI rate in this study showed 4.05% (3/74) and we suggest to investigate other students LTBI rate for decreasing tuberculosis.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.1
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• pp.67-74
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• 2020

Objectives: Previous study has shown that the positive rate of latent tuberculosis infection(LTBI) among former workers in dusty environments was higher than that among high-risk groups of tuberculosis(TB). The objective of the present study was to identify the development of active TB among former workers in dusty environments diagnosed with LTBI. Methods: Between January 2015 and May 2017, 796 former workers in dusty environments who had been subjects of epidemiology research for work-related chronic obstructive pulmonary disease(COPD) had received the QuantiFERON-TB® Gold In-Tube(QFT-GIT) from the Institute of Occupation and Environment(IOE) under the Korea Workers' Compensation and Welfare Service(KCOMWEL). Among them, 437 participants who received a health examination for work-related pneumoconiosis between January 2015 and December 2018 were selected as study subjects. Active TB was defined as a positive result for active PTB and non-tuberculosis mycobacteria infection in the result of the Pneumoconiosis Examination Council's assessment by KCOMWEL. Results: A total of 437 subjects were followed up for 2.1 years. Four of them(4/437, 0.9%) developed active TB during the follow-up period. The attack rate of active TB among subjects who were diagnosed LTBI positive and those who were diagnosed LTBI negative were 0.9%(3/320) and 0.9%(1/115), respectively. Conclusions: Most previous studies reported that the attack rate of the development of active TB in subjects who had been diagnosed LTBI positive was higher than that among subjects who had been diagnosed LTBI negative. To the contrary, the present study found that the rate of developing active TB among former workers in dusty environments diagnosed as LTBI positive was not higher than that in those who were diagnosed LTBI negative.