• Tuberculosis and Respiratory Diseases
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• 제73권3호
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• pp.143-150
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• 2012

Background: The release of interferon-gamma (IFN-${\gamma}$) by T lymphocytes increases after rechallenge with Mycobacterium tuberculosis antigen, especially, at a localized site of tuberculosis (TB) infection. We aimed to compare the clincial efficacy of two commercial IFN-${\gamma}$ release assays from pleural fluid for the diagnosis in tuberculous pleurisy. Methods: We performed T-SPOT.TB and QuantiFERON-TB Gold tests simultaneously on pleural fluid and peripheral blood samples from patients with pleural effusion, in South Korea, an area with intermediate TB burden. Results: Thirty-six patients were enrolled prospectively, and tuberculous pleurisy was found in 21 patients. Both the numbers of IFN-${\gamma}$ secreting T cells and the concentration of IFN-${\gamma}$ were greater in the pleural tuberculous group, comparing with the non-tuberculous group. Moreover, in the tuberculous group, there was a significant difference in IFN-${\gamma}$ producing spot-forming cells using the T-SPOT.TB method between pleural fluid and peripheral blood. The receiver operating characteristic (ROC) curve, was the greatest for pleural fluid T-SPOT.TB test, followed by peripheral blood T-SPOT.TB test, peripheral blood QuantiFERON-TB Gold test, and pleural fluid QuantiFERON-TB Gold test (area under the ROC curve of 0.956, 0.890, 0.743, and 0.721, respectively). The T-SPOT.TB assay produced less indeterminate results than did QuantiFERON-TB Gold assay in both pleural fluid and peripheral blood. Conclusion: These findings suggest that the pleural fluid T-SPOT.TB test could be the most useful test among the IFN-${\gamma}$ release assays for diagnosing tuberculous pleurisy in an area with an intermediate prevalence of TB infection.

• Tuberculosis and Respiratory Diseases
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• 제81권1호
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• pp.59-72
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• 2018

Background: It remains uncertain if $interferon-{\gamma}$ release assays (IGRAs) are superior to the tuberculin skin test (TST) for the diagnosis of active tuberculosis (TB) or latent tuberculosis infection (LTBI) in immunosuppressed populations including people with human immunodeficiency virus (HIV) infection. The purpose of this study was to systematically review the performance of IGRAs and the TST in people with HIV with active TB or LTBI in low and high prevalence TB countries. Methods: We searched the MEDLINE database from 1966 through to January 2017 for studies that compared results of the TST with either the commercial QuantiFERON-TB Gold in Tube (QFTGT) assay or previous assay versions, the T-SPOT.TB assay or in-house IGRAs. Data were summarized by TB prevalence. Tests for concordance and differences in proportions were undertaken as appropriate. The variation in study methodology was appraised. Results: Thirty-two studies including 4,856 HIV subjects met the search criteria. Fourteen studies compared the tests in subjects with LTBI in low TB prevalence settings. The QFTGT had a similar rate of reactivity to the TST, although the first-generation version of that assay was reactive more commonly. IGRAs were more frequently positive than the TST in HIV infected subjects with active TB. There was considerable study methodology and population heterogeneity, and generally low concordance between tests. Both the TST and IGRAs were affected by CD4 T-cell immunodeficiency. Conclusion: Our review of comparative data does not provide robust evidence to support the assertion that the IGRAs are superior to the TST when used in HIV infected subjects to diagnose either active TB or LTBI.

• Tuberculosis and Respiratory Diseases
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• 제83권4호
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• pp.283-288
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• 2020

Background: Latent tuberculosis (TB) infection among TB contacts is diagnosed using plain chest radiography and interferon-gamma release assays (IGRAs). However, plain chest radiographs often miss active TB, and the results of IGRA could fluctuate over time. The purpose of this study was to elucidate changes in the results of the serial IGRAs and in the findings of the serial submillisievert chest computed tomography (CT) scans among the close contacts of active pulmonary TB patients. Methods: Patients age 20 or older with active pulmonary TB and their close contacts were invited to participate in this study. Two types of IGRA (QuantiFERON-TB Gold In-Tube assay [QFT-GIT] and the T-SPOT.TB test [T-SPOT]) and submillisievert chest CT scanning were performed at baseline and at 3 and 12 months after enrollment. Results: In total, 19 close contacts participated in this study. One was diagnosed with active pulmonary TB and was excluded from further analysis. At baseline, four of 18 contacts (22.2%) showed positive results for QFT-GIT and T-SPOT; there were no discordant results. During the follow-up, transient and permanent positive or negative conversions and discordant results between the two types of IGRAs were observed in some patients. Among the 17 contacts who underwent submillisievert chest CT scanning, calcified nodules were identified in seven (41.2%), noncalcified nodules in 14 (82.4%), and bronchiectasis in four (23.5%). Some nodules disappeared over time. Conclusion: The results of the QFT-GIT and T-SPOT assays and the CT images may change during 1 year of observation of close contacts of the active TB patients.

• Tuberculosis and Respiratory Diseases
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• 제78권2호
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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 Microbiology and Biotechnology
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• 제26권3호
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• pp.588-595
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• 2016

IFN-γ release assays (IGRAs) have been developed as viable alternative diagnostic tools for detecting latent tuberculosis infection (LTBI). A customized homogeneous sandwich luminescent oxygen channeling immunoassay (LOCI) was used to quantify IFN-γ levels in IGRAs. Samples were collected from healthy volunteers (n = 40) who were T-Spot-negative and T-Spot-positive patients (n = 32) at rest. Then the amount of IFN-γ in the supernatant of IGRAs was measured by LOCI. The results demonstrated a low background, and high sensitivity, specificity, accuracy, and reproducibility, and a short assay time (only 30 min) with LOCI for IFN-γ. The recovery range was 81.63-102.06%, the coefficients of variation were below 5%, and the limit of detection was 19.0 mIU/ml. Excellent agreement between LOCI IFN-γ and the T-SPOT.TB test was obtained (97.2% agreement, κ = 0.94). The LOCI IFN-γ concentrations were significantly higher in T-Spot-positive patients than in the healthy group (p < 0.001). Moreover, as observed for the comparative LOCI IFN-γ assay, IFN-γ concentrations were related to the numbers of T-SPOT.TB spots. We have established an in vitro blood test for LTBI diagnosis, defined as LOCI IFN-γ. A high level of agreement between the LOCI IFN-γ method and T-SPOT.TB assay was observed in clinical studies that showed the LOCI IFN-γ method could determine LTBI. This study shows acceptable performance characteristics of the LOCI IFN-γ assay to diagnose LTBI.

• Pediatric Infection and Vaccine
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• 제23권1호
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• pp.18-24
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• 2016

목적: 국내와 같이 결핵의 유병률이 높은 지역에서 결핵을 정확하게 진단하는 것은 중요하다. 본 예비연구는 국내의 소아청소년에서 결핵진단 시 TST 및 2가지 IGRA 검사법 (QFT-G 및 T-SPOT.TB) 간의 일치도를 알아보고자 하였다. 방법: 2014년 1월부터 2015년 4월까지 잠복결핵감염 또는 결핵질환의 진단을 위해 서울아산병원을 방문한 20세 이하 환자 중, TST, T-SPOT.TB 및 QFT-G 검사 중 최소 2가지 이상의 검사를 동시에 시행한 경우를 연구에 포함하였다. 이들의 의무기록을 후향적으로 분석하여 각 검사 간의 일치도를 평가하였다. 결과: 연구에 포함된 총 20명의 연령의 중앙값은 13.3세(범위: 3.8-18.1세)이었고, 이 중 11명은 면역저하와 관련된 기저질환이 있었다. T-SPOT.TB와 QFT-G 결과의 일치도는 90%였으며, TST와 T-SPOT.TB의 일치도는 50%, TST와 QFT-G의 일치도는 42.9%였다. T-SPOT.TB, QFT-G 및 TST의 결핵질환에 대한 특이도는 93.3%, 86.7% 및 58.3%였다. 결론: T-SPOT.TB과 QFT-G 간의 일치도는 높으나 TST와 T-SPOT.TB 또는 QFT-G 간의 일치도는 낮았다. 추후 국내 소아청소년의 정확한 결핵의 진단을 위한 각 검사들의 일치도 및 진단적 유용성에 대한 추가적인 연구가 필요하다.

• Tuberculosis and Respiratory Diseases
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• 제76권6호
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• pp.261-268
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• 2014

Patients with immune-mediated inflammatory diseases (IMIDs) are increasingly being treated with anti-tumor necrosis factor (TNF) agents and are at increased risk of developing tuberculosis (TB). Therefore, diagnosis and treatment of latent TB infection (LTBI) is recommended in these patients due to the initiation of anti-TNF therapy. Traditionally, LTBI has been diagnosed on the basis of clinical factors and a tuberculin skin test. Recently, interferon-gamma releasing assays (IGRAs) that can detect TB infection have become available. Considering the high-risk of developing TB in patients on anti-TNF therapy, the use of both a tuberculin skin test and an IGRA should be considered to detect and treat LTBI in patients with IMIDs. The traditional LTBI treatment regimen consisted of isoniazid monotherapy for 9 months. However, shorter regimens such as 4 months of rifampicin or 3 months of isoniazid/rifampicin are increasingly being used to improve treatment completion rates. In this review, the screening methods for diagnosing latent and active TB before anti-TNF therapy in patients with IMIDs will be briefly described, as well as the current LTBI treatment regimens, the recommendations for managing TB that develops during anti-TNF therapy, the necessity of regular monitoring to detect new TB infection, and the re-initiation of anti-TNF therapy in patients who develop TB.

• Tuberculosis and Respiratory Diseases
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• 제72권5호
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• pp.416-425
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• 2012

Background: The sensitivities and specificities of interferon-gamma release assays (IGRAs) vary among different population studies, and the data on the routine use of IGRAs are limited. The aim of this study was to evaluate the role of QuantiFERON-TB Gold In-Tube (QFT-GIT) test in the diagnosis of active tuberculosis. Methods: We conducted a prospective study, enrolling 77 patients with suspected pulmonary tuberculosis (TB), at a secondary care teaching hospital in Seoul. Results: In total, 12 (15.6%) patients showed indeterminate results due to positive control failure on the QFT-GIT test. Indeterminate results were significantly associated with the elderly, history of the intensive care unit stay, lymphocytopenia, especially low CD4 count, increased C-reactive protein and decreased protein levels. Of the 77 patients, 44 (57.1%) were diagnosed with active pulmonary tuberculosis, and the percentage of false negative results of the QFT-GIT was 36.4% (vs. 31.8% with TST). In the TB group with >65 years old (n=12), the proportions of the indeterminate (33.3% vs. 3.1%) and the false negative results (58.3% vs. 25.0%) of the QFT-GIT were significantly higher than in the younger TB group (n=32). Conclusion: Indeterminate and false negative results of QFT-GIT test were not infrequent in tuberculosis, especially in the elderly. Care should be considered for the interpretation with the elderly, immunocompromised, chronic and severely diseased patients.

• Pediatric Infection and Vaccine
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• 제18권1호
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• pp.48-53
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• 2011

목 적 : 활동성 결핵의 진단으로 투베르쿨린 피부반응 검사(TST)가 널리 사용되어 왔으나 민감도가 낮고 BCG 예방접종을 한 경우 교차반응이 일어날 수 있는 한계가 있어 이를 극복하기 위해 인터페론감마검사(IGRA)에 대한 연구가 보고되고 있다. 이에 본 연구는 소아 활동성 결핵을 진단하는 초기검사로서 IGRA의 유용성에 대해 알아보았다. 방 법: 2007년 4월부터 2008년 8월까지 부산대학교병원 소아청소년과에서 활동성결핵이 의심되어 입원한 18세 이하의 환자 33명을 대상으로 성별, 나이, BCG 접종력, 임상양상과 IGRA 검사결과를 분석하였다. 결 과:총 33명의 환아 중 9명이 활동성 결핵으로 진단되었고 ELISpot에 양성은 10명, 음성은 23명이었다. 활동성 결핵이었던 환아는 모두 양성이었다. 검사의 민감도는 활동성 결핵 환자에서 100%이었다. 23명의 환아가 ELISpot에 음성 반응을 보였는데 이들은 모두 임상적으로 결핵이 아닌 것으로 확진되었고 검사의 특이도는 95.8%였다. 결 론:소아의 활동성 결핵 진단에 있어 ELISpot은 유용한 것으로 생각된다.

• The Korean Journal of Medicine
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• 제93권6호
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• pp.509-517
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• 2018

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 of LTBI are important for tuberculosis (TB) control in public and private healthcare facilities, particularly in high-risk populations. The updated 2017 Korean guidelines for TB recommend that tuberculin skin tests, interferon-gamma release assays, or a combination of them can be used for the diagnosis of LTBI, depending on the age and immune status of the patient as well as their TB contact history. For diagnosis of LTBI, exclusion of active TB is essential, and the possibility of healed TB in those without a history of treatment for TB but at risk of its development must be considered. The treatment options for LTBI include isoniazid, rifampicin, isoniazid/rifampicin, and isoniazid/rifapentine. The benefits and risks of these agents based on the age of the patient and their hepatotoxicity must be considered when selecting the appropriate drug. Standardized diagnosis and treatment of LTBI based on the updated 2017 guidelines will contribute to the control of TB in Korea as well as to further revisions of the guidelines.