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BACKGROUND Reduced sensitivity of tuberculosis (TB) interferon-γ release assays (IGRAs) among the elderly has been reported, which is presumably due to diminished immune function. We evaluated the clinical performance of QuantiFERON®-TB Gold plus (QFT-Plus) compared with QuantiFERON®-TB Gold In-Tube (QFT-GIT) and T-Spot®.TB (T-SPOT) in the elderly. METHODS Blood samples for all three IGRAs were drawn at the same time from all the participants. Both CD4 and CD8 T-cell counts in patients' peripheral blood were also measured. RESULTS A total of 142 active pulmonary TB patients (median age: 84, interquartile range; 76-89 years) were recruited. The sensitivities of the tested IGRAs (excluding invalid/indeterminate cases) were as follows: QFT-Plus, 93.6%; QFT-GIT, 91.4%; and T-SPOT 68.1%. QFT-Plus displayed significantly higher sensitivity than T-SPOT (p

Background Immune checkpoint inhibitors are a standard treatment for advanced lung cancer, although it remains important to identify biomarkers that can accurately predict treatment response. Immune checkpoint inhibitors enhance the antitumor T‐cell response, and interferon‐γ plays an important role in this process. Therefore, this study evaluated whether the number of interferon‐γ‐releasing peripheral T cells after phytohemagglutinin stimulation in the interferon‐γ release assay might act as a biomarker for the response of non‐small cell lung cancer to immune checkpoint inhibitor treatment. Methods Data were retrospectively collected regarding 74 patients with non‐small cell lung cancer who had received immune checkpoint inhibitors. Pretreatment screening tests had been performed using the T‐SPOT.TB assay, which quantifies the number of interferon‐γ‐releasing T cells (as immunospots) in response to phytohemagglutinin and tuberculosis‐specific antigen stimulation. Clinical factors and the number of spots in the T‐SPOT fields were evaluated for associations with patient outcomes. The median number of spots was used to categorize patients as having high or low values, and the two groups were compared. Results Relative to patients with a low ratio, patients with a high ratio of phytohemagglutinin/tuberculosis‐specific antigen spots (i.e. more responsive T cells) had significantly better progression‐free survival after immune checkpoint inhibitor treatment. When we only considered patients with negative T‐SPOT results, a high number of phytohemagglutinin‐stimulated spots corresponded to significantly longer progression‐free survival. Conclusion The T‐SPOT.TB assay can be used to quantify the number of immunospots in response to antigen stimulation, which may predict the response to immune checkpoint inhibitors in patients with non‐small cell lung cancer., This study evaluated whether the T‐SPOT test could be used to predict the response to immune checkpoint inhibitor treatment in patients with non‐small cell lung cancer. Among patients with negative T‐SPOT results, a high number of phytohemagglutinin‐stimulated spots was associated with longer progression‐free survival.

Objective: Early diagnosis of osteoarticular tuberculosis helps improve patients’ outcomes, but little is known about the accuracy of noninvasive diagnostic methods. This case-control study aimed to assess the diagnostic value of peripheral blood T-cell spot of tuberculosis assay (T-SPOT.TB) and magnetic resonance imaging (MRI). Methods: Patients suspected with osteoarticular tuberculosis were retrospectively included and diagnosed according to the composite reference standard. T-SPOT.TB was used to detect the number of cells secreting Interferon gamma. Diagnostic performance of T-SPOT.TB and MRI alone and combined were evaluated. Results: Among the suspected patients, 92 had osteoarticular tuberculosis and 137 non- osteoarticular tuberculosis. T-SPOT.TB assay alone had a higher sensitivity (0.73 vs. 0.60) but a lower specificity (0.69 vs. 0.91 P>0.05) in diagnosing osteoarticular tuberculosis. Combined serial test showed a sensitivity and specificity 0.47, 0.97, respectively, whereas combined parallel test showed a sensitivity and specificity of 0.86, 0.65, respectively. Specificity was higher in the combined serial test than in the T-SPOT.TB assay (P=0.007) or MRI alone (P < 0.001). Furthermore, sensitivity was higher in the combined parallel test than in the T-SPOT.TB assay (P < 0.001) or MRI alone (P < 0.001). Conclusions: Combined blood T-cell spot of tuberculosis assay and osteoarticular MRI have higher sensitivity and specificity for noninvasive osteoarticular tuberculosis diagnosis, compared with either method alone.

Background: Controling Latent Tuberculosis Infection (LTBI) is important for the End TB Strategy program. The prevalence of LTBI and reactivation to active tuberculosis are increased in immunodeficiency conditions, such on hemodialialysis patients. Laten tuberculosis can be diagnosted by Tuberculin Skin Test (TST) and immunoglobulin release assay (IGRA). This diagnostic study aimed to determine the agreement level of TST and T-SPOT.TB, accurancy of T-SPOT.TB, and the correlation between T cluster of differentiation 4 (CD4+) cell counts with TST and T-SPOT.TB. Methods: This is a cross sectional study design was performed in hemodialysis patients of Dr. Moewardi Surakarta Hospital in May 2018. The study subject had TST and T-SPOT.TB examinations by using 2 Tuberkulin Unit (TU) of intradermal purified protein derivate (PPD) RT 23 (Biofarma, Bandung) and venous blood ELISPOT analysis, respectively. Statistical analysis used windows SPSS 21. Results: There were 30 study subjects. The prevalence of LTBI was 23.3%. The agreement level of TST and T-SPOT.TB was substantial (K=0.667;P

The way to monitor tuberculosis (TB) treatment is extremely lacking in clinical practice. The aim of the study is to assess the role of the TBAg/PHA ratio in the treatment monitoring of TB. TB patients were followed up for 6 months and serial T-SPOT.TB (T-SPOT) assays were performed. In patients with successful treatment outcomes, the ESAT-6 sfc, CFP-10 sfc, and TBAg/PHA ratio all showed a decreased trend after the initiation of treatment. Conversely, PHA sfc showed an increased trend after 2 months of treatment. However, these indicators had moderate performance in distinguishing between before and after 6 months of treatment, and the AUC ranged from 0.702 to 0.839. Notably, the TBAg/PHA ratio in patients without risk factors was of important value in differentiation between before and after treatment. The optimal AUC of TBAg/PHA ratio reached up to 0.890. Patients with unsuccessful treatment outcomes showed persistently high levels of TBAg/PHA ratio. The TBAg/PHA ratio in patients after 6 months of treatment showed a certain potential in distinguishing between patients with successful and unsuccessful treatment outcomes. A further calculation of the TBAg/PHA ratio in T-SPOT assay has potential value in the treatment monitoring of TB, but further confirmation is needed.

Objectives This study evaluated the efficacy of the following interferon (IFN)-γ release assays (IGRAs): QuantiFERON-TB Gold Plus (QFT-Plus), QFT-Gold In-Tube (QFT-GIT), and T-SPOT. TB (T-SPOT) with the quantitative values of IFN-γ response. Methods Blood samples were collected from patients with active tuberculosis (TB), latent TB infection (LTBI), individuals with previous TB infection, and healthy volunteers enrolled between May 2017 and June 2018. Results IGRAs results were analyzed in 175 subjects (76 had active TB, 14 had LTBI, 35 had prior TB infection, and 50 were healthy). QFT-Plus and QFT-GIT revealed equal efficacy for IFN-γ values, and the IFN-γ response in QFTs tended to increase with the spot counts in T-SPOT, with similar high sensitivities (approximately 90%) in the active TB group. The test concordance of two of three IGRAs was optimal among all subjects (κ coefficients: 0.82–0.96). Additionally, the median quantitative values of IFN-γ with QFT-Plus and QFT-GIT were higher in the active TB group than in the LTBI and previous TB groups. Conclusion Three IGRAs showed equivalent efficacy with high sensitivities and higher IFN-γ response in active TB group than that in non-active TB group.

This study aimed to determine whether increased cut-off of the T-SPOT.TB could aid in diagnosing active tuberculosis (ATB).Patients suspected of having TB were enrolled to derive a T-SPOT.TB threshold value to help diagnose ATB, which was subsequently validated in real-world clinical practice.In total, 701 adult patients suspected of having tuberculosis who had undergone the T-SPOT.TB assay were included in the derivation cohort. The numbers of ESAT-6 (U = 43583, P = 0.0002) and CFP-10 (U = 41753, P 0.0001) spot-forming cells (SFCs) significantly increased in the ATB group compared with the Latent tuberculosis infection (LTBI) group. According to receiver operating characteristic analysis, when a cut-off of 37.5 SFCs/2.5 × 10In high-burden countries, a higher threshold value of 173.5 SFCs/2.5 × 10

For the immunodiagnosis of tuberculosis infection, in addition to standard skin tests (Mantoux test with 2 TU PPD-L and Diaskintest), in vitro tests are currently used, one of which is the T-spot.TB test. Purpose of research . Evaluate the T-SPOT test as a method of early detection of tuberculosis infection in children and adolescents and its role as an additional method in solving the problem of the need for chemoprophylaxis. Materials and methods. The analysis of the results of T-SPOT.TB in 794 children aged 2 to 17 years inclusive in the period from 2016 to 2019 was carried out. Two groups were allocated: 1 group (n = 596) — children who underwent T-SPOT.TB as the main methodology; Group 2 — 198 children with positive skin test results for a recombinant tuberculosis allergen after screening. The results of T-SPOT.TB were evaluated taking into account the data of previous immunodiagnostics and associated pathology. Results. It is established that T-SPOT.TB. can be used as an independent method in case of rejection of skin tests. The level of latent tuberculosis infection is higher among children with concomitant pathology according to the results of T-SPOT.TB twice. Conclusion. T-SPOT.TB can be an alternative method for diagnosing tuberculosis infection during screening. In children with concomitant pathology of the T-SPOT.TB can serve as the leading method of tuberculosis immunodiagnosis. A positive T-SPOT.TB can serve as an additional method for deciding on the appointment of preventive chemotherapy.

For the immunodiagnosis of tuberculosis infection, in addition to standard skin tests (Mantoux test with 2 TU PPD-L and Diaskintest), in vitro tests are currently used, one of which is the T-spot.TB test.Purpose of research. Evaluate the T-SPOT test as a method of early detection of tuberculosis infection in children and adolescents and its role as an additional method in solving the problem of the need for chemoprophylaxis.Materials and methods. The analysis of the results of T-SPOT.TB in 794 children aged 2 to 17 years inclusive in the period from 2016 to 2019 was carried out. Two groups were allocated: 1 group (n = 596) — children who underwent T-SPOT.TB as the main methodology; Group 2 — 198 children with positive skin test results for a recombinant tuberculosis allergen after screening. The results of T-SPOT.TB were evaluated taking into account the data of previous immunodiagnostics and associated pathology.Results. It is established that T-SPOT.TB. can be used as an independent method in case of rejection of skin tests. The level of latent tuberculosis infection is higher among children with concomitant pathology according to the results of T-SPOT.TB twice.Conclusion. T-SPOT.TB can be an alternative method for diagnosing tuberculosis infection during screening. In children with concomitant pathology of the T-SPOT.TB can serve as the leading method of tuberculosis immunodiagnosis. A positive T-SPOT.TB can serve as an additional method for deciding on the appointment of preventive chemotherapy.

Longitudinal studies regarding the reproducibility of Interferon-gamma release assay (IGRA) T-SPOT.TB for the diagnosis of Mycobacterium tuberculosis (M. tb) infection in serial testing are limited. We retrospectively analysed results of serially tested subjects in a medical laboratory in Germany over a time period of 14 years. From October 2004 to December 2018, a total of 5440 subjects were identified with a second T-SPOT.TB test after a median time interval of 258 days (interquartile range [IQR] 62-665). Consistently negative (n = 4520) or positive results (n = 682) were observed in 5202 (95.6%) subjects, indicating a high degree of concordance in serial testing (κ = 0.83). Test conversions occurred in 101 of 4621 (2.2%) subjects with initially negative tests. Of 819 subjects with initially positive test results, 137 (16.7%) had a test reversion which was associated with low spot numbers of the first test. Of 529 subjects retested within 1 year, only 60 (11.3%) displayed a test reversion. In subjects retested after more than 1 year, 77 of 290 (26.6%) tests reverted. This significantly higher rate of test reversions after more than 1 year was age-dependent and only observed in subjects above the age of 40 years. In the medical laboratory, the T-SPOT.TB test demonstrates a high reproducibility in serial testing.

In addition to standard skin tests (Mantoux test with 2 TU PPD-L and diaskintest) for the diagnosis of tuberculosis infection, in vitro tests are used. One of these tests is T-SPOT.TB being more widely used in recent years.The objective: to evaluate the effectiveness of T-SPOT.TB test for early detection of tuberculosis infection in children and adolescents in Samara Region.Subjects and methods. From 2016 to 2019, results of T-SPOT.TB tests performed in 596 children aged 2 to 17 years inclusive were analyzed; those children had no immunodiagnosis of tuberculosis infection using skin tests since their parents refused to have it.Results. It was found out that the major reason for refusing skin tests was the “fear” of visiting a TB dispensary if the result had been positive — 38.43% (n = 229). The latent tuberculosis infection according to the results of T-SPOT.TB among children with concomitant pathology made 2.6%, among healthy children – 0.7%.Conclusion. T-SPOT.TB test may be used as an alternative method for diagnosis of tuberculosis infection, should the parent refuse to have skin tests. In children with concomitant pathology, T-SPOT.TB test can serve as a leading method for immunodiagnosis of tuberculosis.The authors state that they have no conflict of interests.

BackgroundsTakayasu arteritis (TAK) is a chronic, granulomatous vasculitis correlated with tuberculosis (TB). The two diseases share similar pathological characteristics and clinical manifestations which increase the difficulty to diagnose. Active tuberculosis (ATB) has implications for treatment strategies in TAK patients. Therefore, the investigation of clinical features and potential risk factors of ATB in TAK patients is vital.MethodsThe study reviewed hospitalized patients diagnosed with TAK in our hospital from 2008, to 2021. TAK patients with ATB were enrolled as the case group. The control group was randomly selected in a 3:1 ratio. The clinical characteristics of TAK patients with and without ATB were compared. Multivariate logistic regression analysis was performed to determine risk factors for ATB in TAK patients.ResultsWe reviewed 1,789 patients and ultimately identified 30 (1.7%) ATB cases. TAK patients with ATB were more prone to develop symptoms including fever (p=0.001), fatigue (p=0.003), cough (p=0.037), expectoration (p8 mg/L (OR 9.108; 95% CI, 1.096–75.711; p=0.041) and positive T-SPOT.TB result (OR 68.669; 95% CI, 7.291–646.738; pConclusionOur study suggested that the diagnosis of ATB should be considered when TAK patients experienced symptoms including fever, fatigue, weight loss, etc. hsCRP >8 mg/L and positive T-SPOT.TB result were identified as independent risk factors for ATB in TAK patients.

The current study compared the QuantiFERON-TB® Gold Plus on LIAISON® XL to the T-SPOT.TB for the diagnosis of latent Mycobacterium tuberculosis infection on 125 patient samples. A high agreement of qualitative results (90%) was observed between both methods with 3% major discrepancies, half of which were false negative results with the T-SPOT.TB.

Diagnosing latent tuberculosis (TB) infection (LTBI) is important globally for TB prevention. LTBI diagnosis requires a positive test for infection and negative evaluation for active disease. Current tests measure an immunologic response and include the tuberculin skin test (TST) and interferon-gamma release assays (IGRAs), T-SPOT.TB and QuantiFERON. The IGRAs are preferred in bacille Calmette-Guérin-vaccinated populations. The TST is still used when cost or logistical advantages over the IGRAs exist. Both TST and IGRAs have low positive predictive values. Tests that differentiate the TB spectrum and better predict future TB risk are needed.

Background The goal of this study was to further investigate the clinical effectiveness of the T-SPOT.TB test in diagnosing tuberculosis (TB), including the effects of T-SPOT.TB test on evaluating diverse TB types and locations. Methods We collected 20,332 specimens from patients suspected to have TB. Afterwards, we performed an integrative analysis of T-SPOT.TB results and clinical diagnoses, and evaluated the composition ratio and positive detection rate of the T-SPOT.TB test in various age groups, sample types, and hospital departments. In addition, we compared the spot number and composition rate between latent TB infection (LTBI), active TB infection, and old TB infection groups. The active TB group was then further divided into pulmonary TB (PTB), pulmonary and extrapulmonary TB (PETB), and extrapulmonary TB (EPTB) subgroups, and we evaluated whether there were statistical differences in spot number and composition rate between subgroups. Results Positive results from the T-SPOT.TB test were found across different age groups, specimen types, and hospital departments. Elderly patient groups, pleural effusion samples, and thoracic surgery departments showed the highest rates of positivity. There were no statistically significant differences in spot number of CFP-10 and ESAT-6 wells between disease groups or active TB subgroups. The composition rate, however, was significantly different when ESAT-6 and CFP-10 wells were double-positive. The spot number and composition rate were statistically different between the three disease groups, but showed no significant differences between the three subgroups of active TB. Conclusions The results of T-SPOT. TB test showed differences in LTBI, active TB and old TB. Additionally, a higher spot number level was observed in the active TB group.

Tuberculosis (TB) is the most common opportunistic infection in human immunodeficiency virus (HIV)-infected patients. Diagnosis and treatment of latent tuberculosis infection (LTBI) is the most important step in preventing the development of active TB. In our country where TB is moderately endemic, HIV-infected patients should be investigated for LTBI. Tuberculin skin test (TST) and interferongamma release assays (IGRA) are used in the diagnosis of LTBI but there isn't a standard practice. The aim of this study is to compare the TST and T-SPOT.TB test efficiency in the diagnosis of LTBI in HIVinfected patients. Patients who had no previous active TB infection, who were not treated for LTBI and who had no active tuberculosis infection at the time of admission were included in the study. A total of 100 HIV-infected patients who were admitted to the Infectious Diseases and Clinical Microbiology outpatient clinic between June 2015 and March 2016 were evaluated cross-sectionally. CD4+ T lymphocyte counts in the last one month were detected. All patients underwent chest radiography at the time of admission. Patients who are not considered as active TB infection with clinical and laboratory findings and who had no TST within the last one month were included in the study. TST was performed after the blood samples were taken for T-SPOT.TB test. In our study, 87% of the patients were male and the mean age was 40.2. The mean CD4+ T lymphocyte count was 605 cells/mm³ (26-1313). 16% of the patients had a history of encountring a person with tuberculosis and 81% had BCG vaccination scar. TST positivity and T-SPOT.TB positivity were 22.9% and 22%, respectively. The concordance between the two tests was found to be moderate (Kappa= 0.491). It was determined that BCG vaccination and the presence of a contact with a patient with TB did not affect TST and T-SPOT.TB test positivity (p> 0.05). There was a positive correlation between CD4+ T lymphocyte count and TST measurement values (r= 0.3, p= 0.003). Accordingly, as the number of CD4+ T lymphocytes increased, TST positivity increased (p= 0.007). T-SPOT.TB test was not affected by CD4+ T lymphocyte count (p= 0.289). Our study showed that TST was affected by CD4+ T lymphocyte count and patients' compliance with this test was also low. On the contrary T-SPOT.TB test was not affected by CD4+ T lymphocyte count. There was no statistically significant difference between T-SPOT.TB test positivity and CD4+ T lymphocyte count (p= 0.289). The concordance between the two tests was found to be moderate. It is thought that the main reason for the discordance between the tests is due to false negative or false positive results of TST. In conclusion, T-SPOT.TB was found more reliable in the diagnosis of LTBI in HIV-infected individuals. In the light of these findings, especially in HIV-infected patients with low CD4+ T lymphocyte counts, T-SPOT.TB test can be considered for LTBI diagnosis.

Renal transplant recipients are at increased risk of reactivating latent tuberculosis infection (LTBI) and developing active tuberculosis. QuantiFERON®-TB Gold Plus (QFT-Plus) has two TB-specific antigens tubes (TB1 and TB2). TB1 elicits CD4 T-cell response, and TB2 elicits both CD4 and CD8 T-cells responses, with expected increased sensitivity. The aim of this study was to estimate the prevalence of LTBI in renal transplant recipients in Japan. We conducted a cross-sectional study by using two interferon-γ release assays (IGRAs), QFT-Plus and T-SPOT®.TB (TSPOT). One hundred thirty-five recipients were prospectively enrolled. The median age was 49 years (range: 20 to 79). The positivity rates of QFT-Plus and TSPOT were 5.9% (95%CI 3.0-11.3) and 3.7% (95%CI 1.6-8.4), respectively, with no significant difference. The concordance rate was 95.5% (κ coefficient, 0.76). Age of 60 years and higher was related to the higher positivity rate in both QFT-Plus and TSPOT. The positivity rates of TB1 and TB2 were 5.1% (95%CI 2.5-10.2) and 5.9% (95%CI 3.0-11.2), respectively, with no significant difference. The concordance rate was 99.3% (κ coefficient, 0.93). TB2 did not show a higher positivity rate compared with TB1. The estimated prevalence of LTBI by using the both IGRAs was 3.7-5.9% in renal transplant recipients. These results were equivalent to the IGRAs positivity rate in the general Japanese population, even under the condition of immunosuppressive therapy. In consideration of the higher risk of developing active TB from LTBI, we can use both IGRAs as acceptable tools for LTBI diagnosis in renal transplant recipients.

Summary Objectives To evaluate the performance of QuantiFERON-TB Gold Plus (QFT-Plus) on Mycobacterium tuberculosis (MTB) infection test among registered village doctors from China. Methods MTB infection of the registered village doctors in Zhongmu County were tested using QFT-Plus and two other interferon-gamma release assays (IGRAs) in parallel: QuantiFERON-TB Gold In-Tube (QFT) and T-SPOT.TB (T-SPOT). Retests were carried out for baseline positives at 3 and 6 months later, respectively. Results A total of 616 village doctors were included in the baseline examination. The positivity of QFT, QFT-Plus and T-SPOT was 27.91% (168/602), 31.22% (187/599) and 27.70% (169/610), respectively. The concordance between QFT and QFT-Plus was 94.81% (Kappa coefficient: 0.87) and between T-SPOT and QFT-Plus was 88.93% (Kappa coefficient: 0.73). Reversions were frequently observed for all three assays. With respect to QFT-Plus, the quantitative results of reversions in the serial testing were mostly distributed in an “uncertain range” zone (0.2-0.7 IU/mL). Similar patterns of distribution were observed for QFT and T-SPOT as well. Conclusion Village doctors should gain more attention as an at-risk group for TB infection control in rural China. Our results support, by means of serial testing, a good agreement between QFT-Plus and QFT in Chinese population.

Summary Objectives Tuberculosis (TB) is a serious infectious disease with high mortality for solid-organ transplantation. Preventive therapy of latent tuberculosis infection (LTBI) has been considered to reduce TB risk and improve outcomes of transplantation. The aim of this study was to evaluate the cost-effectiveness of the interferon-gamma release assays (IGRAs); QuantiFERON®-TB Gold in-Tube (QFT) and T-SPOT®.TB (TSPOT)), for kidney, liver and lung transplant recipients in low TB incidence countries. Methods Decision trees and Markov models were developed for four strategies; QFT, TSPOT, the tuberculin skin test (TST) and no screening. Targeted populations were hypothetical cohorts of kidney, liver and lung transplant recipients aged 40 years using a societal perspective on a lifetime horizon. Per-person costs, effectiveness and incremental cost effectiveness ratios were calculated and compared. Results QFT was the most cost-effective (Kidney; US$ 5679, 3.026 QALYs, Liver; US$ 5914, 2.365 QALYs, Lung; US$ 6092, 3.761 QALYs). No screening was the least effective. Cost-effectiveness was not sensitive to BCG vaccination rate, and the costs of screening tests and treatment. Conclusions TB screening using IGRA with individualized TB risk assessment and follow-up monitoring of drug toxicity during LTBI treatment is recommended for solid organ transplantation, on the basis of the benefits and cost-effectiveness.

BackgroundDistinguishing between active tuberculosis (ATB) and latent tuberculosis infection (LTBI) remains challenging.MethodsBetween 2013 and 2019, 2,059 (1,097 ATB and 962 LTBI) and another 883 (372 ATB and 511 LTBI) participants were recruited based on positive T-SPOT.TB (T-SPOT) results from Qiaokou (training) and Caidian (validation) cohorts, respectively. Blood routine examination (BRE) was performed simultaneously. Diagnostic model was established according to multivariate logistic regression.ResultsSignificant differences were observed in all indicators of BRE and T-SPOT assay between ATB and LTBI. Diagnostic model built on BRE showed area under the curve (AUC) of 0.846 and 0.850 for discriminating ATB from LTBI in the training and validation cohorts, respectively. Meanwhile, TB-specific antigens spot-forming cells (SFC) (the larger of early secreted antigenic target 6 and culture filtrate protein 10 SFC in T-SPOT assay) produced lower AUC of 0.775 and 0.800 in the training and validation cohorts, respectively. The diagnostic model based on combination of BRE and T-SPOT showed an AUC of 0.909 for differentiating ATB from LTBI, with 78.03% sensitivity and 90.23% specificity when a cutoff value of 0.587 was used in the training cohort. Application of the model to the validation cohort showed similar performance. The AUC, sensitivity, and specificity were 0.910, 78.23%, and 90.02%, respectively. Furthermore, we also assessed the performance of our model in differentiating ATB from LTBI with lung lesions. Receiver operating characteristic analysis showed that the AUC of established model was 0.885, while a threshold of 0.587 yield a sensitivity of 78.03% and a specificity of 85.69%, respectively.ConclusionsThe diagnostic model based on combination of BRE and T-SPOT could provide a reliable differentiation between ATB and LTBI.

T-SPOT®.TB (T-SPOT) is an interferon-gamma release assay (IGRA) used to detect infection with Mycobacterium tuberculosis based on the number of spot-forming T-cells; however, delays in sample processing have been shown to reduce the number of these spots that are detected following laboratory processing. Adding T-Cell Xtend (XT) into blood samples before processing reportedly extends the amount of time allowed between blood collection and processing up to 32 hours. In this study, paired blood samples from 306 adolescents and adults at high risk for latent tuberculosis (TB) infection (LTBI) or progression to TB disease were divided into three groups: 1) early processing (∼4.5 hours after collection) with and without XT, 2) delayed processing (∼24 hours after collection) with and without XT, and 3) early processing without XT and delayed processing with XT. The participants' paired samples were processed at a local laboratory and agreement of qualitative and quantitative results were assessed. The addition of XT did not consistently increase or decrease the number of spots. In groups 1, 2, and 3, samples processed with XT had 13% (10/77), 28.0% (30/107) and 24.6% (30/122), respectively, more spots while 33.8% (26/77), 26.2% (28/107), and 38.5% (47/122) had less spots compared with samples processed without XT. The findings suggest that XT does not reliably mitigate the loss of spot-forming T-cells in samples with processing delay.

BackgroundThe prompt diagnosis of pulmonary tuberculosis (PTB) remains a challenge in clinical practice. The present study aimed to optimize an algorithm for rapid diagnosis of PTB in a real-world setting.Methods28,171 adult inpatients suspected of having PTB in China were retrospectively analyzed. Bronchoalveolar lavage fluid (BALF) and/or sputum were used for acid-fast bacilli (AFB) smear, Xpert MTB/RIF (Xpert), and culture. A positive mycobacterial culture was used as the reference standard. Peripheral blood mononuclear cells (PBMC) were used for T-SPOT.TB. We analyzed specimen types’ effect on these assays’ performance, determined the number of smears for diagnosing PTB, and evaluated the ability of these assays performed alone, or in combination, to diagnose PTB and nontuberculous mycobacteria (NTM) infections.ResultsSputum and BALF showed moderate to substantial consistency when they were used for AFB smear or Xpert, with a higher positive detection rate by BALF. 3-4 smears had a higher sensitivity than 1-2 smears. Moreover, simultaneous combination of AFB and Xpert correctly identified 44/51 of AFB+/Xpert+ and 6/7 of AFB+/Xpert- cases as PTB and NTM, respectively. Lastly, when combined with AFB/Xpert sequentially, T-SPOT showed limited roles in patients that were either AFB+ or Xpert+. However, T-SPOTMDC (manufacturer-defined cut-off) showed a high negative predicative value (99.1%) and suboptimal sensitivity (74.4%), and TBAg/PHA (ratio of Mycobacterium tuberculosis-specific antigens to phytohaemagglutinin spot-forming cells, which is a modified method calculating T-SPOT.TB assay results) ≥0.3 demonstrated a high specificity (95.7%) and a relatively low sensitivity (16.3%) in AFB-/Xpert- patients.ConclusionsConcurrently performing AFB smear (at least 3 smears) and Xpert on sputum and/or BALF could aid in rapid diagnosis of PTB and NTM infections in a real-world high-burden setting. If available, BALF is preferred for both AFB smear and Xpert. Expanding this algorithm, PBMC T-SPOTMDC and TBAg/PHA ratios have a supplementary role for PTB diagnosis in AFB-/Xpert- patients (moderately ruling out PTB and ruling in PTB, respectively). Our findings may also inform policy makers’ decisions regarding prevention and control of TB in a high burden setting.

The T-SPOT.TB assay detects cellular immune responses to 2 core Mycobacterium tuberculosis antigens, early secreted antigenic target of 6-kDa protein (ESAT-6) and culture filtrate protein-10 (CFP-10). T-SPOT.TB has been recently used for auxiliary diagnosis of active pulmonary tuberculosis (PTB). However, testing can produce inconsistent results due to differential PTB patient immune responses to these antigens, prompting us to identify factors underlying inconsistent results. Data were retrospectively analyzed from 1225 confirmed PTB patients who underwent T-SPOT.TB testing at 5 specialized tuberculosis hospitals in China between December 2012 and November 2015. Numbers of spot-forming cells (SFCs) reflecting T cell responses to ESAT-6 and CFP-10 antigens were recorded then analyzed via multivariable logistic regression to reveal factors underlying discordant T cell responses to these antigens. The agreement rate of 84.98% (82.85%–86.94%) between PTB patient ESAT-6 and CFP-10 responses demonstrated high concordance. Additionally, positivity rates were higher for ESAT-6 than for CFP-10 (84.8% vs 80.7%, P .99), while spot numbers of the single positive group were lower than numbers for the double positive group (P

Background: The ability of T-SPOT.TB to differentiate Mycobacterium tuberculosis infection of the spine from other infections is little known. This study quantified the efficiency, sensitivity, and specificity of the T-SPOT.TB assay to distinguish between spinal tuberculosis (STB) caused by M. tuberculosis and other infections of the spine and evaluated whether diagnostic performance was improved by adjusting the T-SPOT.TB assay criteria. Methods: From January 2010 to May 2020, 147 patients with spinal infections were recruited. Peripheral blood mononuclear cells were collected, and the number of spot-forming cells was observed. Patients’ white blood cell (WBC) counts, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), procalcitonin (PCT), and TB antibodies were recorded. Specimen/tissue bacteriological culture was the reference standard for sensitivity and specificity. Results: There were 77 (52.4%) participants with confirmed TB and 70 (47.6%) with other infections. The groups were comparable in T-SPOT.TB assay results, age, sex, lesions in the segments, WBC count, CRP, procalcitonin, ESR, and TB antibodies. The sensitivity and specificity of the T-SPOT.TB assay for identifying STB was 88.3% and 40.0%, respectively. On the basis of Relative operating characteristic curve (ROC) analysis and the Youden index, when we adjusted the T-SPOT.TB assay’s diagnostic criteria, ESAT-6>12 or CFP-10>19,the sensitivity and specificity of the T-SPOT.TB assay for identifying STB was 83.1% and 64.3%, respectively. Conclusion: The T-SPOT.TB assay has great sensitivity to distinguish STB from other spinal infections; however, the specificity is extremely low. Specificity can be significantly improved while sensitivity is guaranteed by adjusting the diagnostic criteria.

BackgroundT-SPOT TB (T-SPOT) assay is widely used for detection of Mycobacterium tuberculosis infection that is based on the detection of M. tuberculosis-specific interferon-γ-secreting T cells (ISCs) in peripheral blood mononuclear cells (PBMCs). Recently, high frequencies of low-density granulocytes (LDGs) were found in the PBMCs of tuberculosis patients. Whether these LDGs affect the detection of T-SPOT has not been investigated. The impact of LDGs on T-SPOT assay and related mechanism were investigated in this study.MethodsThe correlations between the frequencies of LDGs and the results of T-SPOT were analyzed. T-SPOT with LDG-removed PBMCs and PBMCs with exogenous addition of LDGs were performed. The possible mechanism was explored by detecting the levels of negative immune regulatory molecules on LDGs. The impact of programmed death ligand 1 (PD-L1) on T-SPOT was evaluated and confirmed by function blocking with neutralizing antibody.ResultsThe positive rates of T-SPOT and ISCs in tuberculosis patients with low LDGs frequency (n = 22) were significantly higher than those with high LDGs frequency (n = 39). Removal or exogenous addition of LDGs significantly increased or decreased the ISCs and the positive rate of T-SPOT. The frequencies of interferon-γ-producing T cells were negatively correlated with the frequencies of LDGs. The expression of PD-L1 was significantly elevated on LDGs. Pretreatment of LDGs with anti-PD-L1 antibody significantly counteracted the impact of LDGs on T-SPOT. Treatment of PBMCs with anti-PD-L1 antibody resulted in comparable ISCs with that of LDG removal.ConclusionLDGs can inhibit the production of interferon-γ in T cells and decrease the positive rated of T-SPOT assay via highly expressed PD-L1.

Background:Tuberculous peritonitis (TP) is a common form of abdominal tuberculosis (TB). Diagnosing TP remains challenging in clinical practice. The aim of the present meta-analysis was to evaluate the diagnostic accuracy of peripheral blood (PB) T-SPOT and peritoneal fluid (PF) T-SPOT for diagnosing TP.Methods:PubMed, EmBase, Cochrane, Scopus, Google scholar, China national knowledge internet, and Wan-Fang databases were searched for relevant articles from August 1, 2005 to July 5, 2020. Statistical analysis was performed using Stata, Revman, and Meta-Disc software. Diagnostic parameters including pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were determined. Summary receiver operating characteristic curve was used to determine the area under the curve (AUC).Results:Twelve studies were eligible and included in the meta-analysis. The analysis showed that the pooled sensitivity and specificity of PB T-SPOT in diagnosing TP were 0.91 (95% CI, 0.88–0.94) and 0.78 (95% CI, 0.73–0.81), respectively, while the pooled PLR, NLR, and DOR were 4.05 (95% CI, 2.73–6.01), 0.13 (95% CI, 0.07–0.23), and 37.8 (95% CI, 15.04–94.98), respectively. On the other hand, the summary estimates of sensitivity, specificity, PLR, NLR, and DOR of PF T-SPOT for TP diagnosis were 0.90 (95% CI, 0.85–0.94), 0.78 (95% CI, 0.72–0.83), 6.35 (95% CI, 2.67–15.07), 0.14 (95% CI, 0.09–0.21), and 58.22 (95% CI, 28.76–117.83), respectively. Furthermore, the AUC of PB T-SPOT and PF T-SPOT for TP diagnosis were 0.91 and 0.94, respectively.Conclusions:Our results indicate that both PB T-SPOT and PF T-SPOT can be served as sensitive approaches for the diagnosis of TP. However, the unsatisfactory specificities of these two methods limit their application as rule-in tests for TP diagnosis. Furthermore, the standardization of the operating procedure of PF T-SPOT is further needed.

Background The positive rate of pathogenic examination about tuberculosis is low. It is still difficult to achieve early diagnosis for some TB patients. The value of Interferon-gamma release assays (IGRA) in the diagnosis of active tuberculosis remains controversial. The purpose of this multicenter prospective study was to verify and validate the role of TBAg/PHA ratio (TB-specific antigen to phytohaemagglutinin) of T-SPOT.TB assay in diagnosing ATB. Methods We prospectively enrolled 2390 suspected pulmonary tuberculosis patients with positive T-SPOT assay results from three tertiary hospitals. Results A total of 1549 ATB (active tuberculosis) patients (including 1091 confirmed and 458 probable ATB) and 724 non-tuberculosis (non-TB) patients with positive T-SPOT results were included. The results of this study showed that ESAT-6 and CFP-10 in the T-SPOT.TB assay were significantly higher in the ATB group compared with the non-TB group, while PHA was lower in the ATB group. Results of ESAT-6, CFP-10 and PHA show a certain diagnostic performance, but moderate sensitivity and specificity. The TBAg/PHA ratio, a further calculation of ESAT-6, CFP-10 and PHA in T-SPOT.TB assay showed improved performance in the diagnosis of active Tuberculosis. If using the threshold value of 0.2004, the specificity and sensitivity of TBAg/PHA ratio in distinguishing ATB from non-TB were 92.3% and 74.4%, PPV was 95.4, PLR was 9.6. Conclusion By recalculating the results of T-SPOT.TB Assay, the TBAg/PHA ratio shows high prospect value in the diagnosis of active tuberculosis in high prediction areas.

Background Infections are one of the most common causes of morbidity and mortality in patients with systemic lupus erythematosus (SLE). SLE patients have a higher risk of tuberculosis (TB) infection due to impaired immune defence. Objectives To investigate the demographics, clinical characteristics and outcomes of patients with SLE and concomitant TB. Methods Medical records of SLE patients with TB who were admitted to Peking Union Medical College (PUMC) Hospital in 1983-2019 were retrospectively reviewed. Age- and sex-matched SLE inpatients without TB were randomly selected as controls. Clinical and laboratory features and treatment were analysed and compared, and subjects were followed up to assess their outcome. Results Of the 10 469 SLE inpatients, 249 (2.4%) were diagnosed with TB. Compared with controls, SLE/TB + patients exhibited higher frequency of prior haematologic, mucocutaneous and musculoskeletal system involvement, and prior treatment with potent glucocorticoid/immunosuppressive agents (GC/ISA). Arthritis and alopecia, positive T-SPOT.TB test and lymphocytopenia were more common in SLE/TB + patients. SLE/TB + patients with lupus before TB (SLE → TB) had higher risk of miliary TB (22.8%) and intracranial TB (16.5%) than SLE/TB + patients with lupus after TB (TB → SLE). SLE/TB + patients exhibited shorter long-term survival than SLE/TB- patients; those with poorer in-hospital outcomes had more severe lymphocytopenia and had received less treatment with ISAs. Conclusion Systemic lupus erythematosus patients treated vigorously with GC/ISA should be alerted of increased risk of TB infection, especially miliary and intracranial TB. Positive T-SPOT.TB and lymphocytopenia served as discriminatory variables between SLE/TB + and SLE/TB- patients. Lymphocytopenia was associated with poorer outcomes in SLE/TB + patients.

The diagnosis of tuberculous pericarditis (TBP) remains challenging. This prospective study evaluated the diagnostic value of Xpert MTB/RIF (Xpert) and T-SPOT.TB and adenosine deaminase (ADA) for TBP in a high burden setting. A total of 123 HIV-negative patients with suspected TBP were enrolled at a tertiary referral hospital in China. Pericardial fluids were collected and subjected to the three rapid tests, and the results were compared with the final confirmed diagnosis. Of 105 patients in the final analysis, 39 (37.1%) were microbiologically, histopathologically or clinically diagnosed with TBP. The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio, negative likelihood ratio and diagnostic odds ratio (DOR) for Xpert were 66.7%, 98.5%, 96.3%, 83.3%, 44.0, 0.338, and 130.0, respectively, compared to 92.3%, 87.9%, 81.8%, 95.1%, 7.6, 0.088, and 87.0, respectively, for T-SPOT.TB, and 82.1%, 92.4%, 86.5%, 89.7%, 10.8, 0.194, and 55.8, respectively, for ADA (≥ 40 U/L). ROC curve analysis revealed a cut-off point of 48.5 spot-forming cells per million pericardial effusion mononuclear cells for T-SPOT.TB, which had a DOR value of 183.8, while a cut-off point of 41.5 U/L for ADA had a DOR value of 70.9. Xpert (Step 1: rule-in) followed by T-SPOT.TB [cut-off point] (Step 2: rule-out) showed the highest DOR value of 252.0, with only 5.7% (6/105) of patients misdiagnosed. The two-step algorithm consisting of Xpert and T-SPOT.TB could offer rapid and accurate diagnosis of TBP.

Introduction Human immunodeficiency virus (HIV) infected individuals are at increased risk of developing active tuberculosis (TB). TB incidence remains higher than in non-HIV subjects after antiretroviral therapy (ART) initiation. This study was conducted to estimate the prevalence of positive IGRA, reflecting latent tuberculosis infection and/or a history of active TB, in HIV-infected individuals after ART initiation in Japan. Methods Two IGRAs (Interferon (IFN)-γ release assays), QuantiFERON®-TB Gold Plus (QFT-Plus) and T-Spot®.TB (TSPOT), were used. We also analyzed the TB associated risk factors for the IGRAs results and the role of CD4+ T-cells, CD8+ T-cells and NK cells for producing IFN-γ. We also analyzed the risk factors for positive IGRA responses and the role of CD4+ T-cells, CD8+ T-cells and NK cells for producing IFN-γ. Results One hundred eight-four subjects were prospectively enrolled. Median age was 49 years. The positivity rates of QFT-Plus and TSPOT were 7.6% [95%CI 4.6–12.4] and 2.7% [95%CI 1.2–6.2], respectively, with significant difference. TB-associated risk factors and NK cells ≥300/μL were selected as independently significant factors by multivariate logistic regression. The NK cell count revealed significant linear regression with IFN-γ production responding to TB-specific antigens. Conclusions The prevalence of positive IGRAs was 2.7%–7.6%. QFT-Plus would be practical for a higher positivity rate and reflect TB risk factors. The innate immune system, referring to IFN-γ production, plays an important role in the immune response to TB-specific antigens even after initiating ART.

Background: The role of T-SPOT.TB (T-SPOT) assay for tuberculous meningitis (TBM) diagnosis has not been fully assessed. Here, we conducted an updated meta-analysis to evaluate the diagnostic accuracy of peripheral blood (PB) T-SPOT and cerebrospinal fluid (CSF) T-SPOT for diagnosing TBM. Methods: Relevant studies in the PubMed database, EmBase database, Cochrane database, Scopus database, Google Scholar, China National Knowledge Internet, and Wan-Fang database were retrieved from August 1, 2005, to June 22, 2020. Statistical analysis was performed using Stata, Revman, and Meta-Disc software. The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), summary receiver operating characteristic curves, and the area under the curve were determined and analyzed. Results: A total of 27 studies were eligible for inclusion within the meta-analysis. The pooled sensitivity and specificity of PB T-SPOT for TBM diagnosis were 0.78 (95% CI, 0.76-0.81) and 0.68 (95% CI, 0.66-0.71), respectively, whereas the pooled PLR, NLR, and DOR were 2.80 (95% CI, 2.29-3.42), 0.32 (95% CI, 0.27-0.38), and 10.08 (95% CI, 7.21-14.08), respectively. On the other hand, the pooled sensitivity and specificity of CSF T-SPOT on diagnosing TBM were 0.76 (95% CI, 0.72-0.80) and 0.88 (95% CI, 0.85-0.90), respectively, whereas the pooled PLR, NLR, and DOR were 5.92 (95% CI, 4.25-8.25), 0.28 (95% CI, 0.21-0.39), and 29.05 (95% CI, 16.40-51.45), respectively. The area under the summary receiver operating characteristic curve values of PB T-SPOT and CSF T-SPOT for TBM diagnosis were 0.83 (95% CI, 0.80-0.86) and 0.92 (95% CI, 0.89-0.94), respectively. Conclusions: CSF T-SPOT showed a higher specificity compared with PB T-SPOT for diagnosing TBM. Both two T-SPOT assays have considerable potential in improving the diagnosis of TBM. Furthermore, the standardization of the operating procedure is further needed when performing CSF T-SPOT.

BACKGROUND: Interferon Gamma Release Assay (IGRA) is still controversial in differentiating tuberculous pleural effusion (TPE), through recommended by World Health Organization (WHO) for identification of latent tuberculosis infection. OBJECTIVES: Aim to in comparison to Adenosine deaminase (ADA), evaluate the IGRA (T-SPOT.TB) diagnostic efficacy for TPE patients of different characteristics, to clarify its appropriate scene in clinical diagnosis. METHODS: A prospective, single-centre study including all suspected pleural effusion patients consecutively from June 2015 to October 2018. Through receiver operating characteristic (ROC) curves, all enrolled participants were determined technical cut-off and the utility of IGRA for pleural fluid (PF). Obtain the independent risk factors by logistic regression analysis for TPE, and evaluate the performance of T-SPOT stratified by risk factors, in comparison to ADA. RESULTS: A total of 601 individuals were consecutively recruited. The maximum of early secretory antigenic target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10) in PF T-SPOT had the best diagnostic efficiency in our study, with a sensitivity of 83.0% and a specificity of 83.1%, corresponding cut-off value is 466 SFCs/10 6 mononuclear cells, which was equal to ADA (0.885 vs 0.887, P=0.957) and superior than in PB; Among the TPE patients with low ADA(45yrs, female or BMI≧22). PF T-SPOT assay is an extremely good choice to supplement ADA to diagnose TPE.

There is an urgent need for precise diagnosis to distinguish nontuberculous mycobacterial (NTM) diseases from pulmonary tuberculosis (PTB) and other respiratory diseases. The aim of this study is to evaluate the diagnostic performance of Interferon-gamma (IFN-γ) release assays (IGRAs), including antigen-specific peripheral blood-based quantitative T cell assay (T-SPOT.TB) and QuantiFERON-TB-Gold-Test (QFT-G), in differentiating NTM infections (N = 1,407) from culture-confirmed PTB (N = 1,828) and other respiratory diseases (N = 2,652). At specie level, 2.56%, 10.73%, and 16.49% of NTM-infected patients were infected by Mycobacterium kansasii, M. abscessus, and with M. avmm-intracellulare complex (MAC), respectively. Valid analyses of T-SPOT.TB (ESAT-6, CFP-10) and QFT-G were available for 37.03% and 85.79% in NTM-infected patients, including zero and 100% (36/36) of M. kansasii infection, 21.85% (33/151) and 92.05% (139/151) of M. abscessus infection, and 17.67% (41/232) and 91.24% (211/232) of MAC infection. Based on means comparisons and further ROC analysis, T-SPOT.TB and QFT-G performed moderate accuracy when discriminating NTM from PTB at modified cut-off values (ESAT-6 < 4 SFCs, CFP-10 < 3 SFCs, and QFT-G < 0.667 IU/ml), with corresponding AUC values of 0.7560, 0.7699, and 0.856. At species level of NTM, QFT-G effectively distinguished between MAC (AUC=0.8778), M. kansasii (AUC=0.8834) or M. abscessus (AUC=0.8783) than T-SPOT.TB. No significant differences in discriminatory power of these three IGRA tools were observed when differentiating NTM and Controls. Our results demonstrated that T-SPOT.TB and QFT-G were both efficient methods for differentiating NTM disease from PTB, and QFT-G possessed sufficient discriminatory power to distinguish infections by different NTM species.

ObjectiveWe evaluated clinical performance of the T-SPOT.TB test for detecting tuberculosis (TB) infection in Meizhou, China.MethodsWe enrolled 2,868 patients who underwent T-SPOT.TB, smear, and TB-DNA at the same time. The tests’ sensitivity and specificity were evaluated and compared in different groups, and in pulmonary TB (PTB) and extrapulmonary TB (EPTB) subgroups. Receiver operator characteristic (ROC) curve analysis was used to evaluate T-SPOT.TB’s diagnostic value and determine its cutoff value.ResultsT-SPOT.TB, TB-DNA, and sputum smear sensitivity was 61.44%, 37.12%, and 14.02%; and specificity was 76.49%, 99.20% and 99.60%, respectively. The T-SPOT.TB positive rate was higher in the PTB and EPTB subgroups than in patients with other pulmonary diseases (61.38% and 61.76% vs. 23.34%). The T-SPOT.TB test had better diagnostic accuracy and sensitivity when the positive cutoff value of marker ESAT-6 was 2.5 [area under ROC curve = 0.701, 95%CI 0.687–0.715] and marker CFP-10 was 6.5 [area under ROC curve = 0.669, 95%CI 0.655–0.683].ConclusionT-SPOT.TB sensitivity was higher than that of TB-DNA or sputum smear, but the specificity was lower. T-SPOT.TB had moderate sensitivity and specificity for diagnosing TB. T-SPOT.TB’s new positive cutoff value may be clinically valuable according to ROC analysis.

BACKGROUND:CD4-positive T cells are the main target of human T-cell leukemia virus type 1 (HTLV-1). Interferon-γ release assays rely on the fact that T-lymphocytes release this cytokine when exposed to tuberculosis-specific antigens and are useful in testing for latent tuberculosis infection before initiating biologic therapy, such as anti-tumor necrosis factor agents. However, the reliability of interferon-γ release assays in detecting tuberculosis infection among HTLV-1-positive patients with rheumatoid arthritis (RA) remains unclear. The present study aimed to evaluate the use of the T-SPOT.TB assay in HTLV-1-positive RA patients. METHODS:Overall, 29 HTLV-1-positive RA patients and 87 age- and sex-matched HTLV-1-negative RA patients (controls) were included from the HTLV-1 RA Miyazaki Cohort Study. Results of the T-SPOT.TB assay for latent tuberculosis infection screening were collected from medical records of patients. RESULTS:Approximately 55% of the HTLV-1-positive RA patients showed invalid T-SPOT.TB assay results (odds ratio: 108, 95% confidence interval: 13.1-890, p < 0.0001) owing to a spot count of >10 in the negative controls. HTLV-1 proviral load values were significantly higher in patients with invalid results compared with those without invalid results (p = 0.003). CONCLUSION:HTLV-1 infection affects T-SPOT.TB assay results in RA patients. Assay results in HTLV-1 endemic regions should be interpreted with caution when screening for latent tuberculosis infection before initiation of biologic therapy.

Background Tuberculous pleural effusion (TPE) is the most common extrapulmonary manifestation and may have lasting effect on lung function. However conventional diagnostic tests for TPE register multiple limitations. This study estimates diagnostic efficacy of the interferon gamma release assay (IGRA: T-SPOT.TB) in TPE patients of different characteristics. Methods We performed a prospective, single-centre study including all suspected pleural effusion patients consecutively enrolled from June 2015 to October 2018. Through receiver operating characteristic (ROC) curves, technical cut-offs and the utility of T-SPOT on pleural fluid (PF) were determined and analysed. Logistic regression analysis was performed to obtain the independent risk factors for TPE, and evaluated the performance of the T-SPOT assay stratified by risk factors in comparison to ADA. Results A total of 601 individuals were consecutively recruited. The maximum spot-forming cells (SFCs) of early secretory antigenic target-6 (ESAT-6) and culture filtrate protein-10 (CFP-10) in the PF T-SPOT assay had the best diagnostic efficiency in our study, which was equal to ADA (0.885 vs 0.887, P = 0.957) and superior to peripheral blood (PB), with a sensitivity of 83.0% and a specificity of 83.1% (The cut-off value was 466 SFCs/106 mononuclear cells). Among the TPE patients with low ADA (P P P = 0.001) were independently associated with the risk of TB by multivariate logistic regression analysis. Notably, when stratified by risk factor, the sensitivity of PF T-SPOT was superior to the sensitivity for ADA (76.5% vs. 23.5%, P = 0.016) and had noninferior specificity (84.4% vs. 96.9%, P = 0.370). Conclusions In conclusion, the PF T-SPOT assay can effectively discriminate TPE patients whose ADA is lower than 40 IU/L and is superior to ADA in unconventional TPE patients (age ≥ 45 yrs., female or BMI ≥ 22). The PF T-SPOT assay is an excellent choice to supplement ADA to diagnose TPE.

Summary Objectives Distinguishing between active tuberculosis (ATB) and latent tuberculosis infection (LTBI) remains challenging. Methods The modified T-SPOT.TB assay was performed in 499 participants (243 ATB and 256 LTBI) and another 322 participants (162 ATB and 160 LTBI) who were diagnosed in Qiaokou (training) and Caidian (validation) cohort respectively. Results The mean spot sizes (MSS) of early secreted antigenic target 6 (ESAT-6) spot-forming cells (SFC) of T-SPOT.TB assay in ATB patients was significantly higher than that in LTBI individuals. 1.0 × 105 was the optimal number of cells added to phytohaemagglutinin (PHA) well for obtaining more accurate TB-specific antigen to phytohaemagglutinin (TBAg/PHA) ratio. The area under the curve of the diagnostic model by combination of ESAT-6 SFC MSS and modified TBAg/PHA ratio in distinguishing ATB from LTBI was 0.959 in training cohort, with a sensitivity of 90.12% and a specificity of 91.02% when a cutoff value of 0.46 was used. This diagnostic model showed similar performance in the validation cohort. The area under the curve, sensitivity, and specificity were 0.962, 93.21%, and 90.00%, respectively. Further flow cytometry analysis showed that ESAT-6 stimulation induced a significantly higher mean fluorescence intensity of IFN-γ+ cells in lymphocytes compared with culture filtrate protein 10 (CFP-10) stimulation. In contrast, CFP-10 stimulation induced a significantly higher percentage of IFN-γ+ cells in lymphocytes compared with ESAT-6 stimulation. Conclusions The combination of the MSS of ESAT-6 SFC and the modified TBAg/PHA ratio of T-SPOT.TB assay showed great value in discriminating ATB from LTBI.

Background: Tuberculosis (TB) is a leading cause of fever of unknown origin (FUO). In recent years, interferon-γ release assays (IGRAs) have been widely utilized and the cut-off values given by the manufacturers are set in countries where rates of TB are not as high. Methods: A prospective cohort study was conducted in a Chinese general hospital to evaluate the diagnostic performance of T-SPOT.TB (T-SPOT) and QuantiFERON-TB Gold (QFT) in detecting active TB (ATB) in a high TB endemic area. Test results were compared with the culture and clinically confirmed diagnosis. Further, we explored an alternative method of interpreting IGRAs by increasing the cut-off values. Results: The sensitivity and specificity of T-SPOT in detecting ATB were 85.3% (95% CI 81.6–94.0%) and 71.8% (95% CI 67.3–76.0%), respectively. The sensitivity and specificity of QFT were 72.3% (95% CI 62.8–80.1%) and 77.0% (95% CI 72.7–80.8%), respectively. Receiver operating characteristic analysis was used for evaluation of different cut-off values. When the cut-off values were adjusted as 125 spot-forming cells (SFCs)/ 2.5*105 cells for T-SPOT and 4.0 IU/ml for QFT, the specificity could be improved to > 90.0% (90.3% and 94.1%, respectively), and the sensitivity were 43.1% and 41.6%, respectively. The new adjusted cut-off values were validated in another independent validation cohort. Conclusion: The adjusted cut-off values of the two assays considerably improved the diagnostic value when applied to FUO patients in clinical settings.

Background T-SPOT.TB may yield indeterminate results, including high nil responses and insufficient mitogen responses. We explored the incidence and risk factors of high nil responses. Methods A 1:1 matched case-control study of patients who underwent T-SPOT.TB tests in Peking Union Medical College Hospital from Jan 1, 2015 to Apr 30, 2017 was conducted. High nil responses were defined as >10 spots in negative control wells. Cases and controls were matched based on when the tests were performed. Demographic, clinical and laboratory data were obtained from the Medical Record System. Results A total of 644 out of 36,316 (1.76%, 95% CI: 1.63%–1.90%) patients presented with high nil responses (280 cases and 280 controls were enrolled). Multivariate analysis revealed that male (OR = 1.882, 95% CI: 1.222–2.899), Behcet's disease (OR = 7.764, 95% CI: 1.714–35.167), heavy use of corticosteroids within a month (OR = 0.357, 95% CI: 0.138–0.921, for >1000 mg group) and hypoalbuminemia (OR = 0.385, 95% CI: 0.241–0.615) are significantly associated with high nil responses. Conclusions High nil responses in T-SPOT.TB assays are quite rare. Male gender and Behcet's disease are suggested as independent risk factors, while recent excessive use of corticosteroids and hypoalbuminemia seem to be independent protective factors.

Background This study was conducted to investigate the value of the T cell spot test for tuberculosis (T-SPOT.TB) for the diagnosis of patients with lung cancer combined with pulmonary tuberculosis (LCTB). Methods Thirty-six patients diagnosed with LCTB who received treatment at Shandong Provincial Chest Hospital from September 2014 to 2017 were randomly chosen and enrolled as an observation group; 63 patients diagnosed with LC alone in the same period were included as the control. The T-SPOT.TB results of the two groups were compared. Results The positive rate of T-SPOT.TB in 36 patients with LCTB was 88.9% (32/36), and in 63 patients with LC was 23.8% (15/63). The median ESAT-6 result in the LCTB group was 22 SFCs/2.5 × 105 peripheral blood monocytes (PBMC) (interquartile range [IQR] 8-53), which was higher than in the LC group with a median of 1 spot-forming cell (SFC)/2.5 × 105 PBMC (IQR 0-5). The median CFP10 result in the LCTB group was 18 SFCs/2.5 × 105 PBMC (IQR 7-30), which was significantly higher than in the LC group with a median of 0 SFC/2.5 × 105 PBMC (IQR 0-4). The receiver operating characteristic curve of the two groups showed sensitivity of 88.9% and specificity of 84.4% when the positive value of T-SPOT.TB was 11 SFCs/2.5 × 105 PBMC. Conclusions T-SPOT.TB has comparatively high value for diagnosing LCTB. The referential cutoff value is 11 SFCs/2.5 × 105 PBMC, which warrants clinical application.

Introduction Before starting tumour necrosis factor (TNF)-α blocking agents, standard tests should be used for the diagnosis of tuberculosis infection. The specificity of traditional tuberculin skin test (TST) is low in immunosuppressed patients due to prior Bacille Calmette Guerin (BCG) vaccination, non-tuberculous mycobacteria infections, false positive and negative results. In this study, we aimed to compare TST and Interferon-Gamma Release Assay (IGRA) tests for detecting latent tuberculosis infection in patients with rheumatic disease planned to receive TNF-α blocking agents. Materials and Methods One hundred and nine patients (45 male, 64 female) with the diagnosis of rheumatoid arthritis (RA) (n= 70) and ankylosing spondylitis (AS) (n= 39) were included in the study. Age, sex, number of BCG scar, results of TST (using the Mantoux method), QuantiFERON-TB Gold test and T-SPOT.TB test were recorded for all patients. Correlation between the tests was assessed by Pearson correlation coefficient. Result The mean age of RA and AS patients were 50 ± 13 (19-78 years). The prevalence of latent tuberculosis was 43.1% for TST, 39.4% for QuantiFERON-TB Gold test and 13.8% for T-SPOT.TB test, compared with the evaluation using the composite criteria such as close contact with active tuberculosis infection and/or suspicious fibrotic/calcific lesions on chest X-Ray without active tuberculosis infection. There was a moderate correlation between BCG scar number and TST (p< 0.001, r= 0.495), T-SPOT.TB test and QuantiFERON-TB Gold test (p= 0.007, r= 0.406), T-SPOT.TB test and composite criteria (p= 0.024, r= 0.343). The specificity of QuantiFERON-TB Gold test was 85.7%, and sensitivity was 73.9% for all patients with rheumatic disease. It was 73.5% and 66.7% for T-SPOT.TB test, respectively. The specificity of TST was 60.3% and sensitivity was 47.8% for TST. Conclusions IGRA tests are not affected prior vaccination and useful for detecting latent tuberculosis infection in patients treated with corticosteroid due to lack of correlation between test negativity and corticosteroid therapy. Also, they are useful tests for diagnosis of latent tuberculosis infection as an alternative to TST due to their specificity and sensitivity.

The IGRA-ELISA and T-SPOT.TB are widely used in China. The aim of the study was to evaluate the performance of the two assays in diagnosis Mycobacterium tuberculosis infection.Of the 3727 patients in the study, 204 underwent testing using both the T-SPOT.TB and IGRA-ELISA, 1794 were tested using the T-SPOT.TB only, and 1729 were tested using the IGRA-ELISA only. The positive rate and consistency of the two assays were analyzed, and their sensitivity and specificity for diagnosing active tuberculosis were compared.There were no significant differences in the positive rate between the T-SPOT.TB test (25.8%) and IGRA-ELISA (28.6%), p = .065. The two assays were highly consistent, with a kappa value of 0.852 (p .0001) and a total coincidence rate of 92.7%. For the diagnosis of active tuberculosis, the sensitivity and specificity values of the T-SPOT.TB test were 82.9% (107/129) and 78.6% (1309/1665), respectively, and those of IGRA-ELISA were 81.7% (94/115) and 75.2% (1214/1614), respectively. There were no significant differences in sensitivity (p .05), but the specificity of the T-SPOT.TB test was slightly higher than that of IGRA-ELISA (p = .023).Both in terms of diagnosing M. tuberculosis infection and ruling out active tuberculosis, the performance of the IGRA-ELISA-a simple, almost labor-free assay that allows simultaneous processing of a very large number of samples-was well-matched with that of T-SPOT.TB test. However, IGRAs cannot be used as the only test to diagnose active tuberculosis.

Objective To evaluate the diagnostic value of interferon-γ release assay of blood and pleural effusion for tuberculous pleurisy. Methods Fifty-six adult patients with suspected tuberculous pleurisy were enrolled in our study. The blood and pleural effusion interferon-γ release assay were measured by T-SPOT.TB test in 38 pleural tuberculosis patients and 18 non-tuberculous pleurisy controls. The diagnostic sensitivity, specificity, predictive value of T-SPOT.TB in pleural effusion mononuclear cells (PE-MC) and peripheral mononuclear cells (PBMC) were analyzed. Results The sensitivities and specificities, positive predictive values and negative predictive values, respectively, of the PE-MC and PBMC for diagnosing were as follows: 86.5%(95% confidence interval[CI] 71.2%-95.5%) and 100%(95%CI 90.5%-100%); 52.9%(95%CI 27.8%-77.0%) and 35.3%(95%CI 14.2%¬61.7%); 80.0%(95%CI 64.4%-90.9%) and 77.1%(95%CI 62.7%-88.0%); 64.3%(95%CI 35.1%-87.2%) and 100%(95%CI 54.1%¬100%). By ROC curve analysis, a cut-off value of 47SFC/2.5×105 cells in PE-MC showed a sensitivity of 89.2% and a specificity of 88.2%. Conclusion T-SPOT.TB in PE-MC could be an accurate diagnostic method for tuberculous pleurisy in TB endemic settings. Moreover, 47SFC/2.5×105 cells might be the optimal cut-off value for diagnosing tuberculous pleurisy. DOI: 10.11855/j.issn.0577-7402.2018.01.11

Sir,In a study recently reported in the present journal, Quantiferon-TB Gold in-Tube (QFT-GIT), an interferon gamma release assay (IGRA), showed a substantial within-person variability and the auth...

Objective To investigate the diagnostic efficacy of an interferon-γ release assay, T-SPOT®. TB, for diagnosing active tuberculosis (TB) and to identify risk factors for false-negative results. Methods This retrospective study enrolled consecutive patients with active TB and with non-TB respiratory diseases to evaluate the risk factors for false-negative results when using the T-SPOT®. TB assay for the diagnosis of active TB. Patients with active TB were categorized as having confirmed pulmonary TB, clinically diagnosed pulmonary TB or extrapulmonary TB (EPTB). Results This study analysed 4964 consecutive patients; 2425 with active TB and 2539 with non-TB respiratory diseases. Multivariate logistic regression analyses identified the following five factors that were all associated with an increased false-negative rate with the T-SPOT®. TB assay: increased age (odds ratio [OR] 1.018; 95% confidence interval [CI] 1.013, 1.024); decreased CD8+ count (OR 0.307; 95% CI 0.117, 0.803); negative sputum acid-fast bacilli (AFB) smear staining (OR 1.821; 95% CI 1.338, 2.477); negative mycobacterial cultures (OR 1.379; 95% CI 1.043, 1.824); and absence of EPTB (OR 1.291; 95% CI 1.026, 1.623). Conclusions Increased age, decreased CD8+ count, negative sputum AFB smear results, negative sputum mycobacterial cultures and absence of EPTB might lead to an increased false-negative rate when using the T-SPOT®. TB assay.

Interferon-γ release assays (IGRAs) are the preferred diagnostic test for tuberculosis (TB) infection in at-risk populations in developed countries. However, IGRAs have high false-negative rates in patients with TB disease. Population-based studies assessing the factors associated with negative IGRA results in TB patients have not been performed. Using statewide TB surveillance data of culture-confirmed TB patients in Texas, USA, during 2013-2015, we describe the patient characteristics and treatment outcomes associated with false-negative IGRA results. Among 2,854 TB patients, 1,527 (53.5%) had an IGRA result; 97.4% (1,487/1,527) of those had a positive (87.7%) or negative (12.3%) result. Older age, HIV co-infection, non-Hispanic white race/ethnicity, and being tested with T-SPOT.TB were associated with negative IGRA results. TB patients with negative IGRA results had a higher mortality, potentially due to delayed treatment. Healthcare providers should consider these risk factors when making decisions for patients with suspected TB and negative IGRA results and potentially provide treatment.

We compared the positive rates of T-SPOT.TB and bacterial culture in the smear-negative PTB, and analyzed the factors affecting the results of negative T-SPOT.TB and bacterial culture. Retrospective evaluation of data from smear-negative PTB patients who underwent T-SPOT.TB and bacterial culture were done. The agreement and concordance were analyzed between T-SPOT.TB and bacterial culture. Multivariable logistic regression analysis was used to explore the factors associated with positive results of T-SPOT.TB and bacterial culture in smear-negative PTB. 858 eligible smear-negative PTB patients were included in the study. The agreement rate was 25.6% (22.7~28.5%) between T-SPOT.TB and bacterial culture in smear- negative PTB patients. The positive rate of T-SPOT.TB was higher than that of bacterial culture in smear-negative PTB patients (p 0.05). Using multivariable logistic regression analysis we found that older age ≥ 60 years (OR = 0.469, 95% CI: 0.287–0.768) and decreased albumin (OR = 0.614, 95% CI: 0.380–0.992) were associated with negative diagnostic results of T-SPOT.TB in smear-negative PTB patients. Female (OR = 0.654, 95% CI: 0.431–0.992) were associated with negative diagnostic results of bacteria culture in smear-negative PTB patients. Our results indicated that the older age and decreased albumin were independently associated with negative T-SPOT.TB responses.

Background The QuantiFERON-TB Gold Plus (QFT-Plus) was introduced in 2015 as a new generation of interferon-gamma release assays (IGRAs) designed to detect Mycobacterium tuberculosis infection (TB). Examination of its diagnostic accuracy is crucial before it is launched in Japan. Method We examined 99 patients with laboratory-confirmed active TB (patients) and 117 healthy volunteers with no risk of TB infection (controls) at a medical center in Tokyo, Japan. Blood samples were collected from both the patients and controls and tested using three types of IGRAs: the QFT-Plus, the QuantiFERON-TB Gold In-Tube (QFT-GIT), and the T-SPOT.TB (T-SPOT). The sensitivity and specificity of each IGRA were examined and compared. Results The sensitivity of the QFT-Plus was 98.9% (95% confidence interval [CI], 0.934–0.998) and similar to that of the QFT-GIT (97.9%; 95% CI, 0.929–0.998) and T-SPOT (96.9%; 95% CI, 0.914–0.994). The specificity of the QFT-Plus was the same as that of the QFT-GIT and T-SPOT (98.1%; 95% CI, 0.934–0.998). One patient with uncontrolled diabetes mellitus showed negative results on all three IGRAs. Conclusions The QFT-Plus showed a high degree of agreement with the QFT-GIT and T-SPOT, with high sensitivity and specificity. Severe diabetes mellitus may influence the results of IGRAs. Larger studies are needed to validate the accuracy of the GFT-Plus and determine whether it can contribute as adjunctive method for the early diagnosis of active TB in Japan.

Rheumatoid arthritis (RA) is an immune mediated inflammatory disorder, and immune suppressive drugs are prescribed. RA patients receiving treatments are in a kind of immunosuppressive condition that presents increased risk of developing active tuberculosis. Accurate diagnosis of latent tuberculosis infection (LTBI) is recommended for RA. QuantiFERON®-TB Gold Plus (QFT-Plus), a novel IGRA, has two tubes (TB1 and TB2). TB2 is designed to elicit both CD4 and CD8 T-cell responses, with expected increased sensitivity. We conducted a cross-sectional study to compare two IGRAs, QFT-Plus and T-SPOT®.TB (TSPOT), in RA. One hundred fifty-two RA patients (median age: 66.5 yrs) were enrolled. QFT-Plus and TSPOT were concurrently conducted. Lymphocyte subsets (CD4 T-cell and CD8 T-cell) were also measured. The positivity rates of QFT-Plus and TSPOT were 9.7% and 4.5%, respectively, with the difference being significant (P

Background Accurate identification of individuals with TB infection, is required to achieve the WHO's End TB Strategy goals. While there is general acceptance that the T-SPOT.TB test borderline category provides an opportunity to increase test resolution of results around the test cut-off point, this has not been investigated. Methods 645,947 tests were analyzed to determine frequency of borderline results, effect of age and time between tests and associations between subjects' clinical risk factors and retest results. Results 645,947 tests produced 93.5% negatives, 4% positives, 0.6% invalids, and 1.8% borderlines. Within the borderline results, 5044 were repeated, with 59.2%, 20.0% and 20.2% resolving to negative, positive and borderline, respectively. Age of subject did not affect retest results; however, time between tests indicated that retest resolution occurred with greatest frequency after 90 days. TB risk factors were provided for 2640 subjects and 17% of low risk subjects with a high initial borderline resolved to negative while 27.6% of subjects with high risk and an initial low borderline resolved to positive, suggesting that these subjects could have been inappropriately classified if using a single cut-off point test with no borderline category. Conclusion This study demonstrates the utility of the T-SPOT.TB test's borderline category to increase test resolution around the test cut-off point.