Quantitative IFN-γ Release Assay and Tuberculin Skin Test Results to Predict Incident Tuberculosis. A Prospective Cohort Study

Rationale: Development of diagnostic tools with improved predictive value for tuberculosis (TB) is a global research priority.Objectives: We evaluated whether implementing higher diagnostic thresholds than currently recommended for QuantiFERON Gold-in-Tube (QFT-GIT), T-SPOT.TB, and the tuberculin skin test (TST) might improve prediction of incident TB.Methods: Follow-up of a UK cohort of 9,610 adult TB contacts and recent migrants was extended by relinkage to national TB surveillance records (median follow-up 4.7 yr). Incidence rates and rate ratios, sensitivities, specificities, and predictive values for incident TB were calculated according to ordinal strata for quantitative results of QFT-GIT, T-SPOT.TB, and TST (with adjustment for prior bacillus Calmette-Guérin [BCG] vaccination).Measurements and Main Results: For all tests, incidence rates and rate ratios increased with the magnitude of the test result (P < 0.0001). Over 3 years' follow-up, there was a modest increase in positive predictive value with the higher thresholds (3.0% for QFT-GIT ≥0.35 IU/ml vs. 3.6% for ≥4.00 IU/ml; 3.4% for T-SPOT.TB ≥5 spots vs. 5.0% for ≥50 spots; and 3.1% for BCG-adjusted TST ≥5 mm vs. 4.3% for ≥15 mm). As thresholds increased, sensitivity to detect incident TB waned for all tests (61.0% for QFT-GIT ≥0.35 IU/ml vs. 23.2% for ≥4.00 IU/ml; 65.4% for T-SPOT.TB ≥5 spots vs. 27.2% for ≥50 spots; 69.7% for BCG-adjusted TST ≥5 mm vs. 28.1% for ≥15 mm).Conclusions: Implementation of higher thresholds for QFT-GIT, T-SPOT.TB, and TST modestly increases positive predictive value for incident TB, but markedly reduces sensitivity. Novel biomarkers or validated multivariable risk algorithms are required to improve prediction of incident TB.

Diagnosis of Tuberculous Infection in Immunosuppressed Patients and/or Candidates for Biologics Using a Combination of 2 IGRA Tests: T-SPOT.TB/QuantiFERON TB Gold In-Tube vs. T-SPOT.TB/QuantiFERON TB Gold Plus

INTRODUCTION

The diagnosis of latent tuberculous infection (LTI) by IGRA continues to generate debate. Experience in the simultaneous use of 2 IGRA tests is scant. The aim of this study was to compare the results of 2 versions of QuantiFERON-TB Gold (In-Tube/Plus) with those of T-SPOT.TB, and to analyse the effectiveness of a dual strategy (T-SPOT.TB + QTF) for the diagnosis of LTI in an immunosuppressed population.

METHODS

We conducted a prospective study (May 2015-June 2017) that included 2,999 immunosuppressed patients and/or candidates for biologics, in whom 2 simultaneous IGRA tests were performed: Group 1 (1535 patients): T-SPOT.TB + QuantiFERON-TB Gold-In-Tube (QTF-GIT); Group 2 (1464 patients): T-SPOT.TB + QuantiFERON-TB Gold Plus (QTF-Plus).

RESULTS

The concordance between QTF-GIT and T-SPOT.TB was 83.19% (κ=0.532). The percentage of positive, negative, and indeterminate results were, respectively: 14.33% vs. 17.06%; 82.41% vs. 74.46%; and 3.25% vs. 8.46%. The concordance between QTF-Plus and T-SPOT.TB was 87.56% (κ=0.609). The percentage of positive, negative, and indeterminate results were, respectively: 15.02% vs. 15.36%; 82.92% vs. 79.37%; and 2.04% vs. 5.25%. Discrepancies between T-SPOT.TB and QTF-Plus were 12.43%, suggesting that 103 patients were positive and another 79 were negative due exclusively to 1 of the 2 IGRAs.

CONCLUSIONS

Greater concordance was found between QTF-Plus and T-SPOT.TB than between QTF-GIT and T-SPOT.TB. However, we believe that the proportion of discrepancies between T-SPOT.TB and QTF-Plus is sufficiently important from a clinical point of view to justify the simultaneous use of 2 IGRA in this specific patient group.

Clinical evaluation of the T-SPOT.TB test for detection of tuberculosis infection in northeastern Guangdong Province, China

OBJECTIVE

We evaluated clinical performance of the T-SPOT.TB test for detecting tuberculosis (TB) infection in Meizhou, China.

METHODS

We 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.

RESULTS

T-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].

CONCLUSION

T-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.

Diagnostic Tests for Latent Tuberculosis Infection

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.

Clinical characteristics and potential indicators for definite diagnosis of tuberculous pleural effusion

AIMS

The study aimed to investigate the clinical characteristics of patients with pleural effusion (PE), and explore the effective indicators for definite diagnosis of tuberculous pleural effusion (TBPE).

METHODS

The adult patients with the presence of PE were enrolled. All the patients received pleural fluid Mycobacterium tuberculosis DNA detection, ADA activity measure and blood T-SPOT.TB test. The clinical characteristics and examination results were recorded.

RESULTS

A total of 77 PE patients, including 30 (38.96%) TBPE, 19 (24.67%) malignant PE, 6 (7.79%) empyema, 10 (12.99%) parapneumonic effusion and 12 (15.58%) miscellaneous causes, were enrolled. The diagnostic sensitivity and specificity of pleural fluid M. tuberculosis DNA detection were 33.3% and 100%, respectively. The diagnostic parameters of pleural fluid ADA for TBPE were as follows: sensitivity 50% and specificity 78.7%. In PE cases with pleural fluid lactate dehydrogenase (LDH) more than 500 U/L, the diagnostic values of DNA detection and ADA activity were enhanced, and DNA detection was superior to ADA activity. In addition, the ratio of blood T-STOP.TB A + B to lymphocyte was a potential diagnostic biomarker for TBPE with the sensitivity of 83.3% and the specificity of 66.0%.

CONCLUSION

The clinical significance of pleural fluid M. tuberculosis DNA detection is superior to ADA activity in the diagnosis of TBPE, especially in PE cases with LDH value more than 500 U/L. The ratio of blood T-STOP.TB A + B to lymphocyte is a potential indicator for definite diagnosis of TBPE, with high sensitivity.

Good Agreement between an Interferon Gamma Release Assay and Tuberculin Skin Tests in Testing for Latent Tuberculosis Infection among HIV-Infected Patients in Indonesia

BACKGROUND

Latent tuberculosis infection is a condition where there is a persistent immune response to Mycobacterium tuberculosis without clinical manifestations of tuberculosis. Currently, there is no gold standard to diagnose latent tuberculosis infection. The tuberculin skin test and interferon-gamma release assay are currently used to diagnose latent tuberculosis infection. However, studies have shown inconsistencies regarding the level of agreement between these tests in different settings. In this study, we aimed to evaluate the agreement between these two tests for diagnosing latent tuberculosis infection in human immunodeficiency virus (HIV)-infected individuals.

METHODS

We screened HIV patients with no clinical symptoms of tuberculosis, a normal chest X-ray, and no history of tuberculosis or use of antituberculous drugs. Participants were tested with tuberculin skin test (TST) and T-SPOT.TB (an interferon gamma release assay) simultaneously. Participants' HIV stage was determined by measuring the level of CD4+ T-lymphocytes. Tuberculosis status was confirmed by sputum examination using GeneXpert. The level of agreement between the TST and T-SPOT.TB results was measured using Cohen's κ coefficient.

RESULTS

Of the 112 participants, 20 had a positive T-SPOT.TB test result, and 21 had a positive TST result. The TST and T-SPOT.TB test results showed a high level of agreement (κ = 0.648, P < 0.001). Performance of the tests did not vary with CD4+ level. However, in participants with CD4+ < 200 cells/mm³, T-SPOT.TB detected more latent tuberculosis infections than the TST.

CONCLUSION

There was good agreement between the TST and T-SPOT.TB results of latent tuberculosis infection in participants. TST is the preferred test for diagnosing latent tuberculosis infection in HIV-infected patients, especially in resource-limited settings, because it is simple and cost-effective. However, T-SPOT.TB may be useful to rule out latent tuberculosis infection in patients with severe immunodeficiency.

Reproducibility of the T-SPOT.TB test for screening Mycobacterium tuberculosis infection in Japan

OBJECTIVES

The interferon-gamma release assay (IGRA) is useful for diagnosing Mycobacterium tuberculosis infections, especially in countries where Bacille Calmette-Guérin vaccinations are performed. However, reproducibility of the IGRA is unclear, as recent data suggest high IGRA conversion and reversion rates in serial tests among healthcare workers. This longitudinal study aimed to evaluate reproducibility of T-SPOT.TB for screening M. tuberculosis infections in Japan.

METHODS

Results of T-SPOT.TB tests performed between April 2014 and March 2016 at two hospitals in Yokohama, Japan, where the incidence of tuberculosis was 18.0 per 100,000 population in 2014, were analyzed.

RESULTS

In total, 3890 T-SPOT.TB tests were included. Overall, positive and negative test rates were 8.4% and 87.6%, respectively. Among 373 serial tests within two years, conversion and reversion rates were only 1.1% and 12.5%, respectively. Almost all patients who were initially negative (98.9%) remained so. There was no statistically significant difference between the outcomes observed at the two hospitals.

CONCLUSIONS

The conversion rate of T-SPOT.TB in Japan is as low as that recently reported in other countries where the incidence of tuberculosis is low. These data indicate that T-SPOT.TB is a reproducible tuberculosis screening tool at local hospitals in areas with a moderate incidence of tuberculosis.

Quantitative investigation of factors relevant to the T cell spot test for tuberculosis infection in active tuberculosis

Background

Previous qualitative studies suggested that the false negative rate of the T cell spot test for tuberculosis infection (T-SPOT.TB) is associated with many risk factors in tuberculosis patients. However, more precise quantitative studies are lacking. The purpose of this study was to investigate the factors affecting quantified spot-forming cells (SFCs) to early secreted antigenic target 6 kDa (ESAT-6) or culture filtrate protein 10 kDa (CFP-10) in patients with active tuberculosis.

Methods

We retrospectively analyzed the data of 360 patients who met the inclusion criteria. Using the SFCs to ESAT-6 or CFP-10 levels as dependent variables, variables with statistical significance in the univariate analysis were subjected to optimal scaling regression analysis. The combination of ESAT-6 and CFP-10 (i.e., T-SPOT.TB) was analyzed by the exact logistic regression model.

Results

The results showed that the SFCs to ESAT-6 regression model had statistical significance (P < 0.001) and that previous treatment and CD4+ and platelet counts were its independent risk factors (all P < 0.05). Their importance levels were 0.095, 0.596 and 0.100, respectively, with a total of 0.791. The SFCs to CFP-10 regression model also had statistical significance (P < 0.001); platelet distribution width and alpha-2 globulin were its independent risk factors (all P < 0.05). Their importance levels were 0.287 and 0.247, respectively, with a total of 0.534. The quantification graph showed that quantified SFCs to ESAT-6 or CFP-10 grading had a linear correlation with risk factors. Albumin-globulin ratio, CD4+ and CD8+ were independent risk factors for false negative T-SPOT.TB (all P < 0.05).

Conclusions

In T-SPOT.TB-assisted diagnosis of patients with active tuberculosis, previous treatment, decreased CD4+ and platelet count might lead to the decreased SFCs to ESAT-6, decreased alpha-2 globulin and high platelet distribution width might lead to the decreased SFCs to CFP-10, decreased albumin-globulin ratio, CD4+ and CD8+ might lead to an increase in the false negative rate of the T-SPOT.TB.

Electronic supplementary material

The online version of this article (10.1186/s12879-019-4310-y) contains supplementary material, which is available to authorized users.

Correlation between the tuberculin skin test and T-SPOT.TB in patients with suspected tuberculosis infection: A pilot study

T-SPOT.TB is a novel screening method for Mycobacterium tuberculosis infection. However, it is controversial whether T-SPOT.TB should become an alternative method to the tuberculin skin test (TST) for screening M. tuberculosis infections. The present study aimed to evaluate this issue based on the retrospective analysis of clinical cases. TST and T-SPOT.TB tests were used on patients with suspected M. tuberculosis infection on admission. Demographic data and clinical information, including previous history of M. tuberculosis infection, were collected. A total of 118 patients were included in the analysis, among whom 30 (25.4%) were diagnosed with active M. tuberculosis infection, and seven patients (5.9%) were currently receiving immunosuppressive treatment. The overall sensitivity and specificity of the TST were 76.7 and 77.3%, respectively, while they were 88.3 and 68.1%, respectively, for the T-SPOT.TB test. Patients with large TST indurations had a higher number of gamma interferon-producing T cells among peripheral blood mononuclear cells compared with those of TST-negative patients. In conclusion, the T-SPOT.TB test had a higher sensitivity than the TST, but the difference was not statistically significant. Neither the T-SPOT.TB test nor the TST was sufficiently accurate to detect active M. tuberculosis infection.

Hepcidin exerts a negative immunological effect in pulmonary tuberculosis without HIV co-infection, prolonging the time to culture-negative

OBJECTIVES

A major regulatory peptide in iron metabolism, hepcidin, has been shown to predict mortality in HIV-infected tuberculosis patients. The aim of this study was to evaluate whether plasma hepcidin levels on admission can be used to predict the treatment outcome of patients with smear-positive pulmonary tuberculosis (PTB) without HIV co-infection.

METHODS

In this prospective observational study, a total of 35 PTB patients with Mycobacterium tuberculosis-positive sputum smears were enrolled. The relationship between plasma hepcidin levels on admission and the time period to sputum culture-negative was explored.

RESULTS

Plasma hepcidin levels of PTB patients were significantly higher than those of healthy subjects (p<0.001). A positive correlation between hepcidin level on admission and the period until culture-negative was also observed (r=0.46, p=0.006). Furthermore, the hepcidin level showed a negative correlation with spot numbers in the positive control wells of the T-SPOT.TB assay; thus the effect of the peptide on interferon-gamma production in T cells was explored. Hepcidin reduced interferon-gamma gene transcription and interferon-gamma production in a dose-dependent manner in Jurkat cells stimulated with phytohaemagglutinin, an antigen non-specific stimulation.

CONCLUSIONS

These findings indicate that hepcidin alters immunological reactions against M. tuberculosis infection and has an influence on the outcomes of PTB patients without HIV co-infection.

Diagnostic value of the interferon-γ release assay for tuberculosis infection in patients with Behçet's disease

Background

To investigate the diagnostic value of the interferon-γ release assay (IGRA) for detecting tuberculosis (TB) infection in patients with Behçet’s disease (BD).

Methods

We retrospective analyzed the data collected from 173 BD patients hospitalized between 2010 and 2015. Ninety-nine healthy volunteers were enrolled as a control group. IGRA was performed using T-SPOT.TB. The diagnosis of active TB (ATB) was based on clinical, radiological, microbiological, histopathological information and the response to anti-TB therapy. Latent TB (LTB) infection was defined as asymptomatic patients with positive T-SPOT.TB.

Results

TB infection was documented in 59 BD patients (34.1%). The sensitivity, specificity, positive predictive value, negative predictive value, positive likelihood ratio and negative likelihood ratio of T-SPOT.TB for the diagnosis of ATB were 88.9%, 74.8%, 29.1%, 98.3%, 3.53 and 0.15, respectively. The receiver-operating-characteristic curve demonstrated that spot-forming cells (SFCs) of 70/10⁶ PBMC was the optimal cutoff for diagnosing ATB, with an area under the curve of 0.891. Furthermore, the median SFCs in ATB group was significantly higher than those in LTB infection (466/10⁶ PBMC vs. 68/10⁶ PBMC, p = 0.007) or previous TB infection (466/10⁶ PBMC vs. 96/10⁶ PBMC, p = 0.018). A significant discrepancy between T-SPOT.TB and tuberculin skin test was noted (kappa coefficient = 0.391, p = 0.002).

Conclusions

T-SPOT.TB, an IGRA, may assist in the diagnosis of ATB in BD patients, and the higher SFCs suggest ATB in BD patients.

Characteristics Associated with Negative Interferon-γ Release Assay Results in Culture-Confirmed Tuberculosis Patients, Texas, USA, 2013-2015

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.

Risk Factors for Indeterminate Interferon-Gamma Release Assay for the Diagnosis of Tuberculosis in Children-A Systematic Review and Meta-Analysis

Background: Interferon-gamma release assays (IGRA) are well-established immunodiagnostic tests for tuberculosis (TB) in adults. In children these tests are associated with higher rates of false-negative and indeterminate results. Age is presumed to be one factor influencing cytokine release and therefore test performance. The aim of this study was to systematically review factors associated with indeterminate IGRA results in pediatric patients. Methods: Systematic literature review guided by the preferred reporting items for systematic reviews and meta-analyses (PRISMA) searching PubMed, EMBASE, and Web of Science. Studies reporting results of at least one commercially available IGRA (QuantiFERON-TB, T-SPOT.TB) in pediatric patient groups were included. Random effects meta-analysis was used to assess proportions of indeterminate IGRA results. Heterogeneity was assessed using the I² value. Risk differences were calculated for studies comparing QuantiFERON-TB and T-SPOT.TB in the same study. Meta-regression was used to further explore the influence of study level variables on heterogeneity. Results: Of 1,293 articles screened, 133 studies were included in the final analysis. These assessed QuantiFERON-TB only in 77.4% (103/133), QuantiFERON-TB and T-SPOT.TB in 15.8% (21/133), and T-SPOT.TB only in 6.8% (9/133) resulting in 155 datasets including 107,418 participants. Overall 4% of IGRA results were indeterminate, and T-SPOT.TB (0.03, 95% CI 0.02-0.05) and QuantiFERON-TB assays (0.05, 95% CI 0.04-0.06) showed similar proportions of indeterminate results; pooled risk difference was-0.01 (95% CI -0.03 to 0.00). Significant differences with lower proportions of indeterminate assays with T-SPOT.TB compared to QuantiFERON-TB were only seen in subgroup analyses of studies performed in Africa and in non-HIV-infected immunocompromised patients. Meta-regression confirmed lower proportions of indeterminate results for T-SPOT.TB compared to QuantiFERON-TB only among studies that reported results from non-HIV-infected immunocompromised patients (p < 0.001). Conclusion: On average indeterminate IGRA results occur in 1 in 25 tests performed. Overall, there was no difference in the proportion of indeterminate results between both commercial assays. However, our findings suggest that in patients in Africa and/or patients with immunocompromising conditions other than HIV infection the T-SPOT.TB assay appears to produce fewer indeterminate results.

Diagnostic Utility of Interferon-Gamma Release Assay in Tuberculous Lymphadenitis

Objective The aim of this study was to evaluate the diagnostic performance of T-SPOT.TB for tuberculous lymphadenitis. Methods Suspected tuberculous lymphadenitis patients between September 2010 and September 2018 who had both peripheral blood T-SPOT.TB test and lymph node biopsy were retrospectively enrolled in this study. The cutoff value of T-SPOT.TB test for peripheral blood was set as 24 spot forming cell (SFC)/10 ⁶ periphreral blood monocyte cell (PBMC) according to the instruction of testing kits. The gold standard for diagnosis of TBL was the combination of microbiology results, histopathology results and patient's response to anti-TB treatment. Diagnostic efficacy of T-SPOT.TB was evaluated, including sensitivity, specificity, accuracy, predictive values, and likelihood ratio. Results Among 91 patients who met the inclusion criteria, we excluded 8 cases with incomplete clinical information and 6 cases who lost to follow-up. According to the gold standard, there were 37 cases of true TBL (9 confirmed TBL and 28 probable TBL), 30 cases of non-TBL, and 10 cases of clinically indeterminate diagnosis who were excluded from the final analyses. The T-SPOT.TB tests yielded 43 cases of positive response and 24 cases of negative response. The sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR) and negative likelihood ratio (NLR) of peripheral blood T-SPOT.TB for diagnosing TBL were 89.2%, 66.7%, 79.1%, 76.7%, 83.3%, 2.68 and 0.16, respectively. The number of SFCs of T-SPOT.TB in TBL patients [432(134-1264)/10 ⁶ PBMCs] was higher than that in non-TBL patients [0 (0-30) /10 ⁶PBMCs] with a significant difference (Z=-5.306, P <0.001).Conclusion T-SPOT.TB is a rapid and simple diagnostic test for TBL with a high sensitivity and negative predictive value.

Evaluation of the performance of two tuberculosis interferon gamma release assays (IGRA-ELISA and T-SPOT.TB) for diagnosing Mycobacterium tuberculosis infection

This data contains information from 3727 patients and shows the performance of two IGRAs tests (T-SPOT.TB and IGRA-ELISA) used in China for screening and diagnostic Mycobacterium tuberculosis infection. The positive results were divided into four groups according with the test values, and the proportions of positives in each group were compared. The positive predictive values (PPVs) at different cutoffs for diagnostic active TB and value change trend for the two IGRAs tests were analyzed.

Comparison between laparoscopy and laboratory tests for the diagnosis of tuberculous peritonitis

Background/aim

Our study aimed to investigate a reliable diagnostic approach for tuberculous peritonitis (TBP) by comparing the commonly used diagnostic tools.

Materials and methods

Fifty-one patients had received a series of diagnoses, including laparoscopy, erythrocyte sedimentation rate (ESR), cancer antigen 125 (CA125), tuberculin skin test, tuberculosis antibody in serum (TB-Ab), the T-SPOT.TB test, or adenosine deaminase (ADA) in ascitic fluid. The positive rate of each method was calculated and the differences of positive rates between laparoscopy and laboratory tests that had higher positive rates were analyzed by McNemar chi-square test.

Results

The most common symptoms and signs of 51 patients were fever (86.3%), abdominal mass (78.4%), abdominal distension (62.7%), abdominal pain (74.5%), and weight loss (66.7%). Furthermore, the positive rates of CA125, laparoscopy, T-SPOT.TB test, and ESR were relatively higher than those of the other three methods (tuberculin skin test, TB-Ab, and ascitic ADA). Additionally, there was no significant difference (P > 0.05) in the positive rates between the diagnoses of laparoscopy and those three laboratory tests.

Conclusion

CA125, laparoscopy, T-SPOT.TB test, and ESR had a stronger diagnostic power for TBP, and they are reliable alternatives for the diagnosis of TBP.

Use of Interferon-γ release assay for the diagnosis of female genital tuberculosis in Northwest China

BACKGROUND

Female genital tuberculosis (FGTB) is one of the major causes of infertility. However, nonspecific manifestations and the lack of easy access to gold-standard diagnostic test render a diagnostic difficult for FGTB. The objective of this study was to determine T-SPOT.TB (an interferon-γ release assay, IGRA) performance in patients with FGTB.

METHODS

A total of 213 female patients with validated T-SPOT.TB results were recruited in this retrospective study. Among which, 103 were confirmed FGTB, and 110 were excluded from tuberculosis (control). Of the confirmed FGTB patients, 52 were confirmed by microbiologically/histopathologically examination, while the remaining 51 were clinically confirmed (successfully responsive to anti-tuberculosis treatment). T-SPOT.TB test was performed in both FGTB and control group during the diagnostic procedure.

RESULTS

The overall sensitivity and specificity of T-SPOT.TB were 86.41% and 75.45% respectively. Sensitivity of T-SPOT.TB was significantly higher when compared with conventional tuberculosis diagnostic tests. Moreover, T-SPOT.TB test using pelvic effusion (PE) showed higher sensitivity than using corresponding peripheral blood (PB) (94.44% vs 72.22%, P < 0.001). Mean value of spot forming cells (SFCs) of T-SPOT.TB using PE was significantly higher than that of PB in FGTB group (193 (IQR 105-280) SFCs/2.5 × 10⁵ PEMCs vs 71 (IQR 36-107) SFCs/2.5 × 10⁵ PBMCs, P = 0.01), while this was not detected in control group (11 (IQR 0-22) SFCs/2.5 × 10⁵ PEMCs vs 9 (IQR 0-18) SFCs/2.5 × 10⁵ PBMCs, P = 0.77).

CONCLUSION

These results demonstrated that T-SPOT.TB, especially PE T-SPOT.TB, is an useful adjunct in FGTB diagnosis.

[Diagnostic performance of T-SPOT.TB on peripheral blood in combination with adenosine deaminase on pleural fluid for the diagnosis of tuberculous pleurisy within different age group]

Objective: To evaluate the performance of T cell enzyme-linked immuno-spot assay (T-SPOT) on peripheral blood in combination with adenosine deaminase (ADA) on pleural fluid for diagnosis of tuberculous (TB) pleurisy within different age groups. Methods: The data of patients with pleural effusion from the Department of Pulmonary and Critical Care Medicine of the First Affiliated Hospital of Wenzhou Medical University from April 2012 to November 2016 were retrospectively analyzed, and the diagnoses of these patients were histopathologically confirmed through medical thoracoscopy. The cases who had confirmed diagnosis, in the same time, received peripheral blood T-SPOT.TB were enrolled. The performance of peripheral blood T-SPOT.TB in combination with pleural fluid ADA on diagnosing TB pleurisy in the younger patients (16-59 years old) and elderly patients (≥60 years old) were analyzed respectively. The sensitivity, specificity and the receiver operating characteristic (ROC) curve were adopted for statistical analysis. Results: A total of 448 cases were finally enrolled, 341(76.1%) confirmed with TB pleurisy, 224 males, 117 females, (47±19) years old; and 107 (23.9%) classified as non-TB pleurisy, 65 males, 42 females, (61±14) years old. There were 285 cases who were classified as younger group, and the other 163 cases were classified as elderly group. The sensitivity and specificity of peripheral blood T-SPOT.TB were 85.4% (204/239) and 71.7% (33/46) in the younger patients, 76.5% (78/102) and 59.0% (36/61) respectively in the elderly patients. The sensitivity of peripheral blood T-SPOT.TB in the younger patients was significantly higher than that in the elderly patients (P=0.047). The sensitivity and specificity were 99.2% and 95.7% in combination with peripheral blood T-SPOT.TB and pleural fluid ADA respectively in the younger patients. The area under ROC curve (AUC) of T-SPOT.TB in the younger patients was 0.833, AUC of T-SPOT.TB combined with ADA was 0.911. The combination test of 2 tests had the sensitivity of 96.1% and the specificity of 90.2% respectively in the elderly patients. The AUC of T-SPOT.TB in the elderly patients was 0.747, AUC of T-SPOT.TB combined with ADA was 0.911. Conclusion: Peripheral blood T-SPOT.TB combined with pleural fluid ADA can improve the diagnostic performance for TB pleurisy with different ages, especially for elderly patients who can't tolerate pleural biopsy.

The Use of TB-Specific Antigen/Phytohemagglutinin Ratio for Diagnosis and Treatment Monitoring of Extrapulmonary Tuberculosis

Extrapulmonary tuberculosis (EPTB) has become more common in recent years; however, the diagnosis of EPTB remains a challenge. In this study, we analyzed the performance of the ratio of TB-specific antigen (TBAg) to phytohemagglutinin (PHA) (TBAg/PHA ratio) in T-SPOT.TB (T-SPOT) assay for diagnosis and treatment monitoring of EPTB. Between 2012 and 2017, 734 EPTB patients were diagnosed and recruited from Tongji hospital, and 1,137 suspected EPTB patients who had other diagnoses were recruited as non-EPTB controls. To validate the study, another small group of EPTB patients and non-EPTB controls were recruited from Sino-French New City Branch of Tongji Hospital. The positive rate of peripheral blood T-SPOT in EPTB and non-EPTB were 88.15 and 32.28%. In T-SPOT positive patients, the direct T-SPOT results had limited value in distinguishing these two conditions. A further calculation of the TBAg/PHA ratio of T-SPOT showed improved performance in each form of EPTB. If using 0.20 as the threshold value of the TBAg/PHA ratio, the pooled sensitivity and specificity were 70.79 and 91.55% in distinguishing EPTB from non-EPTB. The validation results showed a better performance of the TBAg/PHA ratio in distinguishing these two conditions, with a sensitivity and specificity of 81.82 and 97.56%, respectively. Comparing with directly using T-SPOT results, the TBAg/PHA ratio was less affected by immunosuppression. Furthermore, PHA value reflected immunosuppression and could help to judge the credibility of T-SPOT results in EPTB patients with different immune status. The TBAg/PHA ratio was significantly decreased during anti-tuberculosis (TB) treatment, which suggests that it can also be used to monitor therapeutic efficacy. These data provide new insights into the role of T-SPOT assay in TB disease, and the TBAg/PHA ratio might be a useful tool for diagnosis and treatment monitoring of EPTB.

Mycobacterium gordonae in Patient with Facial Ulcers, Nosebleeds, and Positive T-SPOT.TB Test, China

Mycobacterium gordonae is often regarded as a weak pathogen that only occasionally causes overt disease. We report a case of M. gordonae infection in the facial skin, nasal mucosa, and paranasal sinus in an immunocompetent patient and review previous cases. The T-SPOT.TB test might be useful in diagnosing such cases.

Evaluation of the performance of two tuberculosis interferon gamma release assays (IGRA-ELISA and T-SPOT.TB) for diagnosing Mycobacterium tuberculosis infection

OBJECTIVES

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Application Values of T-SPOT.TB in Clinical Rapid Diagnosis of Tuberculosis

BACKGROUND

This paper aims to explore the application value of tuberculosis-specific enzyme-linked immunospot assay (T-SPOT.TB) in the diagnosis of tuberculosis.

METHODS

Fifty one patients with tuberculosis (TB) admitted to Wuxi No.5 People's Hospital, Wuxi, China from June 2015 to June 2017 were selected as the TB group, and 40 patients without tuberculosis admitted in the same period were randomly selected as the non-TB group. Patients in the two groups received T-SPOT.TB, TB antibody (TB-Ab) test and mycobacterium TB deoxyribonucleic acid (TB-DNA) test, and the results were compared.

RESULTS

Comparisons of the sensitivity of the three methods showed that the sensitivity of T-SPOT.TB was the highest, followed by TB-DNA from sputum samples, and that of TB-Ab was the lowest. The specificity of TB-Ab was the highest, followed by T-SPOT.TB, and that of TB-DNA from sputum samples was the lowest. In the receiver operating characteristic (ROC) curve analysis, the area under curve (AUC) of T-SPOT.TB (0.896) was the highest, followed by TB-DNA from sputum samples (0.772), and that of sputum smears (0.698) was the lowest.

CONCLUSION

T-SPOT.TB can quickly and accurately determine the presence of tuberculosis infection, and it is a non-invasive examination, which can further assist in the diagnosis and guide the treatment.

Tuberculous spondylitis after vertebral augmentation: A case report with a literature review

Tuberculous spondylitis of vertebral augmentation following percutaneous vertebroplasty or kyphoplasty is rare. We report an unusual case of tuberculous spondylitis diagnosed after percutaneous kyphoplasty (PKP). A 54-year-old woman presented to hospital complaining of back pain following a fall 20 days prior. Radiology showed an acute osteoporotic compression (L3 fracture). The patient denied a history of pulmonary tuberculosis and there were no signs of infection. The patient was discharged from hospital 2 days after undergoing L3 PKP with a dramatic improvement in her back pain. The patient was readmitted 10 months later with a history of recurrent back pain and low-grade fever for 3 months. Imaging examinations showed severe spondylitis at the L2-L3 level, with paravertebral abscess formation and bony destruction of L2 and L3. A positive result of the T-SPOT test preliminarily confirmed the diagnosis of tuberculous spondylitis. The tuberculosis test was positive, and serum C-reactive protein levels and erythrocyte sedimentation were relatively high. Treatment for tuberculous spondylitis was started. She underwent posterior fusion and instrumentation from T12-L5 after markers for infection returned to normal. After surgery, the patient continued antituberculous and anti-osteoporosis treatments. Her low back pain was relieved and low-grade fever and sweating disappeared.

Diagnostic Value of Cerebrospinal Fluid T-SPOT.TB for Tuberculousis Meningitis in China

The aim of this study was to evaluate the diagnostic value of the cerebrospinal fluid (CSF) T-SPOT.TB test for the diagnosis of TB meningitis (TBM). A retrospective analysis of 96 patients with manifested meningitis was conducted; T-SPOT.TB test was performed for diagnosing TBM to determine the diagnostic sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). A receiver operating characteristic (ROC) curve was also drawn to assess the diagnostic accuracy. The sensitivity, specificity, PPV, and NPV of CSF T-SPOT.TB test were 97.8%, 78.0%, 80.3%, and 97.5%, respectively, for 52 patients (54.2%) of the 96 enrolled patients. The area under the curve (AUC) was 0.910, and the sensitivities of CSF T-SPOT.TB for patients with stages I, II, and III of TBM were 96.7%, 97.2%, and 98.9%, respectively. CSF T-SPOT.TB test is a rapid and accurate diagnostic method with higher sensitivity and specificity for diagnosing TBM.

Use of IFN-γ and IP-10 detection in the diagnosis of latent tuberculosis infection in patients with inflammatory rheumatic diseases

OBJECTIVES

Biologic agents are used against rheumatic diseases, however, they increase the risk of developing severe infections and diseases such as tuberculosis. We aimed to determine the benefits of IP-10 detection to diagnose latent tuberculosis infection (LTBI) in patients with inflammatory rheumatic diseases on different immunosuppressive drug regimens, and compare these results with IFN-γ detection.

MATERIALS AND METHODS

We included 64 patients with inflammatory rheumatic diseases. We used QuantiFERON Gold In-Tube (QFN-G-IT) and T-SPOT.TB to detect IFN-γ production, and an in-house ELISA for IP-10 detection from the previous QFN-G-IT stimulated samples. We assessed the combined use of IFN-γ release assays (IGRAs) and IP-10 test, and analyzed the influence of immunotherapy on the tests performance.

RESULTS

We obtained 34.9% positive results by T-SPOT.TB, 25.0% by QFN-G-IT and 31.3% by IP-10 test. The combined use of IGRAs and IP-10 detection increased significantly the amount of positive results (p < 0.0001). Treatment intake had no significant effect on in vitro tests (p > 0.05).

CONCLUSIONS

IP-10 and IFN-γ detection is comparable and their combined use could increase the number of positive results in the diagnosis of LTBI in rheumatic patients. The tested assays were not influenced by rheumatoid immunosuppressive therapy. Thus, IP-10 could be of use in the development of new and improved LTBI diagnostic tools.