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Background: Mycobacterium tuberculosis (Mtb)-specific perforin were significantly increased in patients with tuberculosis. This study aims to evaluate the diagnosis value of Mtb-specific perforin in pediatric patients with tuberculosis., Methods: Diagnostic performance of perforin levels induced by 6-kDa early secreted antigen target (ESAT6) or culture filtered protein 10 (CFP10) were evaluated in eighty-six samples from children participants by receiver operating characteristic curve analysis. Flow cytometry was used to detect the expression of perforin and INF-γ of CD4 + , CD8 + T cells in response to CFP10 stimulation., Results: After ex vivo stimulation, levels of ESAT6/CFP10-specific perforin in LTBI patients were significantly higher than active TB (ATB) patients, non-tuberculosis infection (non-TB), and health control (HC) individuals. The diagnostic efficacy of CFP10-specific perforin for TB diagnosis was significantly higher than ESAT6-specific perforin and T-SPOT assay, and when 0.74 ng/mL was taken as the cutoff value, the sensitivity, specificity, and accuracy were 97.83%, 87.5%, and 93.02%. CFP10-specific perforin in both CD4 + and CD8 + T cells were significantly higher in ATB patients compared to HCs and further increased in LTBI patients. However, INF-γ was mainly secreted by CD4 + T cells and showed no significant difference between LTBI and ATB patients. In addition, CFP10-specific perforin can effectively distinguish between ATB and LTBI with the cutoff value of 1.80 ng/mL. Sensitivity and specificity were 88.46% and 85.62%, respectively., Conclusions: CFP10-specific perforin may be used as a novel cellular immunity-based diagnostic marker of pediatric patients with tuberculosis, and with the potential for discriminating ATB from LTBI., (© 2020 The Authors. Journal of Clinical Laboratory Analysis published by Wiley Periodicals LLC.)

Urinary detection of Mycobacterium tuberculosis lipoarabinomannan (LAM) for tuberculosis (TB) diagnosis is well characterized, but the utility of serum LAM detection remains unclear. We developed an assay for serum LAM detection using single-molecule array (Simoa), purified M. tuberculosis LAM, and anti-LAM monoclonal antibodies and evaluated performance on diluted/heat-treated serum samples from patients with and without active TB and/or HIV. The Simoa assay had a limit of detection of 0.35 pg/mL and lower limit of quantification of 0.942 pg/mL. Corrected serum LAM concentrations ranged from 0 to 132.0 pg/mL [median 1.71, interquartile range (IQR) 0.94-6.80] in 90 TB+ patients and from 0 to 2.29 pg/mL (median 1.03, IQR 0.47-1.69) in 55 TB- patients. Using a cutoff of 2.3 pg/mL for 100% specificity, assay sensitivity was 37% in all TB+ subjects (33/90; 95% CI 0.27-0.48), 47% in TB+/HIV+ subjects (26/55; 0.34-0.61), and 60% in TB+/HIV+/smear+ subjects (21/35; 0.42-0.76). Mycobacterial LAM is detectable in serum with high specificity and reasonable sensitivity using Simoa., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Tuberculosis (TB) remains a public health challenge and its control requires the use efficient diagnostic tools. Mycobacterium tuberculosis (MTB) elicits a strong immune response upon infection, a phenomenon measured by the old tuberculin skin test (TST). However, this test has many limitations and a high rate of positivity in BCG-vaccinated subjects. Recent studies have identified several MTB-antigens for diagnostic use, including the ESAT-6 and CFP-10 proteins. Based on these antigens, one of the most significant developments in the diagnostic armamentarium for TB has been the assays based on IFN- determination (IGRAs). The assays stem from the principle that T-cells of infected individuals produce IFN-gamma when they re-encounter the MTB antigens in vitro and this can be measured by a conventional ELISA test. The evaluation of IGRAs in different clinical settings showed many advantages over TST. The worldwide diffusion of IGRAs has increased the knowledge on their clinical use and a number of guidelines have been devised for their application. The two-step approach (first using TST followed by IGRA for confirmation) is the most favored strategy for IGRA-use in the general population, while the use of IGRAs alone is suggested in particular clinical settings and/or patient groups. Even if these tests are still costly there are a number of cost effective advantages in the "targeted" use of IGRAs over the TST. The work we present summarises all these aspects.

Background: In parts of Great Britain and Ireland, Eurasian badgers (Meles meles) constitute a reservoir of Mycobacterium bovis infection and a potential source of infection for cattle. In vitro diagnostic tests for live badgers are an important component of strategies to control TB in this species. Immunological tests have been developed for badgers, although little is known about the influence of the age of the animal on test performance. To address this, we evaluated the performance of three immunological tests for badgers with respect to the age of the animal: the Brock Test and BrockTB STAT-PAK serological tests and the recently developed interferon-gamma enzyme immunoassay (IFNgamma EIA). Data published elsewhere suggested that seropositivity was associated with more progressive forms of TB in the badger. To gain further evidence for this, we used longitudinal data from a well-studied population of badgers to test for an association between the sensitivity of the Brock Test and the duration of TB infection., Results: Sensitivity of the two serological tests was approximately 54% for both cubs and adults. Sensitivity of the IFNgamma EIA was lower in cubs (57%) compared with adults (85%) when a common cut-off value was used to define test positivity. Taking data from the cubs alone, the IFNgamma EIA cut-off value could be adjusted to increase the sensitivity to 71% with no loss in specificity. As a general observation, specificity of all tests was higher in cubs, although only significantly so in the case of the Brock Test. Using logistic regression analysis to adjust for age, sensitivity of the Brock Test was significantly lower at first culture positive event (58%), but increased to >80% as infection progressed., Conclusion: These data suggest that serodiagnosis could be a valuable tool for detecting a higher proportion of badgers with the greatest probability of transmitting infection. The age category of the badger appeared to exert little influence on the performance of the serological tests. Although data were only available for the IFNgamma EIA in a small number of cubs, reduced sensitivity of the test in these individuals suggests a lower cut-off may be needed when testing younger animals.

Background: The clinical application of IFN-gamma release assays (IGRAs) has recently improved the diagnosis of latent tuberculosis infection. In a multicenter study of the Tuberculosis Network European Trialsgroup (TBNET) we aimed to ascertain in routine clinical practice the accuracy of a novel assay using selected peptides encoded in the mycobacterial genomic region of difference (RD) 1 for the diagnosis of active tuberculosis in comparison with tuberculin skin test (TST), QuantiFERON-TB GOLD In-Tube (Cellestis Ltd., Carnegie, Australia) and T-SPOT.TB (Oxfordimmunotec, Abingdon, UK)., Principal Findings: 425 individuals from 6 different European centres were prospectively enrolled. We found that sensitivity of the novel test, TST, QuantiFERON-TB GOLD In-Tube and T-SPOT.TB was respectively 73.1%, 85.3%, 78.1%, and 85.2%; specificity was respectively 70.6%, 48.0%, 61.9% and 44.3%; positive likelihood ratios were respectively 2.48, 1.64, 2.05, and 1.53; negative likelihood ratios were respectively 0.38, 0.31, 0.35, 0.33. Sensitivity of TST combined with the novel test, QuantiFERON-TB GOLD In-Tube and T-SPOT.TB increased up to 92.4%, 97.7% and 97.1%, respectively. The likelihood ratios of combined negative results of TST with, respectively, the novel test, QuantiFERON-TB GOLD In-Tube and T-SPOT.TB were 0.19, 0.07 and 0.10., Conclusions: The assay based on RD1 selected peptides has similar accuracy for active tuberculosis compared with TST and commercial IGRAs. Then, independently of the spectrum of antigens used in the assays to elicit mycobacterial specific immune responses, the novel test, IGRAs, and the TST do not allow an accurate identification of active tuberculosis in clinical practice. However, the combined use of the novel assay or commercial IGRAs with TST may allow exclusion of tuberculosis.

Background: Until recently, the tuberculin skin test was the only test for detecting latent tuberculosis (TB) infection, but 2 ex vivo interferon-gamma release assays (IGRAs) are now commercially licensed., Purpose: To estimate sensitivity, specificity, and reproducibility of IGRAs (commercial or research versions of QuantiFERON [QFT] and Elispot) for diagnosing latent TB infection in healthy and immune-suppressed persons., Data Sources: The authors searched MEDLINE and reviewed citations of all original articles and reviews for studies published in English., Study Selection: Studies had evaluated IGRAs using Mycobacterium tuberculosis-specific antigens (RD1 antigens) and overnight (16- to 24-h) incubation times. Reference standards had to be clearly defined without knowledge of test results. DATA EXTRACTION AND QUALITY ASSESSMENT: Specific criteria for quality assessment were developed for sensitivity, specificity, and reproducibility., Data Synthesis: When newly diagnosed active TB was used as a surrogate for latent TB infection, sensitivity of all tests was suboptimal, although it was higher with Elispot. No test distinguishes active TB from latent TB. Sensitivity of the tuberculin skin test and IGRAs was similar in persons who were categorized into clinical gradients of exposure. Pooled specificity was 97.7% (95% CI, 96% to 99%) and 92.5% (CI, 86% to 99%) for QFT and for Elispot, respectively. Both assays were more specific than the tuberculin skin test in samples vaccinated with bacille Calmette-Guérin. Elispot was more sensitive than the tuberculin skin test in 3 studies of immune-compromised samples. Discordant tuberculin skin test and IGRA reactions were frequent and largely unexplained, although some may be related to varied definitions of positive test results. Reversion of IGRA results from positive to negative was common in 2 studies in which it was assessed., Limitations: Most studies used cross-sectional designs with the inherent limitation of no gold standard for latent TB infection, and most involved small samples with a widely varying likelihood of true-positive and false-positive test results. There is insufficient evidence on IGRA performance in children, immune-compromised persons, and the elderly., Conclusions: New IGRAs show considerable promise and have excellent specificity. Additional studies are needed to better define their performance in high-risk populations and in serial testing. Longitudinal studies are needed to define the predictive value of IGRAs.

Until 2001, the only test used to diagnose latent tuberculosis infection (LTBI) was the tuberculin skin test (TST). However, in 2001, a new test (QuantiFERON-TB or QFT; manufactured by Cellestis Limited, Carnegie, Victoria, Australia) that measures the release of interferon-gamma in whole blood in response to stimulation by purified protein derivative was approved by the Food and Drug Administration. This statement provides interim recommendations for using and interpreting QFT. As with TST, interpretation and indicated applications of QFT differ for persons according to their risk for LTBI and for developing tuberculosis (TB). This report provides guidance for public health officials, health-care providers, and laboratorians with responsibility for TB control activities in the United States in their efforts to incorporate QFT testing for detecting and treating LTBI. Regardless of the test used to identify LTBI, testing should be primarily targeted at diagnosing infected patients who will benefit from treatment.

The sensitivity and specificity of intradermal tuberculin test (Tb test) were studied in an infected red deer (Cervus elaphus) herd (n = 109) in comparison to the results of other examinations including gross pathology, histopathology, Mycobacterium bovis culture, and the lymphocyte-stimulation test (LST). In our case, relative sensitivity was 79.5% and relative specificity was 45.7%. The predictive value in negative and positive cases was 80.0% and 44.9%, respectively. On the basis of the results obtained, eradication of tuberculosis by the selection procedure from a herd of newly captured and colonized deer was performed using the Tb test. For the purposes of eradication by selection all deer responding to B-PPD were considered positive.