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The new generation of the IGRA QuantiFERON-TB Gold Plus (QFT-Plus) includes two antigen tubes, TB1 and TB2 which contain specific Mycobacterium tuberculosis peptides designed to stimulate both CD4 and CD8 T-cells. TB1 is designed to target cell mediated responses from CD4 T-cells, while TB2 contains newly designed peptides designed to also stimulate CD8 T-cells. We identified specific CD4 and CD8 T-cell clones that recognize different regions spanning the length of the CFP-10 protein in M. tuberculosisto directly test in QFT-Plus TB1 and TB2 tubes, followed by Interferon-gamma detection by the QFT-Plus ELISA. These clones showed specific responses to the different QFT-Plus tubes, the CD4 T-cell clone showed dose-dependent responses to both TB1 and TB2 tubes, while the CD8 T-cell clones showed specific and targeted responses to the QFT-Plus TB2 tube (>140-fold difference) versus the QFT-Plus TB1 tubes using the QFT-Plus ELISA. This testing provides direct evidence of the specificity of CD8 T-cell mediated response in QFT-Plus TB2 tubes., (Copyright © 2018. Published by Elsevier Ltd.)

Much effort has been made to reduce the cost of LTBI diagnosis with equivalent efficacy and efficiency of interferon-γ release assay (IGRA). This study showed that repeatability, intermediate precision, and accuracy of the Bionote-ELISA were comparable to QFT-ELISA. The Bionote-ELISA could provide the alternative method., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Introduction: This study is a part of the project on interferon gamma release assays performed in the group of untreated sarcoidosis patients formerly BCG vaccinated. The aim of the study was to assess the rate of positive commercial interferon g release assays in sarcoidosis patients. We discussed the results in the context of hypothesis that M. tuberculosis antigens may play a role in the pathogenesis of sarcoidosis., Material and Methods: 151 patients, mean age 38 ± 10.3, treatment naive, with newly diagnosed pulmonary sarcoidosis were enrolled into the study. All participants underwent QFT-GIT assay. A subgroup of 81 patients underwent also T-SPOT.TB assay., Results: QFT-GIT was positive in 7/151. T-SPOT.TB was positive in 3/81. There were no indeterminate results in both IGRAs. There was no statistically significant relationship between IGRAs results and sarcoidosis parameters such as the radiologic stage, disease duration and the presence of Löfgren's syndrome., Conclusions: In sarcoidosis patients formerly BCG vaccinated, positive rate of IGRAs was 4.6% for QFT-GIT and 3.7% for T-SPOT. TB. We did not find the influence of the selected parameters of sarcoidosis on IGRAs results.

Triggers of indeterminate results from interferon-gamma release assays (IGRA) in patients with rheumatic diseases are still elusive. The aim of the present study was to describe predictors of indeterminate results from IGRA in the field of rheumatology. This cross-sectional study was retrospectively performed by using a database of patients with a request for QuantiFERON-TB Gold-In Tube test (QFT-GIT) for screening of latent tuberculosis infection. The study cohort included 631 patients with rheumatic diseases. All variables influencing indeterminate QFT-GIT results were investigated by logistic regression analysis. The overall frequency of indeterminate IGRA results was 6.8 % (43/631). Those with indeterminate results were more likely to be aged ≥70 years, female, visitors in winter, suffering from systemic lupus erythematosus (SLE), and using sulfasalazine or a tumor necrosis factor (TNF)-α inhibitor. In addition, a longer incubation time of >6 h increased the odds ratio of indeterminate IGRA results. In contrast, the automated ELISA processor, ankylosing spondylitis, and the use of a non-steroidal anti-inflammatory drug decreased the likelihood of indeterminate IGRA results. Lymphopenia, thrombocytopenia, anemia, and hypoalbuminemia were significantly associated with indeterminate IGRA results. Multivariate analysis revealed that SLE, use of sulfasalazine or a TNF-α inhibitor, and a manual ELISA system were significantly independent predictors of indeterminate IGRA results. The proportion of indeterminate results in patients with rheumatic diseases is not infrequent. Careful attention to the pre-analytical conditions should minimize the indeterminate results. Automation of the ELISA process seems to be a promising solution to decrease the rate of indeterminate response.