The greatest diagnostic accuracy in discriminating active TB vs. LTBI or cured TB was reached by evaluating the CD27(+) CD45RA(-) cells within the IFN-γ⁺ CD4⁺ T-cell subset (76.92 sensitivity for both, and 90% and 91.67% specificity, respectively), although the use of the CD27 MFI RATIO allows for stricter data analysis, independent of the operator.
These persons do not exhibit adaptive immune priming as measured by tuberculin skin test (TST) and interferon-γ (IFN-γ) release assay (IGRA) responses, nor do they develop active tuberculosis (TB).
Interferon gamma (IFN-γ) values in response to TB antigen and mitogen were significantly higher in children than in adults (TB antigen, median of 10 versus 1.66 IU IFN-γ/ml; mitogen, median of 10 versus 6.70 IU IFN-γ/ml; <i>P</i> < 0.0001).
The results suggest that the ultra-sensitive SiMoA IFNγ assay could represent a useful tool for the identification of true positive and negative samples among those giving indeterminate or uncertain results with the TB IGRA assay currently used.
<b>Methods:</b> Screening for TB was performed in children in asylum seeker reception centres by tuberculin skin test (TST) or interferon gamma release assay (IGRA).
M. tb heparin-binding-hemagglutinin (HBHA) induces relatively high IFN-γ responses in LTBI individuals and low responses in ATB patients, but purification of the native methylated HBHA from cultures of M. tb for immunological tests is complex and time-consuming.
However, Mtb-specific IFN-γ-producing T cells do not distinguish active tuberculosis (ATB) patients from individuals with asymptomatic latent Mtb infection (LTBI).
Currently available interferon-γ release assays (IGRAs) are inadequate to diagnose active TB, with reported pooled sensitivity and specificity both under 81%.
<b>Methods:</b> Peripheral blood mononuclear cells from subjects with latent MTB infection (<i>n</i> = 16) and aTB (<i>n</i> = 39) at baseline, weeks 9, 12, and 26 (end of treatment) were analyzed after intracellular interferon gamma staining and overnight stimulation with tuberculin.
Serum MIF, IFN-γ and TNF-α profiles distinguish tuberculosis from the more inflammatory phenotype and may play a role in pathogenesis and as biomarkers of active tuberculosis.
Comparing interferon-gamma release assays with tuberculin skin test for identifying latent tuberculosis infection that progresses to active tuberculosis: systematic review and meta-analysis.
The IFN-γ release responses to Rv1986-P9, P15, P16, Rv1988-P4, P11, and Rv1987-P11 were significantly higher in the active TB group than in the control groups (p<0.05).
In particular, interleukin-18 (IL-18), an inducer of interferon-gamma (IFN-γ), playing an important role in anti-mycobacterial immune responses, may influence the risk of developing active tuberculosis (TB).
In patients with positive ELISpot in pleural fluid (n = 16), the PPV for TB was 85.7%, which increased to 91.7% for the ESAT-6 panel and 92.3% for the CFP-10 panel after the introduction of a cut-off >1.0 for the ratio between the pleural fluid and blood interferon-gamma responses.
Moreover, IFNG- and TNFA-expressing CD4+ T cells (Th1 cells) were more frequent in active TB than in LTBI, a difference that is undetectable with conventional, protein-based cytokine assays.
In healthy household contacts (HHC), all the tested antigens induced significantly higher levels of IFN-γ and Interlukin-8 (IL-8) compared with those in PTB.
Immunosuppression during active tuberculosis is characterized by decreased interferon- gamma production and CD25 expression with elevated forkhead box P3, transforming growth factor- beta , and interleukin-4 mRNA levels.