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Kavsak P.A.,McMaster University | Walsh M.,McMaster University | Srinathan S.,University of Manitoba | Thorlacius L.,University of Manitoba | And 32 more authors.
Clinical Biochemistry | Year: 2011

Objectives: To determine the proportion of noncardiac surgery patients exceeding the published 99th percentile or change criteria with the high sensitivity Troponin T (hs-TnT) assay. Design and methods: We measured hs-TnT preoperatively and postoperatively on days 1, 2 and 3 in 325 adults. Results: Postoperatively 45% (95% CI: 39-50%) of patients had hs-TnT. ≥. 14 ng/L and 22% (95% CI:17-26%) had an elevation (≥. 14 ng/L) and change (>. 85%) in hs-TnT. Conclusion: Further research is needed to inform the optimal hs-TnT threshold and change in this setting. © 2011 The Canadian Society of Clinical Chemists.


PubMed | University of Oslo, University of Bergen, St Johns Medical College And St Johns Research Institute, St Johns Research Institute and 2 more.
Type: Journal Article | Journal: PloS one | Year: 2014

QuantiFERON-TB Gold In-Tube (QFT) is an IFN-release assay used in the diagnosis of Mycobacterium tuberculosis (MTB) infection. The risk of TB progression increases with the magnitude of the MTB-specific IFN-response. QFT reversion, also associated with low Tuberculin Skin Test responses, may therefore represent a transient immune response with control of M. tuberculosis infection. However, studies at the single cell level have suggested that the quality (polyfunctionality) of the T-cell response is more important than the quantity of cytokines produced.To explore the quality and/or magnitude of mycobacteria-specific T-cell responses associated with QFT reversion and persistent QFT-positivity.Multi-color flowcytometry on prospectively collected peripheral blood mononuclear cells was applied to assess mycobacteria-specific T-cell responses in 42 QFT positive Indian adolescents of whom 21 became QFT negative (reverters) within one year. Ten QFT consistent negatives were also included as controls.There was no difference in the qualitative PPD-specific CD4+ T-cell response between QFT consistent positives and reverters. However, compared with QFT consistent positives, reverters displayed lower absolute frequencies of polyfunctional (IFN+IL2+TNF+) CD4+ T-cells at baseline, which were further reduced to the point where they were not different to QFT negative controls one year later. Moreover, absolute frequencies of these cells correlated well with the magnitude of the QFT-response.Whereas specific polyfunctional CD4+ T-cells have been suggested to protect against TB progression, our data do not support that higher relative or absolute frequencies of PPD-specific polyfunctional CD4+ T-cells in peripheral blood can explain the reduced risk of TB progression observed in QFT reverters. On the contrary, absolute frequencies of these cells correlated with the QFT-response, suggesting that this readout reflects antigenic load.


Uppada D.R.,St Johns Emmaus Tb Research Initiatives Setri | Selvam S.,St Johns Research Institute | Jesuraj N.,St Johns Emmaus Tb Research Initiatives Setri | Bennett S.,Gilead Sciences Inc. | And 3 more authors.
BMC infectious diseases | Year: 2014

BACKGROUND: India has generally used 1 TU purified protein derivative (PPD) as opposed to 2 TU PPD globally, limiting comparisons. It is important to assess latent TB infection in adolescents given that they may be a target group for new post-exposure TB vaccines. The aim of this study is to describe the pattern and associations of tuberculin skin test (TST) responses (0.1 ml 2 TU) in adolescents in South India.METHODS: 6643 school-going adolescents (11 to <18 years) underwent TST. Trained tuberculin reader made the reading visit between 48 and 96 hours after the skin testRESULTS: Of 6608 available TST results, 9% had 0 mm, and 12% ≥10 mm responses. The proportion of TST positive (≥10 mm) was higher among older children, boys, those with a history of TB contact and reported BCG immunization Those with no TST response (0 mm) included younger participants (<14 years), those whose mothers were illiterate and those with a recent history of weight loss. Those of a higher socio-economic status (houses with brick walls, LPG gas as cooking fuel) and those with a visible BCG scar were less likely to be non-responders.CONCLUSION: Proportion of non-responders was lower than elsewhere in the world. Proportion of TST positivity was higher in those already exposed to TB and in children who had been BCG immunized, with a zero response more likely in younger adolescents and those with recent weight loss.

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