Browsing by Author "Mendy, Joseph F."

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    Analysis of ex vivo host biomarkers in sputum samples for diagnosis of pulmonary tuberculosis
    (Stellenbosch : Stellenbosch University, 2019-12) Mendy, Joseph F.; Chegou, Novel N.; Sutherland, Jayne; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences: Molecular Biology and Human Genetics
    Background Despite all the interventions deployed to control tuberculosis (TB), the disease still continues to be the principal cause of death from a single infectious agent in resource constrained settings. An estimated 60% of suspected TB patients do not have access to TB diagnostic tests. With the limitations of the current diagnostic tests and the importance of early diagnosis and initiation of treatment, biomarker diagnosis of TB would be an optimal option. For biomarkers are indicators of immune activity and state. Therefore, host or pathogen biomarker of TB disease would be ideal. Hence, the aim of this project was to profile a broad array of host markers for development of optimal signatures for detection of pulmonary tuberculosis from other respiratory disorders using ex vivo sputum samples Methods We recruited patients who were seeking medical attention at the MRCG at LSHTM outpatients department and Tuberculosis clinic with symptoms suggestive of TB, prior to clinical or microbiological diagnosis. All age groups were recruited. Sputa were collected at baseline from all participants and at 1 and 2 months from the confirmed TB cases. The sputa were digested with Sputolysin and the supernatant analysed using Luminex arrays while RNA extracted from the pellet were analysed with RT-qPCR. Statistical analyses and graphs were generated using R programming Language and GraphPad Prism, with a q value ≤ 0.05 considered significant. A receiver operating curve (ROC) was used to assess the diagnostic performance of individual and combination markers. Results Confirmed TB (428) and ORD (313) patients were analysed, 70 markers were assessed for diagnostic potential and treatment response. Of these, 37 were significantly different between TB and ORD. The best single marker was MMP-2 with an AUC of 0.73. An eight-marker signature (IFNү, IL-1β, IL-8, IL-10, IL-12p70, MIP-1β, RANTES and VEGF) was able to diagnose smear and culture positive TB from ORD with an AUC of 0.77, sensitivity of 78% and specificity of 70%, while a threemarker signature (IL-1β, IL-7 and VEGF) classified smear negative but culture positive TB from ORD with an AUC of 0.74, sensitivity of 86% and specificity of 60%. Among children who had TB, a fourmarker signature (FGF, IL-4, MIP-1a and RANTES) differentiated those with TB from ORD, with an AUC of 0.87, sensitivity of 82% and specificity of 87% and a five-marker signature consisting of BAFF, C3L1, IL-22, MMP-3 and sTNFR1 was able to discriminate TB and HIV co-infected from ORD with an AUC of 0.90, sensitivity of 88% and specificity of 85%. We also found a four-marker signature consisting of EGF, IL-15, MIP-1β and TNF-β that could predict slow versus fast treatment responders at baseline with an AUC of 0.74, sensitivity of 75% and specificity of 80%. Conclusion We have discovered novel sputum host biomarkers and biosignatures for screening of tuberculosis and treatment response. The data is promising for potential translation into a user friendly device as a rapid screening test for pulmonary TB. However, this markers and signatures require further investigations to authenticate their usefulness.