Masters Degrees (Molecular Biology and Human Genetics)

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Browsing Masters Degrees (Molecular Biology and Human Genetics) by Subject "Antibodies"

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    Evaluation of novel host markers detected in plasma and saliva as biosignatures for the rapid diagnosis of TB disease and monitoring of the response to TB treatment
    (Stellenbosch : Stellenbosch University, 2016-12) Jacobs, Ruschca; Chegou, Novel N.; Walzl, Gerhard; Stellenbosch University. Faculty of Medicine and Health Sciences. Dept. of Biomedical Sciences: Molecular Biology and Human Genetics.
    ENGLISH SUMMARY: BACKGROUND: There is an urgent need for new tools for the rapid diagnosis of tuberculosis (TB) disease and monitoring of the response to treatment. OBJECTIVES: To investigate the usefulness of host markers detected in plasma and saliva, as well as antibodies against M. tuberculosis (M.tb) antigens, as biomarkers for the diagnosis of TB disease and monitoring of the response to treatment. To investigate the usefulness of a diagnostic approach involving the combination of antibodies and cytokines as a tool for diagnosing TB disease. METHODS: We prospectively collected plasma and saliva samples from individuals that presented with symptoms requiring investigation for TB disease at a health centre in Cape Town, South Africa, prior to the establishment of a clinical diagnosis. Patients were later classified as having TB disease or other respiratory diseases (ORD), using a combination of clinical, radiological and laboratory findings. The concentrations of host inflammatory biomarkers were investigated in plasma and saliva samples from all study participants using a multiplex platform, whereas antibody responses against seven M.tb antigens, were investigated by ELISA. The diagnostic accuracies of individual biomarkers were assessed by receiver operator characteristics (ROC) curve analysis, whereas the accuracies of combinations between different biomarkers were assessed by General Discriminant Analysis (GDA). RESULTS: Of the 74 host markers evaluated in plasma, 18 showed diagnostic potential as determined by area under the ROC curve (AUC), with the most promising being NCAM, CRP, SAP, IP-10, ferritin, TPA, I-309, and MIG, which diagnosed TB disease individually with AUC ≥0.80. A six-marker plasma protein biosignature comprising of NCAM, SAP, IL-1β, sCD40L, IL-13 and Apo A-1 diagnosed TB disease with a sensitivity of 100% (95% CI, 86.3-100%) and specificity of 89.3% (95% CI, 67.6-97.3%), irrespective of HIV status, whereas six-marker plasma protein biosignatures diagnosed TB disease with 100% accuracy in the absence of HIV. Of the 69 host markers that were investigated in saliva, only two (IL-16 and IL-23) showed diagnostic potential with AUC ≥0.70. A five-marker salivary biosignature comprising of IL-1β, IL-23, ECM-1, HCC1 and fibrinogen diagnosed TB disease with a sensitivity of 88.9% (95% CI,76.7-99.9%) and specificity of 89.7% (95% CI, 60.4-96.6%), regardless of HIV infection status, whereas eight-marker salivary biosignatures performed with a sensitivity of 100% (95% CI, 83.2-100%) and specificity of 95% (95% CI, 68.1-99.9%) in the absence of HIV infection. IgA responses against four M.tb antigens (NarL, Rv3019c, “Kit1” and “Kit2”) were significantly different between TB patients and individuals with ORD, with combinations between different antibodies diagnosing TB disease with an AUC of 0.80. The diagnostic accuracy of the antibodies increased when used in combination with patient’s symptoms or cytokines. Finally, the concentrations of biomarkers detected in plasma and saliva changed during TB treatment, thereby indicating that they may be useful in monitoring of the response to TB treatment. CONCLUSIONS: We have identified novel plasma and salivary biosignatures which may be useful in the diagnosis of TB disease and monitoring of the response to TB treatment. Our findings require further validation in larger studies.