Setting: Tygerberg district, Western Cape Province, South Africa. Objective: To measure the agree... more Setting: Tygerberg district, Western Cape Province, South Africa. Objective: To measure the agreement of two interferon-gamma release assays (IGRAs) and the tuberculin skin test (TST) for the detection of Mycobacterium tuberculosis infection in human immunodeficiency virus (HIV) infected adults and children in a setting highly endemic for tuberculosis (TB). Design: Cross-sectional study. Results: In HIV-infected adults (n=20) and children (n=23), tests yielded discordant results, with 61% of individuals testing positive with T-SPOT.TB, 41% with TST and 28% with QuantiFERON TB Gold (QTF). In children, there was poor agreement between the TST and T-SPOT.TB (kappa [kappa]=-0.02), but moderate agreement between the TST and QTF (kappa=0.44). In adults, there was moderate agreement between the TST and T-SPOT.TB (kappa=0.43), and the TST and QTF (kappa = 0.46). In children and adults, there was fair agreement between the T-SPOT.TB and QTF (kappa=0.33). Twenty per cent of adults had >or=1 indeterminate IGRA results. Conclusions: There is poor to moderate agreement between the TST and IGRAs in HIV-infected adults and children. T-SPOT.TB may have improved sensitivity for detection of M. tuberculosis infection in HIV-infected individuals compared to the QTF and the TST. In HIV-infected individuals, IGRA test properties are affected by test cut-off point and nil control responses.
There is an urgent need for new tools for the rapid diagnosis of tuberculosis (TB) disease in res... more There is an urgent need for new tools for the rapid diagnosis of tuberculosis (TB) disease in resource-constrained settings. Tests based on host immunological biomarkers maybe useful, especially if based on easily available samples. We investigated host biomarkers detected in saliva samples from individuals with suspected pulmonary TB disease, as tools for the diagnosis of TB disease and monitoring of the response to treatment. We collected saliva samples from 104 individuals that presented with symptoms requiring investigation for TB disease at a primary health care clinic in the outskirts of Cape Town, South Africa, prior to assessment for TB disease. We evaluated the concentrations of 33 host markers in stored saliva samples using a multiplex cytokine platform. Using a combination of clinical, radiological and laboratory results and a pre-established diagnostic algorithm, participants were later classified as having TB disease or other respiratory diseases (ORD). The diagnostic potentials of individual analytes were analysed by the receiver operator characteristics curve approach while the predictive abilities of combinations of analytes for TB disease were analysed by general discriminant analysis, with leave-one-out cross validation. Of the 104 individuals enrolled, 32 were pulmonary TB cases. There were significant differences in the levels of 10 of the markers investigated between the patients with TB disease and those with ORDs. However, the optimal diagnostic biosignature was a seven-marker combination of salivary CRP, ferritin, serum amyloid P, MCP-1, alpha-2-macroglobulin, fibrinogen and tissue plasminogen activator. This biosignature diagnosed TB disease with a sensitivity of 78.1% (95% CI, 59.6-90.1%) and specificity of 83.3% (95% CI, 72.3-90.7%) after leave-one-out cross validation. When compared to baseline levels, the concentrations of 9 markers including granzyme A, MCP-1, IL-1β, IL-9, IL-10, IL-15, MIP-1β, ferritin and serum amyloid A changed significantly by months 2 or 6 after initiation of TB treatment, thereby indicating that they might be useful in monitoring the response to TB treatment. We have identified candidate biomarkers in saliva, which may be useful in the diagnosis of TB disease and monitoring of the response to TB treatment. These results require further validation in larger studies.
Background: Pleural tuberculosis (TB) remains difficult to diagnose despite numerous diagnostic t... more Background: Pleural tuberculosis (TB) remains difficult to diagnose despite numerous diagnostic tools. Recently, in vitro interferon (IFN)-γ-based assays have been introduced in the diagnosis of latent TB, but these techniques have not been established in the diagnosis of active TB disease, including pleural TB. Objectives: It was the aim of this study to assess the accuracy of the commercially available QuantiFERON® TB Gold assay and adapted variants of the assay, using pleural fluid or isolated pleural fluid cells for the diagnosis of pleural TB. Methods: We recruited 66 consecutive patients with a pleural effusion of unknown cause presenting at a tertiary academic health care centre in Cape Town, South Africa, a high prevalence area of TB. Blood and pleural fluid were collected at presentation for IFN-γ assays and the results evaluated for diagnostic accuracy. Results: The clinical diagnosis was TB in 30 (46%), malignancy in 20 (30%), parapneumonic effusion/empyema in 8 (12%) and effusion due to other causes in 8 patients (12%). Ex vivo pleural fluid IFN-γ levels accurately identified TB in all patients and were superior to the QuantiFERON In Tube assay using blood and pleural fluid (73 and 57% sensitivity, with 71 and 87% specificity, respectively) and the QuantiFERON Gold assay applied to isolated pleural fluid cells (100% sensitivity and 67% specificity). Conclusion: The ex vivo pleural fluid interferon-γ level is an accurate marker for the diagnosis of pleural TB, and the QuantiFERON TB Gold assay performed with peripheral blood or adapted for pleural fluid cells does not add diagnostic value.
Background: New tests are urgently needed for the diagnosis of TB disease. Serodiagnostic tests m... more Background: New tests are urgently needed for the diagnosis of TB disease. Serodiagnostic tests may be useful, as they may be easily adaptable into point-of-care tests. Aim: To evaluate the usefulness of antibody responses against novel M. tuberculosis (M.tb) antigens as tools for the diagnosis of TB disease. Methods: We prospectively collected plasma samples from individuals presenting with symptoms suggestive of TB disease at a primary health care clinic in Cape Town, South Africa. Patients were later classified as having TB or other respiratory diseases. We evaluated IgA and IgM antibody responses against seven M.tb antigens in plasma samples and assessed their diagnostic potentials by receiver operator characteristics (ROC) curve analysis. We also assessed the utility of biosignatures comprising antibodies and host inflammatory biomarkers in the diagnosis of TB disease. Results: Out of the 156 study participants, 28 (18%) were HIV infected and 26 were diagnosed with TB disease. IgA and IgM responses against single antigens including NarL, Rv3019c, and two other proteins showed potential in the diagnosis of TB disease, with area under the ROC curve (AUC) up to 0.74. A seven-antibody biosignature diagnosed TB disease with an AUC of 0.8, whereas a combination of two antibodies and five host biomarkers diagnosed TB disease with a sensitivity of 95% (CI, 73-100%) and specificity of 89% (CI, 68.7-97%). Conclusion: Although antibodies showed potential in the diagnosis of TB disease, the use of host inflammatory biomarkers in combination with antibodies may result in more accurate diagnostic tools for TB disease.
There is an urgent need for new tools for the rapid diagnosis of tuberculosis (TB) disease, and m... more There is an urgent need for new tools for the rapid diagnosis of tuberculosis (TB) disease, and monitoring of the response to TB treatment, especially in resource-poor settings. Immunodiagnostic approaches might be beneficial, especially if based on the detection of host biomarkers in easily available samples such as serum, plasma or saliva, as they may be easily adaptable into point-of-care tests. The aim of the current study was to identify such candidate biomarkers. We recruited 22 TB patients and 33 individuals with suspected TB, but in whom TB disease was ruled out, at a health centre in Cape Town, South Africa. Using a multiplex platform, we evaluated the levels of 74 host markers in plasma and saliva samples from these individuals, as candidates for the diagnosis of TB disease or monitoring of TB treatment response. The concentrations of 23 host markers detected in plasma and 5 detected in saliva diagnosed TB disease AUC ≥ 0.80. However, the optimal diagnostic biosignature was a combination of neural cell adhesion molecule (NCAM),IL-17A, thrombopoietin(TPO),complement C4 and transthyretin, which diagnosed TB disease with a sensitivity of 100% and specificity of 86% after leave-one-out cross validation. When compared to baseline levels, multiple host markers detected in plasma and saliva were significantly different between diagnosis and end of TB treatment, thereby indicating that they may be potentially useful in monitoring of TB treatment response. In conclusion, we have identified candidate host biomarkers in plasma and saliva samples, 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.
Please help us populate SUNScholar with the post print version of this article. It can be e-maile... more Please help us populate SUNScholar with the post print version of this article. It can be e-mailed to: scholar@sun.ac.zaGeneeskundePediatrie En Kindergesondhei
Background To improve tuberculosis (TB) diagnosis, the World Health Organisation (WHO) has called... more Background To improve tuberculosis (TB) diagnosis, the World Health Organisation (WHO) has called for a non-sputum based triage test to focus TB testing on people with a high likelihood of having active pulmonary tuberculosis (TB). Various host or pathogen biomarker-based testing devices are in design stage and require validity assessment. Host biomarkers have shown promise to accurately rule out active TB, but further research is required to determine generalisability. The TriageTB diagnostic test study aims to assess the accuracy of diagnostic test candidates, as well as field-test, finalise the design and biomarker signature, and validate a point-of-care multi-biomarker test (MBT). Methods This observational diagnostic study will evaluate sensitivity and specificity of biomarker-based diagnostic candidates including the MBT and Xpert® TB Fingerstick cartridge compared with a gold-standard composite TB outcome classification defined by symptoms, sputum GeneXpert® Ultra, smear and ...
IntroductionBiomarkers predicting mortality among critical Coronavirus disease 2019 (COVID-19) pa... more IntroductionBiomarkers predicting mortality among critical Coronavirus disease 2019 (COVID-19) patients provide insight into the underlying pathophysiology of fatal disease and assist with triaging of cases in overburdened settings. However, data describing these biomarkers in Sub-Saharan African populations are sparse.MethodsWe collected serum samples and corresponding clinical data from 87 patients with critical COVID-19 on day 1 of admission to the intensive care unit (ICU) of a tertiary hospital in Cape Town, South Africa, during the second wave of the COVID-19 pandemic. A second sample from the same patients was collected on day 7 of ICU admission. Patients were followed up until in-hospital death or hospital discharge. A custom-designed 52 biomarker panel was performed on the Luminex® platform. Data were analyzed for any association between biomarkers and mortality based on pre-determined functional groups, and individual analytes.ResultsOf 87 patients, 55 (63.2%) died and 32 ...
Setting: Tygerberg district, Western Cape Province, South Africa. Objective: To measure the agree... more Setting: Tygerberg district, Western Cape Province, South Africa. Objective: To measure the agreement of two interferon-gamma release assays (IGRAs) and the tuberculin skin test (TST) for the detection of Mycobacterium tuberculosis infection in human immunodeficiency virus (HIV) infected adults and children in a setting highly endemic for tuberculosis (TB). Design: Cross-sectional study. Results: In HIV-infected adults (n=20) and children (n=23), tests yielded discordant results, with 61% of individuals testing positive with T-SPOT.TB, 41% with TST and 28% with QuantiFERON TB Gold (QTF). In children, there was poor agreement between the TST and T-SPOT.TB (kappa [kappa]=-0.02), but moderate agreement between the TST and QTF (kappa=0.44). In adults, there was moderate agreement between the TST and T-SPOT.TB (kappa=0.43), and the TST and QTF (kappa = 0.46). In children and adults, there was fair agreement between the T-SPOT.TB and QTF (kappa=0.33). Twenty per cent of adults had >or=1 indeterminate IGRA results. Conclusions: There is poor to moderate agreement between the TST and IGRAs in HIV-infected adults and children. T-SPOT.TB may have improved sensitivity for detection of M. tuberculosis infection in HIV-infected individuals compared to the QTF and the TST. In HIV-infected individuals, IGRA test properties are affected by test cut-off point and nil control responses.
There is an urgent need for new tools for the rapid diagnosis of tuberculosis (TB) disease in res... more There is an urgent need for new tools for the rapid diagnosis of tuberculosis (TB) disease in resource-constrained settings. Tests based on host immunological biomarkers maybe useful, especially if based on easily available samples. We investigated host biomarkers detected in saliva samples from individuals with suspected pulmonary TB disease, as tools for the diagnosis of TB disease and monitoring of the response to treatment. We collected saliva samples from 104 individuals that presented with symptoms requiring investigation for TB disease at a primary health care clinic in the outskirts of Cape Town, South Africa, prior to assessment for TB disease. We evaluated the concentrations of 33 host markers in stored saliva samples using a multiplex cytokine platform. Using a combination of clinical, radiological and laboratory results and a pre-established diagnostic algorithm, participants were later classified as having TB disease or other respiratory diseases (ORD). The diagnostic potentials of individual analytes were analysed by the receiver operator characteristics curve approach while the predictive abilities of combinations of analytes for TB disease were analysed by general discriminant analysis, with leave-one-out cross validation. Of the 104 individuals enrolled, 32 were pulmonary TB cases. There were significant differences in the levels of 10 of the markers investigated between the patients with TB disease and those with ORDs. However, the optimal diagnostic biosignature was a seven-marker combination of salivary CRP, ferritin, serum amyloid P, MCP-1, alpha-2-macroglobulin, fibrinogen and tissue plasminogen activator. This biosignature diagnosed TB disease with a sensitivity of 78.1% (95% CI, 59.6-90.1%) and specificity of 83.3% (95% CI, 72.3-90.7%) after leave-one-out cross validation. When compared to baseline levels, the concentrations of 9 markers including granzyme A, MCP-1, IL-1β, IL-9, IL-10, IL-15, MIP-1β, ferritin and serum amyloid A changed significantly by months 2 or 6 after initiation of TB treatment, thereby indicating that they might be useful in monitoring the response to TB treatment. We have identified candidate biomarkers in saliva, which may be useful in the diagnosis of TB disease and monitoring of the response to TB treatment. These results require further validation in larger studies.
Background: Pleural tuberculosis (TB) remains difficult to diagnose despite numerous diagnostic t... more Background: Pleural tuberculosis (TB) remains difficult to diagnose despite numerous diagnostic tools. Recently, in vitro interferon (IFN)-γ-based assays have been introduced in the diagnosis of latent TB, but these techniques have not been established in the diagnosis of active TB disease, including pleural TB. Objectives: It was the aim of this study to assess the accuracy of the commercially available QuantiFERON® TB Gold assay and adapted variants of the assay, using pleural fluid or isolated pleural fluid cells for the diagnosis of pleural TB. Methods: We recruited 66 consecutive patients with a pleural effusion of unknown cause presenting at a tertiary academic health care centre in Cape Town, South Africa, a high prevalence area of TB. Blood and pleural fluid were collected at presentation for IFN-γ assays and the results evaluated for diagnostic accuracy. Results: The clinical diagnosis was TB in 30 (46%), malignancy in 20 (30%), parapneumonic effusion/empyema in 8 (12%) and effusion due to other causes in 8 patients (12%). Ex vivo pleural fluid IFN-γ levels accurately identified TB in all patients and were superior to the QuantiFERON In Tube assay using blood and pleural fluid (73 and 57% sensitivity, with 71 and 87% specificity, respectively) and the QuantiFERON Gold assay applied to isolated pleural fluid cells (100% sensitivity and 67% specificity). Conclusion: The ex vivo pleural fluid interferon-γ level is an accurate marker for the diagnosis of pleural TB, and the QuantiFERON TB Gold assay performed with peripheral blood or adapted for pleural fluid cells does not add diagnostic value.
Background: New tests are urgently needed for the diagnosis of TB disease. Serodiagnostic tests m... more Background: New tests are urgently needed for the diagnosis of TB disease. Serodiagnostic tests may be useful, as they may be easily adaptable into point-of-care tests. Aim: To evaluate the usefulness of antibody responses against novel M. tuberculosis (M.tb) antigens as tools for the diagnosis of TB disease. Methods: We prospectively collected plasma samples from individuals presenting with symptoms suggestive of TB disease at a primary health care clinic in Cape Town, South Africa. Patients were later classified as having TB or other respiratory diseases. We evaluated IgA and IgM antibody responses against seven M.tb antigens in plasma samples and assessed their diagnostic potentials by receiver operator characteristics (ROC) curve analysis. We also assessed the utility of biosignatures comprising antibodies and host inflammatory biomarkers in the diagnosis of TB disease. Results: Out of the 156 study participants, 28 (18%) were HIV infected and 26 were diagnosed with TB disease. IgA and IgM responses against single antigens including NarL, Rv3019c, and two other proteins showed potential in the diagnosis of TB disease, with area under the ROC curve (AUC) up to 0.74. A seven-antibody biosignature diagnosed TB disease with an AUC of 0.8, whereas a combination of two antibodies and five host biomarkers diagnosed TB disease with a sensitivity of 95% (CI, 73-100%) and specificity of 89% (CI, 68.7-97%). Conclusion: Although antibodies showed potential in the diagnosis of TB disease, the use of host inflammatory biomarkers in combination with antibodies may result in more accurate diagnostic tools for TB disease.
There is an urgent need for new tools for the rapid diagnosis of tuberculosis (TB) disease, and m... more There is an urgent need for new tools for the rapid diagnosis of tuberculosis (TB) disease, and monitoring of the response to TB treatment, especially in resource-poor settings. Immunodiagnostic approaches might be beneficial, especially if based on the detection of host biomarkers in easily available samples such as serum, plasma or saliva, as they may be easily adaptable into point-of-care tests. The aim of the current study was to identify such candidate biomarkers. We recruited 22 TB patients and 33 individuals with suspected TB, but in whom TB disease was ruled out, at a health centre in Cape Town, South Africa. Using a multiplex platform, we evaluated the levels of 74 host markers in plasma and saliva samples from these individuals, as candidates for the diagnosis of TB disease or monitoring of TB treatment response. The concentrations of 23 host markers detected in plasma and 5 detected in saliva diagnosed TB disease AUC ≥ 0.80. However, the optimal diagnostic biosignature was a combination of neural cell adhesion molecule (NCAM),IL-17A, thrombopoietin(TPO),complement C4 and transthyretin, which diagnosed TB disease with a sensitivity of 100% and specificity of 86% after leave-one-out cross validation. When compared to baseline levels, multiple host markers detected in plasma and saliva were significantly different between diagnosis and end of TB treatment, thereby indicating that they may be potentially useful in monitoring of TB treatment response. In conclusion, we have identified candidate host biomarkers in plasma and saliva samples, 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.
Please help us populate SUNScholar with the post print version of this article. It can be e-maile... more Please help us populate SUNScholar with the post print version of this article. It can be e-mailed to: scholar@sun.ac.zaGeneeskundePediatrie En Kindergesondhei
Background To improve tuberculosis (TB) diagnosis, the World Health Organisation (WHO) has called... more Background To improve tuberculosis (TB) diagnosis, the World Health Organisation (WHO) has called for a non-sputum based triage test to focus TB testing on people with a high likelihood of having active pulmonary tuberculosis (TB). Various host or pathogen biomarker-based testing devices are in design stage and require validity assessment. Host biomarkers have shown promise to accurately rule out active TB, but further research is required to determine generalisability. The TriageTB diagnostic test study aims to assess the accuracy of diagnostic test candidates, as well as field-test, finalise the design and biomarker signature, and validate a point-of-care multi-biomarker test (MBT). Methods This observational diagnostic study will evaluate sensitivity and specificity of biomarker-based diagnostic candidates including the MBT and Xpert® TB Fingerstick cartridge compared with a gold-standard composite TB outcome classification defined by symptoms, sputum GeneXpert® Ultra, smear and ...
IntroductionBiomarkers predicting mortality among critical Coronavirus disease 2019 (COVID-19) pa... more IntroductionBiomarkers predicting mortality among critical Coronavirus disease 2019 (COVID-19) patients provide insight into the underlying pathophysiology of fatal disease and assist with triaging of cases in overburdened settings. However, data describing these biomarkers in Sub-Saharan African populations are sparse.MethodsWe collected serum samples and corresponding clinical data from 87 patients with critical COVID-19 on day 1 of admission to the intensive care unit (ICU) of a tertiary hospital in Cape Town, South Africa, during the second wave of the COVID-19 pandemic. A second sample from the same patients was collected on day 7 of ICU admission. Patients were followed up until in-hospital death or hospital discharge. A custom-designed 52 biomarker panel was performed on the Luminex® platform. Data were analyzed for any association between biomarkers and mortality based on pre-determined functional groups, and individual analytes.ResultsOf 87 patients, 55 (63.2%) died and 32 ...
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