Browsing by Author "Dockrell, Hazel M."

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    Diagnostic accuracy of the Cepheid 3-gene host response fingerstick blood test in a prospective, multi-site study: interim results
    (Clinical Infectious Diseases, 2021) Sutherland, Jayne S.; Spuy, Gian van der; Gindeh, Awa; Thuong, Nguyen Thuy; Namuganga, AnnRitah; Owolabi, Olumuyiwa; Mayanja-Kizza, Harriet; Nsereko, Mary; Thwaites, Guy; Winter, Jill; Dockrell, Hazel M.; Scriba, Thomas J.; Geluk, Annemieke; Corstjens, Paul; Stanley, Kim; Richardson, Tracy; Shaw, Jane A.; Smith, Bronwyn; Walzl, Gerhard
    The development of a fast and accurate, non-sputum-based point-of-care triage test for tuberculosis (TB) would have a major impact on combating the TB burden worldwide. A new fingerstick blood test has been developed by Cepheid (the Xpert-MTB-Host Response (HR)-Prototype), which generates a ‘TB score’ based on mRNA expression of 3 genes. Here we describe the first prospective findings of the MTB-HR prototype.
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    Evaluation of cytokine responses against novel Mtb antigens as diagnostic markers for TB disease
    (Journal of Infection, 2016) Awoniyi, Dolapo O.; Teuchert, Andrea; Sutherland, Jayne S.; Mayanja-Kizza, Harriet; Howe, Rawleigh; Mihret, Adane; Loxton, Andre G.; Sheehama, Jacob; Kassa, Desta; Crampin, Amelia C.; Dockrell, Hazel M.; Kidd, Martin; Rosenkrands, Ida; Geluk, Annemieke; Ottenhoff, Tom H.M.; Chegou, Novel N.; Walzl, Gerhard
    We investigated the accuracy of host markers detected in Mtb antigenstimulated whole blood culture supernatant in the diagnosis of TB. Methods: Prospectively, blood from 322 individuals with presumed TB disease from six African sites was stimulated with four different Mtb antigens (Rv0081, Rv1284, ESAT-6/CFP-10, and Rv2034) in a 24 h whole blood stimulation assay (WBA). The concentrations of 42 host markers in the supernatants were measured using the Luminex multiplex platform. Diagnostic biosignatures were investigated through the use of multivariate analysis techniques. Results: 17% of the participants were HIV infected, 106 had active TB disease and in 216 TB was excluded. Unstimulated concentrations of CRP, SAA, ferritin and IP-10 had better discriminating ability than markers from stimulated samples. Accuracy of marker combinations by general discriminant analysis (GDA) identified a six analyte model with 77% accuracy for TB cases and 84% for non TB cases, with a better performance in HIV uninfected patients. Conclusions: A biosignature of 6 cytokines obtained after stimulation with four Mtb antigens has moderate potential as a diagnostic tool for pulmonary TB disease individuals and stimulated marker expression had no added value to unstimulated marker performance.
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    Impact of Co-Infections and BCG Immunisation on Immune Responses among Household Contacts of Tuberculosis Patients in a Ugandan Cohort
    (PLoS ONE, 2014) Biraro, Irene A.; Egesa, Moses; Toulza, Frederic; Levin, Jonathan; Cose, Stephen; Joloba, Moses; Smith, Steven; Dockrell, Hazel M.; Katamba, Achilles; Elliott, Alison M.
    Tuberculosis incidence in resource poor countries remains high. We hypothesized that immune modulating co-infections such as helminths, malaria, and HIV increase susceptibility to latent tuberculosis infection (LTBI), thereby contributing to maintaining the tuberculosis epidemic. Methods: Adults with sputum-positive tuberculosis (index cases) and their eligible household contacts (HHCs) were recruited to a cohort study between May 2011 and January 2012. HHCs were investigated for helminths, malaria, and HIV at enrolment. HHCs were tested using the QuantiFERON-TB Gold In-Tube (QFN) assay at enrolment and six months later. Overnight whole blood culture supernatants from baseline QFN assays were analyzed for cytokine responses using an 11- plex Luminex assay. Associations between outcomes (LTBI or cytokine responses) and exposures (co-infections and other risk factors) were examined using multivariable logistic and linear regression models. Results: We enrolled 101 index cases and 291 HHCs. Among HHCs, baseline prevalence of helminths was 9% (25/291), malaria 16% (47/291), HIV 6% (16/291), and LTBI 65% (179/277). Adjusting for other risk factors and household clustering, there was no association between LTBI and any co-infection at baseline or at six months: adjusted odds ratio (95% confidence interval (CI); p-value) at baseline for any helminth, 1.01 (0.39–2.66; 0.96); hookworm, 2.81 (0.56–14.14; 0.20); malaria, 1.06 (0.48–2.35; 0.87); HIV, 0.74 (0.22–2.47; 0.63). HHCs with LTBI had elevated cytokine responses to tuberculosis antigens but co-infections had little effect on cytokine responses. Exploring other risk factors, Th1 cytokines among LTBIpositive HHCs with BCG scars were greatly reduced compared to those without scars: (adjusted geometric mean ratio) IFNc 0.20 (0.09–0.42), ,0.0001; IL-2 0.34 (0.20–0.59), ,0.0001; and TNFa 0.36 (0.16–0.79), 0.01. Conclusions: We found no evidence that co-infections increase the risk of LTBI, or influence the cytokine response profile among those with LTBI. Prior BCG exposure may reduce Th1 cytokine responses in LTBI.
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    The impact of maternal infection with Mycobacterium tuberculosis on the infant response to bacille Calmette–Gue´rin immunization
    (Philosophical Transactions of the Royal Society B: Biological Sciences, 2015) Mawa, Patrice A.; Nkurunungi, Gyaviira; Egesa, Moses; Webb, Emily L.; Smith, Steven G.; Kizindo, Robert; Akello, Mirriam; Lule, Swaib A.; Muwanga, Moses; Dockrell, Hazel M.; Cose, Stephen; Elliott, Alison M.
    Bacille Calmette–Gue´rin (BCG) immunization provides variable protection against tuberculosis. Prenatal antigen exposure may have lifelong effects on responses to related antigens and pathogens. We therefore hypothesized that maternal latent Mycobacterium tuberculosis infection (LTBI) influences infant responses to BCG immunization at birth. We measured antibody (n ¼ 53) and cellular (n ¼ 31) responses to M. tuberculosis purified protein derivative (PPD) in infants of mothers with and without LTBI, in cord blood and at one and six weeks after BCG. The concentrations of PPD-specific antibodies declined between birth (median [interquartile range (IQR)]) 5600 ng ml21 [3300–11 050] in cord blood) and sixweeks (0.00 ng ml21 [0–288]). Frequencies of PPD-specific IFN-g-expressing CD4þT cells increased at one week and declined between one and six weeks ( p ¼ 0.031). Frequencies of IL-2- and TNF-a-expressing PPD-specific CD4þT cells increased between one and six weeks ( p ¼ 0.019, p ¼ 0.009, respectively). At one week, the frequency of PPD-specific CD4þT cells expressing any of the three cytokines, combined, was lower among infants of mothers with LTBI, in crude analyses ( p ¼ 0.002) and after adjusting for confounders (mean difference, 95% CI 20.041% (20.082, 20.001)). In conclusion, maternal LTBI was associated with lower infant anti-mycobacterial T-cell responses immediately following BCGimmunization. These findings are being explored further in a larger study.
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    The Use of Interferon Gamma Inducible Protein 10 as a Potential Biomarker in the Diagnosis of Latent Tuberculosis Infection in Uganda
    (PLoS ONE, 2016) Biraro, Irene Andia; Kimuda, Simon; Egesa, Moses; Cose, Stephen; Webb, Emily L.; Joloba, Moses; Smith, Steven G.; Elliott, Alison M.; Dockrell, Hazel M.; Katamba, Achilles
    In the absence of a gold standard for the diagnosis of latent tuberculosis (TB) infection (LTBI), the current tests available for the diagnosis of LTBI are limited by their inability to differentiate between LTBI and active TB disease. We investigated IP-10 as a potential biomarker for LTBI among household contacts exposed to sputum positive active TB cases. Methods Active TB cases and contacts were recruited into a cohort with six months’ follow-up. Contacts were tested for LTBI using QuantiFERON1-TB Gold In-Tube (QFN) assay and the tuberculin skin test (TST). Baseline supernatants from the QFN assay of 237 contacts and 102 active TB cases were analysed for Mycobacterium tuberculosis (MTB) specific and mitogen specific IP-10 responses. Results Contacts with LTBI (QFN+TST+) had the highest MTB specific IP-10 responses at baseline, compared to uninfected contacts (QFN-TST-) p<0.0001; and active cases, p = 0.01. Using a cut-off of 8,239 pg/ml, MTB specific IP-10 was able to diagnose LTBI with a sensitivity of 87.1% (95% CI, 76.2–94.3) and specificity of 90.9%(95% CI, 81.3–96.6). MTB specific to mitogen specific IP-10 ratio was higher in HIV negative active TB cases, compared to HIV negative latently infected contacts, p = 0.0004. Concentrations of MTB specific IP-10 were higher in contacts with TST conversion (negative at baseline, positive at 6-months) than in those that were persistently TST negative, p = 0.001. Conclusion IP-10 performed well in differentiating contacts with either latent or active TB from those who were uninfected but was not able to differentiate LTBI from active disease except when MTB specific to mitogen specific ratios were used in HIV negative adults. In addition, IP-10 had the potential to diagnose ‘recent TB infection’ in persons classified as having LTBI using the TST. Such individuals with strong IP-10 responses would likely benefit from chemoprophylaxis.