Publications
493 results found
Morfill C, Pankratova S, Machado P, et al., 2023, Addition to "Nanostars Carrying Multifunctional Neurotrophic Dendrimers Protect Neurons in Preclinical In Vitro Models of Neurodegenerative Disorders"., ACS Appl Mater Interfaces
Davis AG, Dreyer AJ, Albertyn C, et al., 2023, Cognitive impairment in tuberculous meningitis, Clinical Infectious Diseases, Vol: 76, Pages: 842-849, ISSN: 1058-4838
BACKGROUND: Cognitive impairment is reported as a common complication in adult tuberculous meningitis (TBM), yet few studies have systematically assessed the frequency and nature of impairment. Moreover, the impact of impairment on functioning and medication adherence is not described. METHODS: A cognitive test battery (10 measures assessing 7 cognitive domains) was administered to 34 participants with HIV-associated TBM 6 months post-diagnosis. Cognitive performance was compared to a comparator group of 66 people living with HIV (PLWH) without a history of TB. A secondary comparison was made between TBM cases and 26 participants with HIV 6-months post diagnosis of TB outside the central nervous system (CNS). Impact on functioning was evaluated, including through assessment of medication adherence. RESULTS: In TBM, 16/34 (47%) of participants had low performance on cognitive testing. Cognition was impaired across all domains. Global cognitive performance was significantly lower in TBM cases compared to PLWH (mean T-score 41 vs 48, p < 0.001). TBM cases also had lower global cognition compared to those with non-CNS TB (mean global T score 41 vs 46, p = 0.016). Functional outcomes did not significantly correlate with cognitive performance in the sub-group of participants where this was assessed (n = 19). CONCLUSIONS: Low cognitive performance following HIV-associated TBM is common. This effect is independent of, and additional to, effects of HIV and non-CNS TB disease. Further studies are needed to understand longer term outcomes, clarify the association with treatment adherence, a key predictor of outcome in TBM, and develop context-specific tools to identify individuals with cognitive difficulties to improve outcomes in TBM.
Gollnick H, Barber J, Wilkinson RJ, et al., 2023, IL-27 inhibits anti- Mycobacterium tuberculosis innate immune activity of primary human macrophages., Tuberculosis (Edinb), Vol: 139
Mycobacterium tuberculosis (M. tuberculosis) is an intracellular pathogen that primarily infects macrophages. Despite a robust anti-mycobacterial response, many times macrophages are unable to control M. tuberculosis. The purpose of this study was to investigate the mechanism by which the immunoregulatory cytokine IL-27 inhibits the anti-mycobacterial activity of primary human macrophages. We found concerted production of IL-27 and anti-mycobacterial cytokines by M. tuberculosis-infected macrophages in a toll-like receptor (TLR) dependent manner. Notably, IL-27 suppressed the production of anti-mycobacterial cytokines TNFα, IL-6, IL-1β, and IL-15 by M. tuberculosis-infected macrophages. IL-27 limits the anti-mycobacterial activity of macrophages by reducing Cyp27B, cathelicidin (LL-37), LC3B lipidation, and increasing IL-10 production. Furthermore, neutralizing both IL-27 and IL-10 increased the expression of proteins involved in LC3-associated phagocytosis (LAP) pathway for bacterial clearance, namely vacuolar-ATPase, NOX2, and RUN-domain containing protein RUBCN. These results implicate IL-27 is a prominent cytokine that impedes M. tuberculosis clearance.
Du Bruyn E, Ruzive S, Howlett P, et al., 2023, Comparison of the frequency and phenotypic profile of Mycobacterium tuberculosis-specific CD4 T cells between the site of disease and blood in pericardial tuberculosis (vol 13, 1009016, 2022), FRONTIERS IN IMMUNOLOGY, Vol: 14, ISSN: 1664-3224
Sheerin D, Lakay F, Esmail H, et al., 2023, Identification and control for the effects of bioinformatic globin depletion on human RNA-seq differential expression analysis, Scientific Reports, Vol: 13, Pages: 1-11, ISSN: 2045-2322
When profiling blood samples by RNA-sequencing (RNA-seq), RNA from haemoglobin (Hgb) can account for up to 70% of the transcriptome. Due to considerations of sequencing depth and power to detect biological variation, Hgb RNA is typically depleted prior to sequencing by hybridisation-based methods; an alternative approach is to deplete reads arising from Hgb RNA bioinformatically. In the present study, we compared the impact of these two approaches on the outcome of differential gene expression analysis performed using RNA-seq data from 58 human tuberculosis (TB) patient or contact whole blood samples-29 globin kit-depleted and 29 matched non-depleted-a subset of which were taken at TB diagnosis and at six months post-TB treatment from the same patient. Bioinformatic depletion of Hgb genes from the non-depleted samples (bioinformatic-depleted) substantially reduced library sizes (median = 57.24%) and fewer long non-coding, micro, small nuclear and small nucleolar RNAs were captured in these libraries. Profiling published TB gene signatures across all samples revealed inferior correlation between kit-depleted and bioinformatic-depleted pairs when the proportion of reads mapping to Hgb genes was higher in the non-depleted sample, particularly at the TB diagnosis time point. A set of putative "globin-fingerprint" genes were identified by directly comparing kit-depleted and bioinformatic-depleted samples at each timepoint. Two TB treatment response signatures were also shown to have decreased differential performance when comparing samples at TB diagnosis to six months post-TB treatment when profiled on the bioinformatic-depleted samples compared with their kit-depleted counterparts. These results demonstrate that failure to deplete Hgb RNA prior to sequencing has a negative impact on the sensitivity to detect disease-relevant gene expression changes even when bioinformatic removal is performed.
Davies M-A, Morden E, Rosseau P, et al., 2023, Outcomes of laboratory-confirmed SARS-CoV-2 infection during resurgence driven by Omicron lineages BA.4 and BA.5 compared with previous waves in the Western Cape Province, South Africa, International Journal of Infectious Diseases, Vol: 127, Pages: 63-68, ISSN: 1201-9712
OBJECTIVE: We aimed to compare clinical severity of Omicron BA.4/BA.5 infection with BA.1 and earlier variant infections among laboratory-confirmed SARS-CoV-2 cases in the Western Cape, South Africa, using timing of infection to infer the lineage/variant causing infection. METHODS: We included public sector patients aged ≥20 years with laboratory-confirmed COVID-19 between 1-21 May 2022 (BA.4/BA.5 wave) and equivalent prior wave periods. We compared the risk between waves of (i) death and (ii) severe hospitalization/death (all within 21 days of diagnosis) using Cox regression adjusted for demographics, comorbidities, admission pressure, vaccination and prior infection. RESULTS: Among 3,793 patients from the BA.4/BA.5 wave and 190,836 patients from previous waves the risk of severe hospitalization/death was similar in the BA.4/BA.5 and BA.1 waves (adjusted hazard ratio (aHR) 1.12; 95% confidence interval (CI) 0.93; 1.34). Both Omicron waves had lower risk of severe outcomes than previous waves. Prior infection (aHR 0.29, 95% CI 0.24; 0.36) and vaccination (aHR 0.17; 95% CI 0.07; 0.40 for at least 3 doses vs. no vaccine) were protective. CONCLUSION: Disease severity was similar amongst diagnosed COVID-19 cases in the BA.4/BA.5 and BA.1 periods in the context of growing immunity against SARS-CoV-2 due to prior infection and vaccination, both of which were strongly protective.
du Bruyn E, Stek C, Daroowala R, et al., 2023, Effects of tuberculosis and/or HIV-1 infection on COVID-19 presentation and immune response in Africa., Nat Commun, Vol: 14
Few studies from Africa have described the clinical impact of co-infections on SARS-CoV-2 infection. Here, we investigate the presentation and outcome of SARS-CoV-2 infection in an African setting of high HIV-1 and tuberculosis prevalence by an observational case cohort of SARS-CoV-2 patients. A comparator group of non SARS-CoV-2 participants is included. The study includes 104 adults with SARS-CoV-2 infection of whom 29.8% are HIV-1 co-infected. Two or more co-morbidities are present in 57.7% of participants, including HIV-1 (30%) and active tuberculosis (14%). Amongst patients dually infected by tuberculosis and SARS-CoV-2, clinical features can be typical of either SARS-CoV-2 or tuberculosis: lymphopenia is exacerbated, and some markers of inflammation (D-dimer and ferritin) are further elevated (p < 0.05). Amongst HIV-1 co-infected participants those with low CD4 percentage strata exhibit reduced total, but not neutralising, anti-SARS-CoV-2 antibodies. SARS-CoV-2 specific CD8 T cell responses are present in 35.8% participants overall but undetectable in combined HIV-1 and tuberculosis. Death occurred in 30/104 (29%) of all COVID-19 patients and in 6/15 (40%) of patients with coincident SARS-CoV-2 and tuberculosis. This shows that in a high incidence setting, tuberculosis is a common co-morbidity in patients admitted to hospital with COVID-19. The immune response to SARS-CoV-2 is adversely affected by co-existent HIV-1 and tuberculosis.
Moseki RM, Barber DL, Du Bruyn E, et al., 2023, Phenotypic profile of Mycobacterium tuberculosis-specific CD4 T-cell responses in people with advanced human immunodeficiency virus who develop tuberculosis-associated immune reconstitution inflammatory syndrome, Open Forum Infectious Diseases, Vol: 10, Pages: 1-10, ISSN: 2328-8957
BACKGROUND: Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a frequent complication of cotreatment for TB and human immunodeficiency virus (HIV)-1. We characterized Mycobacterium tuberculosis (Mtb)-specific CD4 T-cell phenotype and transcription factor profile associated with the development of TB-IRIS. METHODS: We examined the role of CD4 T-cell transcription factors in a murine model of mycobacterial IRIS. In humans, we used a longitudinal study design to compare the magnitude of antiretroviral therapy, activation, transcription factor profile, and cytotoxic potential of Mtb-specific CD4 T cells between TB-IRIS (n = 25) and appropriate non-IRIS control patients (n = 18) using flow cytometry. RESULTS: In the murine model, CD4 T-cell expression of Eomesodermin (Eomes), but not Tbet, was associated with experimentally induced IRIS. In patients, TB-IRIS onset was associated with the expansion of Mtb-specific IFNγ+CD4 T cells (P = .039). Patients with TB-IRIS had higher HLA-DR expression (P = .016), but no differences in the expression of T-bet or Eomes were observed. At TB-IRIS onset, Eomes+Tbet+Mtb-specific IFNγ+CD4+ T cells showed higher expression of granzyme B in patients with TB-IRIS (P = .026). CONCLUSIONS: Although the murine model of Mycobacterium avium complex-IRIS suggests that Eomes+CD4 T cells underly IRIS, TB-IRIS was not associated with Eomes expression in patients. Mycobacterium tuberculosis-specific IFNγ+CD4 T-cell responses in TB-IRIS patients are differentiated, highly activated, and potentially cytotoxic.
Davis AG, Wasserman S, Stek C, et al., 2022, A phase 2A trial of the safety and tolerability of increased dose rifampicin and adjunctive linezolid, with or without aspirin, for human immunodeficiency virus-associated tuberculous meningitis: the LASER-TBM trial, Clinical Infectious Diseases, ISSN: 1058-4838
Background:Drug regimens that include intensified antibiotics alongside effective anti-inflammatory therapies may improve outcomes in tuberculous meningitis (TBM). Safety data on their use in combination and in the context of human immunodeficiency virus (HIV) are needed to inform clinical trial design.Methods:We conducted a phase 2, open-label, parallel-design, randomized, controlled trial to assess the safety of high-dose rifampicin, linezolid, and high-dose aspirin in HIV-associated TBM. Participants were randomized (1.4:1:1) to 3 treatment arms (1, standard of care [SOC]; 2, SOC + additional rifampicin [up to 35 mg/kg/d] + linezolid 1200 mg/d reducing after 28 days to 600 mg/d; 3, as per arm 2 + aspirin 1000 mg/d) for 56 days, when the primary outcome of adverse events of special interest (AESI) or death was assessed.Results:A total of 52 participants with HIV-associated TBM were randomized; 59% had mild disease (British Medical Research Council (MRC) grade 1) vs 39% (grade 2) vs 2% (grade 3). AESI or death occurred in 10 of 16 (63%; arm 3) vs 4 of 14 (29%; arm 2) vs 6 of 20 (30%; arm 1; P = .083). The cumulative proportion of AESI or death (Kaplan–Meier) demonstrated worse outcomes in arm 3 vs arm 1 (P = .04); however, only 1 event in arm 3 was attributable to aspirin and was mild. There was no difference in efficacy (modified Rankin scale) between arms.Conclusions:High-dose rifampicin and adjunctive linezolid can safely be added to the standard of care in HIV-associated TBM. Larger studies are required to determine whether potential toxicity associated with these interventions, particularly high-dose aspirin, is outweighed by mortality or morbidity benefit.Clinical Trials Registration:NCT03927313.
Meier S, Seddon JA, Maasdorp E, et al., 2022, Neutrophil degranulation, NETosis and platelet degranulation pathway genes are co-induced in whole blood up to six months before tuberculosis diagnosis, PLoS One, Vol: 17, ISSN: 1932-6203
Mycobacterium tuberculosis (M.tb) causes tuberculosis (TB) and remains one of the leading causes of mortality due to an infectious pathogen. Host immune responses have been implicated in driving the progression from infection to severe lung disease. We analyzed longitudinal RNA sequencing (RNAseq) data from the whole blood of 74 TB progressors whose samples were grouped into four six-month intervals preceding diagnosis (the GC6-74 study). We additionally analyzed RNAseq data from an independent cohort of 90 TB patients with positron emission tomography-computed tomography (PET-CT) scan results which were used to categorize them into groups with high and low levels of lung damage (the Catalysis TB Biomarker study). These groups were compared to non-TB controls to obtain a complete whole blood transcriptional profile for individuals spanning from early stages of M.tb infection to TB diagnosis. The results revealed a steady increase in the number of genes that were differentially expressed in progressors at time points closer to diagnosis with 278 genes at 13-18 months, 742 at 7-12 months and 5,131 detected 1-6 months before diagnosis and 9,205 detected in TB patients. A total of 2,144 differentially expressed genes were detected when comparing TB patients with high and low levels of lung damage. There was a large overlap in the genes upregulated in progressors 1-6 months before diagnosis (86%) with those in TB patients. A comprehensive pathway analysis revealed a potent activation of neutrophil and platelet mediated defenses including neutrophil and platelet degranulation, and NET formation at both time points. These pathways were also enriched in TB patients with high levels of lung damage compared to those with low. These findings suggest that neutrophils and platelets play a critical role in TB pathogenesis, and provide details of the timing of specific effector mechanisms that may contribute to TB lung pathology.
Abdelgawad N, Chirehwa M, Schutz C, et al., 2022, Pharmacokinetics of antitubercular drugs in patients hospitalized with HIV-associated tuberculosis: a population modeling analysis, Wellcome Open Research, Vol: 7, Pages: 72-72
<ns4:p>Background.</ns4:p><ns4:p> Early mortality among hospitalized HIV-associated tuberculosis (TB/HIV) patients is high despite treatment. The pharmacokinetics of rifampicin, isoniazid, and pyrazinamide were investigated in hospitalized TB/HIV patients and a cohort of outpatients with TB (with or without HIV) to determine whether drug exposures differed between groups.</ns4:p><ns4:p> Methods.</ns4:p><ns4:p> Standard first-line TB treatment was given daily as per national guidelines, which consisted of oral 4-drug fixed-dose combination tablets containing 150 mg rifampicin, 75 mg isoniazid, 400 mg pyrazinamide, and 275 mg ethambutol. Plasma samples were drawn on the 3rd day of treatment over eight hours post-dose. Rifampicin, isoniazid, and pyrazinamide in plasma were quantified and NONMEM<ns4:sup>®</ns4:sup> was used to analyze the data.</ns4:p><ns4:p> Results.</ns4:p><ns4:p> Data from 60 hospitalized patients (11 of whom died within 12 weeks of starting treatment) and 48 outpatients were available. Median (range) weight and age were 56 (35 - 88) kg, and 37 (19 - 77) years, respectively. Bioavailability and clearance of the three drugs were similar between TB/HIV hospitalized and TB outpatients. However, rifampicin’s absorption was slower in hospitalized patients than in outpatients; mean absorption time was 49.9% and 154% more in hospitalized survivors and hospitalized deaths, respectively, than in outpatients. Higher levels of conjugated bilirubin correlated with lower rifampicin clearance. Isoniazid’s clearance estimates were 25.5 L/h for fast metabolizers and 9.76 L/h for slow metabolizers. Pyrazinamide’s clearance was more variable among hospitalized patients. The variability in clearance among patients was 1.70 and 3.56 times more for hospitalized survivors and hospitalized deaths, respectively, than outpatients. </ns4:p><ns4:p> Conclu
Du Bruyn E, Ruzive S, Howlett P, et al., 2022, Comparison of the frequency and phenotypic profile of Mycobacterium tuberculosis-specific CD4 T cells between the site of disease and blood in pericardial tuberculosis, Frontiers in Immunology, Vol: 13, Pages: 1-13, ISSN: 1664-3224
Studies of the immune response at the site of disease in extra-pulmonary tuberculosis (EPTB) disease are scarce. In this study, we compared the cellular profile of Mycobacterium tuberculosis (Mtb)-specific T cells in pericardial fluid and peripheral blood in patients with pericardial TB (PCTB). Whole blood and pericardial fluid (PCF) samples were collected at the time of diagnostic sampling, with repeat blood sampling after completion of anti-tubercular treatment (ATT) in 16 PCTB patients, most of them being HIV-1 infected (n=14). These samples were stimulated ex vivo and the phenotypic and functional cellular profile of PCF and blood was assessed by flow cytometry. We found that lymphocytes were the predominant cell type in PCF in PCTB, with a preferential influx of CD4 T cells. The frequencies of TNF-α producing Mtb-specific granulocytes and Mtb-specific CD4 T cells were significantly higher in PCF compared to blood. Mtb-specific CD4 T cells in PCF exhibited a distinct phenotype compared to those in blood, with greater GrB expression and lower CD27 and KLRG1 expression. We observed no difference in the production IFNγ, TNF or IL-2 by Mtb-specific CD4 T cells between the two compartments, but MIP-1β production was lower in the PCF T cells. Bacterial loads were not associated with alterations in the phenotype or function of Mtb-specific CD4 T cells. Upon ATT completion, HLA-DR, Ki-67 and GrB expression was significantly decreased, and relative IL-2 production was increased in peripheral Mtb-specific CD4 T cells. Overall, using an ex vivo assay to compare the immune response towards Mtb in PCF and in blood, we identified significant difference in the phenotypic profile of Mtb-specific CD4 T response between these two compartments. Moreover, we show that the activation profile of peripheral Mtb-specific CD4 T cells could be used to monitor treatment response in PCTB.
Maitre T, Bonnet M, Calmy A, et al., 2022, Intensified tuberculosis treatment to reduce the mortality of HIV-infected and uninfected patients with tuberculosis meningitis (INTENSE-TBM): study protocol for a phase III randomized controlled trial, TRIALS, Vol: 23
Thungana Y, Wilkinson R, Zingela Z, 2022, Comorbidity of mental ill-health in tuberculosis patients under treatment in a rural province of South Africa: a cross-sectional survey, BMJ OPEN, Vol: 12, ISSN: 2044-6055
Fendler A, Shepherd STC, Au L, et al., 2022, Functional immune responses against SARS-CoV-2 variants of concern after fourth COVID-19 vaccine dose or infection in patients with blood cancer, Cell Reports Medicine, Vol: 3, ISSN: 2666-3791
Patients with blood cancer continue to have a greater risk of inadequate immune responses following three COVID-19 vaccine doses and risk of severe COVID-19 disease. In the context of the CAPTURE study (NCT03226886), we report immune responses in 80 patients with blood cancer who received a fourth dose of BNT162b2. We measured neutralizing antibody titers (NAbTs) using a live virus microneutralization assay against wild-type (WT), Delta, and Omicron BA.1 and BA.2 and T cell responses against WT and Omicron BA.1 using an activation-induced marker (AIM) assay. The proportion of patients with detectable NAb titers and T cell responses after the fourth vaccine dose increased compared with that after the third vaccine dose. Patients who received B cell-depleting therapies within the 12 months before vaccination have the greatest risk of not having detectable NAbT. In addition, we report immune responses in 57 patients with breakthrough infections after vaccination.
Morfill C, Pankratova S, Machado P, et al., 2022, Nanostars Carrying Multifunctional Neurotrophic Dendrimers Protect Neurons in Preclinical In Vitro Models of Neurodegenerative Disorders, ACS APPLIED MATERIALS & INTERFACES, Vol: 14, Pages: 47445-47460, ISSN: 1944-8244
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Wouters E, Stek C, Swartz A, et al., 2022, Prednisone for the prevention of tuberculosis-associated IRIS (randomized controlled trial): Impact on the health-related quality of life, Frontiers in Psychology, Vol: 13, ISSN: 1664-1078
Background: Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is an important complication in patients with HIV-associated tuberculosis (TB) starting antiretroviral treatment (ART) in sub-Saharan Africa. The PredART-trial recently showed that prophylactic prednisone reduces the incidence of paradoxical TB-IRIS by 30% in a population at high risk. This paper reports the impact of the intervention on health-related quality of life (HRQoL), a secondary endpoint of the trial, measured by an amended version of the PROQOL-HIV instrument—the instrument’s validity and reliability is also assessed.Methods: A total of 240 adult participants (antiretroviral treatment (ART)-naïve, TB-HIV co-infected with CD4 count ≤100 cells/μL) were recruited and randomized (1:1) to (1) a prednisone arm or (2) a placebo arm. In this sub-study of the PredART-trial we evaluated (1) the performance of an HIV-specific HR-QoL instrument amended for TB-IRIS, i.e., the PROQOL-HIV/TB in patients with HIV-associated TB starting ART (reliability, internal and external construct validity and invariance across time) and (2) the impact of prednisone on self-reported HR-QoL in this population through mixed models.Results: The PROQOL-HIV/TB scale displayed acceptable internal reliability and good internal and external validity. This instrument, including the factor structure with the eight sub-dimensions, can thus be applied for measuring HR-QoL among HIV-TB patients at high risk for TB-IRIS. Prophylactic prednisone was statistically significantly associated only with the ‘Physical Health and Symptoms’-subscale: a four-week course of prednisone resulted in an earlier improvement in the physical dimension of HR-QoL compared to placebo.Conclusion: We demonstrated that the PROQOL-HIV/TB scale adequately measures different aspects of self-reported HR-QoL in HIV-TB patients. Although more research is needed to understand how other domains related to H
Fowler PW, Barilar I, Battaglia S, et al., 2022, Epidemiological cut-off values for a 96-well broth microdilution plate for high-throughput research antibiotic susceptibility testing of M. tuberculosis, EUROPEAN RESPIRATORY JOURNAL, Vol: 60, ISSN: 0903-1936
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Spies R, Schutz C, Ward A, et al., 2022, Rifampicin resistance and mortality in patients hospitalised with HIV-associated tuberculosis, Southern African Journal of HIV Medicine, Vol: 23, ISSN: 1608-9693
Background: Patients with HIV and drug-resistant tuberculosis (TB) are at high risk of death. Objectives: We investigated the association between rifampicin-resistant TB (RR-TB) and mortality in a cohort of patients who were admitted to hospital at the time of TB diagnosis. Method: Adults hospitalised at Khayelitsha Hospital and diagnosed with HIV-associated TB during admission, were enrolled between 2013 and 2016. Clinical, biochemical and microbiological data were prospectively collected and participants were followed up for 12 weeks. Results: Participants with microbiologically confirmed TB (n = 482) were enrolled a median of two days (interquartile range [IQR]: 1-3 days) following admission. Fifty-three participants (11.0%) had RR-TB. Participants with rifampicin-susceptible TB (RS-TB) received appropriate treatment a median of one day (IQR: 1-2 days) following enrolment compared to three days (IQR: 1-9 days) in participants with RR-TB. Eight participants with RS-TB (1.9%) and six participants with RR-TB (11.3%) died prior to the initiation of appropriate treatment. Mortality at 12 weeks was 87/429 (20.3%) in the RS-TB group and 21/53 (39.6%) in the RR-TB group. RR-TB was a significant predictor of 12-week mortality (hazard ratio: 1.88; 95% confidence interval: 1.07-3.29; P = 0.03). Conclusion: Mortality at 12 weeks in participants with RR-TB was high compared to participants with RS-TB. Delays in the initiation of appropriate treatment and poorer regimen efficacy are proposed as contributors to higher mortality in hospitalised patients with HIV and RR-TB.
Amaral E, Foreman TW, Namasivayam S, et al., 2022, GPX4 regulates cellular necrosis and host resistance in Mycobacterium tuberculosis infection, Journal of Experimental Medicine, Vol: 219, ISSN: 0022-1007
Cellular necrosis during Mycobacterium tuberculosis (Mtb) infection promotes both immunopathology and bacterial dissemination. Glutathione peroxidase-4 (Gpx4) is an enzyme that plays a critical role in preventing iron-dependent lipid peroxidation–mediated cell death (ferroptosis), a process previously implicated in the necrotic pathology seen in Mtb-infected mice. Here, we document altered GPX4 expression, glutathione levels, and lipid peroxidation in patients with active tuberculosis and assess the role of this pathway in mice genetically deficient in or overexpressing Gpx4. We found that Gpx4-deficient mice infected with Mtb display substantially increased lung necrosis and bacterial burdens, while transgenic mice overexpressing the enzyme show decreased bacterial loads and necrosis. Moreover, Gpx4-deficient macrophages exhibited enhanced necrosis upon Mtb infection in vitro, an outcome suppressed by the lipid peroxidation inhibitor, ferrostatin-1. These findings provide support for the role of ferroptosis in Mtb-induced necrosis and implicate the Gpx4/GSH axis as a target for host-directed therapy of tuberculosis.
del Rosario RCH, Poschmann J, Lim C, et al., 2022, Histone acetylome-wide associations in immune cells from individuals with active Mycobacterium tuberculosis infection (vol 7, pg 312, 2022), NATURE MICROBIOLOGY, Vol: 7, Pages: 1943-1943, ISSN: 2058-5276
Hussey H, Davies M-A, Heekes A, et al., 2022, Higher mortality associated with the SARS-CoV-2 Delta variant in the Western Cape, South Africa, using RdRp target delay as a proxy: a cross-sectional study., Gates Open Research, Vol: 6, Pages: 1-10, ISSN: 2572-4754
Background: The SARS-CoV-2 Delta variant (B.1.617.2) has been associated with more severe disease, particularly when compared to the Alpha variant. Most of this data, however, is from high income countries and less is understood about the variant’s disease severity in other settings, particularly in an African context, and when compared to the Beta variant.Methods: A novel proxy marker, RNA-dependent RNA polymerase (RdRp) target delay in the Seegene AllplexTM 2019-nCoV (polymerase chain reaction) PCR assay, was used to identify suspected Delta variant infection in routine laboratory data. All cases diagnosed on this assay in the public sector in the Western Cape, South Africa, from 1 April to 31 July 2021, were included in the dataset provided by the Western Cape Provincial Health Data Centre (PHDC). The PHDC collates information on all COVID-19 related laboratory tests, hospital admissions and deaths for the province. Odds ratios for the association between the proxy marker and death were calculated, adjusted for prior diagnosed infection and vaccination status.Results: A total of 11,355 cases with 700 deaths were included in this study. RdRp target delay (suspected Delta variant) was associated with higher mortality (adjusted odds ratio [aOR] 1.45; 95% confidence interval [CI]: 1.13-1.86), compared to presumptive Beta infection. Prior diagnosed infection during the previous COVID-19 wave, which was driven by the Beta variant, was protective (aOR 0.32; 95%CI: 0.11-0.92) as was vaccination (aOR [95%CI] 0.15 [0.03-0.62] for complete vaccination [≥28 days post a single dose of Ad26.COV2.S or ≥14 days post second BNT162b2 dose]).Conclusion: RdRp target delay, a proxy for infection with the Delta variant, is associated with an increased risk of mortality amongst those who were tested for COVID-19 in our setting.
Makatsa MS, Omondi FMA, Bunjun R, et al., 2022, Characterization of Mycobacterium tuberculosis-Specific Th22 Cells and the Effect of Tuberculosis Disease and HIV Coinfection, JOURNAL OF IMMUNOLOGY, Vol: 209, Pages: 446-455, ISSN: 0022-1767
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Moseki RM, Barber DL, Bruyn ED, et al., 2022, Phenotypic profile of <i>Mycobacterium tuberculosis</i>-specific CD4 T cell responses in HIV-positive patients who develop Tuberculosis-associated Immune Reconstitution Inflammatory Syndrome
<jats:title>ABSTRACT</jats:title><jats:sec><jats:title>Background</jats:title><jats:p>Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a frequent complication of co-treatment for TB and HIV-1. We characterized Mtb-specific CD4 T cell phenotype and transcription factor profile associated with the development of TB-IRIS.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>We examined the role of CD4 T-cell transcription factors in a murine model of mycobacterial IRIS. In humans, we compared longitudinally on antiretroviral therapy (ART) the magnitude, activation, transcription factor profile and cytotoxic potential of Mtb-specific CD4 T cells between TB-IRIS (n=25) and appropriate non-IRIS control patients (n=18) using flow cytometry.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>In the murine model, CD4 T cell expression of Eomes, but not Tbet, was associated with experimentally induced IRIS. In patients, TB-IRIS onset was associated with the expansion of Mtb-specific IFNγ+CD4 T cells (p=0.039). TB-IRIS patients had higher HLA-DR expression (p=0.016), but no differences in the expression of T-bet or Eomes were observed. At TB-IRIS onset, Eomes+Tbet+Mtb-specific IFNγ+CD4+ T cells showed higher expression of Granzyme B in TB-IRIS patients (p=0.026).</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>While the murine model of MAC-IRIS suggests that Eomes+CD4 T cells underly IRIS, TB-IRIS was not associated with Eomes expression in patients. Mtb-specific IFNγ+CD4 T cell responses in TB-IRIS patients are differentiated, highly activated and potentially cytotoxic.</jats:p></jats:sec>
Fowler PW, Wright C, Spiers H, et al., 2022, A crowd of BashTheBug volunteers reproducibly and accurately measure the minimum inhibitory concentrations of 13 antitubercular drugs from photographs of 96-well broth microdilution plates, eLife, Vol: 11, ISSN: 2050-084X
Tuberculosis is a respiratory disease that is treatable with antibiotics. An increasing prevalence of resistance means that to ensure a good treatment outcome it is desirable to test the susceptibility of each infection to different antibiotics. Conventionally, this is done by culturing a clinical sample and then exposing aliquots to a panel of antibiotics, each being present at a pre-determined concentration, thereby determining if the sample isresistant or susceptible to each sample. The minimum inhibitory concentration (MIC) of a drug is the lowestconcentration that inhibits growth and is a more useful quantity but requires each sample to be tested at a range ofconcentrations for each drug. Using 96-well broth micro dilution plates with each well containing a lyophilised pre-determined amount of an antibiotic is a convenient and cost-effective way to measure the MICs of several drugs at once for a clinical sample. Although accurate, this is still an expensive and slow process that requires highly-skilled and experienced laboratory scientists. Here we show that, through the BashTheBug project hosted on the Zooniverse citizen science platform, a crowd of volunteers can reproducibly and accurately determine the MICs for 13 drugs and that simply taking the median or mode of 11-17 independent classifications is sufficient. There is therefore a potential role for crowds to support (but not supplant) the role of experts in antibiotic susceptibility testing.
Davies M-A, Morden E, Rosseau P, et al., 2022, Outcomes of laboratory-confirmed SARS-CoV-2 infection during resurgence driven by Omicron lineages BA.4 and BA.5 compared with previous waves in the Western Cape Province, South Africa., Publisher: PubMedCentral
Objective: We aimed to compare clinical severity of Omicron BA.4/BA.5 infection with BA.1 and earlier variant infections among laboratory-confirmed SARS-CoV-2 cases in the Western Cape, South Africa, using timing of infection to infer the lineage/variant causing infection. Methods: We included public sector patients aged ≥20 years with laboratory-confirmed COVID-19 between 1-21 May 2022 (BA.4/BA.5 wave) and equivalent prior wave periods. We compared the risk between waves of (i) death and (ii) severe hospitalization/death (all within 21 days of diagnosis) using Cox regression adjusted for demographics, comorbidities, admission pressure, vaccination and prior infection. Results: Among 3,793 patients from the BA.4/BA.5 wave and 190,836 patients from previous waves the risk of severe hospitalization/death was similar in the BA.4/BA.5 and BA.1 waves (adjusted hazard ratio [aHR] 1.12; 95% confidence interval [CI] 0.93; 1.34). Both Omicron waves had lower risk of severe outcomes than previous waves. Prior infection (aHR 0.29, 95% CI 0.24; 0.36) and vaccination (aHR 0.17; 95% CI 0.07; 0.40 for boosted vs. no vaccine) were protective. Conclusion: Disease severity was similar amongst diagnosed COVID-19 cases in the BA.4/BA.5 and BA.1 periods in the context of growing immunity against SARS-CoV-2 due to prior infection and vaccination, both of which were strongly protective.
Ariza-Vioque E, Ello F, Andriamamonjisoa H, et al., 2022, Capacity building in Sub-Saharan Africa as part of the INTENSE-TBM Project during the COVID-19 pandemic, Infectious Diseases and Therapy, Vol: 11, Pages: 1327-1341, ISSN: 2193-8229
Tuberculous meningitis (TBM) is the most severe and disabling form of tuberculosis (TB), with at least 100,000 cases per year and a mortality rate of up to 50% in individuals co-infected with human immunodeficiency virus type 1 (HIV-1). To evaluate the efficacy and safety of an intensified anti-tubercular regimen and an anti-inflammatory treatment, the INTENSE-TBM project includes a phase III randomised clinical trial (TBM-RCT) in four countries in sub-Saharan Africa (SSA). Within this framework, we designed a comprehensive capacity-building work package ensuring all centres had, or would acquire, the ability to conduct the TBM-RCT and developing a network of skilled researchers, clinical centres and microbiology laboratories. Here, we describe these activities, identify strengths/challenges and share tools adaptable to other projects, particularly in low- and lower-middle income countries with heterogeneous settings and during the coronavirus disease 2019 (COVID-19) pandemic. Despite major challenges, TBM-RCT initiation was achieved in all sites, promoting enhanced local healthcare systems and encouraging further clinical research in SSA. In terms of certified trainings, the achievement levels were 95% (124/131) for good clinical practice, 91% (39/43) for good clinical laboratory practice and 91% (48/53) for infection prevention and control. Platform-based research, developed as part of capacity-building activities for specific projects, may be a valuable tool in fighting future infectious diseases and in developing high-level research in Africa.
Davies M-A, Kassanjee R, Rousseau P, et al., 2022, Outcomes of laboratory-confirmed SARS-CoV-2 infection in the Omicron-driven fourth wave compared with previous waves in the Western Cape Province, South Africa., Tropical medicine & international health : TM & IH, Vol: 27, Pages: 564-573, ISSN: 1360-2276
<h4>Objectives</h4>The objective was to compare COVID-19 outcomes in the Omicron-driven fourth wave with prior waves in the Western Cape, assess the contribution of undiagnosed prior infection to differences in outcomes in a context of high seroprevalence due to prior infection and determine whether protection against severe disease conferred by prior infection and/or vaccination was maintained.<h4>Methods</h4>In this cohort study, we included public sector patients aged ≥20 years with a laboratory-confirmed COVID-19 diagnosis between 14 November and 11 December 2021 (wave four) and equivalent prior wave periods. We compared the risk between waves of the following outcomes using Cox regression: death, severe hospitalisation or death and any hospitalisation or death (all ≤14 days after diagnosis) adjusted for age, sex, comorbidities, geography, vaccination and prior infection.<h4>Results</h4>We included 5144 patients from wave four and 11,609 from prior waves. The risk of all outcomes was lower in wave four compared to the Delta-driven wave three (adjusted hazard ratio (aHR) [95% confidence interval (CI)] for death 0.27 [0.19; 0.38]. Risk reduction was lower when adjusting for vaccination and prior diagnosed infection (aHR: 0.41, 95% CI: 0.29; 0.59) and reduced further when accounting for unascertained prior infections (aHR: 0.72). Vaccine protection was maintained in wave four (aHR for outcome of death: 0.24; 95% CI: 0.10; 0.58).<h4>Conclusions</h4>In the Omicron-driven wave, severe COVID-19 outcomes were reduced mostly due to protection conferred by prior infection and/or vaccination, but intrinsically reduced virulence may account for a modest reduction in risk of severe hospitalisation or death compared to the Delta-driven wave.
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Boloko L, Schutz C, Sibiya N, et al., 2022, Xpert Ultra testing of blood in severe HIV-associated tuberculosis to detect and measure Mycobacterium tuberculosis blood stream infection: a diagnostic and disease biomarker cohort study, The Lancet Microbe, Vol: 3, ISSN: 2666-5247
BACKGROUND: Mycobacterium tuberculosis bloodstream infection is a leading cause of death in people living with HIV and disseminated bacillary load might be a key driver of disease severity. We aimed to assess Xpert MTB/RIF Ultra (Xpert Ultra) testing of blood as a diagnostic for M tuberculosis bloodstream infection and investigate cycle threshold as a quantitative disease biomarker. METHODS: In this cohort study, we obtained biobanked blood samples from a large and well characterised cohort of adult patients admitted to hospital in Western Cape, South Africa with suspected HIV-associated tuberculosis and a CD4 count less than 350 cells per μL. Patients already receiving antituberculosis therapy were excluded. Samples were obtained on recruitment within 72 h of admission to hospital, and patients were followed up for 12 weeks to determine survival. We tested the biobanked blood samples using the Xpert Ultra platform after lysis and wash processing of the blood. We assessed diagnostic yield (proportion of cases detected, with unavailable test results coded as negative) against a microbiological reference, both as a function of markers of critical-illness and compared with other rapid diagnostics (urine lipoarabinomannan and sputum Xpert). Quantitative blood Xpert Ultra results were evaluated as a disease biomarker by assessing association with disease phenotype defined by principal component analysis of 32 host-response markers. Prognostic value compared to other tuberculosis biomarkers was assessed using likelihood ratio testing of nested models predicting 12-week mortality. FINDINGS: Between Jan 16, 2014, and Oct 19, 2016, of the 659 participants recruited to the parent study, 582 had an available biobanked blood sample. 447 (77%) of 582 met the microbiological reference standard for tuberculosis diagnosis. Median CD4 count was 62 (IQR 221-33) cells per μL, and 123 (21%) of participants died by 12-weeks follow-up. Blood Xpert Ultra was positive in 165 (37%) of
Hussey H, Davies M-A, Heekes A, et al., 2022, Assessing the clinical severity of the Omicron variant in the Western Cape Province, South Africa, using the diagnostic PCR proxy marker of RdRp target delay to distinguish between Omicron and Delta infections - a survival analysis, International Journal of Infectious Diseases, Vol: 118, Pages: 150-154, ISSN: 1201-9712
BACKGROUND: The extent to which the reduced risk of severe disease seen with SARS-CoV-2 Omicron is due to a decrease in variant virulence, or higher levels of population immunity, is currently not clear. METHODS: RdRp target delay (RTD) in the Seegene AllplexTM 2019-nCoV PCR assay is a proxy marker for the Delta variant. The absence of this proxy marker in the transition period was used to identify suspected Omicron infections. Cox regression was performed for the outcome of hospital admission in those who tested positive for SARS-CoV-2 on the Seegene AllplexTM assay from 1 November to 14 December 2021 in the Western Cape Province, South Africa, public sector. Vaccination status and prior diagnosed infection, were adjusted for. RESULTS: 150 cases with RTD and 1486 cases without RTD were included. Cases without RTD had a lower hazard of admission (adjusted Hazard Ratio [aHR] of 0.56, 95%CI 0.34-0.91). Complete vaccination was protective of admission with an aHR of 0.45 (95%CI 0.26-0.77). CONCLUSION: Omicron has resulted in a lower risk of hospital admission, compared to contemporaneous Delta infection, when using the proxy marker of RTD. Under-ascertainment of reinfections with an immune escape variant remains a challenge to accurately assessing variant virulence.
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