Search

Background The present study aimed to evaluate the diagnostic utility of creatine kinase-MB (CK-MB), hepcidin (HEPC), phospholipase A2 group IIA (PLa2G2A), and myosin-binding protein C (MYBPC1) for tuberculosis (TB). These four biomarkers are differentially regulated between quiescent Mycobacterium tuberculosis (Mtb) infected individuals (non-progressors to TB disease) and Mtb-infected TB disease progressors 6 months before the onset of symptoms. Methods We enrolled samples from patients experiencing moderate-to-severe pulmonary infections diseases including 23 TB cases confirmed by smear microscopy and culture, and 34 TB-negative cases. For each participant, the serum levels of the four biomarkers were measured using ELISA. Results The levels of CK-MB and HEPC were significantly reduced in patients with active TB disease. CK-MB median level was 2045 pg/ml (1455–4000 pg/ml) in active TB cases and 3245 pg/ml (1645–4000 pg/ml) in non-TB pulmonary diseases. Using the receiver operating characteristic curve (ROC) analysis, HEPC and CK-MB had the Area Under the Curve (AUC) of 79% (95% CI 67–91%) and 81% (95% CI 69–93%), respectively. Both markers correlated with TB diagnosis as a single marker. PLa2G2A and MYBPC1 with AUCs of 48% (95% CI 36–65%) and 62% (95% CI 48–76%) did not performed well as single biomarkers. The three markers’model (CK-MB-HEPC-PLa2G2A) had the highest diagnostic accuracy at 82% (95% CI 56–82%) after cross-validation. Conclusion CK-MB and HEPC levels were statistically different between confirmed TB cases and non-TB cases. This study yields promising results for the rapid diagnosis of TB disease using a single marker or three biomarkers model.

In a context where SARS-CoV-2 population-wide testing is implemented, clinical features and antibody response in those infected have never been documented in Africa. Yet, the information provided by analyzing data from population-wide testing is critical to understand the infection dynamics and devise control strategies. We described clinical features and assessed antibody response in people screened for SARS-CoV-2 infection. We analyzed data from a cohort of 3464 people that we molecularly screened for SARS-CoV-2 infection in our routine activity. We recorded people SARS-CoV-2 diagnosis, age, gender, blood types, white blood cells (WBC), symptoms, chronic disease status and time to SARS-CoV-2 RT-PCR conversion from positive to negative. We calculated the age-based distribution of SARS-CoV-2 infection, analyzed the proportion and the spectrum of COVID-19 severity. Furthermore, in a nested sub-study, we screened 83 COVID-19 patients and 319 contact-cases for anti-SARS-CoV-2 antibodies. Males and females accounted for respectively 51% and 49% of people screened. The studied population median and mean age were both 39 years. 592 out of 3464 people (17.2%) were diagnosed with SARS-CoV-2 infection with males and females representing, respectively, 53% and 47%. The median and mean ages of SARS-CoV-2 infected subjects were 37 and 38 years respectively. The lowest rate of infection (8%) was observed in the elderly (aged > 60). The rate of SARS-Cov-2 infection in both young (18–35 years old) and middle-aged adults (36–60 years old) was around 20%. The analysis of SARS-CoV-2 infection age distribution showed that middle-aged adults accounted for 54.7% of SARS-CoV-2 positive persons, followed respectively by young adults (33.7%), children (7.7%) and elderly (3.8%). 68% (N = 402) of SARS-CoV-2 infected persons were asymptomatic, 26.3% (N = 156) had influenza-like symptoms, 2.7% (N = 16) had influenza-like symptoms associated with anosmia and ageusia, 2% (N = 11) had dyspnea and 1% (N = 7) had respiratory failure, which resulted in death. Data also showed that 12% of SARS-CoV-2 infected subjects, had chronic diseases. Hypertension, diabetes, and asthma were the top concurrent chronic diseases representing respectively 58%, 25% and 12% of recorded chronic diseases. Half of SARS-CoV-2 RT-PCR positive patients were cured within 14 days following the initiation of the anti-COVID-19 treatment protocol. 78.3% of COVID-19 patients and 55% of SARS-CoV-2 RT-PCR confirmed negative contact-cases were positive for anti-SARS-CoV-2 antibodies. Patients with severe-to-critical illness have higher leukocytes, higher neutrophils and lower lymphocyte counts contrarily to asymptomatic patients and patients with mild-to-moderate illness. Neutrophilic leukopenia was more prevalent in asymptomatic patients and patients with mild-to-moderate disease for 4 weeks after diagnosis (27.1–42.1%). In Patients with severe-to-critical illness, neutrophilic leukocytosis or neutrophilia (35.6–50%) and lymphocytopenia (20–40%) were more frequent. More than 60% of participants were blood type O. It is also important to note that infection rate was slightly higher among A and B blood types compared with type O. In this African setting, young and middle-aged adults are most likely driving community transmission of COVID-19. The rate of critical disease is relatively low. The high rate of anti-SARS-CoV-2 antibodies observed in SARS-CoV-2 RT-PCR negative contact cases suggests that subclinical infection may have been overlooked in our setting.

Objective: Circulating levels of sex hormones vary with age. Moreover, there is emerging evidence supporting that sex hormones have an influence on the immune response of women. Here, we investigated age-associated levels of sex hormones and Mycobacterium tuberculosis (Mtb) specific cytokines response in women. Design: Using immunoassay methods, we have measured and compared secretion levels of E2, P4 and Mtb specific secretion of 11 cytokines including Granulocyte-macrophage colony-stimulating factor (GM-CSF), Interferon gamma (IFN-γ), Interleukin 1 beta (IL-1β), IL-10, IL-12 (p70), IL-2, IL-4, IL-5, IL-6, IL-8, and Tumor necrosis factor (TNF-α) in forty-two (42) HIV-negative females. Results: Estradiol (E2) and progesterone (P4) levels were significantly higher in younger women irrespective of their LTB status (p Mtb IL-8 specific response was significantly higher in women above 40 years old than in women under 40 years old. Conclusion: In premenopausal women, there is an increase in the pro-inflammatory cytokine IL-8 secretion in response to Mtb-antigen. This observation suggests an underlying link between the pro-inflammatory cytokine and age associated hormonal changes, which may have implications on the course of tuberculosis infection women.

Background A recombinant vesicular stomatitis virus vector expressing the Zaire Ebola virus glycoprotein (rVSV Delta G-ZEBOV-GP) vaccine has been reported as safe, immunogenic, and highly protective in a ring vaccination trial. We aimed to identify transcriptomic immune response biomarker signatures induced by vaccination and associated signatures with its immunogenicity and reactogenicity to better understand the potential mechanisms of action of the vaccine.Methods 354 healthy adult volunteers were vaccinated in randomised, double-blind, placebo-controlled trials in Europe (Geneva, Switzerland [November, 2014, to January, 2015]) and North America (USA [Dec 5, 2014, to June 23, 2015]), and dose-escalation trials in Africa (Lambarene, Gabon [November, 2014, to January, 2015], and Kilifi, Kenya [December, 2014, to January, 2015]) using different doses of the recombinant vesicular stomatitis virus vector expressing the Zaire Ebola virus glycoprotein (rVSV Delta G-ZEBOV-GP; 3x 10(5) to 1 x 10(8) plaque-forming units [pfu]). Longitudinal transcriptomic responses (days 0, 1, 2, 3, 7, 14, and 28) were measured in whole blood using a targeted gene expression profiling platform (dual-colour reverse-transcriptase multiplex ligation-dependent probe amplification) focusing on 144 immune-related genes. The effect of time and dose on transcriptomic response was also assessed. Logistic regression with lasso regularisation was applied to identify host signatures with optimal discriminatory capability of vaccination at day 1 or day 7 versus baseline, whereas random-effects models and recursive feature elimination combined with regularised logistic regression were used to associate signatures with immunogenicity and reactogenicity.Findings Our results indicated that perturbation of gene expression peaked on day 1 and returned to baseline levels between day 7 and day 28. The magnitude of the response was dose-dependent, with vaccinees receiving a high dose (>= 9x 10(6) pfu) of rVSV Delta G-ZEBOV-GP exhibiting the largest amplitude. The most differentially expressed genes that were significantly upregulated following vaccination consisted of type I and II interferon-related genes and myeloid cell-associated markers, whereas T cell, natural killer cell, and cytotoxicity-associated genes were downregulated. A gene signature associated with immunogenicity (common to all four cohorts) was identified correlating gene expression profiles with ZEBOV-GP antibody titres and a gene signatures associated with reactogenicity (Geneva cohort) was identified correlating gene expression profiles with an adverse event (ie, arthritis).Interpretation Collectively, our results identify and cross-validate immune-related transcriptomic signatures induced by rVSV Delta G-ZEBOV-GP vaccination in four cohorts of adult participants from different genetic and geographical backgrounds. These signatures will aid in the rational development, testing, and evaluation of novel vaccines and will allow evaluation of the effect of host factors such as age, co-infection, and comorbidity on responses to vaccines. Copyright (C) 2021 The Author(s). Published by Elsevier Ltd.

HIV-exposed uninfected infants (HEU) represent a growing population in developing countries including Gabon. Several studies have shown the vulnerability of these infants toward infectious diseases. The aim of the study was to contribute to the global effort to understand how HIVexposure or anti retroviral therapy affects infants’ blood elements. We assessed HEU infants’ complete blood count using a blood analyzer instrument. Our investigations showed that among the observed clinically relevant hematological abnormalities events, thrombocytosis was the most prevalent clinically relevant hematological abnormality associated with HEU infants’. We showed that HEU infants had significantly higher platelets count than HUinfants. Therefore, higher level of platelets seems to characterize HEU infants when compared to HU infants.

Tuberculosis (TB) is the leading cause of death due to an infectious agent, but only a small fraction of those infected develop the disease. Cytokines are involved in the mediation and regulation of immunity, and their secretion patterns may reflect the infection status. To increase our understanding of immune response to M. tuberculosis infection, we conducted a cross-sectional study investigating M. tuberculosis infection status and comparing the release profiles of cytokines GM-CSF, IFN-γ, IL-1β, IL-10, IL-12 (p70), IL-2, IL-4, IL-5, IL-6, IL-8, TNF-α, in community controls (CCs) and healthy healthcare workers (HCWs) highly exposed to TB. Among HCWs and CCs, the probability of latent M. tuberculosis (LTB+) infection was respectively 5.4 (p = 0.002) and 3.4 (p = 0.006) times higher in men than women. The odds ratio of LTB infection was 4 times higher among HCWs in direct contact with active TB patients than other HCW (p = 0.01). Whole blood supernatant cytokine responses to M. tuberculosis antigens showed differential pro-inflammatory responses between HCWs and CCs. CCsLTB− had higher IL-1β responses than HCWsLTB− (p = 0.002). HCWsLTB+ had significantly higher IL-8 responses to M. tuberculosis antigens than HCWsLTB− (p = 0.003) and CCsLTB− (p = 0.015). HCWsLTB+/− showed weak but positive TNF-α responses to M. tuberculosis antigen stimulation compared to CCsLTB+/− (p ≤ 0.015). Looking at T-helper (1 and 2) responses, HCWsLTB+ and CCsLTB+ had significantly higher IFN-γ and IL-2 responses compared to HCWsLTB− and CCsLTB− (p LTB+ and CCsLTB+ than in non-infected CCsLTB− (p M. tuberculosis antigen specific responses in HCWsLTB+ varied based on active TB exposure gradient. HCWsLTB+ who were highly exposed to active TB (≥3 hours per day) had significantly higher IFN-γ and IL-8 responses (p ≤ 0.02) than HCWs LTB+ not in direct contact with active TB patients. HCWsLTB+ working with active TB patients for 5 to 31 years had a significantly enhanced secretion of proinflammatory cytokines (GM-CSF, IFN-γ, IL-1β, IL-2, IL-6, IL-8, IL-12p70, TNF-α) compared to HCWsLTB− (p LTB+ than HCWsLTB−. In conclusion, LTBI individuals controlling the M. tuberculosis infection have an enhanced TB specific Th1-cytokines/proinflammatory response combined with selected Th2 type/anti-inflammatory cytokines induction.

Pathogen sensing and recognition through pattern recognition receptors, and subsequent production of pro-inflammatory cytokines, is the cornerstone of the innate immune system. Despite the fact that HIV-exposed uninfected (HEU) infants are prone to serious bacterial infections, no study has focused on the functionality of their bacteria recognition system. This is the first study to investigate baseline levels of three critically important immune response molecules in this population: complement component (C)-3, toll-like receptor (TLR)-4, and C-reactive protein (CRP). We enrolled 16 HEU and 6 HIV-unexposed (HU) infants. TLR4 function was investigated by stimulating whole blood with increasing concentrations of TLR4-agonist ultrapure lipopolysaccharides. TLR4/TLR4-agonist dose response were assessed by measuring IL-6 secretion. Complement C3 and CRP were measured by photo spectrometry. Data showed no significant differences in baseline concentration of CRP between HEU and HU infants. Complement C3 was significantly higher in HEU infants than HU infants. TLR4 anergy was observed in 7 of 12 HEU infants, whereas the rest of HEU infants (n = 4) and the control HU infants tested (n = 3) showed responsive TLR4. None of the HEU infants investigated in this study had severe infections in the year after their birth. In conclusion, TLR4 anergy can occur in HEU infants without necessarily translating to increased vulnerability to infectious diseases.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

An increased risk of serious bacterial infections in HIV exposed uninfected (HEU) infants has been demonstrated. Although neutrophils are essential for the protection of infants against bacterial infections, no study has investigated their profile in HEU infants to date. In this study, we assessed the function of neutrophils in HEU infants using the Nitroblue tetrazolium (NBT) reduction test. Among 25 HEU infants, 9 (36%) showed a reduced ability of their neutrophils to produce Reactive Oxygen Species (ROS) upon stimulation with bacteria. No alteration of total neutrophil counts was noted in the blood of HEU infants indicating that the alteration observed in the 36% of HEU infants may only be functional. Conclusively, impaired neutrophil function could be a factor of vulnerability in HEU infants.

Background: Diagnosis and treatment monitoring of patients with tuberculosis remain challenging. Objective: We have evaluated whether Mycobacterium-specific interferon (IFN)-γ and interleukin (IL)-2 bifunctional cytokine immune response assays improve the diagnosis of and correlate to treatment response in pulmonary tuberculosis. Methods: Early secretory antigenic target (ESAT)6/culture filtrate protein 10 (CFP10), microsomal triglyceride transfer protein 65 (MTP65) and the purified protein derivative (PPD) tuberculin-specific immune profiles were investigated in peripheral blood mononuclear cells from 19 patients with culture-confirmed tuberculosis and 23 healthy community controls (HCCs; 82.6% with latent M. tuberculosis infection) using a novel fluorescence-based dual-colour enzyme-linked immunospot (EliSpot) technology (FluoroSpot). Results: The frequency of ESAT6/CFP10-induced IFN-γ+IL-2- producing cells was elevated (p < 0.001), whereas the percentages of specific IFN-γ-IL-2+ (p = 0.002) and IFN-γ+IL-2+ double producing cells (p = 0.037) were diminished in tuberculosis patients in comparison to HCCs. A 3-host marker model using a combination of those IFN-γ and IL-2 single-cell responses showed 93.8% sensitivity and 77.8% specificity for tuberculosis. During tuberculosis treatment, the PPD-induced immune responses shifted from an IFN-γ+IL-2- dominated profile towards a balance of IFN-γ-IL-2+ and IFN-γ+IL-2+ double producing cells (all p ≤ 0.05). Conclusions: The addition of antigen-specific IL-2 production to IFN-γ responses by EliSpot in IFN-γ release assays increases diagnostic sensitivity for active tuberculosis.

Background Confirming tuberculosis (TB) disease in suspects in resource limited settings is challenging and calls for the development of more suitable diagnostic tools. Different Mycobacterium tuberculosis (M.tb) infection phase-dependent antigens may be differentially recognized in infected and diseased individuals and therefore useful as diagnostic tools for differentiating between M.tb infection states. In this study, we assessed the diagnostic potential of 118 different M.tb infection phase-dependent antigens in TB patients and household contacts (HHCs) in a high-burden setting. Methods Antigens were evaluated using the 7-day whole blood culture technique in 23 pulmonary TB patients and in 19 to 21 HHCs (total n = 101), who were recruited from a high-TB incidence community in Cape Town, South Africa. Interferon-gamma (IFN-γ) levels in culture supernatants were determined by ELISA. Results Eight classical TB vaccine candidate antigens, 51 DosR regulon encoded antigens, 23 TB reactivation antigens, 5 TB resuscitation promoting factors (rpfs), 6 starvation and 24 other stress response-associated TB antigens were evaluated in the study. The most promising antigens for ascertaining active TB were the rpfs (Rv0867c, Rv2389c, Rv2450c, Rv1009 and Rv1884c), with Areas under the receiver operating characteristics curves (AUCs) between 0.72 and 0.80. A combination of M.tb specific ESAT-6/CFP-10 fusion protein, Rv2624c and Rv0867c accurately predicted 73% of the TB patients and 80% of the non-TB cases after cross validation. Conclusions IFN-γ responses to TB rpfs show promise as TB diagnostic candidates and should be evaluated further for discrimination between M.tb infection states.

Background: Recent interferon gamma (IFN-gamma)-based studies have identified novel Mycobacterium tuberculosis (M.tb) infection phase-dependent antigens as diagnostic candidates. In this study, the levels of 11 host markers other than IFN-gamma, were evaluated in whole blood culture supernatants after stimulation with M.tb infection phase-dependent antigens, for the diagnosis of TB disease. Methodology and Principal Findings: Five M.tb infection phase-dependent antigens, comprising of three DosR-regulon-encoded proteins (Rv2032, Rv0081, Rv1737c), and two resucitation promoting factors (Rv0867c and Rv2389c), were evaluated in a case-control study with 15 pulmonary TB patients and 15 household contacts that were recruited from a high TB incidence setting in Cape Town, South Africa. After a 7-day whole blood culture, supernatants were harvested and the levels of the host markers evaluated using the Luminex platform. Multiple antigen-specific host markers were identified with promising diagnostic potential. Rv0081-specific levels of IL-12(p40), IP-10, IL-10 and TNF-alpha were the most promising diagnostic candidates, each ascertaining TB disease with an accuracy of 100%, 95% confidence interval for the area under the receiver operating characteristics plots, (1.0 to 1.0). Conclusions: Multiple cytokines other than IFN-gamma in whole blood culture supernatants after stimulation with M.tb infection phase-dependent antigens show promise as diagnostic markers for active TB. These preliminary findings should be verified in well-designed diagnostic studies employing short-term culture assays.