Post-tuberculosis respiratory impairment in Gambian children and adolescents: A cross-sectional analysis.

BACKGROUND: Although post-tuberculosis lung disease (PTLD) is a known consequence of pulmonary tuberculosis (pTB), few studies have reported the prevalence and spectrum of PTLD in children and adolescents. METHODS: Children and adolescent (≤19 years) survivors of pTB in the Western Regions of The Gambia underwent a respiratory symptom screening, chest X-ray (CXR) and spirometry at TB treatment completion. Variables associated with lung function impairment were identified through logistic regression models. RESULTS: Between March 2022 and July 2023, 79 participants were recruited. The median age was 15.6 years (IQR: 11.8, 17.9); the majority, 53/79 (67.1%), were treated for bacteriologically confirmed pTB, and 8/79 (10.1%) were children and adolescents living with HIV. At pTB treatment completion, 28/79 (35.4%) reported respiratory symptoms, 37/78 (47.4%) had radiological sequelae, and 45/79 (57.0%) had abnormal spirometry. The most common respiratory sequelae were cough (21/79, 26.6%), fibrosis on CXR (22/78, 28.2%), and restrictive spirometry (41/79, 51.9%). Age at TB diagnosis over ten years, undernutrition and fibrosis on CXR at treatment completion were significantly associated with abnormal spirometry (p = .050, .004, and .038, respectively). CONCLUSION: Chronic respiratory symptoms, abnormal CXR, and impaired lung function are common and under-reported consequences of pTB in children and adolescents. Post-TB evaluation and monitoring may be necessary to improve patient outcomes.

Acetic Acid Enables Molecular Enumeration of Mycobacterium tuberculosis from Sputum and Eliminates the Need for a Biosafety Level 3 Laboratory.

BACKGROUND: Improved monitoring of Mycobacterium tuberculosis response to treatment is urgently required. We previously developed the molecular bacterial load assay (MBLA), but it is challenging to integrate into the clinical diagnostic laboratory due to a labor-intensive protocol required at biosafety level 3 (BSL-3). A modified assay was needed. METHODS: The rapid enumeration and diagnostic for tuberculosis (READ-TB) assay was developed. Acetic acid was tested and compared to 4 M guanidine thiocyanate to be simultaneously bactericidal and preserve mycobacterial RNA. The extraction was based on silica column technology and incorporated low-cost reagents: 3 M sodium acetate and ethanol for the RNA extraction to replace phenol-chloroform. READ-TB was fully validated and compared directly to the MBLA using sputa collected from individuals with tuberculosis. RESULTS: Acetic acid was bactericidal to M. tuberculosis with no significant loss in 16S rRNA or an unprotected mRNA fragment when sputum was stored in acetic acid at 25°C for 2 weeks or -20°C for 1 year. This novel use of acetic acid allows processing of sputum for READ-TB at biosafety level 2 (BSL-2) on sample receipt. READ-TB is semiautomated and rapid. READ-TB correlated with the MBLA when 85 human sputum samples were directly compared (R2 = 0.74). CONCLUSIONS: READ-TB is an improved version of the MBLA and is available to be adopted by clinical microbiology laboratories as a tool for tuberculosis treatment monitoring. READ-TB will have a particular impact in low- and middle-income countries (LMICs) for laboratories with no BSL-3 laboratory and for clinical trials testing new combinations of anti-tuberculosis drugs.

Childhood TB sequel: evaluating respiratory function after treatment for pulmonary tuberculosis in a prospective cohort of Gambian children - a study protocol.

BACKGROUND: 1.2 million children under 15 years are estimated to have developed tuberculosis (TB) in 2021. 85% of paediatric patients achieve successful treatment outcomes if treated for the first episode of TB. However, despite so-called successful treatment, TB leaves many survivors with permanently destroyed or damaged lungs. Data from prospective paediatric cohorts to establish the burden and evolution of post-TB lung disease (PTLD) are still absent. The Childhood TB Sequel study aims to describe respiratory consequences associated with pulmonary TB in Gambian children, describe the evolution of these sequelae, and determine associated epidemiological risk factors. METHODS: We aim to recruit up to 80 subjects aged 19 years and below who have recently completed treatment for pulmonary TB. Recruitment started in April 2022 and is expected to continue until June 2024. Clinical assessment, chest X-ray, and comprehensive lung function assessment are carried out at treatment completion and again six and 12 months later. DISCUSSION: The Childhood TB Sequel study will address existing research gaps to enhance our knowledge and understanding of the burden of PTLD in Gambian children. The study will also contribute to formulating a plan for post-TB evaluation and long-term follow-up strategies. TRIAL REGISTRATION: ClinicalTrials.gov: NCT05325125, April 13, 2022.

Contribution of school meals to the recommended nutrient and energy intake of children enrolled in the National Homegrown School Feeding Program in Zaria, Nigeria.

BACKGROUND: A poor nutritional status in children results in reduced physical and mental health and poor academic performance. The National Homegrown School Feeding Program (NHSFP) was introduced in Nigeria in 2016 to ameliorate short-term hunger and improve the nutritional status of school-aged children (SAC). At least 33% of the recommended nutrient intake (RNI) for the enrolled students should be met by the school meals. However, to our knowledge, the contribution of school meals served through the NHSFP to the RNI of SAC in Zaria, Nigeria, remains to be explored. METHODS: We conducted a school-based cross-sectional study among 276 eligible SAC recruited from public primary schools in the Zaria Local Government Area. Portion sizes of the meals served through the NHSFP were determined using an electronic scale, meal samples were collected for nutrient analysis, and the average daily nutrient intake of the participants from the meals was calculated. The average daily intake of nutrients and energy of the participants was compared with the age- and sex-specific RNI to estimate the percentage contribution of the meals. RESULTS: The portion sizes recorded were 199.3 ± 20.6 g, 263.9 ± 11.5 g, 242.1 ± 16.8 g, 311 ± 17.3 g, and 160.3 ± 1.9 mL, respectively, for moi-moi, jollof rice and beans, bean porridge, jollof rice and boiled egg, and yoghurt. In addition, the meals contained moisture (30.13-66.11%), ash (0.73-7.08%), crude fat (9-32.61%), crude protein (7.25-24.5%), crude fiber (0-2.45%), and total carbohydrate (2.19-29.74%) with an energy content ranging from 183.6 to 330.57 kcal. Similarly, the meals contained calcium (82.58-711 mg), potassium (133-797 mg), sodium (340-1720 mg), iron (0.078-8.60 mg), zinc (1.84-13.4 mg), vitamin A (2.38-100.56 RAE), and vitamin C (0.04-1.57 mg) per 100 g of the school meals. The meals contributed 18.2-19.1%, 102.8-183.7%, 13.04-13.6%, and 26.1%-35.8% of the RNI for carbohydrates, proteins, fiber, and energy, respectively. Furthermore, they contributed 137-175%, 314.3-502.2%, 87.6-142.1%, 21.5-25.1%, 279.2-348.5%, 3.3-5.9%, 24.7-48.8%, and 3.3-5.9% of the RNI for iron, zinc, calcium, potassium, sodium, vitamin A, and vitamin C, respectively. CONCLUSION: The meals served through the NHSFP contributed at least 33% of the RNI for energy, protein, iron, calcium, sodium, vitamin A, and zinc. However, they could not meet the 33% of the RNI for carbohydrates, fiber, potassium, and vitamin C. Increasing the portion sizes and the diversity of the meals can address the suboptimal contribution of the meals to the RNI for carbohydrates, fiber, potassium, and vitamin C.

Exhaled Mycobacterium tuberculosis Predicts Incident Infection in Household Contacts.

BACKGROUND: Halting transmission of Mycobacterium tuberculosis (Mtb) by identifying infectious individuals early is key to eradicating tuberculosis (TB). Here we evaluate face mask sampling as a tool for stratifying the infection risk of individuals with pulmonary TB (PTB) to their household contacts. METHODS: Forty-six sputum-positive PTB patients in The Gambia (August 2016-November 2017) consented to mask sampling prior to commencing treatment. Incident Mtb infection was defined in 181 of their 217 household contacts as QuantiFERON conversion or an increase in interferon-γ of ≥1 IU/mL, 6 months after index diagnosis. Multilevel mixed-effects logistical regression analysis with cluster adjustment by household was used to identify predictors of incident infection. RESULTS: Mtb was detected in 91% of PTB mask samples with high variation in IS6110 copies (5.3 × 102 to 1.2 × 107). A high mask Mtb level (≥20 000 IS6110 copies) was observed in 45% of cases and was independently associated with increased likelihood of incident Mtb infection in contacts (adjusted odds ratio, 3.20 [95% confidence interval, 1.26-8.12]; P = .01), compared with cases having low-positive/negative mask Mtb levels. Mask Mtb level was a better predictor of incident Mtb infection than sputum bacillary load, chest radiographic characteristics, or sleeping proximity. CONCLUSIONS: Mask sampling offers a sensitive and noninvasive tool to support the stratification of individuals who are most infectious in high-TB-burden settings. Our approach can provide better insight into community transmission in complex environments.

Reduced lung function and health-related quality of life after treatment for pulmonary tuberculosis in Gambian children: a cross-sectional comparative study.

BACKGROUND: Post-tuberculosis (post-TB) lung disease is an under-recognised consequence of pulmonary tuberculosis (pTB). We aimed to estimate the prevalence of residual lung function impairment and reduced health-related quality of life (HRQoL) in children after pTB treatment completion. METHODS: We conducted a cross-sectional comparative study of children aged less than 15 years at TB diagnosis who had completed treatment for pTB at least 6 months previously with a comparator group of age-matched children without a history of pTB. Symptoms, spirometry and HRQoL measured with PedsQL scale were collected. Variables associated with lung function impairment were identified through logistic regression models. RESULTS: We enrolled 68 post-TB cases (median age 8.9 (IQR 7.2-11.2) years) and 91 children in the comparison group (11.5 (8.0-13.7) years). Spirometry from 52 (76.5%) post-TB cases and 89 (94.5%) of the comparison group met the quality criteria for acceptability and repeatability. Lung function impairment was present in 20/52 (38.5%) post-TB cases and 15/86 (17.4%) in the comparison group, p=0.009. Previous pTB and a history of chronic cough were significantly associated with the presence of lung function impairment (p=0.047 and 0.006 respectively). Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC z-scores were significantly lower in the post-TB cases compared with the comparison group (p= <0.001, 0.014 and <0.001, respectively). The distribution of the self-reported physical health score, and parent-reported physical, emotional, psychological, social and total HRQoL scores were significantly lower in the post-TB cases compared with the comparison group. CONCLUSIONS: Previous TB in children is associated with significantly impaired lung function and HRQoL.

The impact of prior SARS-CoV-2 infection on host inflammatory cytokine profiles in patients with TB or other respiratory diseases.

Background: Tuberculosis (TB) and COVID-19 are the two leading causes of infectious disease mortality worldwide, and their overlap is likely frequent and inevitable. Previous research has shown increased mortality in TB/COVID-coinfected individuals, and emerging evidence suggests that COVID-19 may increase susceptibility to TB. However, the immunological mechanisms underlying these interactions remain unclear. In this study, we aimed to elucidate the impact of prior or concurrent COVID-19 infection on immune profiles of TB patients and those with other respiratory diseases (ORD). Methods: Serum and nasopharyngeal samples were collected from 161 Gambian adolescents and adults with either TB or an ORD. Concurrent COVID-19 infection was determined by PCR, while prior COVID-19 was defined by antibody seropositivity. Multiplex cytokine immunoassays were used to quantify 27 cytokines and chemokines in patient serum samples at baseline, and throughout treatment in TB patients. Results: Strikingly, TB and ORD patients with prior COVID-19 infection were found to have significantly reduced expression of several cytokines, including IL-1ß, TNF-α and IL-7, compared to those without (p<0.035). Moreover, at month-six of anti-TB treatment, seropositive patients had lower serum Basic FGF (p=0.0115), IL-1ß (p=0.0326) and IL-8 (p=0.0021) than seronegative. TB patients with acute COVID-19 coinfection had lower levels of IL-8, IL-13, TNF-α and IP-10 than TB-only patients, though these trends did not reach significance (p>0.035). Conclusions: Our findings demonstrate that COVID-19 infection alters the subsequent response to TB and ORDs, potentially contributing to pathogenesis. Further work is necessary to determine whether COVID-19 infection accelerates TB disease progression, though our results experimentally support this hypothesis.

Tuberculosis and Sexual and Reproductive Health of Women in Four African Countries.

Tuberculosis (TB) is a major reason of maternal mortality in low-income countries, and it increases the probability of adverse sexual and reproductive health (SRH) outcomes, including ectopic pregnancy and perinatal mortality. The data presented here is from the TB Sequel observational cohort conducted in four African countries. For this sub-study, we selected only female participants, who were diagnosed with drug susceptible TB and followed-up until the end of anti-TB treatment. The data collection included questionnaires, clinical examination and laboratory tests at TB diagnosis, day 14, month 2, 4 and 6. A total of 486 women, with 88.3% being 18-49 years old, were included in the analysis. Around 54.7% were HIV positive. Most of the participants (416/486; 85.6%) in our cohort were considered cured at month 6. Only 40.4% of non-pregnant women of reproductive age used contraception at TB diagnosis. A total of 31 out of 486 women experienced pregnancy during TB treatment. Pregnancy outcomes varied between live birth (16/31; 51.6%), induced abortion (6/31; 19.4%), miscarriage (4/31; 12.9%) and stillbirth (3/31; 9.6%). Integration and linking of SRH services with TB programmes are vital to increase contraception use and protect women from obstetric risks associated with pregnancy during TB treatment.

Neutrophils Contribute to Severity of Tuberculosis Pathology and Recovery From Lung Damage Pre- and Posttreatment.

BACKGROUND: Despite microbiological cure, about 50% of tuberculosis (TB) patients have poor lung recovery. Neutrophils are associated with lung pathology; however, CD16/CD62L-defined subsets have not been studied in TB. Using flow cytometry, we monitored frequencies, phenotype, and function of neutrophils following stimulation with Mycobacterium tuberculosis (Mtb) whole cell lysate (WCL) and ESAT-6/CFP-10 fusion protein (EC) in relation to lung pathology. METHODS: Fresh blood from 42 adult, human immunodeficiency virus (HIV)-negative TB patients were analyzed pre- and post-therapy, with disease severity determined using chest radiography and bacterial load. Flow cytometry was used to monitor frequencies, phenotype, and function (generation of reactive oxygen species [ROS], together with CD11b, tumor necrosis factor, and interleukin 10 [IL-10] expression) of neutrophils following 2-hour stimulation with Mtb-specific antigens. RESULTS: Total neutrophils decreased by post-treatment compared to baseline (P = .0059); however, CD16brCD62Lbr (segmented) neutrophils increased (P = .0031) and CD16dimCD62Lbr (banded) neutrophils decreased (P = .038). Banded neutrophils were lower in patients with severe lung damage at baseline (P = .035). Following WCL stimulation, ROS from segmented neutrophils was higher in patients with low Mtb loads even after adjusting for sex (P = .038), whereas IL-10-expressing CD16dimCD62Llo cells were higher in patients with mild damage (P = .0397) at baseline. CONCLUSIONS: High ROS generation, low levels of banded neutrophils, and high levels of IL-10-expressing CD16dimCD62Llo neutrophils are associated with reduced lung pathology at diagnosis. Hence, neutrophils are potential early indicators of TB severity and promising targets for TB host-directed therapy.

Diagnostic Accuracy of the Cepheid 3-gene Host Response Fingerstick Blood Test in a Prospective, Multi-site Study: Interim Results.

BACKGROUND: 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 [MTB-HR] prototype), which generates a "TB score" based on messenger RNA (mRNA) expression of 3 genes. Here we describe the first prospective findings of the MTB-HR prototype. METHODS: Fingerstick blood from adults presenting with symptoms compatible with TB in South Africa, The Gambia, Uganda, and Vietnam was analyzed using the Cepheid GeneXpert MTB-HR prototype. Accuracy of the Xpert MTB-HR cartridge was determined in relation to GeneXpert Ultra results and a composite microbiological score (GeneXpert Ultra and liquid culture) with patients classified as having TB or other respiratory diseases (ORD). RESULTS: When data from all sites (n = 75 TB, 120 ORD) were analyzed, the TB score discriminated between TB and ORD with an area under the curve (AUC) of 0.94 (95% confidence interval [CI], .91-.97), sensitivity of 87% (95% CI, 77-93%) and specificity of 94% (88-97%). When sensitivity was set at 90% for a triage test, specificity was 86% (95% CI, 75-97%). These results were not influenced by human immunodeficiency virus (HIV) status or geographical location. When evaluated against a composite microbiological score (n = 80 TB, 111 ORD), the TB score was able to discriminate between TB and ORD with an AUC of 0.88 (95% CI, .83-.94), 80% sensitivity (95% CI, 76-85%) and 94% specificity (95% CI, 91-96%). CONCLUSIONS: Our interim data indicate the Cepheid MTB-HR cartridge reaches the minimal target product profile for a point of care triage test for TB using fingerstick blood, regardless of geographic area or HIV infection status.

Dyslipidaemia-related cardiovascular risk among pregnant women attending Aminu Kano Teaching Hospital Kano: A longitudinal study.

OBJECTIVE: Maternal dyslipidaemia and atherogenic lipid profiles have undesirable effects on maternal and foetal well-being throughout gestation. This study investigates the changes in serum lipid profiles, the prevalence of dyslipidaemia, and the risk of cardiovascular disease among pregnant women attending the antenatal care unit of the Aminu Kano Teaching Hospital (AKTH), Kano. METHODS: A total of 112 pregnant women visiting AKTH in their second trimester were recruited and followed up within their third trimester. The demographic characteristics, daily dietary consumption patterns, and lipid profiles of all women were assessed using standard methods. RESULTS: The results revealed that the mean age and gestational age of the pregnant women were approximately 29 ± 6 years and 20 ± 3 weeks, respectively. Most pregnant women were multiparous (76) and multigravida (93). Regarding daily dietary consumption patterns, 20.5%, 63.4%, 13.4%, and 8.0% of the pregnant women consumed nuts, palm oil, butter, and sardines at least one to three times, respectively. Moreover, the serum lipid profiles revealed that the prevalence of dyslipidaemia, hypercholesterolaemia, hypertriglyceridaemia, increased low-density lipoprotein levels, and decreased high-density lipoprotein levels among pregnant women during the second trimester were 69.6%, 19.6%, 36.6%, 18.8%, and 49.1%, respectively. All these parameters significantly increased to 91.8%, 54.1%, 75.3%, 40.0%, and 62.4%, respectively, in the third trimester. Pregnant women showed a high risk of cardiovascular disease in both the second (81.0%) and third (85.0%) trimesters. CONCLUSION: Progression from mid-pregnancy to delivery is associated with an increased risk of maternal dyslipidaemia and cardiovascular diseases among pregnant women.

Major Neutrophil-Derived Soluble Mediators Associate With Baseline Lung Pathology and Post-Treatment Recovery in Tuberculosis Patients.

Background: The inflammatory response to Mycobacterium tuberculosis results in variable degrees of lung pathology during active TB (ATB) with central involvement of neutrophils. Little is known about neutrophil-derived mediators and their role in disease severity at baseline and recovery upon TB treatment initiation. Methods: 107 adults with confirmed pulmonary TB were categorised based on lung pathology at baseline and following successful therapy using chest X-ray scores (Ralph scores) and GeneXpert bacterial load (Ct values). Plasma, sputum, and antigen-stimulated levels of MMP1, MMP3, MMP8, MMP9, MPO, S100A8/9, IL8, IL10, IL12/23(p40), GM-CSF, IFNγ, and TNF were analysed using multiplex cytokine arrays. Results: At baseline, neutrophil counts correlated with plasma levels of MMP8 (rho = 0.45, p = 2.80E-06), S100A8 (rho = 0.52, p = 3.00E-08) and GM-CSF (rho = 0.43, p = 7.90E-06). Levels of MMP8 (p = 3.00E-03), MMP1 (p = 1.40E-02), S100A8 (p = 1.80E-02) and IL12/23(p40) (p = 1.00E-02) were associated with severe lung damage, while sputum MPO levels were directly linked to lung damage (p = 1.80E-03), Mtb load (p = 2.10E-02) and lung recovery (p = 2.40E-02). Six months of TB therapy significantly decreased levels of major neutrophil-derived pro-inflammatory mediators: MMP1 (p = 4.90E-12 and p = 2.20E-07), MMP8 (p = 3.40E-14 and p = 1.30E-05) and MMP9 (p = 1.60E-04 and p = 1.50E-03) in plasma and sputum, respectively. Interestingly, following H37Rv whole cell lysate stimulation, S100A8 (p = 2.80E-02), MMP9 (p = 3.60E-02) and MPO (p = 9.10E-03) levels at month 6 were significantly higher compared to baseline. Sputum MMP1 (p = 1.50E-03), MMP3 (p = 7.58E-04), MMP9 (p = 2.60E-02) and TNF (p = 3.80E-02) levels were lower at month 6 compared to baseline in patients with good lung recovery. Conclusion: In this study, patients with severe lung pathology at baseline and persistent lung damage after treatment were associated with higher plasma and sputum levels of major pro-inflammatory neutrophil-derived mediators. Interestingly, low sputum MPO levels were associated with severe lung damage, higher Mtb burden and low recovery. Our data suggest that therapeutic agents which target these mediators should be considered for future studies on biomarkers and host-directed therapeutic approaches against TB-related lung pathology and/or lung recovery.

Exploring the perspectives of members of international tuberculosis control and research networks on the impact of COVID-19 on tuberculosis services: a cross sectional survey.

BACKGROUND: The COVID-19 pandemic has caused major disruption to healthcare services globally and has impacted on tuberculosis (TB) patients and TB diagnosis and treatment services both in low- and high-income countries. We therefore explored the perspectives of members of regional and international TB control and research networks to further understand TB service disruptions and compared the experiences of members from West African and European countries. METHODS: This cross-sectional, explorative descriptive study was conducted from May to July 2020 using an open online survey with target respondents from both West African and European countries. The survey comprised discrete questions exploring challenges faced with TB screening, diagnosis, treatment, prevention, and changes implemented. Additionally, respondents were asked to provide recommendations for remedial actions. RESULTS: We analysed responses from 124 respondents based in 29 countries located in Europe and West Africa. About half of the respondents reported challenges in delivering routine TB services during the COVID-19 pandemic, with over one third reporting having some form of guidance issued regarding maintaining delivery of routine TB services. Respondents emphasised the need for strengthening TB services especially in light of COVID-19 pandemic. Considerable similarities were found between the challenges experienced by TB professionals in both West African and European settings. Responses also highlighted the hidden challenges faced in some countries prior to the COVID-19 pandemic, especially in some West African settings where staff shortages and laboratory issues predated COVID-19. CONCLUSIONS: TB control and research professionals in West African and European settings experienced similar challenges to the delivery of TB diagnosis and treatment services due to the COVID-19 pandemic, and highlighted the need for clear communication of guidelines, prioritisation of routine TB service delivery, ongoing health education, and possible integration of TB and COVID-19 services to ensure that TB services are more resilient against the impact of the pandemic.

Delay in the diagnosis of pulmonary tuberculosis in The Gambia, West Africa: A cross-sectional study.

OBJECTIVES: To investigate the pattern of tuberculosis (TB) care initiation and risk factors for TB diagnostic delay in The Gambia. METHODS: In this cross-sectional study, adult patients diagnosed with pulmonary TB (pTB) in public facilities in the Greater Banjul Area of The Gambia were consecutively recruited from October 2016 to March 2017. Diagnostic delay was defined as >21 days from the onset of at least one symptom suggestive of pTB to diagnosis. Logistic regression analyses were used to investigate risk factors for diagnostic delay. RESULTS: Overall, 216 pTB patients were included in the study; the median (Interquartile Range (IQR)) age was 30 (23-39) years and 167 (77%) were male patients. Of the 216 patients, 110 (50.9%) of them initiated care-seeking in the formal and informal private sector and 181/216 (83.8%) had TB diagnostic delay. The median (IQR) duration from the onset of symptoms to TB diagnosis was 34 (28-56) days. Age groups 18-29 years (aOR 3.2; 95% CI 1.2-8.8 [p = 0.02]) and 30-49 years (aOR 5.1; 95% CI 1.6-16.2 [p = 0.006]) and being employed (aOR 4.2; 95% CI 1.7-10.5 [p = 0.002]) were independent risk factors for TB diagnostic delay. CONCLUSION: There is considerable TB diagnostic delay in The Gambia, and this is likely to be worsened by the COVID-19 pandemic.

Mycobacterium tuberculosis-specific plasmablast levels are differentially modulated in tuberculosis infection and disease.

BACKGROUND: While T cell responses to Mycobacterium tuberculosis (Mtb) have been extensively studied, the role of B-cells and antibodies are less well characterised. The aim of this study was to assess levels of Mtb-specific IgG + plasmablasts across the Mtb infection spectrum. METHODS: Patients with active TB were analysed at baseline and 6 months of therapy (n = 20).Their exposed household contacts (HHC) included individuals with latent TB infection (LTBI; n = 20); evident at baseline; individuals with a negative Tuberculin Skin Test (TST) at baseline who became; positive at 6 months (converters; n = 11) and those who remained negative (non-converters; n = 10). An e x-vivo B-cell ELISPOT was performed to analyse plasmablast responses. RESULTS: Frequencies of ESAT-6/CFP-10 (EC)- but not Whole Cell Lysate (WCL)-specific plasmablasts were significantly higher in patients with active TB pre-treatment compared to post-treatment (p = 0.002) and compared to HHC with LTBI (p < 0.0001). Conversely, total IgG + plasmablasts were significantly decreased in TB patients at baseline. No difference was seen in levels of plasmablasts between TST converters and non-converters at baseline. CONCLUSIONS: We show that EC-specific plasmablast levels are differentially modulated during TB infection and disease, with levels highest during active TB. These data provide new insights into TB biomarker development and avenues for novel immune interventions.

Monitoring Anti-tuberculosis Treatment Response Using Analysis of Whole Blood Mycobacterium tuberculosis Specific T Cell Activation and Functional Markers.

Background: Blood-based biomarkers have been proposed as an alternative to current sputum-based treatment monitoring methods in active tuberculosis (ATB). The aim of this study was to validate previously described phenotypic, activation, and cytokine markers of treatment response in a West African cohort. Methods: Whole blood immune responses to Mycobacterium tuberculosis ESAT-6/CFP-10 (EC) and purified protein derivative (PPD) were measured in twenty adults at baseline and after 2 months of standard TB treatment. Patients were classified as fast or slow responders based on a negative or positive sputum culture result at 2 months, respectively. Cellular expression of activation markers (CD38, HLA-DR), memory markers (CD27), and functional intracellular cytokine and proliferation (IFN-γ, Ki-67, TNF-α) markers were measured using multi-color flow cytometry. Results: There was a significant increase in the proportion of CD4+CD27+ cells expressing CD38 and HLA-DR following EC stimulation at 2 months compared to baseline (p = 0.0328 and p = 0.0400, respectively). Following PPD stimulation, slow treatment responders had a significantly higher proportion of CD8+CD27-IFN-γ+ (p = 0.0105) and CD4+CD27+HLA-DR+CD38+ (p = 0.0077) T cells than fast responders at baseline. Receiver operating curve analysis of these subsets resulted in 80% sensitivity and 70 and 100% specificity, respectively (AUC of 0.82, p = 0.0156 and 0.84, p = 0.0102). Conclusion: Our pilot data show reductions in expression of T cell activation markers were seen with treatment, but this was not associated with fast or slow sputum conversion at 2 months. However, baseline proportions of activated T cell subsets are potentially predictive of the subsequent speed of response to treatment.

Vitamin D status and risk of incident tuberculosis disease: A nested case-control study, systematic review, and individual-participant data meta-analysis.

BACKGROUND: Few studies have evaluated the association between preexisting vitamin D deficiency and incident tuberculosis (TB). We assessed the impact of baseline vitamins D levels on TB disease risk. METHODS AND FINDINGS: We assessed the association between baseline vitamin D and incident TB in a prospective cohort of 6,751 HIV-negative household contacts of TB patients enrolled between September 1, 2009, and August 29, 2012, in Lima, Peru. We screened for TB disease at 2, 6, and 12 months after enrollment. We defined cases as household contacts who developed TB disease at least 15 days after enrollment of the index patient. For each case, we randomly selected four controls from among contacts who did not develop TB disease, matching on gender and year of age. We also conducted a one-stage individual-participant data (IPD) meta-analysis searching PubMed and Embase to identify prospective studies of vitamin D and TB disease until June 8, 2019. We included studies that assessed vitamin D before TB diagnosis. In the primary analysis, we defined vitamin D deficiency as 25-(OH)D < 50 nmol/L, insufficiency as 50-75 nmol/L, and sufficiency as >75nmol/L. We estimated the association between baseline vitamin D status and incident TB using conditional logistic regression in the Lima cohort and generalized linear mixed models in the meta-analysis. We further defined severe vitamin D deficiency as 25-(OH)D < 25 nmol/L and performed stratified analyses by HIV status in the IPD meta-analysis. In the Lima cohort, we analyzed 180 cases and 709 matched controls. The adjusted odds ratio (aOR) for TB risk among participants with baseline vitamin D deficiency compared to sufficient vitamin D was 1.63 (95% CI 0.75-3.52; p = 0.22). We included seven published studies in the meta-analysis and analyzed 3,544 participants. In the pooled analysis, the aOR was 1.48 (95% CI 1.04-2.10; p = 0.03). The aOR for severe vitamin D deficiency was 2.05 (95% CI 0.87-4.87; p trend for decreasing 25-(OH)D levels from sufficient vitamin D to severe deficiency = 0.02). Among 1,576 HIV-positive patients, vitamin D deficiency conferred a 2-fold (aOR 2.18, 95% CI 1.22-3.90; p = 0.01) increased risk of TB, and the aOR for severe vitamin D deficiency compared to sufficient vitamin D was 4.28 (95% CI 0.85-21.45; p = 0.08). Our Lima cohort study is limited by the short duration of follow-up, and the IPD meta-analysis is limited by the number of possible confounding covariates available across all studies. CONCLUSION: Our findings suggest vitamin D predicts TB disease risk in a dose-dependent manner and that the risk of TB disease is highest among HIV-positive individuals with severe vitamin D deficiency. Randomized control trials are needed to evaluate the possible role of vitamin D supplementation on reducing TB disease risk.

Analysis of cellular and soluble profiles in QuantiFERON nonconverters, converters, and reverters in the Gambia.

BACKGROUND: Tuberculosis (TB) is the leading cause of death from a single infectious agent worldwide. The immune system is capable of clearing the pathogen before establishment of latent infection but the mechanisms for this are not yet understood. METHODS: This study analysed highly exposed household contacts (HHC) of TB index cases who were categorised according to QuantiFERON (QFT) results at recruitment and 6 months. Seventeen (17) QFT nonconverters, 14 QFT converters, 18 QFT reverters and 18 latent TB infection (LTBI) were analysed. Supernatants generated following QFT stimulation at both time-points were analysed using a 64-plex cytokine array. Flow cytometry was performed on QFT converters and nonconverters at baseline only. RESULTS: Interleukin-2 (IL-2), IL-5, IL-13, APRIL, IL-17A, IP-10, MIP-1ß, sIL-6rb, OPN, and sTNFR2 were all significantly higher in the QFT converters compared with nonconverters at baseline. Levels of interferon-α2 (IFN-α2) and IL-2 were significantly lower in QFT reverters compared with nonconverters at baseline. Analysis of Ag-specific IL-2 levels resulted in an area under the curve (AUC) of 0.93 (95% confidence interval [CI], 0.84-1.00) for QFT converters compared to nonconverters and an AUC of 0.80 (0.65-0.95) for QFT reverters compared with LTBI. Purified protein derivative (PPD)-specific CD4 + CD26 + IFN-γ + cells were significantly increased (P = .0007) in QFT nonconverters compared with QFT converters at baseline. CONCLUSIONS: Our results provide insight into the underlying mechanisms of resistance to sustained Mycobacterium tuberculosis infection.

Immunogenicity of pneumococcal conjugate vaccine formulations containing pneumococcal proteins, and immunogenicity and reactogenicity of co-administered routine vaccines - A phase II, randomised, observer-blind study in Gambian infants.

BACKGROUND: Two conserved pneumococcal proteins, pneumolysin toxoid (dPly) and pneumococcal histidine triad protein D (PhtD), combined with 10 polysaccharide conjugates from the pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) in two investigational pneumococcal vaccine (PHiD-CV/dPly/PhtD) formulations were immunogenic and well-tolerated when administered to Gambian children. Here, we report immunogenicity of the polysaccharide conjugates, and immunogenicity and reactogenicity of co-administered routine vaccines. METHODS: In this phase II, controlled, observer-blind, single-centre study, healthy infants aged 8-10 weeks were randomised (1:1:1:1:1:1) to six groups. Four groups received 3+0 schedule (2-3-4 months [M]) of PHiD-CV/dPly/PhtD (10 or 30 µg of each protein), PHiD-CV, or 13-valent pneumococcal conjugate vaccine; and two groups received 2+1 schedule (2-4-9 M) of PHiD-CV/dPly/PhtD (30 µg of each protein) or PHiD-CV. All infants received diphtheria-tetanus-whole cell pertussis-hepatitis B-Haemophilus influenzae type b (DTPw-HBV/Hib) and oral trivalent polio vaccines (OPV) at 2-3-4 M, and measles, yellow fever, and OPV vaccines at 9 M. We evaluated immune responses at 2-5-9-12 M; and reactogenicity 0-3 days post-vaccination. RESULTS: 1200 infants were enrolled between June 2011 and May 2012; 1152 completed the study. 1 M post-primary vaccination, for each PHiD-CV serotype except 6B and 23F, ≥97.4% (3+0 schedule) and ≥96.4% (2+1 schedule) of infants had antibody concentrations ≥0.2 µg/mL. Immune responses were comparable between groups within the same vaccination schedules. Observed antibody geometric mean concentrations (GMCs) increased by 1 M post-primary vaccination compared to pre-vaccination. In the following months, GMCs and opsonophagocytic activity titres waned, with an increase post-booster for the 2+1 schedule. Immune responses to protein D and, DTPw-HBV/Hib, OPV, measles, and yellow fever vaccines were not altered by co-administration with pneumococcal proteins. Reactogenicity of co-administered vaccines was comparable between groups and did not raise concerns. CONCLUSION: Immune responses to the 10 PHiD-CV polysaccharide conjugates and co-administered vaccines were not altered by addition of dPly and PhtD. ClinicalTrials.gov identifier NCT01262872.