Protein Expression of TLR2, TLR4, and TLR9 on Monocytes in TB, HIV, and TB/HIV.

Toll-like receptors (TLRs) have a critical role in recognizing pathogenic patterns and initiating immune responses against TB and HIV. Previously, studies described the gene expression of TLRs in patients with TB and HIV. Here, we demonstrated TLRs protein expressions and their association with clinical status and plasma markers in TB, HIV, and TB/HIV coinfection. The phenotyping of TLR2, TLR4, and TLR9 on CD14+ monocytes and their subsets were determined by multicolor flow cytometry. Host plasma biomarkers and microbial indices were measured using Luminex Multiplex assay and standard of care tools, respectively. TLR2 expression significantly enhanced in TB, slightly increased in HIV but slightly reduced in TB/HIV coinfection compared to apparently health controls (HC). On the other hand, TLR4 expression was significantly increased in TB, HIV, and TB/HIV compared to HC. Expression of TLR4 was equally enhanced on classical and intermediate monocytes while higher TLR2 expression on intermediate than classical monocytes. TLR4 had a positive correlation pattern with plasma biomarkers while TLR2 had an inverse correlation pattern. TLR4 is associated with disease severity while TLR2 is with the immune-competent status of patients. Our findings demonstrated that the pattern of TLR expression is disease as well as monocyte subset specific and distinct factors drive these differences.

Diagnostics of Tuberculosis with Single-Walled Carbon Nanotube-Based Field-Effect Transistors.

Tuberculosis (TB) is still threatening millions of people's lives, especially in developing countries. One of the major factors contributing to the ongoing epidemic of TB is the lack of a fast, efficient, and inexpensive diagnostic strategy. In this work, we developed a semiconducting single-walled carbon nanotube (SWCNT)-based field-effect transistor (FET) device functionalized with anti-Mycobacterium tuberculosis antigen 85B antibody (Ab85B) to detect the major M. tuberculosis-secreted antigen 85B (Ag85B). Through optimizing the device fabrication process by evaluating the mass of the antibody and the concentration of the gating electrolyte, our Ab85B-SWCNT FET devices achieved the detection of the Ag85B spiked in phosphate-buffered saline (calibration samples) with a limit of detection (LOD) of 0.05 fg/mL. This SWCNT FET biosensor also showed good sensing performance in biological matrices including artificial sputum and can identify Ag85B in serum after introducing bovine serum albumin (BSA) into the blocking layer. Furthermore, our BSA-blocked Ab85B-SWCNT FET devices can distinguish between TB-positive and -negative clinical samples, promising the application of SWCNT FET devices in point-of-care TB diagnostics. Moreover, the robustness of this SWCNT-based biosensor to the TB diagnosis in blood serum was enhanced by blocking SWCNT devices directly with a glutaraldehyde cross-linked BSA layer, enabling future applications of these SWCNT-based biosensors in clinical testing.

LINC00870 regulates Th1/Th2 via the JAK/STAT pathway in peripheral blood mononuclear cells infected with Mycobacterium tuberculosis.

Long, noncoding RNAs reportedly play vital roles in tuberculosis (TB). For example, upregulation of LINC00870 has been observed in tuberculosis, though its role and underlying mechanism remains unclear. In this study, we investigated the expression and effect of LINC00870 in Mycobacterium tuberculosis (MTB) infection by comparing MTB-infected peripheral blood mononuclear cells (PBMCs) with controls. The results showed LINC00870 was significantly increased in MTB infected PBMCs. Additionally, LINC00870 overexpression inhibited Th1-secreted cytokines while promoted Th2-secreted cytokine in MTB-infected PBMCs. Furthermore, LINC00870 promoted p-STAT5 and p-JAK2 protein expression, thus activating JAK/STAT signaling in MTB-infected PBMCs. Sputum and plasma samples were obtained from TB, latent tuberculosis infection (LTBI) patients and healthy controls. The qRT-PCR results showed higher levels of LINC00870 in the sputum and plasma from TB and LTBI patients compared to healthy controls. In addition, LINC00870 were decreased in both TB and LTBI patients after three month of therapy, respectively. The results showed a correlation between LINC00870 inhibition and Th1/Th2, as well as JAK/STAT signaling pathway in PBMCs from active TB patients. In conclusion, higher levels of LINC00870 in tuberculosis might be associated with Th1/Th2-related immune responses by activating JAK/STAT signaling. LINC00870 thus may be a novel biomarker for diagnosing and treating tuberculosis.

A simple assay to quantify mycobacterial lipid antigen-specific T cell receptors in human tissues and blood.

T cell receptors (TCRs) encode the history of antigenic challenge within an individual and have the potential to serve as molecular markers of infection. In addition to peptide antigens bound to highly polymorphic MHC molecules, T cells have also evolved to recognize bacterial lipids when bound to non-polymorphic CD1 molecules. One such subset, germline-encoded, mycolyl lipid-reactive (GEM) T cells, recognizes mycobacterial cell wall lipids and expresses a conserved TCR-ɑ chain that is shared among genetically unrelated individuals. We developed a quantitative PCR assay to determine expression of the GEM TCR-ɑ nucleotide sequence in human tissues and blood. This assay was validated on plasmids and T cell lines. We tested blood samples from South African subjects with or without tuberculin reactivity or with active tuberculosis disease. We were able to detect GEM TCR-ɑ above the limit of detection in 92% of donors but found no difference in GEM TCR-ɑ expression among the three groups after normalizing for total TCR-ɑ expression. In a cohort of leprosy patients from Nepal, we successfully detected GEM TCR-ɑ in 100% of skin biopsies with histologically confirmed tuberculoid and lepromatous leprosy. Thus, GEM T cells constitute part of the T cell repertoire in the skin. However, GEM TCR-ɑ expression was not different between leprosy patients and control subjects after normalization. Further, these results reveal the feasibility of developing a simple, field deployable molecular diagnostic based on mycobacterial lipid antigen-specific TCR sequences that are readily detectable in human tissues and blood independent of genetic background.

Estimation of lifetime survival and predictors of mortality among TB with HIV co-infected children after test and treat strategies launched in Northwest, Ethiopia, 2021; a multicentre historical follow-up study.

INTRODUCTION: In resource-limited settings, the mortality rate among tuberculosis and human Immunodeficiency virus co-infected children is higher. However, there is no adequate evidence in Ethiopia in general and in the study area in particular. Hence, this study aims to estimate lifetime survival and predictors of mortality among TB with HIV co-infected children after test and treat strategies launched in Northwest Ethiopia Hospitals, 2021. METHODS: Institution-based historical follow-up study was conducted in Northwest Ethiopia Hospitals among 227 Tuberculosis and Human Immunodeficiency Virus co-infected children from March 1, 2014, to January 12, 2021. The data were entered into Epi info-7 and then exported to STATA version 14 for analysis. The log-rank test was used to estimate the curve difference of the predictor variables. Bivariable cox-proportional hazard models were employed for each predictor variable. Additionally, those variables having a p-value < 0.25 in bivariate analysis were fitted into a multivariable cox-proportional hazards model. P-value < 0.05 was used to declare significance associated with the dependent variable. RESULTS: From a total of 227 TB and HIV co-infected children, 39 died during the follow-up period. The overall mortality rate was 3.7 (95% CI (confidence interval): 2.9-4.7) per 100 person-years with a total of 1063.2-year observations. Cotrimoxazole preventive therapy (CPT) non-users [Adjusted Hazarded Ratio (AHR) = 3.8 (95% CI: 1.64-8.86)], presence of treatment failure [AHR = 3.0 (95% CI: 1.14-78.17)], and Cluster of differentiation 4(CD4) count below threshold [AHR = 2.7 (95% CI: 1.21-6.45)] were significant predictors of mortality. CONCLUSION: In this study, the mortality rate among TB and HIV co-infected children was found to be very high. The risk of mortality among TB and HIV co-infected children was associated with treatment failure, CD4 count below the threshold, and cotrimoxazole preventive therapy non-users. Further research should conduct to assess and improve the quality of ART service in Northwest Ethiopia Hospitals.

Superior Mesenteric Artery Stenosis Due to Disseminated Tuberculosis in a Pediatric Patient.

Disseminated tuberculosis (TB) associated with mesenteric arteritis has not been established in children. We present the case of an 8-year-old woman who presented with TB and superior mesenteric artery stenosis. Although rare, large vessel involvement from Takayasu arteritis can occur in TB. Evaluation for mesenteric vessel involvement should be considered in pediatric patients presenting with widely disseminated TB and abdominal pain.

Positive QuantiFERON test and the severity of COVID-19 disease: A prospective study.

BACKGROUND: A strong negative correlation is reported between the Bacille Calmette Guerin (BCG) index and COVID-19 mortality. The present study explored if frequent exposure to strong Th1 antigens like Mycobacteria or Salmonella have any effect on the progression of the disease in COVID-19 patients. METHODS: This prospective comparative study comprised of 3 groups of 20 each of mild or asymptomatic COVID-19 patients (A), severely ill patients (S) and healthy volunteers with a COVID Negative report (H). RESULTS: QuantiFERON TB Gold (QFT) which is interferon gamma release assay (IGRA) against Mtb antigen was used to quantify immunity status of patients against the tuberculosis. Group S showed positive QFT in only 15% patients as against 50% QFT positive patients in group A and H. All fourteen patients in group S with QFT negative report died while 5 of six survived patients showed positive QFT report either on initial or repeat testing done at 6 weeks. The sixth survived patient was QFT negative but showed high antibody titre against H antigen (TH) on Widal test. All severely ill group S patients showed huge reduction of IGRA even to the mitogen stimulus thus suggesting gross general unresponsiveness of T cells. Presence of BCG scar showed no correlation with prevalence or progression of the disease. CONCLUSION: Population in an endemic area of tuberculosis and typhoid with good community exposure to these antigen is likely to withstand COVID -19 better and show reduced mortality following it.

A 10-gene biosignature of tuberculosis treatment monitoring and treatment outcome prediction.

The clinical utility of blood transcriptomic biosignatures for the treatment monitoring and outcome prediction of tuberculosis (TB) remains limited. In this study, we aimed to discover and validate biomarkers for pulmonary TB treatment monitoring and outcome prediction based on kinetic responses of gene expression during treatment. In particular, differentially expressed genes (DEGs) were identified by time-series comparison. Subsequently, DEGs with the monotonic expression alterations during the treatment were selected. Ten consistently down-regulated genes (CD274, KIF1B, IL15, TLR1, TLR5, FCGR1A, GBP1, NOD2, GBP2, EGF) exhibited significant potential in treatment monitoring, demonstrated via biological and technical validation. Additionally, the biosignature showed potential in predicting the cured versus relapsed patients. Furthermore, the biosignature could be utilized for TB diagnosis, latent tuberculosis infection/active TB differential diagnosis, and risk of progression to active TB. Benchmarking analysis of the 10-gene biosignature with other biosignatures showed equivalent performance in tested data sets. In conclusion, we established a 10-gene transcriptomic biosignature that represents the kinetic responses of TB treatment. Subsequent studies are warranted to validate, refine and translate the biosignature into a precise assay to assist clinical decisions in a broad spectrum of TB management.

Clinical Features and Risk Factors for Active Tuberculosis in Takayasu Arteritis: A Single-Center Case-Control Study.

Backgrounds: Takayasu arteritis (TAK) is a chronic, granulomatous vasculitis correlated with tuberculosis (TB). The two diseases share similar pathological characteristics and clinical manifestations which increase the difficulty to diagnose. Active tuberculosis (ATB) has implications for treatment strategies in TAK patients. Therefore, the investigation of clinical features and potential risk factors of ATB in TAK patients is vital. Methods: The study reviewed hospitalized patients diagnosed with TAK in our hospital from 2008, to 2021. TAK patients with ATB were enrolled as the case group. The control group was randomly selected in a 3:1 ratio. The clinical characteristics of TAK patients with and without ATB were compared. Multivariate logistic regression analysis was performed to determine risk factors for ATB in TAK patients. Results: We reviewed 1,789 patients and ultimately identified 30 (1.7%) ATB cases. TAK patients with ATB were more prone to develop symptoms including fever (p=0.001), fatigue (p=0.003), cough (p=0.037), expectoration (p<0.001), weight loss (p=0.003), and night sweating (p<0.001). Increased level of hypersensitive C reactive protein (hsCRP, p=0.001), decreased level of albumin (p=0.031), and higher positive rate of T-SPOT.TB test (p<0.001) were observed in the case group. Multivariate logistic regression analysis revealed that hsCRP >8 mg/L (OR 9.108; 95% CI, 1.096-75.711; p=0.041) and positive T-SPOT.TB result (OR 68.669; 95% CI, 7.291-646.738; p<0.001) were risk factors for ATB in TAK patients. The proportion of patients undergoing subsequent surgery for Takayasu arteritis was lower in patients with ATB (p<0.001). Conclusion: Our study suggested that the diagnosis of ATB should be considered when TAK patients experienced symptoms including fever, fatigue, weight loss, etc. hsCRP >8 mg/L and positive T-SPOT.TB result were identified as independent risk factors for ATB in TAK patients.

Transcriptomic Biomarkers for Tuberculosis: Validation of NPC2 as a Single mRNA Biomarker to Diagnose TB, Predict Disease Progression, and Monitor Treatment Response.

External validation in different cohorts is a key step in the translational development of new biomarkers. We previously described three host mRNA whose expression in peripheral blood is significantly higher (NPC2) or lower (DOCK9 and EPHA4) in individuals with TB compared to latent TB infection (LTBI) and controls. We have now conducted an independent validation of these genes by re-analyzing publicly available transcriptomic datasets from Brazil, China, Haiti, India, South Africa, and the United Kingdom. Comparisons between TB and control/LTBI showed significant differential expression of all three genes (NPC2high p < 0.01, DOCK9low p < 0.01, and EPHA4low p < 0.05). NPC2high had the highest mean area under the ROC curve (AUROC) for the differentiation of TB vs. controls (0.95) and LTBI (0.94). In addition, NPC2 accurately distinguished TB from the clinically similar conditions pneumonia (AUROC, 0.88), non-active sarcoidosis (0.87), and lung cancer (0.86), but not from active sarcoidosis (0.66). Interestingly, individuals progressing from LTBI to TB showed a constant increase in NPC2 expression with time when compared to non-progressors (p < 0.05), with a significant change closer to manifestation of active disease (≤3 months, p = 0.003). Moreover, NPC2 expression normalized with completion of anti-TB treatment. Taken together, these results validate NPC2 mRNA as a diagnostic host biomarker for active TB independent of host genetic background. Moreover, they reveal its potential to predict progression from latent to active infection and to indicate a response to anti-TB treatment.

LC-MS/MS method for simultaneous quantification of the first-line anti-tuberculosis drugs and six primary metabolites in patient plasma: Implications for therapeutic drug monitoring.

The pharmacokinetic profiling of drug substances and corresponding metabolites in the biological matrix is one of the most informative tools for the treatment efficacy assessment. Therefore, to satisfy the need for comprehensive monitoring of anti-tuberculosis drugs in human plasma, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous quantification of first-line anti-tuberculosis drugs (ethambutol, isoniazid, pyrazinamide, and rifampicin) along with their six primary metabolites. Simple single-step protein precipitation with methanol was chosen as the most convenient sample pre-treatment method. Chromatographic separation of the ten analyte mixture was achieved within 10 minutes on a reverse-phase C8 column using mobile phase gradient mode. The multiple reaction monitoring mode (MRM) was used for analyte detection and quantification in patient samples. The chosen quantification ranges fully covered expected plasma concentrations. The method exhibited acceptable selectivity; the within- and between-run accuracy ranged from 87.2 to 113.6%, but within- and between-run precision was between 1.6 and 14.9% (at the LLOQ level CV < 20%). Although the response of the isonicotinic acid varied depending on the matrix source (CV 21.8%), validation results proved that such inconsistency does not affect the accuracy and precision of results. If stored at room temperature plasma samples should be processed within 4 h after collection, temporary storage at -20 °C up to 24 h is acceptable due to stability issues of analytes. The developed method was applied for the patient sample analysis (n = 34) receiving anti-tuberculosis treatment with the first-line drugs.

Increased levels of circulating LPS during Tuberculosis prevails in patients with advanced pulmonary involvement.

Our earlier studies in tuberculosis (TB) patients indicate that in those where the process evolves to a larger pulmonary involvement, the immune endocrine response may promote an unfavorable environment. Chronic infectious diseases, and their persistent proinflammatory response, may affect mucosal barriers integrity favoring the translocation of gastrointestinal bacteria, leading to an increase of circulating lipopolysaccharides (LPS). Consequently, we quantified LPS levels in TB patients, with different degrees of pulmonary involvement, and controls (Co) and analyzed the possible relationship between LPS and inflammatory mediators i.e., C reactive protein (CRP), interleukin 6 (IL-6) and Interferon-gamma (IFN-γ), Erythrocyte Sedimentation Rate (ESR), steroid hormones (Cortisol and Dehydroepiandrosterone, DHEA), and inflammatory transcripts from peripheral blood mononuclear cells (IL-1ß, IL-6, IFN-γ). LPS was assessed by the Limulus amoebocyte lysate assay and the ELISA technique was used to quantify hormones and cytokines in the plasma samples. Cytokine transcripts from PBMC were evaluated by qRT-PCR. Non-parametric tests were used. LPS levels were increased in TB patients, as did levels of CRP, IL-6, IFN-γ, cortisol and ESR. Severe patients had the highest amounts of circulating LPS; with moderate and severe cases showing much higher levels of CRP, ESR, IL-6, IFN-γ and cortisol/DHEA ratio, as an endocrine imbalance. Only in PBMC from severe cases was mRNA for IL-1ß increased. Correlation analysis showed that levels of LPS from severe patients were positively associated with IL-6 and IFN-γ plasma concentrations and with IL-1ß transcripts, while IL-6 had a positive correlation with the cortisol/DHEA ratio. The higher levels of circulating LPS during progressive TB may emerge as a contributing factor for the persistence of the greater immune endocrine imbalance distinctive of advanced disease, which might suggest a vicious cycle among LPS, inflammation and endocrine imbalance.

Longitudinal Dynamics of a Blood Transcriptomic Signature of Tuberculosis.

Rationale: Performance of blood transcriptomic tuberculosis (TB) signatures in longitudinal studies and effects of TB-preventive therapy and coinfection with HIV or respiratory organisms on transcriptomic signatures has not been systematically studied. Objectives: We evaluated longitudinal kinetics of an 11-gene blood transcriptomic TB signature, RISK11, and effects of TB-preventive therapy (TPT) and respiratory organisms on RISK11 signature score, in HIV-uninfected and HIV-infected individuals. Methods: RISK11 was measured in a longitudinal study of RISK11-guided TPT in HIV-uninfected adults, a cross-sectional respiratory organisms cohort, or a longitudinal study in people living with HIV (PLHIV). HIV-uninfected RISK11+ participants were randomized to TPT or no TPT; RISK11- participants received no TPT. PLHIV received standard-of-care antiretroviral therapy and TPT. In the cross-sectional respiratory organisms cohort, viruses and bacteria in nasopharyngeal and oropharyngeal swabs were quantified by real-time quantitative PCR. Measurements and Main Results: RISK11+ status was transient in most of the 128 HIV-negative participants with longitudinal samples; more than 70% of RISK11+ participants reverted to RISK11- by 3 months, irrespective of TPT. By comparison, reversion from a RISK11+ state was less common in 645 PLHIV (42.1%). Non-HIV viral and nontuberculous bacterial organisms were detected in 7.2% and 38.9% of the 1,000 respiratory organisms cohort participants, respectively, and among those investigated for TB, 3.8% had prevalent disease. Median RISK11 scores (%) were higher in participants with viral organisms alone (46.7%), viral and bacterial organisms (42.8%), or prevalent TB (85.7%) than those with bacterial organisms other than TB (13.4%) or no organisms (14.2%). RISK11 could not discriminate between prevalent TB and viral organisms. Conclusions: Positive RISK11 signature status is often transient, possibly due to intercurrent viral infection, highlighting potentially important challenges for implementation of these biomarkers as new tools for TB control.

Non-IFNγ Whole Blood Cytokine Responses to Mycobacterium tuberculosis Antigens in HIV-exposed Infants.

BACKGROUND: HIV-exposed uninfected (HEU) infants have increased risk of tuberculosis (TB). Testing for Mycobacterium tuberculosis (Mtb) infection is limited by reduced Quantiferon (QFT) sensitivity in infants and tuberculin skin test (TST) cross-reactivity with Bacillus Calmette-Guérin vaccine. Our objective is to assess if non-IFNγ cytokine responses to Mtb-specific antigens have improved sensitivity in detecting Mtb infection in HEU infants compared with QFT. METHODS: HEU infants were enrolled in a randomized clinical trial of isoniazid preventive therapy (IPT) to prevent Mtb infection in Kenya (N = 300) and assessed at 12 months postrandomization (14 months of age) by TST and QFT-Plus. Non-IFNγ cytokine secretion (IL2, TNF, IP10, N = 229) in QFT-Plus supernatants was measured using Luminex assay. Logistic regression was used to assess the effect of IPT on Mtb infection outcomes in HEU infants. RESULTS: Three of 251 (1.2%) infants were QFT-Plus positive. Non-IFNγ Mtb antigen-specific responses were detected in 12 additional infants (12/229, 5.2%), all TST negative. IPT was not associated with Mtb infection defined as any Mtb antigen-specific cytokine response (odds ratio = 0.7, P = 0.54). Mtb antigen-specific IL2/IP10 responses had fair correlation (τ = 0.25). Otherwise, non-IFNγ cytokine responses had minimal correlation with QFT-Plus and no correlation with TST size. CONCLUSIONS: We detected non-IFNg Mtb antigen-specific T-cell responses in 14-month HEU infants. Non-IFNg cytokines may be more sensitive than IFNg in detecting infant Mtb infection. IPT during the first year of life was not associated with Mtb infection measured by IFNg, IL2, IP10 and TNF Mtb-specific responses.

MicroRNA­502­3p promotes Mycobacterium tuberculosis survival in macrophages by modulating the inflammatory response by targeting ROCK1.

Tuberculosis (TB) is caused by Mycobacterium tuberculosis (M. tuberculosis) infection and has the highest mortality rate of any single infectious disease worldwide. The aim of the present study was to investigate the function of microRNA (miR)­502­3p in M. tuberculosis­infected macrophages. The Gene Expression Omnibus database was used to analyze miR­502­3p expression in patients with TB and healthy individuals. THP­1 and RAW 264.7 cells were transfected with miR­502­3p mimic, miR­502­3p inhibitor, pcDNA3.1­ROCK1 or their negative controls. The expression levels of miR­502­3p and inflammatory cytokines were evaluated using reverse transcription­quantitative PCR. The colony­forming unit assay was performed to assess the survival of M. tuberculosis in macrophages, and Toll­like receptor (TLR)4/NF­κB signaling pathway­associated protein expression levels were detected by western blotting. The nuclear translocation of NF­κB p65 was detected via immunocytochemistry. TargetScan was used to predict the binding sites between miR­502­3p and ROCK1. The interaction between miR­502­3p and Rho­associated coiled­coil­forming protein kinase 1 (ROCK1) was confirmed using a dual­luciferase reporter assay; ROCK1 was demonstrated to be a direct target gene of miR­502­3p. Results from the present study demonstrated that miR­502­3p expression was significantly increased during M. tuberculosis infection in macrophages. Upregulation of miR­502­3p expression levels significantly enhanced the survival of intracellular M. tuberculosis. IL­6, TNF­α, and IL­1ß mRNA expression levels were significantly upregulated during M. tuberculosis infection but were downregulated by miR­502­3p overexpression. Moreover, miR­502­3p mimics transfection significantly downregulated TLR4/NF­κB signaling pathway­associated protein expression and significantly reduced nuclear transcription of NF­κB in M. tuberculosis­infected macrophages. ROCK1 overexpression reversed the miR­502­3p inhibitory effect on cytokine production in M. tuberculosis­infected macrophages. In conclusion, miR­502­3p/ROCK1 may serve an anti­inflammatory role and may improve the survival of M. tuberculosis within macrophages, which may provide a promising therapeutic target for TB.

Retrospective Performance Analyses of over Two Million U.S. QuantiFERON Blood Sample Results.

Both the QuantiFERON-TB Gold Plus (QFT-Plus) and the QuantiFERON-TB Gold In-Tube (QFT-GIT) tests are interferon gamma (IFN-γ) release assays (IGRAs) intended to detect in vitro cell-mediated immune responses to Mycobacterium tuberculosis antigens. In this study, we retrospectively analyzed performance data for both the QFT-GIT and QFT-Plus test systems from over 2 million samples. QFT-Plus and QFT-GIT testing was performed as specified in the respective package inserts at 23 Quest Diagnostics sites. Blood specimens were collected from individuals in all 50 states from November 2018 through December 2019. Retrospective analyses compared the proportion of positive, indeterminate, and conversion/reversion results. The overall proportion of QFT-positive results was 7% for both the QFT-Plus and QFT-GIT. The proportion of positive results was highest for QFT-GIT (7.5%) followed by the heparin 1-tube QFT-Plus (7.2%); a lower proportion of positives was observed with the 4-tube (all four QFT tubes were used in blood collection) QFT-Plus (6.0%). The proportions of indeterminate results for the 1-tube (heparin-only tube collection) and 4-tube QFT-Plus methods were less than 1% and 4%, respectively. This study indicates a higher proportion of positive results for M. tuberculosis than data from other studies. Additionally, the proportion of indeterminate QFT results were markedly lower when the sample was transported in one lithium-heparin tube instead of direct inoculation into 4 QFT-Plus tubes at the site of blood collection. IMPORTANCE In this study, we retrospectively analyzed results from both the QFT-GIT and QFT-Plus test systems from over 2 million blood specimens. The variables analyzed were (i) QFT positivity rates among various U.S. populations, (ii) indeterminate rates among various types of blood draws and how often an indeterminate result was resolved within 30 days after the initial draw, and (iii) the association of TB1 and TB2 antigen tubes with IGRA reversion and conversion events from serial QFT testing. This is, to our knowledge, the largest QFT study representing patients from an extensive geographic coverage across the United States and U.S. territories.

Multi-country evaluation of RISK6, a 6-gene blood transcriptomic signature, for tuberculosis diagnosis and treatment monitoring.

There is a crucial need for non-sputum-based TB tests. Here, we evaluate the performance of RISK6, a human-blood transcriptomic signature, for TB screening, triage and treatment monitoring. RISK6 performance was also compared to that of two IGRAs: one based on RD1 antigens (QuantiFERON-TB Gold Plus, QFT-P, Qiagen) and one on recombinant M. tuberculosis HBHA expressed in Mycobacterium smegmatis (IGRA-rmsHBHA). In this multicenter prospective nested case-control study conducted in Bangladesh, Georgia, Lebanon and Madagascar, adult non-immunocompromised patients with bacteriologically confirmed active pulmonary TB (ATB), latent TB infection (LTBI) and healthy donors (HD) were enrolled. ATB patients were followed-up during and after treatment. Blood RISK6 scores were assessed using quantitative real-time PCR and evaluated by area under the receiver-operating characteristic curve (ROC AUC). RISK6 performance to discriminate ATB from HD reached an AUC of 0.94 (95% CI 0.89-0.99), with 90.9% sensitivity and 87.8% specificity, thus achieving the minimal WHO target product profile for a non-sputum-based TB screening test. Besides, RISK6 yielded an AUC of 0.93 (95% CI 0.85-1) with 90.9% sensitivity and 88.5% specificity for discriminating ATB from LTBI. Moreover, RISK6 showed higher performance (AUC 0.90, 95% CI 0.85-0.94) than IGRA-rmsHBHA (AUC 0.75, 95% CI 0.69-0.82) to differentiate TB infection stages. Finally, RISK6 signature scores significantly decreased after 2 months of TB treatment and continued to decrease gradually until the end of treatment reaching scores obtained in HD. We confirmed the performance of RISK6 signature as a triage TB test and its utility for treatment monitoring.

Multidimensional analysis of immune responses identified biomarkers of recent Mycobacterium tuberculosis infection.

The risk of tuberculosis (TB) disease is higher in individuals with recent Mycobacterium tuberculosis (M.tb) infection compared to individuals with more remote, established infection. We aimed to define blood-based biomarkers to distinguish between recent and remote infection, which would allow targeting of recently infected individuals for preventive TB treatment. We hypothesized that integration of multiple immune measurements would outperform the diagnostic performance of a single biomarker. Analysis was performed on different components of the immune system, including adaptive and innate responses to mycobacteria, measured on recently and remotely M.tb infected adolescents. The datasets were standardized using variance stabilizing scaling and missing values were imputed using a multiple factor analysis-based approach. For data integration, we compared the performance of a Multiple Tuning Parameter Elastic Net (MTP-EN) to a standard EN model, which was built to the individual adaptive and innate datasets. Biomarkers with non-zero coefficients from the optimal single data EN models were then isolated to build logistic regression models. A decision tree and random forest model were used for statistical confirmation. We found no difference in the predictive performances of the optimal MTP-EN model and the EN model [average area under the receiver operating curve (AUROC) = 0.93]. EN models built to the integrated dataset and the adaptive dataset yielded identically high AUROC values (average AUROC = 0.91), while the innate data EN model performed poorly (average AUROC = 0.62). Results also indicated that integration of adaptive and innate biomarkers did not outperform the adaptive biomarkers alone (Likelihood Ratio Test χ2 = 6.09, p = 0.808). From a total of 193 variables, the level of HLA-DR on ESAT6/CFP10-specific Th1 cytokine-expressing CD4 cells was the strongest biomarker for recent M.tb infection. The discriminatory ability of this variable was confirmed in both tree-based models. A single biomarker measuring M.tb-specific T cell activation yielded excellent diagnostic potential to distinguish between recent and remote M.tb infection.