The Immune Response to Mycobacterium tuberculosis in HIV-1-Coinfected Persons

The role of T regulatory cells in the immunopathogenesis of HIV: Clinical implications

Human Immunodeficiency Virus (HIV) infection is among the most challenging issues in the healthcare system, presenting significant financial and hygiene problems with a wide range of clinical manifestations. Despite the hopeful outcomes of Antiretroviral Therapies (ARTs), the current strategies for the treatment of patients with HIV infection have not shown clinical significance for all subjects, which is mainly due to the complexity of the disease. Therefore, the need for collaborative and interdisciplinary research focused on deciphering the multifaceted cellular, and molecular immunopathogenesis of HIV remains essential in the development of innovative and more efficacious therapeutic approaches. T-regulatory (Treg) cells function as suppressors of effector T-cell responses contributing to the inhibition of autoimmune disorders and the limitation of chronic inflammatory diseases. Notably, these cells can play substantial roles in regulating immune responses, immunopathogenesis, viral persistence and disease progression, and affect therapeutic responses in HIV patients. In this review, we aim elucidating the role of T-regulatory cells (Tregs) in the immunopathogenesis of HIV, including immunological fatigue and seroconversion. In particular, the focus of the current study is exploration of novel immunotherapeutic approaches to target HIV or related co-infections.

Plasma Ribonuclease Activity in Antiretroviral Treatment-Naive People With Human Immunodeficiency Virus and Tuberculosis Disease

BACKGROUND

The role of ribonucleases in tuberculosis among people with human immunodeficiency virus (HIV; PWH) is unknown. We explored ribonuclease activity in plasma from PWH with and without tuberculosis.

METHODS

Participants were identified from a cohort of treatment-naive PWH in Ethiopia who had been classified for tuberculosis disease (HIV positive [HIV+]/tuberculosis positive [tuberculosis+] or HIV+/tuberculosis negative [tuberculosis-]). Ribonuclease activity in plasma was investigated by quantification of synthetic spike-in RNAs using sequencing and quantitative polymerase chain reaction and by a specific ribonuclease activity assay. Quantification of ribonuclease 1, 2, 3, 6, 7, and T2 proteins was performed by enzyme-linked immunosorbent assay. Ribonuclease activity and protein concentrations were correlated with markers of tuberculosis and HIV disease severity and with concentrations of inflammatory mediators.

RESULTS

Ribonuclease activity was significantly higher in plasma of HIV+/tuberculosis+ (n = 51) compared with HIV+/tuberculosis- (n = 78), causing reduced stability of synthetic spike-in RNAs. Concentrations of ribonucleases 2, 3, and T2 were also significantly increased in HIV+/tuberculosis+ compared with HIV+/tuberculosis-. Ribonuclease activity was correlated with HIV viral load, and inversely correlated with CD4 cell count, mid-upper arm circumference, and body mass index. Moreover, ribonuclease activity was correlated with concentrations of interleukin 27, procalcitonin and the kynurenine-tryptophan ratio.

CONCLUSIONS

PWH with tuberculosis disease have elevated plasma ribonuclease activity, which is also associated with HIV disease severity and systemic inflammation.

Reappraising the Role of T Cell-Derived IFN-γ in Restriction of Mycobacterium tuberculosis in the Murine Lung

T cells producing IFN-γ have long been considered a stalwart for immune protection against Mycobacterium tuberculosis (Mtb), but their relative importance to pulmonary immunity has been challenged by murine studies that achieved protection by adoptively transferred Mtb-specific IFN-γ-/- T cells. Using IFN-γ-/- T cell chimeric mice and adoptive transfer of IFN-γ-/- T cells into TCRβ-/-δ-/- mice, we demonstrate that control of lung Mtb burden is in fact dependent on T cell-derived IFN-γ, and, furthermore, mice selectively deficient in T cell-derived IFN-γ develop exacerbated disease compared with T cell-deficient control animals, despite equivalent lung bacterial burdens. Deficiency in T cell-derived IFN-γ skews infected and bystander monocyte-derived macrophages to an alternative M2 phenotype and promotes neutrophil and eosinophil influx. Our studies support an important role for T cell-derived IFN-γ in pulmonary immunity against tuberculosis.

A time-to-event modelling of sputum conversion within two months after antituberculosis initiation among drug-susceptible smear positive pulmonary tuberculosis patients: Implementation of internal and external validation

Delayed sputum conversion has been associated with a higher risk of treatment failure or relapse among drug susceptible smear-positive pulmonary tuberculosis patients. Several contributing factors have been identified in many studies, but the results varied across regions and countries. Therefore, the current study aimed to develop a predictive model that explained the factors affecting time to sputum conversion within two months after initiating antituberculosis agents among Malaysian with drug-susceptible smear-positive pulmonary tuberculosis patients. Retrospective data of pulmonary tuberculosis patients followed up at a tertiary hospital in the Northern region of Malaysia from 2013 until 2018 were collected and analysed. Nonlinear mixed-effect modelling software (NONMEM 7.3.0) was used to develop parametric survival models. The final model was further validated using Kaplan-Meier-visual predictive check (KM-VPC) approach, kernel-based hazard rate estimation method and sampling-importance resampling (SIR) method. A total of 224 patients were included in the study, with 34.4 % (77/224) of the patients remained positive at the end of 2 months of the intensive phase. Gompertz hazard function best described the data. The hazard of sputum conversion decreased by 39 % and 33 % for moderate and advanced lesions as compared to minimal baseline of chest X-ray severity, respectively (adjusted hazard ratio (aHR), 0.61; 95 % confidence intervals (95 % CI), (0.44-0.84) and 0.67, 95 % CI (0.53-0.84)). Meanwhile, the hazard also decreased by 59 % (aHR, 0.41; 95 % CI, (0.23-0.73)) and 48 % (aHR, 0.52; 95 % CI, (0.35-0.79)) between active and former drug abusers as compared to non-drug abuser, respectively. The successful development of the internally and externally validated final model allows a better estimation of the time to sputum conversion and provides a better understanding of the relationship with its predictors.

Intravenous BCG induces a more potent airway and lung immune response than intradermal BCG in SIV-infected macaques 1

Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is one of the leading causes of death due to an infectious agent. Coinfection with HIV exacerbates Mtb infection outcomes in people living with HIV (PLWH). Bacillus Calmette-Guérin (BCG), the only approved TB vaccine, is effective in infants, but its efficacy in adolescents and adults is limited. Here, we investigated the immune responses elicited by BCG administered via intravenous (IV) or intradermal (ID) routes in Simian Immunodeficiency Virus (SIV)-infected Mauritian cynomolgus macaques (MCM) without the confounding effects of Mtb challenge. We assessed the impact of vaccination on T cell responses in the airway, blood, and tissues (lung, thoracic lymph nodes, and spleen), as well as the expression of cytokines, cytotoxic molecules, and key transcription factors. Our results showed that IV BCG induces a robust and sustained immune response, including tissue-resident memory T (T RM ) cells in lungs, polyfunctional CD4+ and CD8αβ+ T cells expressing multiple cytokines, and CD8αβ+ T cells and NK cells expressing cytotoxic effectors in airways. We also detected higher levels of mycobacteria-specific IgG and IgM in the airways of IV BCG-vaccinated MCM. Although IV BCG vaccination resulted in an influx of T RM cells in lungs of MCM with controlled SIV replication, MCM with high plasma SIV RNA (>10 5 copies/mL) typically displayed reduced T cell responses, suggesting that uncontrolled SIV or HIV replication would have a detrimental effect on IV BCG-induced protection against Mtb.

The immunosuppressive tuberculosis-associated microenvironment inhibits viral replication and promotes HIV-1 latency in CD4+ T cells

Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), is the most common coinfection among people living with HIV-1. This coinfection is associated with accelerated HIV-1 disease progression and reduced survival. However, the impact of the HIV-1/TB coinfection on HIV-1 replication and latency in CD4+ T cells remains poorly studied. Using the acellular fraction of tuberculous pleural effusion (TB-PE), we investigated whether viral replication and HIV-1 latency in CD4+ T cells are affected by a TB-associated microenvironment. Our results revealed that TB-PE impaired T cell receptor-dependent cell activation and decreased HIV-1 replication in CD4+ T cells. Moreover, this immunosuppressive TB microenvironment promoted viral latency and inhibited HIV-1 reactivation. This study indicates that the TB-induced immune response may contribute to the persistence of the viral reservoir by silencing HIV-1 expression, allowing the virus to persist undetected by the immune system, and increasing the size of the latent HIV-1 reservoir.

Role of Type I Interferons during Mycobacterium tuberculosis and HIV Infections

Tuberculosis and AIDS remain two of the most relevant human infectious diseases. The pathogens that cause them, Mycobacterium tuberculosis (Mtb) and HIV, individually elicit an immune response that treads the line between beneficial and detrimental to the host. Co-infection further complexifies this response since the different cytokines acting on one infection might facilitate the dissemination of the other. In these responses, the role of type I interferons is often associated with antiviral mechanisms, while for bacteria such as Mtb, their importance and clinical relevance as a suitable target for manipulation are more controversial. In this article, we review the recent knowledge on how these interferons play distinct roles and sometimes have opposite consequences depending on the stage of the pathogenesis. We highlight the dichotomy between the acute and chronic infections displayed by both infections and how type I interferons contribute to an initial control of each infection individually, while their chronic induction, particularly during HIV infection, might facilitate Mtb primo-infection and progression to disease. We expect that further findings and their systematization will allow the definition of windows of opportunity for interferon manipulation according to the stage of infection, contributing to pathogen clearance and control of immunopathology.

Re-appraising the role of T-cell derived interferon gamma in restriction of Mycobacterium tuberculosis in the murine lung: T-cell derived IFNγ is required to restrict pulmonary Mtb

T cells producing interferon gamma (IFNγ) have long been considered a stalwart for immune protection against Mycobacterium tuberculosis (Mtb), but their relative importance to pulmonary immunity has been challenged by murine studies which achieved protection by adoptively transferred Mtb-specific IFNγ-/- T cells. Using IFNγ-/- T cell chimeric mice and adoptive transfer of IFNγ-/- T cells into TCRβ-/-δ-/- mice, we demonstrate that control of lung Mtb burden is in fact dependent on T cell-derived IFNγ, and furthermore, mice selectively deficient in T cell-derived IFNγ develop exacerbated disease compared to T cell-deficient controls despite equivalent lung bacterial burdens. Deficiency in T cell-derived IFNγ skews infected and bystander monocyte-derived macrophages (MDMs) to an alternative M2 phenotype, and promotes neutrophil and eosinophil influx. Our studies support an important role for T cell-derived IFNγ in pulmonary immunity against TB.

Uncovering the Bronchoalveolar Single-Cell Landscape of Patients With Pulmonary Tuberculosis With Human Immunodeficiency Virus Type 1 Coinfection

BACKGROUND

Coinfection of human immunodeficiency virus type 1 (HIV-1) is the most significant risk factor for tuberculosis (TB). The immune responses of the lung are essential to restrict the growth of Mycobacterium tuberculosis and avoid the emergence of the disease. Nevertheless, there is still limited knowledge about the local immune response in people with HIV-1-TB coinfection.

METHODS

We employed single-cell RNA sequencing (scRNA-seq) on bronchoalveolar lavage fluid from 9 individuals with HIV-1-TB coinfection and 10 with pulmonary TB.

RESULTS

A total of 19 058 cells were grouped into 4 major cell types: myeloid cells, T/natural killer (NK) cells, B cells, and epithelial cells. The myeloid cells and T/NK cells were further divided into 10 and 11 subsets, respectively. The proportions of dendritic cell subsets, CD4+ T cells, and NK cells were lower in the HIV-1-TB coinfection group compared to the TB group, while the frequency of CD8+ T cells was higher. Additionally, we identified numerous differentially expressed genes between the CD4+ and CD8+ T-cell subsets between the 2 groups.

CONCLUSIONS

HIV-1 infection not only affects the abundance of immune cells in the lungs but also alters their functions in patients with pulmonary TB.

Global prevalence, burden and trend in HIV and drug-susceptible tuberculosis co-infection from 1990 to 2019 and prediction to 2040

Objectives

The purpose of this study is to describe the current situation and forecast the trends of co-infection between the human immunodeficiency virus (HIV) and drug-susceptible tuberculosis (DS-TB) in different countries, across various age groups and genders.

Methods

We obtained data on the number of cases, age-standardized incidence rate, age-standardized prevalence rate, age-standardized rate of disability-adjusted life years (DALYs), and age-standardized death rate from the Global Burden of Disease (GBD) 2019 database. These data were used to describe the distribution and burden of co-infection between the human immunodeficiency virus (HIV) and DS-TB in different regions, genders, and age groups. We employed joinpoint regression analysis to analyze the temporal trends from 1990 to 2019. Additionally, an age-period-cohort model was established to forecast the future trends of co-infection up to 2040.

Results

The prevalence and burden of co-infection varied across different age groups and genders. The territories with the higher disease burden were distributed in some Asian and African countries. In terms of temporal trends, the age-standardized incidence rate and age-standardized prevalence rate of HIV and DS-TB co-infection exhibited an overall increasing trend from 1990 to 2019, and the prediction indicated a slow downward trend from 2019 to 2040.

Conclusions

The co-infection of HIV and DS-TB posed a grave threat to public health and economic development. What's more, there existed a significant disparity between the actual state of co-infection and the desired goals for prevention and control.

CD4+ T cells are homeostatic regulators during Mtb reinfection

Immunological priming - either in the context of prior infection or vaccination - elicits protective responses against subsequent Mycobacterium tuberculosis (Mtb) infection. However, the changes that occur in the lung cellular milieu post-primary Mtb infection and their contributions to protection upon reinfection remain poorly understood. Here, using clinical and microbiological endpoints in a non-human primate reinfection model, we demonstrate that prior Mtb infection elicits a long-lasting protective response against subsequent Mtb exposure and that the depletion of CD4+ T cells prior to Mtb rechallenge significantly abrogates this protection. Leveraging microbiologic, PET-CT, flow cytometric, and single-cell RNA-seq data from primary infection, reinfection, and reinfection-CD4+ T cell depleted granulomas, we identify differential cellular and microbial features of control. The data collectively demonstrate that the presence of CD4+ T cells in the setting of reinfection results in a reduced inflammatory lung milieu characterized by reprogrammed CD8+ T cell activity, reduced neutrophilia, and blunted type-1 immune signaling among myeloid cells, mitigating Mtb disease severity. These results open avenues for developing vaccines and therapeutics that not only target CD4+ and CD8+ T cells, but also modulate innate immune cells to limit Mtb disease.

Perspectives on pregnant women's educational needs to prevent TB complications during pregnancy and the neonatal period. A qualitative study

BACKGROUND

Tuberculosis (TB) during pregnancy could confer a high risk for maternal and infant morbidity. Literature indicates that the global burden of active TB disease among pregnant women is not well researched. Statistics for South Africa from WHO give an estimated incidence of 360, 000 cases of TB in 2019; 14,000 people became ill with multidrug-resistant TB in 2019, with a rate of 615 per 100,000 population, implying that the cohorts included pregnant women with and without a diagnosis of TB infection. Therefore, the study aims to increase the understanding of the educational needs required to prevent TB complications during pregnancy and the neonatal period in women diagnosed with TB infection.

METHODS

The study used cross-sectional qualitative and descriptive designs to collect data in the clinical setting of the primary health care services of Limpopo Province, South Africa. The population comprised pregnant women diagnosed with TB infection. A non-probability purposive sampling technique was used to sample 2 health centers and 5 clinics in each of the three sampled districts. The targeted sample size was 63 and it was achieved even though data saturation was observed. Individual interviews were conducted, audiotaped, and transcribed. Guided by the study questions, a thematic content analysis of the findings was used. Ethical considerations were also observed.

RESULTS

Despite that pregnant women have general knowledge about TB disease, the knowledge and awareness regarding the prevention of TB complications in pregnancy and the neonatal period, information on TB/HIV and COVID-19 co-infections, and participants' knowledge about other non-infectious diseases that may affect the mother with TB infection and foetus showed a deficit.

CONCLUSION

Pregnant women with TB disease need to be educated on the negative effects of non-adherence to TB treatment during pregnancy and the neonatal period. There is a need to educate pregnant women about the variant signs and symptoms of TB, HIV and COVID-19 infections since there is a misconception that the three diseases are similar. It is important that pregnant mothers diagnosed with TB should start treatment as soon as possible.

Converging Epidemics: A Narrative Review of Tuberculosis (TB) and Human Immunodeficiency Virus (HIV) Coinfection

Tuberculosis (TB), primarily caused by Mycobacterium tuberculosis (MTB), remains a leading cause of mortality in individuals living with human immunodeficiency virus (HIV) infection, posing a significant strain on healthcare systems. Coinfection of HIV and TB results in a mutually advantageous relationship that accelerates the progression of both diseases. TB is a major contributor to mortality in individuals with HIV. However, diagnosing coinfected individuals is challenging due to the prevalence of extrapulmonary TB and smear-negative disease. Over the past decade, significant progress has been made in the fight against TB, thanks to advances in molecular techniques. Yet, these molecular diagnostic assays remain inaccessible to many individuals coinfected with HIV and TB due to their high cost. To expedite treatment and reduce transmission, it is crucial to integrate HIV and TB control programs more closely, thereby minimizing diagnostic delays and enhancing early case detection. This review aims to provide a comprehensive overview of the current state of knowledge regarding the interplay between HIV and TB. It highlights recent developments in sensitive and rapid TB diagnostic tests, cutting-edge preventive strategies, and the screening of individuals coinfected with both HIV and TB. The objectives of this review are to shed light on the complex relationship between these two diseases and to emphasize the importance of integrated efforts in combating their impact on public health.

Best practice guidelines for professional nurses to provide self-management support to adults with tuberculosis-human immunodeficiency virus coinfection: A scoping review

BACKGROUND

Adults with tuberculosis-human immunodeficiency virus coinfection require professional nurses' support to manage their illness, treatment and its effect on their daily lives. This scoping review maps recommendations in clinical or best practice guidelines that guide professional nurses to provide self-management support to adults with tuberculosis-human immunodeficiency virus coinfection in primary healthcare settings.

METHODS

We conducted a scoping review by searching for guidelines in six online databases, guideline clearing houses and search engines from 16th April 2022 to 25th May 2022. The title, abstract and full-text screening of guidelines were conducted independently and in duplicate by two reviewers based on predetermined eligibility criteria. The guidelines were critically appraised with the Appraisal of Guidelines Research and Evaluation (AGREE) II instrument. Relevant data regarding the characteristics of the guideline, recommendations and underlying evidence were extracted, analysed and reported.

RESULTS

The six guidelines on self-management support found were developed in four high-income countries. Five of the guidelines recorded <60% across all six domains of the AGREE II instrument. One high-quality guideline scored >60% in all AGREE II domains but was informed by outdated evidence produced between 1977 to 2010. Twenty-five practice, education and organisational/policy recommendations were extracted from the high-quality guideline. The guidelines did not report evidence-to-decision frameworks and the strength of the recommendations. The guidelines also lacked direct underlying evidence on the effectiveness and cost of self-management support. Lastly, the review found a paucity of contextual (equity, acceptability and feasibility) evidence on self-management support among adults with tuberculosis-human immunodeficiency virus in the guidelines.

CONCLUSION

There is a dearth of updated and relevant high-quality guidelines that guide healthcare professionals to provide self-management support to adults with tuberculosis-human immunodeficiency virus coinfection in primary healthcare settings. Systematic reviews of effectiveness, economic and contextual evidence related to self-management support interventions are required for guideline production.

The impact of comorbidities on tuberculosis treatment outcomes in Poland: a national cohort study

Background

Tuberculosis (TB) is a complex disease associated with other medical conditions, that may affect disease severity. This study aimed to investigate the impact of comorbidities on treatment outcomes and mortality rates in patients with TB in Poland.

Methods

We analyzed a national cohort of 19,217 adult TB patients diagnosed between 2011 and 2016 in Poland. We compared treatment success rates and mortality rates in patients with comorbidities and those without to assess the impact of various comorbidities on these outcomes. Odds ratios (OR) were calculated to quantify the association between comorbidities and TB treatment outcomes.

Results

Patients with comorbidities had lower treatment success rates and higher mortality rates. Diabetes was identified as a significant risk factor for increased TB mortality (OR = 1.9) and mortality from all other causes (OR = 4.5). Similar associations were found for alcoholism (OR = 8.3 and OR = 7.1), immunosuppressive therapy (OR = 5.7 and OR = 5.9), and cancer (OR = 3.4 and OR = 15.4). HIV and tobacco use were associated with an increased risk of mortality from causes other than TB, with odds ratios of 28.6 and 2.2, respectively. The overall treatment success rate in the study population was 88.0%, with 9.2% of patients failing to achieve treatment success and 2.8% dying. Comorbidities such as diabetes, alcoholism, substance addiction, immunosuppressive therapy, cancer, and tobacco use increased the risk of tuberculosis treatment failure.

Conclusion

Patients with comorbidities face a higher risk of unsuccessful treatment outcomes and increased mortality. It is essential to implement integrated management strategies that address both TB and comorbid conditions to improve treatment success rates and reduce mortality.

Mycobacterium tuberculosis and SARS-CoV-2 co-infections: The knowns and unknowns

Health impacts of Mycobacterium tuberculosis (Mtb) and SARS-CoV-2 co-infections are not fully understood. Both pathogens modulate host responses and induce immunopathology with extensive lung damage. With a quarter of the world's population harboring latent TB, exploring the relationship between SARS-CoV-2 infection and its effect on the transition of Mtb from latent to active form is paramount to control this pathogen. The effects of active Mtb infection on establishment and severity of COVID-19 are also unknown, despite the ability of TB to orchestrate profound long-lasting immunopathologies in the lungs. Absence of mechanistic studies and co-infection models hinder the development of effective interventions to reduce the health impacts of SARS-CoV-2 and Mtb co-infection. Here, we highlight dysregulated immune responses induced by SARS-CoV-2 and Mtb, their potential interplay, and implications for co-infection in the lungs. As both pathogens master immunomodulation, we discuss relevant converging and diverging immune-related pathways underlying SARS-CoV-2 and Mtb co-infections.

HIV/Mtb Co-Infection: From the Amplification of Disease Pathogenesis to an “Emerging Syndemic”

Human immunodeficiency virus (HIV) and Mycobacterium tuberculosis (Mtb) are pathogens responsible for millions of new infections each year; together, they cause high morbidity and mortality worldwide. In addition, late-stage HIV infection increases the risk of developing tuberculosis (TB) by a factor of 20 in latently infected people, and even patients with controlled HIV infection on antiretroviral therapy (ART) have a fourfold increased risk of developing TB. Conversely, Mtb infection exacerbates HIV pathogenesis and increases the rate of AIDS progression. In this review, we discuss this reciprocal amplification of HIV/Mtb coinfection and how they influence each other’s pathogenesis. Elucidating the infectious cofactors that impact on pathogenesis may open doors for the design of new potential therapeutic strategies to control disease progression, especially in contexts where vaccines or the sterile clearance of pathogens are not effectively available.

The role of sialic acid-binding immunoglobulin-like-lectin-1 (siglec-1) in immunology and infectious disease

Siglec-1, also known as Sialoadhesin (Sn) and CD169 is highly conserved among vertebrates and with 17 immunoglobulin-like domains is Siglec-1 the largest member of the Siglec family. Expression of Siglec-1 is found primarily on dendritic cells (DCs), macrophages and interferon induced monocyte. The structure of Siglec-1 is unique among siglecs and its function as a receptor is also different compared to other receptors in this class as it contains the most extracellular domains out of all the siglecs. However, the ability of Siglec-1 to internalize antigens and to pass them on to lymphocytes by allowing dendritic cells and macrophages to act as antigen presenting cells, is the main reason that has granted Siglec-1's key role in multiple human disease states including atherosclerosis, coronary artery disease, autoimmune diseases, cell-cell signaling, immunology, and more importantly bacterial and viral infections. Enveloped viruses for example have been shown to manipulate Siglec-1 to increase their virulence by binding to sialic acids present on the virus glycoproteins allowing them to spread or evade immune response. Siglec-1 mediates dissemination of HIV-1 in activated tissues enhancing viral spread via infection of DC/T-cell synapses. Overall, the ability of Siglec-1 to bind a variety of target cells within the immune system such as erythrocytes, B-cells, CD8+ granulocytes and NK cells, highlights that Siglec-1 is a unique player in these essential processes.

Dysregulation of the IFN-I signaling pathway by Mycobacterium tuberculosis leads to exacerbation of HIV-1 infection of macrophages

While tuberculosis (TB) is a risk factor in HIV-1-infected individuals, the mechanisms by which Mycobacterium tuberculosis (Mtb), the agent of TB in humans, worsens HIV-1 pathogenesis still need to be fully elucidated. Recently, we showed that HIV-1 infection and spread are exacerbated in macrophages exposed to TB-associated microenvironments. Transcriptomic analysis of macrophages conditioned with medium of Mtb-infected human macrophages (cmMTB) revealed an up-regulation of the typeI interferon (IFN-I) pathway, characterized by the overexpression of IFN-inducible genes. Historically, IFN-I are well known for their antiviral functions, but our previous work showed that this is not the case in the context of coinfection with HIV-1. Here, we show that the IFN-I response signature in cmMTB-treated macrophages matches the one observed in the blood of active TB patients, and depends on the timing of incubation with cmMTB. This suggests that the timing of macrophage's exposure to IFN-I can impact their capacity to control HIV-1 infection. Strikingly, we found that cmMTB-treated macrophages are hyporesponsive to extrastimulation with exogenous IFN-I, used to mimic HIV-1 infection. Yet, depleting STAT1 by gene silencing to block the IFN-I signaling pathway reduced TB-induced exacerbation of HIV-1 infection. Altogether, by aiming to understand why TB-derived IFN-I preexposure of macrophages did not induce antiviral immunity against HIV-1, we demonstrated that these cells are hyporesponsive to exogenous IFN-I, a phenomenon that prevents macrophage activation against HIV-1.

Impact of COVID-19 on Tuberculosis Indicators in Brazil: A Time Series and Spatial Analysis Study

Background: We aimed to visualize and classify the time series of COVID-19, tuberculosis (TB) notification, and TB outcomes (cure, treatment abandonment, and death), verify the impact of the new coronavirus pandemic on these indices in Brazil, and verify the presence of spatial autocorrelation between COVID-19 and TB. Methods: This was an ecological time series study that considered TB and COVID-19 cases. Seasonal Trend Decomposition using Loess (STL) was used to trace the temporal trend, Prais–Winsten was used to classify the temporal trend, Interrupted Time Series (ITS) was used to verify the impact of COVID-19 on TB rates, and the Bivariate Moran Index (Global and Local) was used to verify the spatial autocorrelation of events. Results: Brazil and its macro-regions showed an increasing temporal trend for the notification of TB in the pre-pandemic period. Only the Northeast Region showed a decreasing temporal trend for cured cases. For treatment abandonment, all regions except for the Northeast showed an increasing temporal trend, and regarding death, Brazil and the Northeast Region showed an increasing temporal trend. With the ITS, COVID-19 caused a decline in TB notification rates and TB outcome rates. With the global spatial analysis, it was possible to identify the existence of spatial autocorrelation between the notification rate of COVID-19 and the TB notification rate and deaths. With the local analysis, it was possible to map the Brazilian municipalities and classify them according to the relationship between the rates of both diseases and space. Conclusions: COVID-19 influenced the follow-up of and adherence to TB treatment and intensified social vulnerability and, consequently, affected the notification of TB since the relationship between the disease and social determinants of health is already known. The restoration and strengthening of essential services for the prevention and detection of cases and treatment of TB in endemic environments such as Brazil have been oriented as a priority in the global health agenda.

Tuberculosis Treatment Response Monitoring by the Phenotypic Characterization of MTB-Specific CD4+ T-Cells in Relation to HIV Infection Status

HIV infection causes systemic immune activation, impacts TB disease progression and hence may influence the diagnostic usability of Mycobacterium tuberculosis-specific T cell profiling. We investigated changes of activation and maturation markers on MTB-specific CD4+ T-cells after anti-tuberculosis treatment initiation in relation to HIV status and the severity of lung impairment. Thawed peripheral blood mononuclear cells from TB patients with (n = 27) and without HIV (n = 17) were analyzed using an intracellular IFN-γ assay and flow cytometry 2 and 6 months post-TB treatment initiation. H37Rv antigen was superior to the profile MTB-specific CD4+ T-cells phenotype when compared to PPD and ESAT6/CFP10. Regardless of HIV status and the severity of lung impairment, activation markers (CD38, HLA-DR and Ki67) on MTB-specific CD4+ T-cells declined after TB treatment initiation (p < 0.01), but the expression of the maturation marker CD27 did not change over the course of TB treatment. The MTB-specific T cell phenotype before, during and after treatment completion was similar between people living with and without HIV, as well as between subjects with severe and mild lung impairment. These data suggest that the assessment of activation and maturation markers on MTB-specific CD4+ T-cells can be useful for TB treatment monitoring, regardless of HIV status and the severity of lung disease.

Diagnosis and treatment of tuberculosis in adults with HIV

Mycobacterium tuberculosis, the causative agent of tuberculosis (TB), continues to pose a major public health problem and is the leading cause of mortality in people infected with human immunodeficiency virus (HIV). HIV infection greatly increases the risk of developing TB even before CD4+ T-cell counts decrease. Co-infection provides reciprocal advantages to both pathogens and leads to acceleration of both diseases. In HIV-coinfected persons, the diagnosis and treatment of tuberculosis are particularly challenging. Intensifying integration of HIV and tuberculosis control programmes has an impact on reducing diagnostic delays, increasing early case detection, providing prompt treatment onset, and ultimately reducing transmission. In this Review, we describe our current understanding of how these two pathogens interact with each other, new sensitive rapid assays for TB, several new prevention methods, new drugs and regimens.

HIV infection and the implication for COVID‐19 vaccination

Abstract

Human immunodeficiency virus (HIV) is associated with altered cellular and humoral immune response, especially in patients with an untreated or chronic infection. This may be due to direct and/or indirect HIV viral activities resulting in T‐ and B‐cells dysfunctions. Although still unclear, various studies have proposed that HIV infection may exacerbate the clinical outcomes of COVID‐19. Indeed, COVID‐19 vaccines were developed in record time and have been shown to reduce the severity of COVID‐19 in the general population. These vaccines were also earmarked as a solution to global disruptions caused by the COVID‐19 pandemic. HIV infection has been reported to reduce the efficacy of various other vaccines including those used against Streptococcus pneumoniae, Clostridium tetani, and influenza viruses. However, current guidelines for the administration of available COVID‐19 vaccines do not account for the immune‐compromised state of people living with HIV (PLWH). We discuss here the potentials, nature, and implications of this HIV‐induced dampening of the humoral immune response on COVID‐19 vaccines by first reviewing the literature about efficacy of previous vaccines in PLWH, and then assessing the proportion of PLWH included in phase III clinical trials of the COVID‐19 vaccines currently available. The clinical and public health implications as well as suggestions for governments and non‐governmental organizations are also proposed in the context of whether findings on the safety and efficacy of the vaccines could be extended to PLWH.

Impacts

The human immunodeficiency virus (HIV) is characterized by attenuated humoral immunity that may reduce the efficacy of vaccines in people living with HIV (PLWH). Vaccination against the SARS‐CoV‐2 infection remains the main public health answer to the COVID‐19 pandemic.

Although no significant safety concerns have been raised regarding the COVID‐19 vaccines in PLWH, the efficacy of these vaccines in PLWH has not received due attention. Indeed, phase III clinical trials for the safety and efficacy of COVID‐19 vaccines involved a significantly low number of PLWH.

There are major gaps in knowledge on the efficacy of COVID‐19 vaccines in PLWH and until further research is carried out, PLWH should be prioritized along with other at‐risk groups for repeated vaccination and safeguard.

Phosphatidylcholine Liposomes Down-Modulate CD4 Expression Reducing HIV Entry in Human Type-1 Macrophages

A strategy adopted to combat human immunodeficiency virus type-1 (HIV-1) infection is based on interfering with virus entry into target cells. In this study, we found that phosphatidylcholine (PC) liposomes reduced the expression of the CD4 receptor in human primary type-1 macrophages but not in CD4⁺ T cells. The down-regulation was specific to CD4, as any effect was not observed in CCR5 membrane expression. Moreover, the reduction of membrane CD4 expression required the Ca²⁺-independent protein kinase C (PKC), which in turn mediated serine phosphorylation in the intracytoplasmic tail of the CD4 receptor. Serine phosphorylation of CD4 was also associated with its internalization and degradation in acidic compartments. Finally, the observed CD4 downregulation induced by PC liposomes in human primary macrophages reduced the entry of both single-cycle replication and replication competent R5 tropic HIV-1. Altogether, these results show that PC liposomes reduce HIV entry in human macrophages and may impact HIV pathogenesis by lowering the viral reservoir.

Kynurenine/tryptophan ratio for detection of active tuberculosis in adults with HIV prior to antiretroviral therapy

OBJECTIVE

The aim of this study was to assess the performance of kynurenine/tryptophan ratio for tuberculosis (TB) case-finding among antiretroviral therapy (ART)-naive people with HIV (PWH), and to investigate other factors associated with kynurenine/tryptophan ratio in this population.

DESIGN

A nested case--control study based on a cohort of 812 ambulatory PWH in the Oromia region, Ethiopia.

METHODS

At enrolment, all participants submitted sputum samples for bacteriological TB investigations. Concentrations of kynurenine and tryptophan in plasma were quantified using liquid chromatography-mass spectrometry. Receiver operator characteristic curves were constructed to assess diagnostic performance (area under the curve; AUC) for kynurenine, tryptophan, and kynurenine/tryptophan ratio. Sensitivity, specificity, and predictive values were calculated. Kynurenine/tryptophan ratios were correlated to plasma levels of nine inflammation mediators, plasma HIV RNA levels, CD4+ cell count, BMI, and mid-upper arm circumference (MUAC).

RESULTS

We included 124 individuals with HIV-TB coinfection (HIV+/TB+) and 125 with HIV mono-infection (HIV+/TB-). Tryptophan levels were lower in HIV+/TB+ than in HIV+/TB- (median 19.5 vs. 29.8 μmol/l, P < 0.01), while kynurenine levels were similar between these groups (median 2.95 vs. 2.94 μmol/l, P = 0.62). Median kynurenine/tryptophan ratio was 0.15 in HIV+/TB+, significantly higher compared with HIV+/TB- (0.11; P < 0.01), with AUC 0.70 for TB detection. Kynurenine/tryptophan ratio was positively correlated to plasma HIV RNA levels, IP-10, IL-18, and IL-27, and negatively correlated to CD4+ cell count, BMI, and MUAC (all P < 0.01).

CONCLUSION

Among ART-naive PWH, kynurenine/tryptophan ratio has modest potential for TB discrimination, limiting its utility for TB case-finding in this population.

CD4 T cells are rapidly depleted from tuberculosis granulomas following acute SIV co-infection

HIV/Mycobacterium tuberculosis (Mtb) co-infected individuals have an increased risk of tuberculosis prior to loss of peripheral CD4 T cells, raising the possibility that HIV co-infection leads to CD4 T cell depletion in lung tissue before it is evident in blood. Here, we use rhesus macaques to study the early effects of simian immunodeficiency virus (SIV) co-infection on pulmonary granulomas. Two weeks after SIV inoculation of Mtb-infected macaques, Mtb-specific CD4 T cells are dramatically depleted from granulomas, before CD4 T cell loss in blood, airways, and lymph nodes, or increases in bacterial loads or radiographic evidence of disease. Spatially, CD4 T cells are preferentially depleted from the granuloma core and cuff relative to B cell-rich regions. Moreover, live imaging of granuloma explants show that intralesional CD4 T cell motility is reduced after SIV co-infection. Thus, granuloma CD4 T cells may be decimated before many co-infected individuals experience the first symptoms of acute HIV infection.

Medical Care for Tuberculosis-HIV-Coinfected Patients in Russia with Respect to a Changeable Patients’ Structure

To date, tuberculosis (TB) remains the primary cause of mortality in human immunodeficiency virus (HIV) patients in Russia. Since the beginning of 2000, a sharp change in the HIV patients’ structure, to the main known risk factors for HIV infection has taken place in Russia. The transmission of HIV through injectable drug use has begun to decline significantly, giving way to the prevalence of sexual HIV transmission today. These changes may require adjustments to organizational approaches to anti-TB care and the treatment of HIV-positive patients. Our study is aimed at identifying changes in TB-HIV coinfection patients’ structures in 2019 compared to 2000. Based on the results obtained, our goal was to point out the parameters that need to be taken into account when developing approaches to improve the organization of TB control care for people with HIV infection. We have carried out a cross-sectional, retrospective, epidemiological study using government TB registry data from four regions in two federal districts of Russia in 2019. The case histories of 2265 patients from two regions with high HIV prevalence, which are part of the Siberian Federal District of Russia, and 89 patient histories from two regions of low HIV prevalence, which are part of the Central Federal District of Russia, were analyzed. We found that parenteral transmission (69.4%) remains the primary route of HIV transmission among the TB-HIV coinfected. The unemployed of working age without disability account for 80.2% of all coinfected people, while the formerly incarcerated account for 53.7% and the homeless account for 4.1%. Those with primary multidrug-resistant TB (MDR-TB) comprise 56.2% of HIV-TB patients. When comparing the incidence of coinfection with HIV among TB patients, statistically significant differences were obtained. Thus, the chances of coinfection increased by 4.33 times among people with active TB (95% CI: 2.31; 8.12), by 2.97 times among people with MDR-TB (95% CI: 1.66; 5.32), by 5.2 times in people with advanced processes in the lungs, including destruction, (95% CI: 2.78; 9.7), as well as by 10.3 times in the case of death within the first year after the TB diagnosis (95% CI: 2.99; 35.5). The absence of data for the presence of TB during preventive examination was accompanied by a decrease in the chances of detecting coinfection (OR 0.36; 95% CI: 0.2; 0.64). We have identified the probable causes of the high incidence of TB among HIV-infected: HIV-patient social maladaptation usually results in delayed medical care, leading to TB treatment regimen violations. Furthermore, self-administration of drugs triggers MDR-TB within this group. Healthcare providers should clearly explain to patients the critical importance of immediately seeking medical care when initial TB symptoms appear.

Defining Discriminatory Antibody Fingerprints in Active and Latent Tuberculosis

Tuberculosis (TB) is among the leading causes of death worldwide from a single infectious agent, second only to COVID-19 in 2020. TB is caused by infection with Mycobacterium tuberculosis (Mtb), that results either in a latent or active form of disease, the latter associated with Mtb spread. In the absence of an effective vaccine, epidemiologic modeling suggests that aggressive treatment of individuals with active TB (ATB) may curb spread. Yet, clinical discrimination between latent (LTB) and ATB remains a challenge. While antibodies are widely used to diagnose many infections, the utility of antibody-based tests to diagnose ATB has only regained significant traction recently. Specifically, recent interest in the humoral immune response to TB has pointed to potential differences in both targeted antigens and antibody features that can discriminate latent and active TB. Here we aimed to integrate these observations and broadly profile the humoral immune response across individuals with LTB or ATB, with and without HIV co-infection, to define the most discriminatory humoral properties and diagnose TB disease more easily. Using 209 Mtb antigens, striking differences in antigen-recognition were observed across latently and actively infected individuals that was modulated by HIV serostatus. However, ATB and LTB could be discriminated, irrespective of HIV-status, based on a combination of both antibody levels and Fc receptor-binding characteristics targeting both well characterized (like lipoarabinomannan, 38 kDa or antigen 85) but also novel Mtb antigens (including Rv1792, Rv1528, Rv2435C or Rv1508). These data reveal new Mtb-specific immunologic markers that can improve the classification of ATB versus LTB.

Frequency of CXCR3+ CD8+ T-Lymphocyte Subsets in Peripheral Blood Is Associated With the Risk of Paradoxical Tuberculosis-Associated Immune Reconstitution Inflammatory Syndrome Development in Advanced HIV Disease

Background

Tuberculosis-associated immune reconstitution inflammatory syndrome (TB-IRIS) is a clinical aggravation of TB symptoms observed among a fraction of HIV coinfected patients shortly after the start of antiretroviral therapy (ART). Of note, TB-IRIS is characterized by exacerbated inflammation and tissue damage that occurs in response to the elevated production of CD4+ T cell-derived IFN-γ. Nevertheless, the possible participation of CD8+ T cells in TB-IRIS development remains unclear.

Methods

We performed a comprehensive assessment of the composition of CD8+ T cell memory subsets and their association with circulating inflammation-related molecules in TB-HIV coinfected patients initiating ART.

Results

We found that TB-IRIS individuals display higher frequencies of Antigen-experienced CD8+ T cells during the onset of IRIS and that the levels of these cells positively correlate with baseline mycobacterial smear grade. TB-IRIS individuals exhibited higher frequencies of effector memory and lower percentages of naïve CD8+ T cells than their Non-IRIS counterparts. In both TB-IRIS and Non-IRIS patients, ART commencement was associated with fewer significant correlations among memory CD8+ T cells and cells from other immune compartments. Networks analysis revealed distinct patterns of correlation between each memory subset with inflammatory cytokines suggesting different dynamics of CD8+ T cell memory subsets reconstitution. TB-IRIS patients displayed lower levels of memory cells positive for CXCR3 (a chemokine receptor that plays a role in trafficking activated CD8+ T cells to the tissues) than Non-IRIS individuals before and after ART. Furthermore, we found that CXCR3+ naïve CD8+ T cells were inversely associated with the risk of TB-IRIS development. On the other hand, we noticed that the frequencies of CXCR3+ effector CD8+ T cells were positively associated with the probability of TB-IRIS development.

Conclusion

Our data suggest that TB-IRIS individuals display a distinct profile of memory CD8+ T cell subsets reconstitution after ART initiation. Moreover, our data point to a differential association between the frequencies of CXCR3+ CD8+ T cells and the risk of TB-IRIS development. Collectively, our findings lend insights into the potential role of memory CD8+ T cells in TB-IRIS pathophysiology.

Expression of MicroRNAs Is Dysregulated by HIV While Mycobacterium tuberculosis Drives Alterations of Small Nucleolar RNAs in HIV Positive Adults With Active Tuberculosis

HIV infection affects the course of tuberculosis (TB), and HIV and Mycobacterium tuberculosis (Mtb) synergize in disease progression through complex immunological interplay. To gain further understanding of these mechanisms, we compared the microRNA (miRNA) and small nucleolar RNA (snoRNA) expression patterns in whole blood of individuals with active TB, with and without HIV coinfection (HIV+/TB+ and HIV-/TB+), and HIV and TB-negative individuals (HIV-/TB-). We found that 218 miRNAs were differentially expressed between HIV+/TB+ and HIV-/TB+, while no statistically significant difference in snoRNA expression was observed between these groups. In contrast, both miRNA (n = 179) and snoRNA (n = 103) expression patterns were significantly altered in HIV+/TB+ individuals compared to those of the HIV-/TB- controls. Of note, 26 of these snoRNAs were also significantly altered between the HIV-/TB+ and HIV-/TB- groups. Normalization toward the miRNA and snoRNA expression patterns of the HIV-/TB- control group was noted during anti-TB and antiretroviral treatment in HIV+/TB+ participants. In summary, these results show that HIV coinfection influences miRNA expression in active TB. In contrast, snoRNA expression patterns differ between individuals with and without active TB, independently of HIV coinfection status. Moreover, in coinfected individuals, therapy-induced control of HIV replication and clearance of Mtb appears to normalize the expression of some small non-coding RNA (sncRNA). These findings suggest that dysregulation of miRNA is a mechanism by which HIV may modify immunity against TB, while active TB alters snoRNA expression. Improved understanding of how regulation of sncRNA expression influences the disease course in coinfected individuals may have implications for diagnostics, risk stratification, and host-directed therapy. Here, we propose a novel mechanism by which HIV alters the immune response to TB.

In the Thick of It: Formation of the Tuberculous Granuloma and Its Effects on Host and Therapeutic Responses

The defining pathology of tuberculosis is the granuloma, an organized structure derived from host immune cells that surrounds infecting Mycobacterium tuberculosis. As the location of much of the bacteria in the infected host, the granuloma is a central point of interaction between the host and the infecting bacterium. This review describes the signals and cellular reprogramming that drive granuloma formation. Further, as a central point of host-bacterial interactions, the granuloma shapes disease outcome by altering host immune responses and bacterial susceptibility to antibiotic treatment, as discussed herein. This new understanding of granuloma biology and the signaling behind it highlights the potential for host-directed therapies targeting the granuloma to enhance antibiotic access and tuberculosis-specific immune responses.

Single-cell transcriptomic landscape identifies the expansion of peripheral blood monocytes as an indicator of HIV-1-TB co-infection

Certain circulating cell subsets are involved in immune dysregulation in human immunodeficiency virus type 1 (HIV-1) and tuberculosis (TB) co-infection; however, the characteristics and role of these subclusters are unknown. Peripheral blood mononuclear cells (PBMCs) of patients with HIV-1 infection alone (HIV-pre) and those with HIV-1-TB co-infection without anti-TB treatment (HIV-pre & TB-pre) and with anti-TB treatment for 2 weeks (HIV-pre & TB-pos) were subjected to single-cell RNA sequencing (scRNA-seq) to characterize the transcriptome of different immune cell subclusters. We obtained > 60,000 cells and identified 32 cell subclusters based on gene expression. The proportion of immune-cell subclusters was altered in HIV-1-TB co-infected individuals compared with that in HIV-pre-group, indicating immune dysregulation corresponding to different disease states. The proportion of an inflammatory CD14+CD16+ monocyte subset was higher in the HIV-pre & TB-pre group than in the HIV-pre group; this was validated in an additional cohort (n = 80) via a blood cell differential test, which also demonstrated a good discriminative performance (area under the curve, 0.8046). These findings depicted the atlas of immune PBMC subclusters in HIV-1-TB co-infection and demonstrate that monocyte subsets in peripheral blood might serve as a discriminating biomarker for diagnosis of HIV-1-TB co-infection.

Nanocages engineered from Bacillus Calmette-Guerin facilitate protective Vγ2Vδ2 T cell immunity against Mycobacterium tuberculosis infection

Tuberculosis (TB), induced by Mycobacterium tuberculosis (Mtb) infection, remains a top killer among infectious diseases. While Bacillus Calmette-Guerin (BCG) is the sole TB vaccine, the clumped-clustered features of BCG in intradermal immunization appear to limit both the BCG protection efficacy and the BCG vaccination safety. We hypothesize that engineering of clumped-clustered BCG into nanoscale particles would improve safety and also facilitate the antigen-presenting-cell (APC)’s uptake and the following processing/presentation for better anti-TB protective immunity. Here, we engineered BCG protoplasts into nanoscale membraned BCG particles, termed as “BCG-Nanocage” to enhance the anti-TB vaccination efficiency and safety. BCG-Nanocage could readily be ingested/taken by APC macrophages selectively; BCG-Nanocage-ingested macrophages exhibited better viability and developed similar antimicrobial responses with BCG-infected macrophages. BCG-Nanocage, like live BCG bacilli, exhibited the robust capability to activate and expand innate-like T effector cell populations of Vγ2+ T, CD4+ T and CD8+ T cells of rhesus macaques in the ex vivo PBMC culture. BCG-Nanocage immunization of rhesus macaques elicited similar or stronger memory-like immune responses of Vγ2Vδ2 T cells, as well as Vγ2Vδ2 T and CD4+/CD8+ T effectors compared to live BCG vaccination. BCG-Nanocage- immunized macaques developed rapidly-sustained pulmonary responses of Vγ2Vδ2 T cells upon Mtb challenge. Furthermore, BCG- and BCG-Nanocage- immunized macaques, but not saline controls, exhibited undetectable Mtb infection loads or TB lesions in the Mtb-challenged lung lobe and hilar lymph node at endpoint after challenge. Thus, the current study well justifies a large pre-clinical investigation to assess BCG-Nanocage for safe and efficacious anti-TB vaccination, which is expected to further develop novel vaccines or adjuvants.

Phosphatidylserine liposomes reduce inflammatory response, mycobacterial viability and HIV replication in coinfected human macrophages

Chronic immune activation is the key pathogenetic event of Mycobacterium tuberculosis (MTB) and human immunodeficiency virus (HIV) coinfection. In the present study, we have assessed the therapeutic value of phosphatidylserine-liposome (PS-L) in an in vitro model of MTB/HIV coinfection. Our results show that PS-L reduce NF-κB activation and the downstream production of TNF-α, IL-1β and IL-6 in BCG-infected macrophages and of TNF-α and IL-1β in MTB-infected and in MTB/HIV-coinfected macrophages. Importantly, a significant reduction of intracellular MTB viability and HIV replication were also observed. These results support the further exploitation of PS-L as a host directed therapy for MTB/HIV coinfection.

Robust IgM responses following intravenous vaccination with Bacille Calmette-Guérin associate with prevention of Mycobacterium tuberculosis infection in macaques

Development of an effective tuberculosis (TB) vaccine has suffered from an incomplete understanding of the correlates of protection against Mycobacterium tuberculosis (Mtb). Intravenous (i.v.) vaccination with Bacille Calmette-Guérin (BCG) provides nearly complete protection against TB in rhesus macaques, but the antibody response it elicits remains incompletely defined. Here we show that i.v. BCG drives superior antibody responses in the plasma and the lungs of rhesus macaques compared to traditional intradermal BCG administration. While i.v. BCG broadly expands antibody titers and functions, IgM titers in the plasma and lungs of immunized macaques are among the strongest markers of reduced bacterial burden. IgM was also enriched in macaques that received protective vaccination with an attenuated strain of Mtb. Finally, an Mtb-specific IgM monoclonal antibody reduced Mtb survival in vitro. Collectively, these data highlight the potential importance of IgM responses as a marker and mediator of protection against TB.

Leprosy: what is new

Leprosy, also known as Hansen's disease, is an age-old chronic granulomatous infection characterized by prominent cutaneous and neurologic findings. Long known to be caused by Mycobacterium leprae, a new etiologic species was identified and linked in 2008, Mycobacterium lepromatosis. The BCG vaccine with highly variable efficacy may soon be replaced by the first leprosy-specific subunit vaccine LepVax, which has recently moved forward in human trials. Recent evidence supporting theories of zoonotic transmission from armadillos and the less-discussed Eurasian red squirrels has emerged. Knowledge on genetic polymorphisms that may increase leprosy susceptibility, such as the newly uncovered mitochondrial ribosomal protein S5 (MRPS5) polymorphism in the Chinese population, has provided a fresh perspective and direction. Further, we will delineate the latest information on leprosy, including the possible effects of leprosy coinfection with COVID-19, HIV, and HTLV-1, and the shift to newer leprosy therapies and treatment regimens.

Association of tuberculosis treatment with pregnancy complications: A protocol for systematic review and meta-analysis

BACKGROUND

The increasing burden of tuberculosis (TB) remains a very serious concern around the world, and account for a decreased quantity and quality of life. However, there is a limited epidemiology of the association of TB treatment with pregnancy. We aim to assess the effects of TB treatment in pregnancy complications.

METHODS

This will be a systematic review and meta-analysis of published studies on the association of TB treatment with pregnancy, retrieved from ScienceDirect, Web of Science, LILACS, Pubmed, Google scholar, Embase, Medline, ResearchGate, EBSCOhost and Cochrane library databases. The eligibility of the studies will be screened in accordance to the selection criteria by two independent reviewers. The quality and risk of bias of eligible studies will be performed by both reviewers using the Hoy tool and Grading of Recommendations Assessment, Development and Evaluation (GRADE) tool in accordance to the measured outcomes (Hypertension in pregnancy, Pre-eclampsia, Hypertensive disorders of pregnancy, Fetal growth restriction, Miscarriage and Recurrent spontaneous abortion). A data charting table will be used to extract background information and process the data items from each eligible study. The data will be analysed using Review Manager 5.3 (RevMan 5.3) software. Generic Inverse Variance method will be used for meta-analysis of both, individually and cluster randomized trials.

ETHICS AND DISSEMINATION

The review and meta-analysis will not require ethical approval and the findings will be published in peer-reviewed journals and presented at local and international conferences. In addition, the study findings will be made accessible to the national committee of TB to formulate TB guidelines for their respective settings.

SYSTEMATIC REVIEW REGISTRATION

International prospective Register of Systematic Reviews (PROSERO) number: CRD42021231872.

Serological and cellular inflammatory signatures in end-stage kidney disease and latent tuberculosis

Objectives

Tuberculosis comorbidity with chronic diseases including diabetes, HIV and chronic kidney disease is of rising concern. In particular, latent tuberculosis infection (LTBI) comorbidity with end‐stage kidney disease (ESKD) is associated with up to 52.5‐fold increased risk of TB reactivation to active tuberculosis infection (ATBI). The immunological mechanisms driving this significant rise in TB reactivation are poorly understood. To contribute to this understanding, we performed a comprehensive assessment of soluble and cellular immune features amongst a unique cohort of patients comorbid with ESKD and LTBI.

Methods

We assessed the plasma and cellular immune profiles from patients with and without ESKD and/or LTBI (N = 40). We characterised antibody glycosylation, serum complement and cytokine levels. We also assessed classical and non‐classical monocytes and T cells with flow cytometry. Using a systems‐based approach, we identified key immunological features that discriminate between the different disease states.

Results

Individuals with ESKD exhibited a highly inflammatory plasma profile and an activated cellular state compared with those without ESKD, including higher levels of inflammatory antibody Fc glycosylation structures and activated CX3CR1⁺ monocytes that correlate with increased inflammatory plasma cytokines. Similar elevated inflammatory signatures were also observed in ESKD⁺/LTBI⁺ compared with ESKD⁻/LTBI⁺, suggesting that ESKD induces an overwhelming inflammatory immune state. In contrast, no significant inflammatory differences were observed when comparing LTBI⁺ and LTBI⁻ individuals.

Conclusion

Our study highlights the highly inflammatory state induced by ESKD. We hypothesise that this inflammatory state could contribute to the increased risk of TB reactivation in ESKD patients.

Cytomegalovirus Infection Is Associated With Increased Prevalence of Latent Tuberculosis Infection

Cytomegalovirus (CMV) increases tuberculosis (TB) risk, but its relationship with latent TB infection (LTBI) is unknown. Using US nationally representative data, we report that CMV was independently associated with LTBI (odds ratio, 2.94; 95% CI, 1.19–7.28; P=.02). CMV and LTBI were associated with higher C-reactive protein, suggesting chronic inflammation.

Th22 Cells Are a Major Contributor to the Mycobacterial CD4+ T Cell Response and Are Depleted During HIV Infection

HIV-1 infection substantially increases the risk of developing tuberculosis (TB). Mechanisms such as defects in the Th1 response to Mycobacterium tuberculosis in HIV-infected persons have been widely reported. However, Th1-independent mechanisms also contribute to protection against TB. To identify a broader spectrum of defects in TB immunity during HIV infection, we examined IL-17A and IL-22 production in response to mycobacterial Ags in peripheral blood of persons with latent TB infection and HIV coinfection. Upon stimulating with mycobacterial Ags, we observed a distinct CD4+ Th lineage producing IL-22 in the absence of IL-17A and IFN-γ. Mycobacteria-specific Th22 cells were present at high frequencies in blood and contributed up to 50% to the CD4+ T cell response to mycobacteria, comparable in magnitude to the IFN-γ Th1 response (median 0.91% and 0.55%, respectively). Phenotypic characterization of Th22 cells revealed that their memory differentiation was similar to M. tuberculosis-specific Th1 cells (i.e., predominantly early differentiated CD45RO+CD27+ phenotype). Moreover, CCR6 and CXCR3 expression profiles of Th22 cells were similar to Th17 cells, whereas their CCR4 and CCR10 expression patterns displayed an intermediate phenotype between Th1 and Th17 cells. Strikingly, mycobacterial IL-22 responses were 3-fold lower in HIV-infected persons compared with uninfected persons, and the magnitude of responses correlated inversely with HIV viral load. These data provide important insights into mycobacteria-specific Th subsets in humans and suggest a potential role for IL-22 in protection against TB during HIV infection. Further studies are needed to fully elucidate the role of IL-22 in protective TB immunity.

Tuberculosis among Patients Admitted to the Department of Medicine of a Tertiary Care Center in Nepal: A Descriptive Cross-sectional Study

Introduction:

Tuberculosis has high burden in developing countries like Nepal. This study aims to determine the prevalence of tuberculosis among patients admitted in the department of medicine of a tertiary hospital.

Methods:

A descriptive cross-sectional study of all the patients admitted to the tertiary care hospital from 1^st January 2017 to 31^st December 2019 was done. Ethical approval was obtained from Institutional Review Committee (Ref: drs2006181387). Convenience sampling method was used. A descriptive analysis of demographic, clinical and laboratory profile of patients was made using Microsoft Excel version 2016. Point estimate at 95% Confidence Interval was calculated along with frequency and proportion for binary data.

Results:

Among 6829 patients admitted to the department of medicine, 209 (3.06%) (2.65-3.47 at 95% CI) patients were diagnosed with tuberculosis. Among them, 147 (70.33%) were males and the mean age was 49.77 years. Pulmonary and extra-pulmonary tuberculosis were present in 153 (73.20%) and 56 (26.79%) patients, respectively. Bacteriological confirmation was limited to 107 (70%) of pulmonary tuberculosis and 3 (5%) of extrapulmonary tuberculosis. Fever was the commonest presentation in 166 (79.42%) followed by cough in 164 (78.46%), anorexia in 108 (51.67%), weight loss 104 (49.76%), and others.

Conclusions:

The study showed that the prevalence of tuberculosis among admitted patients was higher than national prevalence.

A Parsimonious Host Inflammatory Biomarker Signature Predicts Incident Tuberculosis and Mortality in Advanced Human Immunodeficiency Virus

BACKGROUND

People with advanced human immunodeficiency virus (HIV) (CD4 < 50) remain at high risk of tuberculosis (TB) or death despite the initiation of antiretroviral therapy (ART). We aimed to identify immunological profiles that were most predictive of incident TB disease and death.

METHODS

The REMEMBER randomized clinical trial enrolled 850 participants with HIV (CD4 < 50 cells/µL) at ART initiation to receive either empiric TB treatment or isoniazid preventive therapy (IPT). A case-cohort study (n = 257) stratified by country and treatment arm was performed. Cases were defined as incident TB or all-cause death within 48 weeks after ART initiation. Using multiplexed immunoassay panels and ELISA, 26 biomarkers were assessed in plasma.

RESULTS

In total, 52 (6.1%) of 850 participants developed TB; 47 (5.5%) died (13 of whom had antecedent TB). Biomarkers associated with incident TB overlapped with those associated with death (interleukin [IL]-1β, IL-6). Biomarker levels declined over time in individuals with incident TB while remaining persistently elevated in those who died. Dividing the cohort into development and validation sets, the final model of 6 biomarkers (CXCL10, IL-1β, IL-10, sCD14, tumor necrosis factor [TNF]-α, and TNF-β) achieved a sensitivity of 0.90 (95% confidence interval [CI]: .87-.94) and a specificity of 0.71(95% CI: .68-.75) with an area under the curve (AUC) of 0.81 (95% CI: .78-.83) for incident TB.

CONCLUSION

Among people with advanced HIV, a parsimonious inflammatory biomarker signature predicted those at highest risk for developing TB despite initiation of ART and TB preventive therapies. The signature may be a promising stratification tool to select patients who may benefit from increased monitoring and novel interventions.

CLINICAL TRIALS REGISTRATION

NCT01380080.

A non-canonical type 2 immune response coordinates tuberculous granuloma formation and epithelialization

The central pathogen-immune interface in tuberculosis is the granuloma, a complex host immune structure that dictates infection trajectory and physiology. Granuloma macrophages undergo a dramatic transition in which entire epithelial modules are induced and define granuloma architecture. In tuberculosis, relatively little is known about the host signals that trigger this transition. Using the zebrafish-Mycobacterium marinum model, we identify the basis of granuloma macrophage transformation. Single-cell RNA-sequencing analysis of zebrafish granulomas and analysis of Mycobacterium tuberculosis-infected macaques reveal that, even in the presence of robust type 1 immune responses, countervailing type 2 signals associate with macrophage epithelialization. We find that type 2 immune signaling, mediated via stat6, is absolutely required for epithelialization and granuloma formation. In mixed chimeras, stat6 acts cell autonomously within macrophages, where it is required for epithelioid transformation and incorporation into necrotic granulomas. These findings establish the signaling pathway that produces the hallmark structure of mycobacterial infection.

Host-directed therapy to combat mycobacterial infections

Upon infection, mycobacteria, such as Mycobacterium tuberculosis (Mtb) and nontuberculous mycobacteria (NTM), are recognized by host innate immune cells, triggering a series of intracellular processes that promote mycobacterial killing. Mycobacteria, however, have developed multiple counter‐strategies to persist and survive inside host cells. By manipulating host effector mechanisms, including phagosome maturation, vacuolar escape, autophagy, antigen presentation, and metabolic pathways, pathogenic mycobacteria are able to establish long‐lasting infection. Counteracting these mycobacteria‐induced host modifying mechanisms can be accomplished by host‐directed therapeutic (HDT) strategies. HDTs offer several major advantages compared to conventional antibiotics: (a) HDTs can be effective against both drug‐resistant and drug‐susceptible bacteria, as well as potentially dormant mycobacteria; (b) HDTs are less likely to induce bacterial drug resistance; and (c) HDTs could synergize with, or shorten antibiotic treatment by targeting different pathways. In this review, we will explore host‐pathogen interactions that have been identified for Mtb for which potential HDTs impacting both innate and adaptive immunity are available, and outline those worthy of future research. We will also discuss possibilities to target NTM infection by HDT, although current knowledge regarding host‐pathogen interactions for NTM is limited compared to Mtb. Finally, we speculate that combinatorial HDT strategies can potentially synergize to achieve optimal mycobacterial host immune control.

Early innate and adaptive immune perturbations determine long-term severity of chronic virus and Mycobacterium tuberculosis coinfection

Chronic viral infections increase severity of Mycobacterium tuberculosis (Mtb) coinfection. Here, we examined how chronic viral infections alter the pulmonary microenvironment to foster coinfection and worsen disease severity. We developed a coordinated system of chronic virus and Mtb infection that induced central clinical manifestations of coinfection, including increased Mtb burden, extra-pulmonary dissemination, and heightened mortality. These disease states were not due to chronic virus-induced immunosuppression or exhaustion; rather, increased amounts of the cytokine TNFα initially arrested pulmonary Mtb growth, impeding dendritic cell mediated antigen transportation to the lymph node and subverting immune-surveillance, allowing bacterial sanctuary. The cryptic Mtb replication delayed CD4 T cell priming, redirecting T helper (Th) 1 toward Th17 differentiation and increasing pulmonary neutrophilia, which diminished long-term survival. Temporally restoring CD4 T cell induction overcame these diverse disease sequelae to enhance Mtb control. Thus, Mtb co-opts TNFα from the chronic inflammatory environment to subvert immune-surveillance, avert early immune function, and foster long-term coinfection.

Concurrent cavitary pulmonary tuberculosis and COVID-19 pneumonia with in vitro immune cell anergy

Tuberculosis (TB) is top infectious disease killer caused by a single organism responsible for 1.5 million deaths in 2018. Both COVID-19 and the pandemic response are risking to affect control measures for TB and continuity of essential services for people affected by this infection in western countries and even more in developing countries. Knowledge about concomitant pulmonary TB and COVID-19 is extremely limited. The double burden of these two diseases can have devastating effects. Here, we describe from both the clinical and the immunological point of view a case of a patient with in vitro immune cell anergy affected by bilateral cavitary pulmonary TB and subsequent COVID-19-associated pneumonia with a worst outcome. COVID-19 can be a precipitating factor in TB respiratory failure and, during ongoing SARS-COV-2 pandemic, clinicians must be aware of this possible co-infection in differential diagnosis of patients with active TB and new or worsening chest imaging.

Immune variations throughout the course of tuberculosis treatment and its relationship with adrenal hormone changes in HIV-1 patients co-infected with Mycobacterium tuberculosis

HIV infection is a major risk factor predisposing for Mycobacterium tuberculosis infection and progression to active tuberculosis (TB). As host immune response defines the course of infection, we aimed to identify immuno-endocrine changes over six-months of anti-TB chemotherapy in HIV+ people. Plasma levels of cortisol, DHEA and DHEA-S, percentages of CD4⁺ regulatory T cell subsets and number of IFN-γ-secreting cells were determined. Several cytokines, chemokines and C-reactive protein levels were measured. Results were correlated with clinical parameters as predictors of infection resolution and compared to similar data from HIV+ individuals, HIV-infected persons with latent TB infection and healthy donors. Throughout the course of anti-TB/HIV treatment, DHEA and DHEA-S plasma levels raised while cortisol diminished, which correlated to predictive factors of infection resolution. Furthermore, the balance between cortisol and DHEA, together with clinical assessment, may be considered as an indicator of clinical outcome after anti-TB treatment in HIV+ individuals. Clinical improvement was associated with reduced frequency of unconventional Tregs, increment in IFN-γ-secreting cells, diminution of systemic inflammation and changes of circulating cytokines and chemokines. This study suggests that the combined anti-HIV/TB therapies result in partial restoration of both, immune function and adrenal hormone plasma levels.