Latent and Active Tuberculosis Infection Increase Immune Activation in Individuals Co-Infected with HIV

Inflammation in HIV and Its Impact on Atherosclerotic Cardiovascular Disease

People living with HIV have a 1.5- to 2-fold increased risk of developing cardiovascular disease. Despite treatment with highly effective antiretroviral therapy, people living with HIV have chronic inflammation that makes them susceptible to multiple comorbidities. Several factors, including the HIV reservoir, coinfections, clonal hematopoiesis of indeterminate potential (CHIP), microbial translocation, and antiretroviral therapy, may contribute to the chronic state of inflammation. Within the innate immune system, macrophages harbor latent HIV and are among the prominent immune cells present in atheroma during the progression of atherosclerosis. They secrete inflammatory cytokines such as IL (interleukin)-6 and tumor necrosis-α that stimulate the expression of adhesion molecules on the endothelium. This leads to the recruitment of other immune cells, including cluster of differentiation (CD)8+ and CD4+ T cells, also present in early and late atheroma. As such, cells of the innate and adaptive immune systems contribute to both systemic inflammation and vascular inflammation. On a molecular level, HIV-1 primes the NLRP3 (NLR family pyrin domain containing 3) inflammasome, leading to an increased expression of IL-1β, which is important for cardiovascular outcomes. Moreover, activation of TLRs (toll-like receptors) by HIV, gut microbes, and substance abuse further activates the NLRP3 inflammasome pathway. Finally, HIV proteins such as Nef (negative regulatory factor) can inhibit cholesterol efflux in monocytes and macrophages through direct action on the cholesterol transporter ABCA1 (ATP-binding cassette transporter A1), which promotes the formation of foam cells and the progression of atherosclerotic plaque. Here, we summarize the stages of atherosclerosis in the context of HIV, highlighting the effects of HIV, coinfections, and antiretroviral therapy on cells of the innate and adaptive immune system and describe current and future interventions to reduce residual inflammation and improve cardiovascular outcomes among people living with HIV.

Cardiac and Renal Comorbidities in Aging People Living With HIV

Contemporary World Health Organization data indicates that ≈39 million people are living with the human immunodeficiency virus. Of these, 24 million have been reported to have successfully accessed combination antiretroviral therapy. In 1996, the World Health Organization endorsed the widespread use of combination antiretroviral therapy, transforming human immunodeficiency virus infection from being a life-threatening disease to a chronic illness characterized by multiple comorbidities. The increased access to combination antiretroviral therapy has translated to people living with human immunodeficiency virus (PLWH) no longer having a reduced life expectancy. Although aging as a biological process increases exposure to oxidative stress and subsequent systemic inflammation, this effect is likely enhanced in PLWH as they age. This narrative review engages the intricate interplay between human immunodeficiency virus associated chronic inflammation, combination antiretroviral therapy, and cardiac and renal comorbidities development in aging PLWH. We examine the evolving demographic profile of PLWH, emphasizing the increasing prevalence of aging individuals within this population. A central focus of the review discusses the pathophysiological mechanisms that underpin the heightened susceptibility of PLWH to renal and cardiac diseases as they age.

HIV-Associated Neurocognitive Disorder: A Look into Cellular and Molecular Pathology

Despite combined antiretroviral therapy (cART) limiting HIV replication to undetectable levels in the blood, people living with HIV continue to experience HIV-associated neurocognitive disorder (HAND). HAND is associated with neurocognitive impairment, including motor impairment, and memory loss. HIV has been detected in the brain within 8 days of estimated exposure and the mechanisms for this early entry are being actively studied. Once having entered into the central nervous system (CNS), HIV degrades the blood-brain barrier through the production of its gp120 and Tat proteins. These proteins are directly toxic to endothelial cells and neurons, and propagate inflammatory cytokines by the activation of immune cells and dysregulation of tight junction proteins. The BBB breakdown is associated with the progression of neurocognitive disease. One of the main hurdles for treatment for HAND is the latent pool of cells, which are insensitive to cART and prolong inflammation by harboring the provirus in long-lived cells that can reactivate, causing damage. Multiple strategies are being studied to combat the latent pool and HAND; however, clinically, these approaches have been insufficient and require further revisions. The goal of this paper is to aggregate the known mechanisms and challenges associated with HAND.

Decreased IL-1 β Secretion as a Potential Predictor of Tuberculosis Recurrence in Individuals Diagnosed with HIV

Background: The mechanisms of the formation of immunological competence against tuberculosis (TB), and especially those associated with HIV co-infection, remain poorly understood. However, there is an urgent need for risk recurrence predictive biomarkers, as well as for predictors of successful treatment outcomes. The goal of the study was to identify possible immunological markers of TB recurrence in individuals with HIV/TB co-infection. Methods: The plasma levels of IFN-γ, TNF-α, IL-10, and IL-1β (cytokines which play important roles in the immune activation and protection against Mycobacterium tuberculosis) were measured using ELISA EIA-BEST kits. The cytokine concentrations were determined using a standard curve obtained with the standards provided by the manufacturer of each kit. Results: A total of 211 individuals were enrolled in the study as follows: 62 patients with HIV/TB co-infection, 52 with HIV monoinfection, 52 with TB monoinfection, and 45 healthy donors. Out of the 62 patients with HIV/TB, 75.8% (47) of patients were newly diagnosed with HIV and TB, and 24.2% (15) displayed recurrent TB and were newly diagnosed with HIV. Decreased levels of IFN-γ, TNF-α, and IL-10 were observed in patients with HIV/TB when compared with HIV and TB patients. However, there was no difference in IFN-γ, TNF-α, or IL-10 secretion between both HIV/TB groups. At the same time, an almost 4-fold decrease in Il-1β levels was detected in the HIV/TB group with TB recurrence when compared with the HIV/TB group (p = 0.0001); a 2.8-fold decrease when compared with HIV patients (p = 0.001); and a 2.2-fold decrease with newly diagnosed TB patients (p = 0.001). Conclusions: Significantly decreased Il-1β levels in HIV/TB patients' cohort with secondary TB indicate that this cytokine can be a potential biomarker of TB recurrence.

Serum cytokine biosignatures for identification of tuberculosis among HIV-positive inpatients

BACKGROUND

Serum cytokines correlate with tuberculosis (TB) progression and are predictors of TB recurrence in people living with HIV. We investigated whether serum cytokine biosignatures could diagnose TB among HIV-positive inpatients.

METHODS

We recruited HIV-positive inpatients with symptoms of TB and measured serum levels of inflammation biomarkers including IL-2, IL-4, IL-6, IL-10, tumour necrosis factor-alpha (TNF-α) and interferon-gamma (IFN-γ). We then built and tested our TB prediction model.

RESULTS

236 HIV-positive inpatients were enrolled in the first cohort and all the inflammation biomarkers were significantly higher in participants with microbiologically confirmed TB than those without TB. A binary support vector machine (SVM) model was built, incorporating the data of four biomarkers (IL-6, IL-10, TNF-α and IFN-γ). Efficacy of the SVM model was assessed in training (n=189) and validation (n=47) sets with area under the curve (AUC) of 0.92 (95% CI 0.88 to 0.96) and 0.85 (95% CI 0.72 to 0.97), respectively. In an independent test set (n=110), the SVM model yielded an AUC of 0.85 (95% CI 0.76 to 0.94) with 78% (95% CI 68% to 87%) specificity and 85% (95% CI 66% to 96%) sensitivity. Moreover, the SVM model outperformed interferon-gamma release assay (IGRA) among advanced HIV-positive inpatients irrespective of CD4+ T-cell counts, which may be an alternative approach for identifying Mycobacterium tuberculosis infection among HIV-positive inpatients with negative IGRA.

CONCLUSIONS

The four-cytokine biosignature model successfully identified TB among HIV-positive inpatients. This diagnostic model may be an alternative approach to diagnose TB in advanced HIV-positive inpatients with low CD4+ T-cell counts.

Impact of Latent M. tuberculosis Infection Treatment on Time to CD4/CD8 Recovery in Acute, Recent, and Chronic HIV Infection

INTRODUCTION

In people living with HIV, active and latent tuberculosis (TB) coinfections are associated with immune activation that correlate with HIV progression and mortality. We investigated the effect of initiating antiretroviral therapy (ART) during acute (AHI), recent (RHI), or chronic HIV infection (CHI) on CD4/CD8 ratio normalization and associated factors, the impact of latent TB infection treatment, and prior/concomitant TB diagnosis at the time of ART initiation.

METHODS

We included sex with men and transgender women individuals initiating ART with AHI, RHI and CHI between 2013 and 2019, from a prospective cohort in Brazil. We compared time from ART initiation to the first normal CD4/CD8 ratio (CD4/CD8 ≥1) using Kaplan-Meier curves and multivariable Cox proportional hazards models. Sociodemographic and clinical variables were explored. Variables with P -values <0.20 in univariable analyses were included in multivariable analyses.

RESULTS

Five hundred fifty participants were included, 11.8% classified as AHI and 6.4% as RHI, 46.7% with CHI-CD4 cell counts ≥350 cells/mm 3 and 35.1% with CHI-CD4 cell counts <350 cells/mm 3 . Time to normalization was shortest among AHI patients, followed by RHI and CHI individuals with higher baseline CD4. In the multivariable model, AHI was associated with a six-fold increased likelihood of achieving a CD4/CD8 ratio ≥1 (hazard ratio [HR]: 6.03; 95% confidence interval [CI]: 3.70 to 9.82; P < 0.001), RHI with HR: 4.47 (95% CI: 2.57 to 7.76; P < 0.001), and CHI CD4 ≥350 cells/mm 3 with HR: 1.87 (95% CI: 1.24 to 2.84; P = 0.003). Latent TB infection treatment was significantly associated with a higher likelihood of the outcome (HR: 1.79; 95% CI: 1.22 to 2.62; P = 0.003). Previous history or concomitant active TB at ART initiation was associated with a lower likelihood of the outcome (HR: 0.41; 95% CI: 0.16 to 1.02; P = 0.054).

CONCLUSIONS

Initiating ART early during AHI may offer an opportunity to mitigate immune damage. Efforts to implement HIV diagnosis and ART initiation during AHI are critical to amplify ART benefits.

Latent tuberculosis is associated with heightened levels of pro-and anti-inflammatory cytokines among Kenyan men and women living with HIV on long-term antiretroviral therapy

BACKGROUND

Persons with HIV (PWH) on antiretroviral therapy (ART) have persistent immune activation associated with increased risk for non-AIDS related diseases. Latent tuberculosis infection (LTBI), endemic in Africa, may contribute to this immune dysregulation. We evaluated the impact of HIV and TB co-infection on plasma pro- and anti-inflammatory cytokines among Kenyan adults.

METHODS

We compared data from 221 PWH on long-term ART and 177 HIV-negative adults examining biomarkers of pro-[sCD14, interleukin (IL)-2, IL-6, interferon gamma (IFN-γ), tumor necrosis factor alpha (TNF-α), IL-12p70, IL-17A] and anti(IL-4, IL-5, IL-13) inflammatory cytokines, by HIV/LTBI status (HIV+LTBI+, HIV+LTBI-, HIV-LTBI+, HIV-LTBI-). LTBI was diagnosed based on a positive QuantiFERON TB Gold-Plus test in the absence of active TB symptoms. Linear regression was used to evaluate the associations of HIV, LTBI, and HIV/LTBI status with biomarkers adjusting for clinical factors including HIV-specific factors.

RESULTS

Half of the participants were women and 52% had LTBI. HIV was independently associated with higher sCD14, IL-15, IL-6, IL-4, IL-5. LTBI was independently associated with higher TNF-α, IL-12p70, IL-17A, IL-4, IL-13 in adjusted models ( P  < 0.05). LTBI status was associated with higher IL-4 and IL-12p70 only among PWH, but not HIV-negative participants ( P  < 0.05 for interactions). In multivariate analysis, only HIV+LTBI+ demonstrated elevated levels of TNF-α, IL-6, IL-12p70, IL-15, IL-17A, IL4, IL-5, IL-13 in comparison to the HIV-LTBI- ( P  < 0.05 for all). The effect of LTBI on cytokines among PWH was independent of CD4 + T-cell count and ART duration.

CONCLUSIONS

Despite viral suppression, persons with HIV and LTBI exhibit abnormal cytokine production accompanied by high concentrations of pro- and anti-inflammatory cytokines.

Exploring the link between cardiovascular risk factors and manifestations in latent tuberculosis infection: a comprehensive literature review

BACKGROUND

The global burden of tuberculosis (TB) and cardiovascular disease (CVD) is overt, and the prevalence of this double burden disease remains steadily rising, particularly in low- and middle-income countries. This review aims to explore the association between latent tuberculosis infection (LTBI) and the development of cardiovascular diseases and risk factors. Furthermore, we elucidated the underlying pathophysiological mechanisms that contribute to this relationship.

MAIN BODY

Approximately 25% of the global population carries a dormant form of tuberculosis (TB) infection. During this latent stage, certain subsets of mycobacteria actively reproduce, and recent research suggests that latent TB infection (LTBI) is connected to persistent, long-term low-grade inflammation that can potentially contribute to the development of atherosclerosis and cardiovascular disease (CVD). The presence of LTBI can be confirmed through a positive result on either a tuberculin skin test (TST) or an interferon-gamma release assay (IGRA). Several plausible explanations for the association between LTBI and CVD include increased inflammation, autoimmunity related to heat shock proteins (HSP), and the presence of pathogens within the developing atherosclerotic plaque. The most commonly observed cardiovascular events and risk factors associated with LTBI are acute myocardial infarction, coronary artery stenosis, diabetes mellitus, and hypertension.

CONCLUSIONS

This article highlights the critical role of LTBI in perpetuating the tuberculosis disease cycle and its association with cardiovascular risk factors. Chronic and persistent low inflammation underlined the association. Identifying high-risk LTBI patients and providing targeted preventive medication are crucial strategies for global TB eradication and interrupting transmission chains.

Quantitative Assessment of a Dual Epidemic Caused by Tuberculosis and HIV in the Philippines

Tuberculosis (TB) and human immunodeficiency virus (HIV) are the two major public health emergencies in the Philippines. The country is ranked fourth worldwide in TB incidence cases despite national efforts and initiatives to mitigate the disease. Concurrently, the Philippines has the fastest-growing HIV epidemic in Asia and the Pacific region. The TB-HIV dual epidemic forms a lethal combination enhancing each other's progress, driving the deterioration of immune responses. In order to understand and describe the transmission dynamics and epidemiological patterns of the co-infection, a compartmental model for TB-HIV is developed. A class of people living with HIV (PLHIV) who did not know their HIV status is incorporated into the model. These unaware PLHIV who do not seek medical treatment are potential sources of new HIV infections that could significantly influence the disease transmission dynamics. Sensitivity analysis using the partial rank correlation coefficient is performed to assess model parameters that are influential to the output of interests. The model is calibrated using available Philippine data on TB, HIV, and TB-HIV. Parameters that are identified include TB and HIV transmission rates, progression rates from exposed to active TB, and from TB-latent with HIV to active infectious TB with HIV in the AIDS stage. Uncertainty analysis is performed to identify the degree of accuracy of the estimates. Simulations predict an alarming increase of 180% and 194% in new HIV and TB-HIV infections in 2025, respectively, relative to 2019 data. These projections underscore an ongoing health crisis in the Philippines that calls for a combined and collective effort by the government and the public to take action against the lethal combination of TB and HIV.

Mycobacterium tuberculosis disease associates with higher HIV-1-specific antibody responses

Mycobacterium tuberculosis (Mtb) is the most common infection among people with HIV (PWH). Mtb disease-associated inflammation could affect HIV-directed immune responses in PWH. We show that HIV antibodies are broader and more potent in PWH in the presence as compared to the absence of Mtb disease. With co-existing Mtb disease, the virus in PWH also encounters unique antibody selection pressure. The Mtb-linked HIV antibody enhancement associates with specific mediators important for B cell and antibody development. This Mtb humoral augmentation does not occur due to cross-reactivity, a generalized increase in all antibodies, or differences in duration or amount of antigen exposure. We speculate that the co-localization of Mtb and HIV in lymphatic tissues leads to the emergence of potent HIV antibodies. PWH's Mtb disease status has implications for the future use of HIV broadly neutralizing antibodies as prophylaxis or treatment and the induction of better humoral immunity.

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.

Peripheral Blood Markers Correlate with the Progression of Active Tuberculosis Relative to Latent Control of Mycobacterium tuberculosis Infection in Macaques

Despite a century of research into tuberculosis (TB), there is a dearth of reproducible, easily quantifiable, biomarkers that can predict disease onset and differentiate between host disease states. Due to the challenges associated with human sampling, nonhuman primates (NHPs) are utilized for recapitulating the closest possible modelling of human TB. To establish a predictive peripheral biomarker profile based on a larger cohort of rhesus macaques (RM), we analyzed results pertaining to peripheral blood serum chemistry and cell counts from RMs that were experimentally exposed to Mtb in our prior studies and characterized as having either developed active TB (ATB) disease or latent TB infection (LTBI). We compared lung CFU burdens and quantitative pathologies with a number of measurables in the peripheral blood. Based on our results, the investigations were then extended to the study of specific molecules and cells in the lung compartments of a subset of these animals and their immune responses. In addition to the elevated serum C-reactive protein (CRP) levels, frequently used to discern the level of Mtb infection in model systems, reduced serum albumin-to-globulin (A/G) ratios were also predictive of active TB disease. Furthermore, higher peripheral myeloid cell levels, particularly those of neutrophils, kynurenine-to-tryptophan ratio, an indicator of induced expression of the immunosuppressive molecule indoleamine dioxygenase, and an influx of myeloid cell populations could also efficiently discriminate between ATB and LTBI in experimentally infected macaques. These quantifiable correlates of disease were then used in conjunction with a regression-based analysis to predict bacterial load. Our results suggest a potential biomarker profile of TB disease in rhesus macaques, that could inform future NHP–TB research. Our results thus suggest that specific biomarkers may be developed from the myeloid subset of peripheral blood or plasma with the ability to discriminate between active and latent Mtb infection.

A novel prediction model to evaluate the probability of CD4+/CD8+ cell ratio restoration in HIV-infected individuals

BACKGROUND

Our study aimed to develop a clinical prediction model to evaluate the possibility of CD4+/CD8+ ratio restoration in HIV-positive individuals.

METHODS

About 1980, HIV/AIDS patients initiated with antiretroviral treatment from 1 January 2013, to 30 December 2016, at Beijing Ditan Hospital and achieved persistent virological suppression during the 4 years follow-up were included in this study. Multivariate Cox proportional regression analysis was used to identify the independent risk factors and establish a predictive model. The model's performance was assessed using the area under the receiver operating characteristic and calibration plots.

RESULTS

Overall, after 4 years of treatment, a total of 455 individuals (22.98%) restored their CD4+/CD8+ ratio (≥1). The area under the receiver operating characteristic was 0.782 and 0.743 in the deriving and validation cohort, respectively. The ultimate model included five indexes: age at AIDS diagnosis, albumin, and syphilis status, and baseline CD4+ and CD8+ values. A nomogram further visualized the model, and the calibration plots indicated high agreement of predicted and observed outcomes.

CONCLUSION

Our prediction model might be practical and easily applied to recognize HIV/AIDS individuals most likely to benefit from modern antiretroviral therapy.

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.

Interferon-γ-Inducible Protein 10 (IP-10) Kinetics after Antiretroviral Treatment Initiation in Ethiopian Adults with HIV

Interferon-γ-inducible protein 10 (IP-10) has been suggested as a marker for targeted viral load (VL) monitoring during antiretroviral treatment (ART). We aimed to determine the kinetics of IP-10 during the initial year of ART, with particular regard to the impact of tuberculosis (TB) co-infection on IP-10 secretion. Longitudinal plasma IP-10 levels were quantified in 112 treatment-naive HIV-positive adults at Ethiopian health centers, through enzyme-linked immunosorbent assay (ELISA) using samples obtained before and during the initial 12 months of ART. All participants underwent bacteriological TB investigation before starting ART. In virological responders (VRs; defined as VL < 150 copies/ml with no subsequent VL ≥ 1,000 copies/ml), IP-10 kinetics were analyzed using linear regression models. Among 91/112 (81.3%) participants classified as VRs, 17 (18.7%) had concomitant TB. Median baseline IP-10 was 650 pg/ml (interquartile range [IQR], 428-1,002) in VRs. IP-10 decline was more rapid during the first month of ART (median 306 pg/ml/month) compared with later time intervals (median 7-48 pg/ml/month, P < 0.001 in each comparison). Although VRs with TB had higher IP-10 levels at baseline (median 1106 pg/ml [IQR, 627-1,704]), compared with individuals without TB (median 628 pg/ml [IQR, 391-885]; P = 0.003), the rate of IP-10 decline during ART was similar, regardless of TB-status. During the initial year of ART, IP-10 kinetics followed a biphasic pattern in VRs, with a more rapid decline in the first month of ART compared with later time intervals. Baseline IP-10 was higher in individuals with TB versus individuals without TB, but the kinetics during ART were similar. IMPORTANCE To reach the goal of elimination of HIV as public health threat, access to antiretroviral treatment (ART) has to be further scaled up. To ensure viral suppression in individuals receiving ART, novel and robust systems for treatment monitoring are required. Targeting viral load monitoring to identify individuals at increased likelihood of treatment failure, using screening tools, could be an effective use of limited resources for viral load testing. Interferon-γ-inducible protein 10 (IP-10), a host inflammation mediator, has shown potential for this purpose. Here, we have investigated IP-10 kinetics in Ethiopian adults with HIV during the initial year after ART initiation. IP-10 levels decreased in parallel with viral load during ART, and prevalent tuberculosis at ART initiation did not influence IP-10 kinetics. This study shows satisfactory performance for IP-10 as a surrogate marker for viral load in persons starting ART, with no influence of concomitant tuberculosis.

Dynamics of Plasmatic Levels of Pro- and Anti-Inflammatory Cytokines in HIV-Infected Individuals with M. tuberculosis Co-Infection

Tuberculosis (TB) and HIV have profound effects on the immune system, which can lead to the activation of viral replication and negatively regulate the activation of T cells. Dysregulation in the production of cytokines necessary to fight HIV and M. tuberculosis may ultimately affect the results of the treatment and be important in the pathogenesis of HIV infection and TB. This work presents the results of a study of the expression of pro- and anti-inflammatory cytokines (IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10, IL-1RA) in drug-naïve patients with dual infection of HIV/TB at the late stages of HIV-infection, with newly diagnosed HIV and TB, and previously untreated HIV in the process of receiving antiretroviral (ART) and TB treatment vs. a cohort of patients with HIV monoinfection and TB monoinfection. The study revealed that during a double HIV/TB infection, both Th1 and Th2 immune responses are suppressed, and a prolonged dysregulation of the immune response and an increased severity of the disease in pulmonary/extrapulmonary tuberculosis is observed in HIV/TB co-infection. Moreover, it was revealed that a double HIV/TB infection is characterized by delayed and incomplete recovery of immune activity. High levels of IL-6 were detected in patients with HIV/TB co-infection before initiation of dual therapy (2.1-fold increase vs. HIV), which persisted even after 6 months of treatment (8.96-fold increase vs. HIV), unlike other cytokines. The persistent enhanced expression of IL-6 in patients with dual HIV/TB co-infection allows the consideration of it as a potential marker of early detection of M. tuberculosis infection in HIV-infected individuals. The results of multivariate regression analysis showed a statistical trend towards an increase in the incidence of IRIS in patients with high IL-1Ra levels (in the range of 1550–2500 pg/mL): OR = 4.3 (95%CI 3.7–14.12, p = 0.53), which also allows IL-1Ra to be considered as a potential predictive biomarker of the development of TB-IRIS and treatment outcomes.

HIV-Related Immune Activation and Inflammation: Current Understanding and Strategies

Although antiretroviral therapy effectively controls human immunodeficiency virus (HIV) replication, a residual chronic immune activation/inflammation persists throughout the disease. This aberrant immune activation and inflammation are considered an accelerator of non-AIDS-related events and one of the driving forces of CD4⁺ T cell depletion. Unfortunately, HIV-associated immune activation is driven by various factors, while the mechanism of excessive inflammation has not been formally clarified. To date, several clinical interventions or treatment candidates undergoing clinical trials have been proposed to combat this systemic immune activation/inflammation. However, these strategies revealed limited results, or their nonspecific anti-inflammatory properties are similar to previous interventions. Here, we reviewed recent learnings of immune activation and persisting inflammation associated with HIV infection, as well as the current directions to overcome it. Of note, a more profound understanding of the specific mechanisms for aberrant inflammation is still imperative for identifying an effective clinical intervention strategy.

Adoption of evidence-informed guidelines in prescribing protease inhibitors for HIV-Tuberculosis co-infected patients on rifampicin and effects on HIV treatment outcomes in Uganda

BACKGROUND

We aimed to determine how emerging evidence over the past decade informed how Ugandan HIV clinicians prescribed protease inhibitors (PIs) in HIV patients on rifampicin-based tuberculosis (TB) treatment and how this affected HIV treatment outcomes.

METHODS

We reviewed clinical records of HIV patients aged 13 years and above, treated with rifampicin-based TB treatment while on PIs between1st-January -2013 and 30th-September-2018 from twelve public HIV clinics in Uganda. Appropriate PI prescription during rifampicin-based TB treatment was defined as; prescribing doubled dose lopinavir/ritonavir- (LPV/r 800/200 mg twice daily) and inappropriate PI prescription as prescribing standard dose LPV/r or atazanavir/ritonavir (ATV/r).

RESULTS

Of the 602 patients who were on both PIs and rifampicin, 103 patients (17.1% (95% CI: 14.3-20.34)) received an appropriate PI prescription. There were no significant differences in the two-year mortality (4.8 vs. 5.7%, P = 0.318), loss to follow up (23.8 vs. 18.9%, P = 0.318) and one-year post TB treatment virologic failure rates (31.6 vs. 30.7%, P = 0.471) between patients that had an appropriate PI prescription and those that did not. However, more patients on double dose LPV/r had missed anti-retroviral therapy (ART) days (35.9 vs 21%, P = 0.001).

CONCLUSION

We conclude that despite availability of clinical evidence, double dosing LPV/r in patients receiving rifampicin-based TB treatment is low in Uganda's public HIV clinics but this does not seem to affect patient survival and viral suppression.

Effects of Folic Acid Supplementation on Inflammatory Markers: A Grade-Assessed Systematic Review and Dose-Response Meta-Analysis of Randomized Controlled Trials

It has been theorized that folic acid supplementation improves inflammation. However, its proven effects on inflammatory markers are unclear as clinical studies on this topic have produced inconsistent results. To bridge this knowledge gap, this systematic review and meta-analysis of randomized controlled trials (RCTs) aimed to evaluate the effects of folic acid supplementation on serum concentrations of the inflammatory markers C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α). Methods: To identify eligible RCTs, a systematic search up to April 2021 was completed in PubMed/Medline, Scopus, Web of Science, EMBASE, Cochrane databases, and Google Scholar using relevant keywords. A fix or random-effects model was utilized to estimate the weighted mean difference (WMD) and 95% confidence interval (95% CI). Results: Twelve RCTs were included in the present meta-analysis. The pooled analysis revealed that serum concentrations of CRP (WMD: −0.59 mg/L, 95% CI −0.85 to −0.33, p < 0.001) were significantly reduced following folic acid supplementation compared to placebo, but did not affect serum concentrations of IL-6 (WMD: −0.12, 95% CI −0.95 to 0.72 pg/mL, p = 0.780) or TNF-α (WMD: −0.18, 95% CI −0.86 to 0.49 pg/mL, p = 0.594). The dose–response analysis demonstrated a significant relationship between an elevated dosage of folic acid supplementation and lower CRP concentrations (p = 0.002). Conclusions: We found that folic acid supplementation may improve inflammation by attenuating serum concentrations of CRP but without significant effects on IL-6 and TNF-α. Future RCTs including a larger number of participants and more diverse populations are needed to confirm and expand our findings.

In-vitro Immunomodulatory activity of Azadirachta indica A.Juss. Ethanol: water mixture against HIV associated chronic CD4+ T-cell activation/ exhaustion

BACKGROUND

In Sub-Saharan Africa, herbal therapy continues to be utilized for HIV-1 disease management. However, the therapeutic benefits of these substances remain ambiguous. To date, little is known about the effects of these plant extracts on chronic CD4 + T-cell activation and exhaustion which is partly driven by HIV-1 associated microbial translocation.

METHODS

Effects of Azadirachta indica, Momordica foetida and Moringa oleifera ethanol: water mixtures on cell viability were evaluated using the Guava PCA system. Then, an in-vitro cell culture model was developed to mimic CD4+ T cell exposures to antigens following HIV-1 microbial translocation. In this, peripheral blood mononuclear cells (PBMCs) isolated from HIV negative (n = 13), viral load < 1000 copies per mL (n = 10) and viral load > 1000 copies per mL (n = 6) study participants from rural Uganda were treated with Staphylococcus enterotoxin B (SEB). Then, the candidate plant extract (A. indica) was added to test the potential to inhibit corresponding CD4+ T cell activation. Following BD Facs Canto II event acquisition, variations in %CD38, %CD69, Human Leukocyte Antigen -DR (HLA-DR), Programmed cell death protein 1 (PD-1), T-cell immunoglobulin and mucin domain-containing protein 3 (Tim-3), interferon gamma (IFN γ) and interleukin 2 (IL-2) CD4 + T cell expression were evaluated.

RESULTS

Following exposure to SEB, only A. indica demonstrated a concentration-dependent ability to downregulate the levels of CD4 + T cell activation. At the final concentration of 0.500 μg/mL of A. indica, a significant downregulation of CD4 + CD38 + HLA-DR+ expression was observed in HIV negative (p < 0.0001) and both HIV infected groups (P = 0.0313). This plant extract also significantly lowered SEB induced % CD4+ T cell HLADR, PD-1 and Tim-3 levels. PD-1 and CD69 markers were only significantly downmodulated in only the HIV negative ((p = 0.0001 and p = 0.0078 respectively) and viral load< 1000 copies per ml (p = 0.0078) groups.

CONCLUSION

A. indica exhibited the in-vitro immunomodulatory potential to inhibit the continuum of SEB induced CD4+ T-cell activation/ exhaustion without impacting general T-cell specific functions such as cytokine secretion. Additional studies are needed to confirm A. indica as a source of natural products for targeting persistent immune activation and inflammation during ART.

Plasma Biomarkers of Risk of Tuberculosis Recurrence in HIV Co-Infected Patients From South Africa

There is an urgent need to identify immunological markers of tuberculosis (TB) risk in HIV co-infected individuals. Previously we have shown that TB recurrence in HIV co-infected individuals on ART was associated with markers of systemic inflammation (IL-6, IL1β and IL-1Rα). Here we examined the effect of additional acute inflammation and microbial translocation marker expression on risk of TB recurrence. Stored plasma samples were drawn from the TB Recurrence upon Treatment with HAART (TRuTH) study, in which individuals with previously treated pulmonary TB were screened for recurrence quarterly for up to 4 years. Recurrent TB cases (n = 37) were matched to controls (n = 102) by original trial study arm assignment and ART start date. Additional subsets of HIV infected (n = 41) and HIV uninfected (n = 37) individuals from Improving Recurrence Success (IMPRESS) study were sampled at active TB and post successful treatment completion. Plasma concentrations of soluble adhesion molecules (sMAdCAM, sICAM and sVCAM), lipopolysaccharide binding protein (LBP) and transforming growth factor-beta (TGF-β1, TGF-β2, TGF-β3) were measured by multiplex immunoassays and ELISA. Cytokine data was square root transformed in order to reduce variability. Multivariable analysis adjusted for a number of potential confounders measured at sample time-point: age, BMI, CD4 count, viral load (VL) and measured at baseline: presence or absence of lung cavities, previous history of TB, and WHO disease stage (4 vs 3). The following analytes were associated with increased risk of TB recurrence in the multivariable model: sICAM (aOR 1.06, 95% CI: 1.02-1.12, p = 0.009), LBP (aOR 8.78, 95% CI: 1.23-62.66, p = 0.030) and TGF-β3 (aOR 1.44, 95% CI 1.01-2.05, p = 0.044). Additionally, we observed a positive correlation between LBP and sICAM (r= 0.347, p<0.0001), and LBP and IL-6, identified to be one of the strongest predictors of TB risk in our previous study (r=0.623, p=0.03). These data show that increased risk of TB recurrence in HIV infected individuals on ART is likely associated with HIV mediated translocation of microbial products and the resulting chronic immune activation.

Enhanced Human Immunodeficiency Virus-1 Replication in CD4+ T Cells Derived From Individuals With Latent Mycobacterium tuberculosis Infection

BACKGROUND

Mycobacterium tuberculosis (Mtb) and human immunodeficiency virus (HIV) coinfection increases mortality, accelerates progression to acquired immune deficiency syndrome, and exacerbates tuberculosis disease. However, the impact of pre-existing Mtb infection on subsequent HIV infection has not been fully explored. We hypothesized that Mtb infection creates an immunological environment that influences the course of HIV infection, and we investigated whether pre-existing Mtb infection impacts the susceptibility of CD4+ T cells to HIV-1 infection.

METHODS

Plasma and blood CD4+ T cells isolated from HIV-negative individuals across the Mtb infection spectrum and non-Mtb-infected control individuals were analyzed for inflammation markers and T-cell phenotypes. CD4+ T cells were infected with HIV-1 in vitro and were monitored for viral replication.

RESULTS

We observed differences in proinflammatory cytokines and the relative proportion of memory T-cell subsets depending on Mtb infection status. CD4+ T cells derived from individuals with latent Mtb infection supported more efficient HIV-1 transcription, release, and replication. Enhanced HIV-1 replication correlated with higher percentages of CD4+ TEM and TTD cells.

CONCLUSIONS

Pre-existing Mtb infection creates an immunological environment that reflects Mtb infection status and influences the susceptibility of CD4+ T cells to HIV-1 replication. These findings provide cellular and molecular insights into how pre-existing Mtb infection influences HIV-1 pathogenesis.

Monocyte activation in persons living with HIV and tuberculosis coinfection

OBJECTIVES

To characterize monocyte subsets and activation in persons living with HIV (PLWH) with tuberculosis coinfection.

DESIGN

Cross-sectional study within a cohort of PLWH and HIV-uninfected participants at the Joint Clinical Research Centre in Kampala, Uganda.

METHODS

Participants were at least 45 years old with at least one cardiovascular risk factor. PLWH had an HIV viral load 1000 copies/ml or less on stable antiretroviral therapy prior to cohort entry. QuantiFERON-TB testing was performed to define latent tuberculosis infection (LTBI). Prior active TB was defined by self-report and verified by medical records. Blood was stained with monocyte subset markers (CD14+, CD16), CD62p, CD69, CX3CR1, HLA-DR, and tissue factor, and examined with flow cytometry.

RESULTS

One hundred and twenty-five participants (83 PLWH and 42 without HIV) were included. Median CD4+ count was 582 cells/μl in PLWH. PLWH had a higher frequency of total monocytes (4.3% vs. 3.2%; P < 0.001) and inflammatory monocyte subset (15.5% vs. 11.7%; P = 0.016) compared with HIV-uninfected individuals. No differences in the frequency of monocyte subsets were observed by TB status. Among PLWH, prior active TB was associated with increased frequency of total monocytes compared with LTBI (5.1% vs. 3.7%; P = 0.013). HLA-DR density on monocytes was three-fold higher in PLWH with LTBI or prior TB compared with PLWH without LTBI (P = 0.002). In multivariate analysis, a higher monocyte HLA-DR density remained associated with LTBI or prior TB in PLWH (log-MFI; b = 1.17; P < 0.001).

CONCLUSION

Our findings indicate enhanced monocyte activation in PLWH with LTBI or prior active TB, which may contribute to the pathogenesis of noncommunicable diseases in HIV.

Generation of Liposomes to Study the Effect of Mycobacterium Tuberculosis Lipids on HIV-1 cis- and trans-Infections

Tuberculosis (TB) is the leading cause of death among HIV-1-infected individuals and Mycobacterium tuberculosis (Mtb) co-infection is an early precipitate to AIDS. We aimed to determine whether Mtb strains differentially modulate cellular susceptibility to HIV-1 infection (cis- and trans-infection), via surface receptor interaction by their cell envelope lipids. Total lipids from pathogenic (lineage 4 Mtb H37Rv, CDC1551 and lineage 2 Mtb HN878, EU127) and non-pathogenic (Mycobacterium bovis BCG and Mycobacterium smegmatis) Mycobacterium strains were integrated into liposomes mimicking the lipid distribution and antigen accessibility of the mycobacterial cell wall. The resulting liposomes were tested for modulating in vitro HIV-1 cis- and trans-infection of TZM-bl cells using single-cycle infectious virus particles. Mtb glycolipids did not affect HIV-1 direct infection however, trans-infection of both R5 and X4 tropic HIV-1 strains were impaired in the presence of glycolipids from M. bovis, Mtb H37Rv and Mtb EU127 strains when using Raji-DC-SIGN cells or immature and mature dendritic cells (DCs) to capture virus. SL1, PDIM and TDM lipids were identified to be involved in DC-SIGN recognition and impairment of HIV-1 trans-infection. These findings indicate that variant strains of Mtb have differential effect on HIV-1 trans-infection with the potential to influence HIV-1 disease course in co-infected individuals.

Latent Tuberculosis Infection and Subclinical Coronary Atherosclerosis in Peru and Uganda

BACKGROUND

Tuberculosis has been linked to an increased risk of atherosclerotic cardiovascular disease (ASCVD). We assessed whether latent tuberculosis infection (LTBI) is associated with subclinical coronary atherosclerosis in two TB-prevalent areas.

METHODS

We analyzed cross-sectional data from studies conducted in Lima, Peru, and Kampala, Uganda. Individuals ≥40 years old were included. We excluded persons with known history of ASCVD events or active TB. Participants underwent QuantiFERON®-TB (QFT) testing to define LTBI, and computed tomography angiography to examine coronary atherosclerosis. A Coronary Artery Disease-Reporting Data System (CAD-RADS) score ≥3 defined obstructive CAD (plaque causing ≥50% stenosis).

RESULTS

113 persons with LTBI and 91 persons without LTBI were included. There were no significant differences between LTBI and non-LTBI participants in terms of age (median [interquartile range]; 56 [51-62] vs. 55 [49-64], p=0.829), male sex (38% vs. 42%; p=0.519), or 10-year ASCVD risk scores (7.1 [3.2-11.7] vs. 6.1 [2.8-10.8]; p=0.533). CAD prevalence (any plaque) was similar between groups (29% vs. 24%; p=0.421). Obstructive CAD was present in 9% of LTBI and 3% of non-LTBI individuals; p=0.095. LTBI was associated with obstructive CAD after adjusting for ASCVD risk score, HIV status, and study site (adjusted odds ratio, 4.96, 95% CI 1.05-23.44; p=0.043). Quantitative QFT TB antigen minus nil interferon-gamma responses were associated with obstructive CAD (adjusted odds ratio, 1.2, 95% CI 1.03-1.41; p=0.022).

CONCLUSIONS

LTBI was independently associated with an increased likelihood of subclinical obstructive CAD. Our data indicates that LTBI is a non-traditional correlate of ASCVD risk.

Antiretroviral therapy reduces but does not normalize immune and vascular inflammatory markers in adults with chronic HIV infection in Kenya

INTRODUCTION

Markers of monocyte/macrophage activation and vascular inflammation are associated with HIV-related cardiovascular diseases (CVD) and mortality. We compared these markers among African people living with HIV (PLWH) and HIV-negative adults, and examined risk factors associated with elevated biomarkers (>75th percentile) in PLWH on antiretroviral therapy (ART).

DESIGN

Cross-sectional study.

METHODS

We measured serum concentrations of a gut integrity biomarker (intestinal-fatty acid binding protein), monocyte/macrophage activation biomarkers (soluble CD14 and CD163), and vascular inflammation biomarkers [soluble intercellular adhesion molecule 1 (sICAM-1) and soluble vascular adhesion molecule 1 (sVCAM-1)]. We assessed the relationship of these inflammatory parameters with HIV, using logistic regression adjusting for traditional CVD risk factors.

RESULTS

Among the 541 participants, median age was 43 years and half were female. Among 275 PLWH, median CD4 T-cell count and duration of ART use was 509 cells/μl and 8 years, respectively. PLWH had significantly higher prevalence of elevated inflammatory biomarkers compared with HIV-negative individuals even after adjustment for traditional CVD risk factors. Compared with individuals without HIV, the prevalence of elevated biomarkers was highest among persons with detectable viral load and CD4 T-cell counts 200 cells/μl or less. In a subanalysis among PLWH, nadir CD4 T-cell count 200 cells/μl or less was associated with elevated soluble CD14 (sCD14); dyslipidemia with elevated sCD14, sICAM-1, and sVCAM-1; and overweight/obesity with reduced sCD14. Longer ART exposure (>4 years) was associated with reduced sVCAM-1 and sICAM-1.

CONCLUSION

HIV and not traditional CVD risk factors is a primary contributor of monocyte/macrophage activation and inflammation despite ART. Anti-inflammatory therapies in addition to ART may be necessary to reduce these immune dysregulations and improve health outcomes of African PLWH.

Chronic Immune Activation in TB/HIV Co-infection

HIV co-infection is the most critical risk factor for the reactivation of latent tuberculosis (TB) infection (LTBI). While CD4+ T cell depletion has been considered the major cause of HIV-induced reactivation of LTBI, recent work in macaques co-infected with Mycobacterium tuberculosis (Mtb)/simian immunodeficiency virus (SIV) suggests that cytopathic effects of SIV resulting in chronic immune activation and dysregulation of T cell homeostasis correlate with reactivation of LTBI. This review builds on compelling data that the reactivation of LTBI during HIV co-infection is likely to be driven by the events of HIV replication and therefore highlights the need to have optimum translational interventions directed at reactivation due to co-infection.

Impact of Latent Tuberculosis Infection on Neurocognitive Functioning and Inflammation in HIV-Infected and Uninfected South Indians

BACKGROUND

HIV-associated neurocognitive disorder persists in some people living with HIV despite optimal antiretroviral therapy. Latent tuberculosis infection (LTBI) may cause systemic inflammation and immune activation that may impair brain function. We assessed cognition and biomarkers of inflammation in both HIV+ and HIV- South Indians with and without LTBI.

METHODS

Adults (≥18 years old) with and without HIV infection were screened for LTBI by interferon-gamma release assays, completed comprehensive neurocognitive assessments, and underwent measurement of serum inflammatory biomarker levels.

RESULTS

The participants (n = 119) were HIV+/LTBI+ (n = 15), HIV+/LTBI- (n = 50), HIV-/LTBI+ (n = 26), and HIV-/LTBI- (n = 28). HIV+ participants, regardless of LTBI status, had more impaired global deficit scores than HIV- participants (odds ratio = 3.42, P = 0.028, adjusted for sex and education differences). Neither global deficit scores nor impairment rates differed in the LTBI+ group compared with the LTBI- group (P = 0.79 and P = 0.41, respectively). The mean log10 interleukin (IL)-6 and monocyte chemoattractant protein-1 values were significantly higher and high sensitivity C-reactive protein lower in the LTBI+ group than the LTBI- group (P = 0.044, 0.023, and 0.03, respectively, adjusting for HIV status and sex).

CONCLUSIONS

In this cross-sectional study of South Indians, HIV infection, but not LTBI, was associated with increased neurocognitive impairment. Proinflammatory biomarkers (IL-6 and monocyte chemoattractant protein-1, but not tumor necrosis factor-α) were elevated in the LTBI+ groups compared with the LTBI- groups. Biomarkers of immune activation (interferon-γ, macrophage inflammatory protein-1β, IL-2, interferon gamma inducible protein-10, RANTES, and IL-22) did not differ between these groups. Larger longitudinal studies should be conducted to confirm our findings that the effect of LTBI on systemic inflammation or neurocognitive impairment is likely small.

Plasma Biomarkers of Human Immunodeficiency Virus-Related Systemic Inflammation and Immune Activation in Sub-Saharan Africa Before and During Suppressive Antiretroviral Therapy

We evaluated immune biomarker profiles in human immunodeficiency virus (HIV)–infected adults (n = 398) from 5 African countries. Although all biomarkers decreased after antiretroviral therapy (ART) initiation, levels of C-X-C chemokine ligand 10 (CXCL10), lipopolysaccharide-binding protein, C-reactive protein, soluble CD163, and soluble scavenger receptor CD14 were significantly higher during ART than in an HIV-uninfected reference group (n = 90), indicating persistent monocyte/macrophage activation, inflammation, and microbial translocation. Before ART initiation, high HIV viral load was associated with elevated CXCL10 and tuberculosis coinfection was associated with elevated soluble CD14. High pre-ART levels of each biomarker strongly predicted residual immune activation during ART. Chemokine (C-C motif) ligand 2, lipopolysaccharide-binding protein, C-reactive protein, and interleukin 6 were differentially expressed between countries. Further research is needed on the clinical implications of residual immune dysregulation.

Factors Affecting Survival Rates Among Adult TB/HIV Co-Infected Patients in Mizan Tepi University Teaching Hospital, South West Ethiopia

Background

Tuberculosis (TB) and human immunodeficiency virus (HIV) co-infection was responsible for approximately 300,000 deaths worldwide in 2017. Despite this burden of death, factors associated with the survival of TB-HIV co-infected patients were not adequately studied; and some of the existing evidences are inconsistent. This study was aimed to identify factors associated with survival rates of TB/HIV co-infected patients.

Methods

The current study was a retrospective analysis of data extracted from 364 TB/HIV co-infected patients treated at Mizan Tepi University Teaching Hospital, Ethiopia, during the years 2007-2017. Time to event was measured from the date of TB treatment initiation till death, loss to follow-up or completion of treatment. Since the event was death, patients lost from follow-up and those on follow-up were considered as censored. Using Cox-regression, the 95% CI of hazard ratio (HR) and P-value <0.05 were used to identify the significant variables in multivariable analysis.

Results

All the 364 patients were followed up for 1654 person-months. There were 83 (22.8%) deaths and the majority, 38 (45.8%), were occurring within the first two months of anti-TB treatment initiation. The overall incidence rate and median survival time were 5.02 per 100 person-months (95% CI: 4.05, 6.22) and 10 months, respectively. Not using CPT (adjusted hazard ratio [AHR] =1.72; P=0.023), bedridden functional status (AHR=2.55; P=0.007), not disclosing HIV status (AHR=4.03; P<0.001) and CD4 < 200 cells/mm³ (AHR=6.05; P<0.001) were factors associated with survival rates of TB/HIV co-infected patients.

Conclusion

Our finding signals that care and attention should be given to the victims of these synergistic diseases. There is room to improve the survival of the patients if those with low CD4 count and bedridden functional status are closely monitored; and if CPT is promptly initiated with encouraging HIV status disclosure.

The Mtb-HIV syndemic interaction: why treating M. tuberculosis infection may be crucial for HIV-1 eradication

Accelerated tuberculosis and AIDS progression seen in HIV-1 and Mycobacterium tuberculosis (Mtb)-coinfected individuals indicates the important interaction between these syndemic pathogens. The immunological interaction between HIV-1 and Mtb has been largely defined by how the virus exacerbates tuberculosis disease pathogenesis. Understanding of the mechanisms by which pre-existing or subsequent Mtb infection may favor the replication, persistence and progression of HIV, is less characterized. We present a rationale for the critical consideration of ‘latent’ Mtb infection in HIV-1 prevention and cure strategies. In support of this position, we review evidence of the effect of Mtb infection on HIV-1 acquisition, replication and persistence. We propose that ‘latent’ Mtb infection may have considerable impact on HIV-1 pathogenesis and the continuing HIV-1 epidemic in sub-Saharan Africa.

Impact of Raltegravir or Efavirenz on Cell-Associated Human Immunodeficiency Virus-1 (HIV-1) Deoxyribonucleic Acid and Systemic Inflammation in HIV-1/Tuberculosis Coinfected Adults Initiating Antiretroviral Therapy

Background

In view of the fast viremia decline obtained with integrase inhibitors, we studied the respective effects of initiating efavirenz (EFV) or raltegravir (RAL)-based antiretroviral therapy (ART) regimens on human immunodeficiency virus (HIV)-1 deoxyribonucleic acid (DNA) levels and inflammation biomarkers in the highly inflammatory setting of advanced HIV-1 disease with tuberculosis (TB) coinfection.

Methods

We followed cell-associated HIV-1 DNA, high-sensitivity C-reactive protein (hsCRP), interleukin 6 (IL-6), soluble CD14 and D-Dimer levels for 48 weeks after ART initiation in the participants to the ANRS12-180 REFLATE-TB study. This phase II open-label randomized study included ART-naive people with HIV and TB treated with rifampicin to receive RAL 400 mg twice daily (RAL400), RAL 800 mg twice daily (RAL800) or EFV 600 mg QD with tenofovir and lamivudine.

Results

In 146 participants, the median (interquartile range [IQR]) week (W)0 HIV-1 DNA level was 4.7 (IQR, 4.3–5.1) log₁₀ copies/10⁶ CD4⁺, and the reduction by W48 was −0.8 log₁₀ copies/10⁶ CD4⁺ on EFV, −0.9 on RAL400, and −1.0 on RAL800 (P = .74). Baseline median (IQR) hsCRP, IL-6, sCD14, and D-Dimer levels were 6.9 (IQR, 3.3–15.6) mg/L, 7.3 (IQR, 3.5–12.3) pg/mL, 3221 (IQR, 2383–4130) ng/mL, and 975 (IQR, 535–1970) ng/mL. All biomarker levels decreased over the study: the overall W0–W48 mean (95% confidence interval) fold-change on ART was 0.37 (IQR, 0.28–0.48) for hsCRP, 0.42 (IQR, 0.35–0.51) for IL-6, 0.51 (IQR, 0.47–0.56) for sCD14, and 0.39 (IQR, 0.32–0.47) for D-Dimers. There were no differences in biomarker reduction across treatment arms.

Conclusions

In participants with HIV and TB, EFV, RAL400, or RAL800 effectively and equally reduced inflammation and HIV-1 DNA levels.

M. Ottenhoff T, M. Cliff J, C. Haks M. Gene expression profiles classifying clinical stages of tuberculosis and monitoring treatment responses in Ethiopian HIV-negative and HIV-positive cohorts

Background

Validation of previously identified candidate biomarkers and identification of additional candidate gene expression profiles to facilitate diagnosis of tuberculosis (TB) disease and monitoring treatment responses in the Ethiopian context is vital for improving TB control in the future.

Methods

Expression levels of 105 immune-related genes were determined in the blood of 80 HIV-negative study participants composed of 40 active TB cases, 20 latent TB infected individuals with positive tuberculin skin test (TST+), and 20 healthy controls with no Mycobacterium tuberculosis (Mtb) infection (TST-), using focused gene expression profiling by dual-color Reverse-Transcription Multiplex Ligation-dependent Probe Amplification assay. Gene expression levels were also measured six months after anti-TB treatment (ATT) and follow-up in 38 TB patients.

Results

The expression of 15 host genes in TB patients could accurately discriminate between TB cases versus both TST+ and TST- controls at baseline and thus holds promise as biomarker signature to classify active TB disease versus latent TB infection in an Ethiopian setting. Interestingly, the expression levels of most genes that markedly discriminated between TB cases versus TST+ or TST- controls did not normalize following completion of ATT therapy at 6 months (except for PTPRCv1, FCGR1A, GZMB, CASP8 and GNLY) but had only fully normalized at the 18 months follow-up time point. Of note, network analysis comparing TB-associated host genes identified in the current HIV-negative TB cohort to TB-associated genes identified in our previously published Ethiopian HIV-positive TB cohort, revealed an over-representation of pattern recognition receptors including TLR2 and TLR4 in the HIV-positive cohort which was not seen in the HIV-negative cohort. Moreover, using ROC cutoff ≥ 0.80, FCGR1A was the only marker with classifying potential between TB infection and TB disease regardless of HIV status.

Conclusions

Our data indicate that complex gene expression signatures are required to measure blood transcriptomic responses during and after successful ATT to fully diagnose TB disease and characterise drug-induced relapse-free cure, combining genes which resolve completely during the 6-months treatment phase of therapy with genes that only fully return to normal levels during the post-treatment resolution phase.

High Activation of γδ T Cells and the γδ2pos T-Cell Subset Is Associated With the Onset of Tuberculosis-Associated Immune Reconstitution Inflammatory Syndrome, ANRS 12153 CAPRI NK

Background: Human Immunodeficiency Virus 1 (HIV-1) and Mycobacterium Tuberculosis (Mtb) co-infected patients are commonly at risk of immune reconstitution inflammatory syndrome (IRIS) when initiating antiretroviral treatment (ART). Evidence indicates that innate immunity plays a role in TB-IRIS. Here, we evaluate the phenotype of Gamma-delta (γδ) T cells and invariant Natural Killer (iNK) T cells in tuberculosis-associated IRIS.

Methods: Forty-eight HIV+/TB+ patients (21 IRIS) and three control groups: HIV–/TB– (HD, n = 11), HIV+/TB– (n = 26), and HIV–/TB+ (n = 22) were studied. Samples were taken at ART initiation (week 2 of anti-tuberculosis treatment) and at the diagnosis of IRIS for HIV+/TB+; before ART for HIV+/TB-, and at week 2 of anti-tuberculosis treatment for HIV–/TB+ patients. γδ T cells and Invariant natural killer T (iNKT) cells were analyzed by flow cytometry.

Results: Before ART, IRIS, and non-IRIS patients showed a similar proportion of γδ^pos T and iNKT cells. HLA-DR on γδ^pos T cells and δ2^posγδ^pos T cells was significantly higher in TB-IRIS vs. non-IRIS patients and controls (p < 0.0001). NKG2D expression on γδ^pos T cells and the δ2^posγδ^pos T cell subset was lower in HIV+/TB+ patients than controls. CD158a expression on γδ^pos T cells was higher in TB-IRIS than non-IRIS (p = 0.02), HIV+/TB–, and HIV–/TB- patients.

Conclusion: The higher activation of γδ^posT cells and the γδ2^posγδ^pos T cell subset suggests that γδ T cells may play a role in the pathogenesis of TB-IRIS.

HIV Infection Functionally Impairs Mycobacterium tuberculosis-Specific CD4 and CD8 T-Cell Responses

Human immunodeficiency virus (HIV) infection is the major risk factor predisposing for Mycobacterium tuberculosis progression from latent tuberculosis infection (LTBI) to tuberculosis disease (TB). Since long-term-treated aviremic HIV-infected individuals remained at higher risk of developing TB than HIV-uninfected individuals, we hypothesized that progression from LTBI to pulmonary TB (PTB) might be due not only to CD4 T-cell depletion but also to M. tuberculosis-specific CD4 T-cell functional impairment. To test this hypothesis, M. tuberculosis-specific T-cell frequencies and cytokine profiles were investigated in untreated Tanzanian individuals suffering from LTBI (n = 20) or PTB (n = 67) and compared to those of untreated M. tuberculosis/HIV-coinfected individuals suffering from LTBI (n = 15) or PTB (n = 10). We showed that HIV infection significantly reduced the proportion of Th2 (interleukin 4 [IL-4]/IL-5/IL-13) producing M. tuberculosis-specific CD4 T cells and IL-2-producing M. tuberculosis-specific CD4 and CD8 T cells in individuals with LTBI or PTB (P < 0.05). Interestingly, the loss of IL-2 production was associated with a significant increase of PD-1 expression on M. tuberculosis-specific CD4 and CD8 T cells (P < 0.05), while the loss of Th2 cytokine production was associated with a significant reduction of Gata-3 expression in memory CD4 T cells (P < 0.05). Finally, we showed that the serum levels of IL-1α, IL-6, C-reactive protein (CRP), IL-23, and IP-10 were significantly reduced in M. tuberculosis/HIV-coinfected individuals with PTB compared to those in HIV-negative individuals with PTB (P < 0.05), suggesting that HIV infection significantly suppresses M. tuberculosis-induced systemic proinflammatory cytokine responses. Taken together, this study suggests that in addition to depleting M. tuberculosis-specific CD4 T cells, HIV infection significantly impairs functionally favorable M. tuberculosis-specific CD4 T-cell responses in Tanzanian individuals with LTBI or PTB.IMPORTANCE Mycobacterium tuberculosis and human immunodeficiency virus (HIV) infections are coendemic in several regions of the world, and M. tuberculosis/HIV-coinfected individuals are more susceptible to progression to tuberculosis disease. We therefore hypothesized that HIV infection would potentially impair M. tuberculosis-specific protective immunity in individuals suffering from latent tuberculosis infection (LTBI) or active pulmonary tuberculosis (PTB). In this study, we demonstrated that M. tuberculosis/HIV-coinfected individuals have fewer circulating M. tuberculosis-specific CD4 T cells and that those that remained were functionally impaired in both LTBI and PTB settings. In addition, we showed that HIV infection significantly interferes with M. tuberculosis-induced systemic proinflammatory cytokine/chemokine responses. Taken together, these data suggest that HIV infection impairs functionally favorable M. tuberculosis-specific immunity.

Circulating HLA-DR+CD4+ effector memory T cells resistant to CCR5 and PD-L1 mediated suppression compromise regulatory T cell function in tuberculosis

Chronic T cell activation is a hallmark of pulmonary tuberculosis (PTB). The mechanisms underpinning this important phenomenon are however, poorly elucidated, though known to rely on control of T effector cells (Teff) by regulatory T cells (Treg). Our studies show that circulating natural Treg cells in adults with PTB preserve their suppressive potential but Teff cells from such subjects are resistant to Treg-mediated suppression. We found this to be due to expansion of an activated Teff subset identified by Human Leukocyte Antigen (HLA)-DR expression. Sensitivity to suppression was restored to control levels by depletion of this subset. Comparative transcriptome analysis of Teff cells that contain HLA-DR⁺ cells versus the fraction depleted of this population identified putative resistance mechanisms linked to IFNG, IL17A, IL22, PD-L1 and β-chemokines CCL3L3, CCL4 expression. Antibody blocking experiments confirmed HLA-DR⁺ Teff cells, but not the fraction depleted of HLA-DR⁺ effectors, to be resistant to Treg suppression mediated via CCR5 and PD-L1 associated pathways. In the presence of HLA-DR⁺ Teff cells, activation of NFκB downstream of CCR5 and PD-L1 was perturbed. In addition, HLA-DR⁺ Teff cells expressed significantly higher levels of Th1/Th17 cytokines that may regulate Treg function through a reciprocal counter-balancing relationship. Taken together, our study provides novel insight on how activated HLA-DR⁺CD4⁺ T cells may contribute to disease associated inflammation by compromising Treg-mediated suppression in PTB.

An important marker of progression to PTB following Mycobacterium tuberculosis (Mtb) infection in humans is elevated frequencies of HLA-DR⁺CD4⁺ T cells, reflecting chronic T cell activation. However, the mechanisms by which activated HLA-DR⁺CD4⁺ T cells contribute to disease process is not known. We show that CD25^- HLA-DR⁺CD4⁺ memory Teff from PTB patients are resistant to suppression mediated by Treg cells. An unbiased transcriptome analysis identified several key pathways that contribute to this resistance. Specifically, presence of HLA-DR⁺CD4⁺ T cells renders the effector population resistant to CCR5 and PD-L1 mediated suppression by Treg cells. In addition, the HLA-DR⁺CD4⁺ memory Teff cells express elevated levels of Th1/Th17 cytokines known to counter-regulate and dampen Treg suppression. These findings provide fresh insight to disease process in TB and identify HLA-DR⁺ Teff resistant to Treg suppression as a potential functional marker of disease.

Plasma Cytokine Predictors of Tuberculosis Recurrence in Antiretroviral-Treated Human Immunodeficiency Virus-infected Individuals from Durban, South Africa

Background

Immune correlates of tuberculosis (TB) risk in populations infected with human immunodeficiency virus (HIV) remain understudied, despite HIV being associated with a high burden of TB disease. Here we describe plasma cytokine correlates of TB recurrence in a well-characterized cohort of HIV-infected individuals on antiretroviral therapy (ART) with a history of prior TB cure.

Methods

Study participants were drawn from a prospective cohort study initiated at the conclusion of a randomized clinical trial in which individuals presented with untreated HIV infection and active pulmonary TB. At baseline, ART was initiated, and TB successfully cured. Participants were screened for TB recurrence quarterly for up to 4 years. TB recurrent cases (n = 63) were matched to controls (n = 123) on sex, study arm assignment in the original trial, and month of enrollment with a subset of cases sampled longitudinally at several time-points.

Results

Three cytokines were associated with increased rates of TB recurrence in univariate models: interleukin 6 (IL6) (odds ratio [OR] 2.66, 95% confidence interval [CI] 1.34-5.28, P = .005), IP10 (OR 4.62, 95% CI 1.69-12.65, P = .003), monokine induced by IFN-γ (MIG) (OR 3.11, 95% CI 1.10-8.82, P = .034). Conversely, interferon β (IFNβ) was associated with decreased TB risk (OR 0.34, 95% CI 0.13-0.87, P = .025). Following multivariate analyses adjusting for covariates IL6, interleukin 1β (IL1β), and interleukin 1Rα (IL1Rα) were associated with increased risk and IFNβ with decreased TB risk. Longitudinal analysis showed that levels of many TB-associated markers, including IL6, IP10, sCD14, and interferon γ (IFNγ) are reduced following TB treatment.

Conclusion

These data show that TB recurrence, in HIV-infected individuals on ART is predicted by biomarkers of systemic inflammation, many of which are implicated in more rapid HIV disease progression.

Clinical Trials Registration

NCT 01539005.

The Relationship Between Latent Tuberculosis Infection and Acute Myocardial Infarction

Background

Tuberculosis has been associated with an increased risk of cardiovascular disease (CVD), including acute myocardial infarction (AMI). We investigated whether latent tuberculosis infection (LTBI) is associated with AMI.

Methods

We conducted a case-control study in 2 large national public hospital networks in Lima, Peru, between July 2015 and March 2017. Case patients were patients with a first time diagnosis of type 1 (spontaneous) AMI. Controls were patients without a history of AMI. We excluded patients with known human immunodeficiency virus infection, tuberculosis disease, or prior LTBI treatment. We used the QuantiFERON-TB Gold In-Tube assay to identify LTBI. We used logistic regression modeling to estimate the odds ratio (OR) of LTBI in AMI case patients versus non-AMI controls.

Results

We enrolled 105 AMI case patients and 110 non-AMI controls during the study period. Overall, the median age was 62 years (interquartile range, 56-70 years); 69% of patients were male; 64% had hypertension, 40% dyslipidemia, and 39% diabetes mellitus; 30% used tobacco; and 24% were obese. AMI case patients were more likely than controls to be male (80% vs 59%; P < .01) and tobacco users (41% vs 20%; P < .01). LTBI was more frequent in AMI case patients than in controls (64% vs 49% [P = .03]; OR, 1.86; 95% confidence interval [CI], 1.08-3.22). After adjustment for age, sex, hypertension, dyslipidemia, diabetes mellitus, tobacco use, obesity, and family history of coronary artery disease, LTBI remained independently associated with AMI (adjusted OR, 1.90; 95% CI, 1.05-3.45).

Conclusions

LTBI was independently associated with AMI. Our results suggest a potentially important role of LTBI in CVD.

Soluble CD14 as a Diagnostic Biomarker for Smear-Negative HIV-Associated Tuberculosis

Sputum smear-negative HIV-associated active tuberculosis (TB) is challenging to diagnose. CD14 is a pattern recognition receptor that is known to mediate monocyte activation. Prior studies have shown increased levels of soluble CD14 (sCD14) as a potential biomarker for TB, but little is known about its value in detecting smear-negative HIV-associated TB. We optimized a sandwich ELISA for the detection of sCD14, and tested sera from 56 smear-negative South African (39 culture-positive and 17 culture-negative) HIV-infected pulmonary TB patients and 24 South African and 43 US (21 positive and 22 negative for tuberculin skin test, respectively) HIV-infected controls. SCD14 concentrations were significantly elevated in smear-negative HIV-associated TB compared with the HIV-infected controls (p < 0.0001), who had similar concentrations, irrespective of the country of origin or the presence or absence of latent M. tuberculosis infection (p = 0.19). The culture-confirmed TB group had a median sCD14 level of 2199 ng/mL (interquartile range 1927-2719 ng/mL), versus 1148 ng/mL (interquartile range 1053-1412 ng/mL) for the South African controls. At a specificity of 96%, sCD14 had a sensitivity of 95% for culture-confirmed smear-negative TB. These data indicate that sCD14 could be a highly accurate biomarker for the detection of HIV-associated TB.

Sexually transmitted infections and immune activation among HIV-infected but virally suppressed youth on antiretroviral therapy

BACKGROUND

Human immunodeficiency virus (HIV) infection is associated with chronic immune activation, and concurrent sexually transmitted infections (STIs) may increase immune activation.

OBJECTIVES

Because HIV-infected youth are at high risk of STIs and little is known about the impact of STIs on immune activation in HIV-infected youth, we conducted an exploratory study examining the association between STIs and systemic inflammation and immune activation among HIV-infected adolescents.

STUDY DESIGN

Forty-nine behaviorally infected U.S. youth ages 18-24 years with baseline CD4⁺ T-cells >350 who maintained viral suppression on therapy by week 48 were included. Evaluation for STIs (herpes simplex virus [HSV], Chlamydia trachomatis, syphilis, Neisseria gonorrhoeae) was conducted as standard of care and reported on case report forms. Measures of T-cell subsets, systemic immune activation, and soluble factors were examined at week 48 for differences between participants with an STI diagnosis during the 48 weeks compared to those without an STI.

RESULTS

Forty-three participants (88%) were male; 57% had baseline CD4+ T-cell counts >500 cells/mm³. Eighteen youth were reported to have ≥1 STI. At week 48, participants with STIs demonstrated lower CD4⁺ T-cell counts (any STI vs. no STI, p = 0.024; HSV vs. no STI, p = 0.022) and evidence of increased systemic immune activation, including higher CD57 intensity, higher HLA-DR intensity, and lower CD28 percentage, when compared to those without STIs. There were no differences in soluble factors between STI groups.

CONCLUSIONS

Results indicate novel activation of CD4⁺ T-cells among HIV-infected youth who have STIs other than HSV, which may contribute to disease progression.

Residual Immune Activation and Latency

The introduction of combination antiretroviral therapy (cART) in the 1990s has dramatically changed the course of HIV infection, decreasing the risk for both AIDS- and non-AIDS-related events. Cancers, cardiovascular disease (CVD), liver and kidney disease, neurological disorders and frailty have become of great importance lately in the clinical management as they represent the principal cause of death in people living with HIV who receive cART (Kirk et al. in Clin Infect Dis 45(1):103-10, 2007; Strategies for Management of Antiretroviral Therapy Study et al. N Engl J Med 355(22):2283-2296, 2006; Ances et al. J Infect Dis 201(3):336-340, 2010; Desquilbet et al. J Gerontol A Biol Sci Med Sci 62(11):1279-1286, 2007; Lifson et al. HIV Clin Trials 9(3):177-185, 2008). Despite the undeniable achievements of cART, we are now faced with its limitations: a considerable proportion of individuals, referred as to immunological non-responders, fails to reconstitute the immune system despite optimal treatment and viral suppression (Kelley et al. Clin Infect Dis 48(6):787-794, 2009; Robbins et al. Clin Infect Dis 48(3):350-361, 2009) and remains at high risk for opportunistic infections and non-AIDS-related events (Strategies for Management of Antiretroviral Therapy Study et al. N Engl J Med 355(22):2283-2296, 2006). Moreover, the generalized state of immune activation and inflammation, linked to serious non-AIDS events, persists despite successful HIV suppression with cART. Finally, the current strategies have so far failed to eradicate the virus, and inflammation appears a driving force in viral persistence. In the light of all this, it is of fundamental importance to investigate the pathophysiological processes that link incomplete immune recovery, immune activation and HIV persistence to design targeted therapies that could impact on the three.

Pathogenesis of HIV-1 and Mycobacterium tuberculosis co-infection

Co-infection with Mycobacterium tuberculosis is the leading cause of death in individuals infected with HIV-1. It has long been known that HIV-1 infection alters the course of M. tuberculosis infection and substantially increases the risk of active tuberculosis (TB). It has also become clear that TB increases levels of HIV-1 replication, propagation and genetic diversity. Therefore, co-infection provides reciprocal advantages to both pathogens. In this Review, we describe the epidemiological associations between the two pathogens, selected interactions of each pathogen with the host and our current understanding of how they affect the pathogenesis of TB and HIV-1/AIDS in individuals with co-infections. We evaluate the mechanisms and consequences of HIV-1 depletion of T cells on immune responses to M. tuberculosis. We also discuss the effect of HIV-1 infection on the control of M. tuberculosis by macrophages through phagocytosis, autophagy and cell death, and we propose models by which dysregulated inflammatory responses drive the pathogenesis of TB and HIV-1/AIDS.

Barriers to HIV remission research in low- and middle-income countries

INTRODUCTION

HIV eradication and remission research has largely taken place in high-income countries. In low- and middle-income countries (LMIC), there may be factors that have a substantial impact on the size of the latent HIV reservoir and the immunological response to infection. If a curative strategy is to be available to all HIV-infected individuals, these factors must be understood.

METHODS

We use a scoping review to examine the literature on biological factors that may have an impact on HIV persistence in LMIC. Three databases were searched without date restrictions.

RESULTS

Uncontrolled viral replication and higher coinfection prevalence may alter the immunological milieu of individuals in LMIC and increase the size of the HIV reservoir. Differences in HIV subtype could also influence the measurement and size of the HIV reservoir. Immune activation may differ due to late presentation to care, presence of chronic infections, increased gut translocation of bacterial products and poor nutrition.

CONCLUSIONS

Research on HIV remission is urgently needed in LMIC. Research into chronic immune activation in resource poor environments, the immune response to infection, the mechanisms of HIV persistence and latency in different viral clades and the effect of the microbiological milieu must be performed. Geographic differences, which may be substantial and may delay access to curative strategies, should be identified.

The Immune Interaction between HIV-1 Infection and Mycobacterium tuberculosis

The modulation of tuberculosis (TB)-induced immunopathology caused by human immunodeficiency virus (HIV)-1 coinfection remains incompletely understood but underlies the change seen in the natural history, presentation, and prognosis of TB in such patients. The deleterious combination of these two pathogens has been dubbed a "deadly syndemic," with each favoring the replication of the other and thereby contributing to accelerated disease morbidity and mortality. HIV-1 is the best-recognized risk factor for the development of active TB and accounts for 13% of cases globally. The advent of combination antiretroviral therapy (ART) has considerably mitigated this risk. Rapid roll-out of ART globally and the recent recommendation by the World Health Organization (WHO) to initiate ART for everyone living with HIV at any CD4 cell count should lead to further reductions in HIV-1-associated TB incidence because susceptibility to TB is inversely proportional to CD4 count. However, it is important to note that even after successful ART, patients with HIV-1 are still at increased risk for TB. Indeed, in settings of high TB incidence, the occurrence of TB often remains the first presentation of, and thereby the entry into, HIV care. As advantageous as ART-induced immune recovery is, it may also give rise to immunopathology, especially in the lower-CD4-count strata in the form of the immune reconstitution inflammatory syndrome. TB-immune reconstitution inflammatory syndrome will continue to impact the HIV-TB syndemic.

Immune Activation by Mycobacterium tuberculosis in HIV-Infected and -Uninfected Subjects

INTRODUCTION

This study investigates the influence of Mycobacterium tuberculosis infection on immune activation biomarkers, both in HIV-infected and -uninfected subjects.

METHODS

Forty-eight treatment-naive HIV-infected patients and 74 HIV-uninfected subjects were recruited and divided into groups according to their M. tuberculosis infection status: latent tuberculosis infection (LTBI), active tuberculosis (TB), and no evidence of M. tuberculosis infection. The expression of cellular markers CD38 and HLA-DR on circulating CD8 T lymphocytes and the plasmatic levels of soluble markers interleukin-6, sCD14, and D-Dimer were measured and compared between groups. The HIV-infected patients with no evidence of M. tuberculosis or with LTBI who initiated antiretroviral treatment were tested again for these biomarkers once viral suppression was reached.

RESULTS

In both HIV-infected and -uninfected groups, patients with TB had higher levels of immune activation markers than subjects with LTBI and with no evidence of M. tuberculosis. Among the HIV-uninfected subjects, no significant difference in biomarker level was found between those presenting LTBI and those with no evidence of M. tuberculosis. The effect of LTBI on activation biomarkers in the HIV-infected groups was inconclusive because of the small number of individuals in the HIV+/LTBI group. sCD14 and D-Dimer levels were significantly higher in the TB-only group than in the HIV-only group.

DISCUSSION

Although TB is associated with an increase in biomarkers of immune activation, the effect of LTBI is less evident. Further investigation is warranted, and according to our results, soluble markers may offer greater sensitivity for the evaluation of M. tuberculosis-associated immune activation than cellular markers.

C-reactive protein is differentially modulated by co-existing infections, vitamin deficiencies and maternal factors in pregnant and lactating indigenous Panamanian women

Background

The usefulness of C-reactive protein (CRP) as a non-specific marker of inflammation during pregnancy and lactation is unclear in impoverished populations where co-existing infections and vitamin deficiencies are common.

Methods

This cross-sectional study in Panama recruited 120 pregnant and 99 lactating Ngäbe-Buglé women from 14 communities in rural Panama. Obstetric history, indoor wood smoke exposure, fieldwork, BMI, vitamins A, B₁₂, D, and folic acid, and inflammation markers (CRP, neutrophil/lymphocyte ratio (NLR), plateletcrit and cytokines) were measured. Multiple regressions explored both associations of CRP with other inflammatory markers and associations of CRP and elevated CRP based on trimester-specific cut-offs with maternal factors, infections and vitamin deficiencies.

Results

CRP was higher in pregnancy (51.4 ± 4.7 nmol/L) than lactation (27.8 ± 3.5 nmol/L) and was elevated above trimester specific cut-offs in 21% of pregnant and 30% of lactating women. Vitamin deficiencies were common (vitamin A 29.6%; vitamin D 68.5%; vitamin B₁₂ 68%; folic acid 25.5%) and over 50% of women had two or more concurrent deficiencies as well as multiple infections. Multiple regression models highlighted differences in variables associated with CRP between pregnancy and lactation. In pregnancy, CRP was positively associated with greater indoor wood smoke exposure, caries and hookworm and negatively associated with Ascaris and vaginal Lactobacillus and Bacteroides/Gardnerella scores. Consistent with this, greater wood smoke exposure, caries as well as higher diplococcal infection score increased the odds of trimester-elevated CRP concentrations whereas longer gestational age lowered the likelihood of a trimester-elevated CRP. During lactation, folic acid deficiency was associated with higher CRP whereas parity, number of eosinophils and Mobiluncus score were associated with lower CRP. Also, a higher BMI and Trichomonas vaginalis score increased the likelihood of an elevated CRP whereas higher parity and number of eosinophils were associated with lower likelihood of an elevated CRP.

Conclusions

Infections both raise and lower CRP concentrations in pregnant and lactating mothers. Only folic acid deficiency during lactation was associated with higher CRP concentrations. Caution is required when interpreting CRP concentrations in pregnant and lactating women who have co-existing nutrient deficiencies and multiple infections.

Electronic supplementary material

The online version of this article (doi:10.1186/s40249-017-0307-1) contains supplementary material, which is available to authorized users.

BCG vaccination induces HIV target cell activation in HIV-exposed infants in a randomized trial

BACKGROUND. Bacillus Calmette-Guérin (BCG) vaccine is administered at birth to protect infants against tuberculosis throughout Africa, where most perinatal HIV-1 transmission occurs. We examined whether BCG vaccination alters the levels of activated HIV target T cells in HIV-exposed South African infants. METHODS. HIV-exposed infants were randomized to receive routine (at birth) or delayed (at 8 weeks) BCG vaccination. Activated and CCR5-expressing peripheral blood CD4⁺ T cell, monocyte, and NK cell frequencies were evaluated by flow cytometry and immune gene expression via PCR using Biomark (Fluidigm). RESULTS. Of 149 infants randomized, 92% (n = 137) were retained at 6 weeks: 71 in the routine BCG arm and 66 in the delayed arm. Routine BCG vaccination led to a 3-fold increase in systemic activation of HIV target CD4⁺CCR5⁺ T cells (HLA-DR⁺CD38⁺) at 6 weeks (0.25% at birth versus 0.08% in delayed vaccination groups; P = 0.029), which persisted until 8 weeks of age when the delayed arm was vaccinated. Vaccination of the infants in the delayed arm at 8 weeks resulted in a similar increase in activated CD4⁺CCR5⁺ T cells. The increase in activated T cells was associated with increased levels of MHC class II transactivator (CIITA), IL12RB1, and IFN-α1 transcripts within peripheral blood mononuclear cells but minimal changes in innate cells. CONCLUSION. BCG vaccination induces immune changes in HIV-exposed infants, including an increase in the proportion of activated CCR5⁺CD4⁺ HIV target cells. These findings provide insight into optimal BCG vaccine timing to minimize the risks of HIV transmissions to exposed infants while preserving potential benefits conferred by BCG vaccination. TRIAL REGISTRATION. ClinicalTrials.gov NCT02062580. FUNDING. This trial was sponsored by the Elizabeth Glaser Pediatric AIDS Foundation (MV-00-9-900-01871-0-00) and the Thrasher Foundation (NR-0095); for details, see Acknowledgments.

Serious Non-AIDS Events: Therapeutic Targets of Immune Activation and Chronic Inflammation in HIV Infection

In the antiretroviral therapy (ART) era, serious non-AIDS events (SNAEs) have become the major causes of morbidity and mortality in HIV-infected persons. Early ART initiation has the strongest evidence for reducing SNAEs and mortality. Biomarkers of immune activation, inflammation and coagulopathy do not fully normalize despite virologic suppression and persistent immune activation is an important contributor to SNAEs. A number of strategies aimed to reduce persistent immune activation including ART intensification to reduce residual viremia; treatment of co-infections to reduce chronic antigen stimulation; the use of anti-inflammatory agents, reducing microbial translocation as well as interventions to improve immune recovery through cytokine administration and reducing lymphoid tissue fibrosis, have been investigated. To date, there is little conclusive evidence on which strategies beyond treatment of hepatitis B and C co-infections and reducing cardiovascular risk factors will result in clinical benefits in patients already on ART with viral suppression. The use of statins seems to show early promise and larger clinical trials are underway to confirm their efficacy. At this stage, clinical care of HIV-infected patients should therefore focus on early diagnosis and prompt ART initiation, treatment of active co-infections and the aggressive management of co-morbidities until further data are available.

Elevated Circulating Concentrations of Interferon-Gamma in Latent Tuberculosis Infection

BACKGROUND

Latent tuberculosis infection (LTBI) has been associated with increased immune activation. We assessed circulating concentrations of interferon-gamma in persons with LTBI.

METHODS

We used the 2011-2012 National Health Nutritional Examination Survey (NHANES) to identify adults with and without LTBI by QuantiFERON®-TB Gold In-Tube (QFT) results. Non-LTBI persons were 1:1 age-, gender-, and race-matched to LTBI persons using propensity scores. We compared the plasma concentrations of interferon-gamma measured from the unstimulated, negative control QFT tube between LTBI and non-LTBI persons. We used Mann-Whitney tests and ordered logistic regressions for comparisons.

RESULTS

There were 430 LTBI and 430 non-LTBI matched persons included in the analysis. LTBI was associated with higher circulating concentrations of interferon-gamma (median, 3 pg/mL; IQR, 2 - 5) compared to non-LTBI (median, 2.5 pg/mL; IQR, 1.5 - 3.5); P < 0.001. LTBI remained associated with higher interferon-gamma concentrations after adjusting for age, gender, race, diabetes, hypertension, tobacco use, HIV status, body mass index, lipid profile, and lymphocyte count (odds ratio, 1.79, 95% CI, 1.26 - 2.53). Results remained similar when tuberculin skin testing defined LTBI.

CONCLUSIONS

LTBI was associated with increased circulating interferon-gamma concentrations. Future studies are needed to further characterize immune activation in LTBI and its potential long-term consequences.