Tuberculosis and HIV co-infection. PLoS Pathog. 2012;8:e1002464. [PMID: 22363214 PMCID: PMC3280977 DOI: 10.1371/journal.ppat.1002464]

Preferential Destruction of Interstitial Macrophages over Alveolar Macrophages as a Cause of Pulmonary Disease in Simian Immunodeficiency Virus-Infected Rhesus Macaques

To our knowledge, this study demonstrates for the first time that the AIDS virus differentially impacts two distinct subsets of lung macrophages. The predominant macrophages harvested by bronchoalveolar lavage (BAL), alveolar macrophages (AMs), are routinely used in studies on human lung macrophages, are long-lived cells, and exhibit low turnover. Interstitial macrophages (IMs) inhabit the lung tissue, are not recovered with BAL, are shorter-lived, and exhibit higher baseline turnover rates distinct from AMs. We examined the effects of SIV infection on AMs in BAL fluid and IMs in lung tissue of rhesus macaques. SIV infection produced massive cell death of IMs that contributed to lung tissue damage. Conversely, SIV infection induced minimal cell death of AMs, and these cells maintained the lower turnover rate throughout the duration of infection. This indicates that SIV produces lung tissue damage through destruction of IMs, whereas the longer-lived AMs may serve as a virus reservoir to facilitate HIV persistence.

Mycobacterium tuberculosis infection in a HIV-positive patient

Mycobacterium tuberculosis (MTB) and human immunodeficiency virus (HIV) coinfection remains a global public health challenge. We report a 40 year old African American male who is a known HIV-positive patient, non-compliant with his antiretrovirals and developed pulmonary tuberculosis. His chief complaints were chronic cough, fever, night sweats and undocumented weight loss. He had a prior positive T-SPOT-TB test; however, chest radiograph and sputum smear examination revealed normal results. PCR-based GeneXPERT MTB/RIF assay was ordered and confirmed MTB infection. The sputum cultures grew MTB and sensitivities showed susceptibility to all primary anti-tuberculosis medications. A delay in diagnosis and initiation of MTB therapy, in the setting of HIV or AIDS, may result in rapid disease progression and worse clinical outcome.

The looming tide of nontuberculous mycobacterial infections in Portugal and Brazil

Nontuberculous mycobacteria (NTM) are widely disseminated in the environment and an emerging cause of infectious diseases worldwide. Their remarkable natural resistance to disinfectants and antibiotics and an ability to survive under low-nutrient conditions allows NTM to colonize and persist in man-made environments such as household and hospital water distribution systems. This overlap between human and NTM environments afforded new opportunities for human exposure, and for expression of their often neglected and underestimated pathogenic potential. Some risk factors predisposing to NTM disease have been identified and are mainly associated with immune fragilities of the human host. However, infections in apparently immunocompetent persons are also increasingly reported. The purpose of this review is to bring attention to this emerging health problem in Portugal and Brazil and to emphasize the urgent need for increased surveillance and more comprehensive epidemiological data in both countries, where such information is scarce and seriously thwarts the adoption of proper preventive strategies and therapeutic options.

Proteomics approach to understand reduced clearance of mycobacteria and high viral titers during HIV-mycobacteria co-infection

Environmental mycobacteria, highly prevalent in natural and artificial (including chlorinated municipal water) niches, are emerging as new threat to human health, especially to HIV-infected population. These seemingly harmless non-pathogenic mycobacteria, which are otherwise cleared, establish as opportunistic infections adding to HIV-associated complications. Although immune-evading strategies of pathogenic mycobacteria are known, the mechanisms underlying the early events by which opportunistic mycobacteria establish infection in macrophages and influencing HIV infection are unclear. Proteomics of phagosome-enriched fractions from Mycobacterium bovis Bacillus Calmette-Guérin (BCG) mono-infected and HIV-M. bovis BCG co-infected THP-1 cells by LC-MALDI-MS/MS revealed differential distribution of 260 proteins. Validation of the proteomics data showed that HIV co-infection helped the survival of non-pathogenic mycobacteria by obstructing phagosome maturation, promoting lipid biogenesis and increasing intracellular ATP equivalents. In turn, mycobacterial co-infection up-regulated purinergic receptors in macrophages that are known to support HIV entry, explaining increased viral titers during co-infection. The mutualism was reconfirmed using clinically relevant opportunistic mycobacteria, Mycobacterium avium, Mycobacterium kansasii and Mycobacterium phlei that exhibited increased survival during co-infection, together with increase in HIV titers. Additionally, the catalogued proteins in the study provide new leads that will significantly add to the understanding of the biology of opportunistic mycobacteria and HIV coalition.

A Description of Mortality Associated with IPT plus ART Compared to ART Alone among HIV-Infected Individuals in Addis Ababa, Ethiopia: A Cohort Study

BACKGROUND

Tuberculosis (TB) is the most common human immunodeficiency virus (HIV) associated opportunistic infection. It is the leading cause of death in HIV-infected individuals in sub-Saharan Africa. Anti-retroviral therapy (ART) and isoniazid preventive therapy (IPT) are the two useful TB preventative strategies available to reduce TB among people living with HIV (PLHIV). Therefore, the aim of this study is to compare mortality associated with IPT taken together with ART, as well as ART alone, among PLHIV.

METHODS

A retrospective cohort study was undertaken at Tikur Anbessa Specialized Hospital (TASH) and Zewditu Memorial Hospital (ZMH) on 185 patients receiving IPT (6 months) plus ART and 557 patients receiving ART alone. Mortality rates (MR) per 100 person-years (PYs) were used to compare mortality rates amongst the groups. Time-to-death and survival probabilities of the patients were determined using the Kaplan Meier Method. The Cox Proportional Hazard Model was employed to estimate the effect of IPT plus ART on survival of PLHIV.

RESULTS

The mortality cases noted in patients treated by IPT plus ART versus ART alone were 18 (4.5 cases/100 PYs) and 116 (10 cases/100 PYs), respectively. In reference to the ART alone, the IPT plus ART reduced the likelihood of death significantly (aHR 0.48; 95% CI 0.38-0.69) and median time to death was about 26 months (IQR 19-34). Moreover, WHO stage IV (aHR 2.42: 95% CI 1.42-4.11), CD4 values ≥350 cells/mm3 (aHR 0.52; 95% CI 0.28-0.94), adherence to ART (aHR 0.12; 95% CI 0.08-0.20), primary levels of education (aHR 2.20; 95% CI 1.07-4.52); and alcohol consumption (aHR 1.71; 95% CI 1.04-2.81) were factors strongly associated with mortality.

CONCLUSION

We found that PLHIV treated by the IPT plus ART had a lower likelihood of mortality and delayed time-to-death when compared to patients treated by ART alone.

The re-emergency and persistence of vaccine preventable diseases

The introduction of vaccination worldwide dramatically reduced the incidence of pathogenic bacterial and viral diseases. Despite the highly successful vaccination strategies, the number of cases among vaccine preventable diseases has increased in the last decade and several of those diseases are still endemic in different countries. Here we discuss some epidemiological aspects and possible arguments that may explain why ancient diseases such as, measles, polio, pertussis, diphtheria and tuberculosis are still with us.

An ethnobotanical survey of medicinal plants used by traditional health practitioners to manage HIV and its related opportunistic infections in Mpoza, Eastern Cape Province, South Africa

ETHNOPHARMACOLOGICAL RELEVANCE

The aim of the study was to identify and document plants traditionally used to manage HIV and treat its opportunistic infections (OIs) in Mpoza, a rural village located in the Mount Frere Alfred Nzo District, Eastern Cape Province, South Africa.

MATERIALS AND METHODS

Semi-structured interviews and focus group discussions (FGDs) were conducted with 18 traditional health practitioners from January 2012 to August 2012 to obtain information about medicinal plants used in the management of HIV and treatment of OIs.

RESULTS

Seventeen plant species belonging to 12 families were identified for the management of HIV and treatment of OIs in Mpoza. The identified plant species belonged mostly to the families Asparagaceae (12%), Araliaceae (12%), Apiaceae (12%), Xanthorrhoeaceae (12%) and Lamiaceae (12%). The remaining 40% of identified plant species was evenly split over seven families - Urticaceae, Hypoxidaceae, Leguminosae, Verbenaceae, Rosaceae, Compositae and Rutaceae. The most frequently used medicinal plants were Hypoxis hemerocallidea (85%), Asparagus densiflorus (68%) and Lessertia frutescens (68%). The leaves (43.5%) and roots (21.7%) were the most frequently used plant parts, usually prepared as infusions and decoctions for oral administration.

CONCLUSION

This study provides documentation of medicinal plants used in the management of HIV and treatment of commonly associated OIs, which might provide a potential lead that will significantly contribute in reducing the burden of HIV infections in South Africa. We envisage that this paper will provide some background for further studies in developing new, effective, safe and affordable plant-derived medicines.

"Target-Site" Drug Metabolism and Transport

The recent symposium on "Target-Site" Drug Metabolism and Transport that was sponsored by the American Society for Pharmacology and Experimental Therapeutics at the 2014 Experimental Biology meeting in San Diego is summarized in this report. Emerging evidence has demonstrated that drug-metabolizing enzyme and transporter activity at the site of therapeutic action can affect the efficacy, safety, and metabolic properties of a given drug, with potential outcomes including altered dosing regimens, stricter exclusion criteria, or even the failure of a new chemical entity in clinical trials. Drug metabolism within the brain, for example, can contribute to metabolic activation of therapeutic drugs such as codeine as well as the elimination of potential neurotoxins in the brain. Similarly, the activity of oxidative and conjugative drug-metabolizing enzymes in the lung can have an effect on the efficacy of compounds such as resveratrol. In addition to metabolism, the active transport of compounds into or away from the site of action can also influence the outcome of a given therapeutic regimen or disease progression. For example, organic anion transporter 3 is involved in the initiation of pancreatic β-cell dysfunction and may have a role in how uremic toxins enter pancreatic β-cells and ultimately contribute to the pathogenesis of gestational diabetes. Finally, it is likely that a combination of target-specific metabolism and cellular internalization may have a significant role in determining the pharmacokinetics and efficacy of antibody-drug conjugates, a finding which has resulted in the development of a host of new analytical methods that are now used for characterizing the metabolism and disposition of antibody-drug conjugates. Taken together, the research summarized herein can provide for an increased understanding of potential barriers to drug efficacy and allow for a more rational approach for developing safe and effective therapeutics.

Innate and Adaptive Cellular Immune Responses to Mycobacterium tuberculosis Infection

Host resistance to Mycobacterium tuberculosis (Mtb) infection requires the coordinated efforts of innate and adaptive immune cells. Diverse pulmonary myeloid cell populations respond to Mtb with unique contributions to both host-protective and potentially detrimental inflammation. Although multiple cell types of the adaptive immune system respond to Mtb infection, CD4 T cells are the principal antigen-specific cells responsible for containment of Mtb infection, but they can also be major contributors to disease during Mtb infection in several different settings. Here, we will discuss the role of different myeloid populations as well as the dual nature of CD4 T cells in Mtb infection with a primary focus on data generated using in vivo cellular immunological studies in experimental animal models and in humans when available.

First Outcome of MDR-TB among Co-Infected HIV/TB Patients from South-West Iran

Background

Tuberculosis (TB) is the leading cause of mortality among human immunodeficiency virus (HIV) patients and the majority of them occur in developing countries. The aims of the present study were to determine the frequency of HIV/TB co-infection and other probable associated factors.

Methods

This 10 year retrospective study was conducted on 824 HIV patients in the south-west of Iran. HIV infection was diagnosed by the enzyme linked immunosorbent assay and confirmed by Western blot. TB diagnosis was based on consistency of the clinical manifestations, chest X-ray, and microscopic examination. Drug susceptibility testing was done by the proportional method on Löwenstein-Jensen media.

Results

Of 824 HIV patients, 59 (7.2%) were identified as TB co-infected and the majority (86.4%) of them were male. Of the overall TB infected patients, 6 cases (10.2%) showed multidrug-resistant with the mean CD4+ lymphocyte count of 163±166 cells/mm³. The main clinical forms of TB were pulmonary (73%). There was a significant (p<0.05) correlation between TB infection and CD4+ lymphocyte counts ≤200 cells/mm³, gender, prison history, addiction history, and highly active anti-retroviral therapy.

Conclusion

We reported novel information on frequency of HIV/TB co-infection and multidrug resistant-TB outcome among co-infected patients that could facilitate better management of such infections on a global scale.

Disulfiram and Copper Ions Kill Mycobacterium tuberculosis in a Synergistic Manner

Tuberculosis is a severe disease affecting millions worldwide. Unfortunately, treatment strategies are hampered both by the prohibitively long treatment regimen and the rise of drug-resistant strains. Significant effort has been expended in the search for new treatments, but few options have successfully emerged, and new treatment modalities are desperately needed. Recently, there has been growing interest in the synergistic antibacterial effects of copper ions (Cu(II/I)) in combination with certain small molecular compounds, and we have previously reported development of a drug screening strategy to harness the intrinsic bactericidal properties of Cu(II/I). Here, we describe the copper-dependent antimycobacterial properties of disulfiram, an FDA-approved and well-tolerated sobriety aid. Disulfiram was inhibitory to mycobacteria only in the presence of Cu(II/I) and exerted its bactericidal activity well below the active concentration of Cu(II/I) or disulfiram alone. No other physiologically relevant bivalent transition metals (e.g., Fe(II), Ni(II), Mn(II), and Co(II)) exhibited this effect. We demonstrate that the movement of the disulfiram-copper complex across the cell envelope is porin independent and can inhibit intracellular protein functions. Additionally, the complex is able to synergistically induce intracellular copper stress responses significantly more than Cu(II/I) alone. Our data suggest that by complexing with disulfiram, Cu(II/I) is likely allowed unfettered access to vulnerable intracellular components, bypassing the normally sufficient copper homeostatic machinery. Overall, the synergistic antibacterial activity of Cu(II/I) and disulfiram reveals the susceptibility of the copper homeostasis system of Mycobacterium tuberculosis to chemical attacks and establishes compounds that act in concert with copper as a new class of bacterial inhibitors.

Disulfiram and Copper Ions Kill Mycobacterium tuberculosis in a Synergistic Manner

Tuberculosis is a severe disease affecting millions worldwide. Unfortunately, treatment strategies are hampered both by the prohibitively long treatment regimen and the rise of drug-resistant strains. Significant effort has been expended in the search for new treatments, but few options have successfully emerged, and new treatment modalities are desperately needed. Recently, there has been growing interest in the synergistic antibacterial effects of copper ions (Cu(II/I)) in combination with certain small molecular compounds, and we have previously reported development of a drug screening strategy to harness the intrinsic bactericidal properties of Cu(II/I). Here, we describe the copper-dependent antimycobacterial properties of disulfiram, an FDA-approved and well-tolerated sobriety aid. Disulfiram was inhibitory to mycobacteria only in the presence of Cu(II/I) and exerted its bactericidal activity well below the active concentration of Cu(II/I) or disulfiram alone. No other physiologically relevant bivalent transition metals (e.g., Fe(II), Ni(II), Mn(II), and Co(II)) exhibited this effect. We demonstrate that the movement of the disulfiram-copper complex across the cell envelope is porin independent and can inhibit intracellular protein functions. Additionally, the complex is able to synergistically induce intracellular copper stress responses significantly more than Cu(II/I) alone. Our data suggest that by complexing with disulfiram, Cu(II/I) is likely allowed unfettered access to vulnerable intracellular components, bypassing the normally sufficient copper homeostatic machinery. Overall, the synergistic antibacterial activity of Cu(II/I) and disulfiram reveals the susceptibility of the copper homeostasis system of Mycobacterium tuberculosis to chemical attacks and establishes compounds that act in concert with copper as a new class of bacterial inhibitors.

Concurrent loss of co-stimulatory molecules and functional cytokine secretion attributes leads to proliferative senescence of CD8(+) T cells in HIV/TB co-infection

The role of T-cell immunosenescence and functional CD8(+) T-cell responses in HIV/TB co-infection is unclear. We examined and correlated surrogate markers of HIV disease progression with immune activation, immunosenescence and differentiation using T-cell pools of HIV/TB co-infected, HIV-infected and healthy controls. Our investigations showed increased plasma viremia and reduced CD4/CD8 T-cell ratio in HIV/TB co-infected subjects relative to HIV-infected, and also a closer association with changes in the expression of CD38, a cyclic ADP ribose hydrolase and CD57, which were consistently expressed on late-senescent CD8(+) T cells. Up-regulation of CD57 and CD38 were directly proportional to lack of co-stimulatory markers on CD8(+) T cells, besides diminished expression of CD127 (IL-7Rα) on CD57(+)CD4(+) T cells. Notably, intracellular IFN-γ, perforin and granzyme B levels in HIV-specific CD8(+) T cells of HIV/TB co-infected subjects were diminished. Intracellular CD57 levels in HIV gag p24-specific CD8(+) T cells were significantly increased in HIV/TB co-infection. We suggest that HIV-TB co-infection contributes to senescence associated with chronic immune activation, which could be due to functional insufficiency of CD8(+) T cells.

The potential impact of coinfection on antimicrobial chemotherapy and drug resistance

Across a range of pathogens, resistance to chemotherapy is a growing problem in both public health and animal health. Despite the ubiquity of coinfection, and its potential effects on within-host biology, the role played by coinfecting pathogens on the evolution of resistance and efficacy of antimicrobial chemotherapy is rarely considered. In this review, we provide an overview of the mechanisms of interaction of coinfecting pathogens, ranging from immune modulation and resource modulation, to drug interactions. We discuss their potential implications for the evolution of resistance, providing evidence in the rare cases where it is available. Overall, our review indicates that the impact of coinfection has the potential to be considerable, suggesting that this should be taken into account when designing antimicrobial drug treatments.

Association of the anti-tuberculosis drug rifampicin with a PAMAM dendrimer

The association of the anti-tuberculosis drug rifampicin (RIF) with a 4th-generation poly(amidoamine) (G4-PAMAM) dendrimer was investigated by means of molecular dynamics simulations. The RIF load capacity was estimated to be around 20 RIF per G4-PAMAM at neutral pH. The complex formed by 20 RIF molecules and the dendrimer (RIF20-PAMAM) was subjected to 100 ns molecular dynamics (MD) simulations at two different pH conditions (neutral and acidic). The complex was found to be significantly more stable in the simulation at neutral pH compared to the simulation at low pH in which the RIF molecules were rapidly and almost simultaneously expelled to the solvent bulk. The high stability of the RIF-PAMAM complex under physiological pH and the rapid release of RIF molecules under acidic medium provide an interesting switch for drug targeting since the Mycobacterium resides within acidic domains of the macrophage. Altogether, these results suggest that, at least in terms of stability and pH-dependent release, PAMAM-like dendrimers may be considered suitable drug delivery systems for RIF and derivatives.

Incidence and Predictors of Tuberculosis among HIV Positive Children at University of Gondar Referral Hospital, Northwest Ethiopia: A Retrospective Follow-Up Study

Background. The aim of this study was to determine the incidence of tuberculosis and its predictors among HIV positive children. Methods. A six-year retrospective follow-up study was conducted among HIV infected children aged less than 15 years. Life table was used to estimate the cumulative probability of tuberculosis free survival. Cox proportional hazards model was used to identify predictors of tuberculosis. Results. A total of 271 HIV positive children were followed for six years and produced 1100.50 person-years of observation. During the follow-up period 52 new TB cases occurred. The overall incidence density of TB was 4.9 per 100 PY. Inappropriate vaccination [AHR: 8.03 (95% CI; 4.61–13.97)], ambulatory functional status [AHR: 1.99 (95% CI; 1.04–3.81)], and having baseline anemia [AHR: 2.23 (95% CI; 1.19–4.15)] were important predictors of time to TB occurrence. Conclusion. TB incidence rate was high. Early diagnosis and treatment of anemia and strengthening immunization program would reduce the risk of TB occurrence.

Pharmacokinetics of Inhaled Rifampicin Porous Particles for Tuberculosis Treatment: Insight into Rifampicin Absorption from the Lungs of Guinea Pigs

Tuberculosis (TB) is a life-threatening infection that requires a lengthy treatment process that is often associated with adverse effects. Pulmonary delivery of anti-TB drugs has the potential to increase efficacy of treatment by increasing drug concentrations at the lungs, the primary site of infection. The aim of the present study is to evaluate the disposition of rifampicin (RIF) after its pulmonary administration as porous particles (PPs) to guinea pigs and contrast it to that after oral administration. RIF microparticles were prepared by spray drying a solution of RIF and L-leucine (9:1), and the resulting particles were characterized for their physicochemical properties. Animals received RIF either as intravenous solution (iv), as oral suspension of micronized RIF (ORS) and RIF-PPs (ORPP), or by insufflation of the PPs (IRPP). Plasma samples were collected at preselected time points, and bronchoalveolar lavage (BAL) was performed at the end of the study. RIF concentrations in biological samples were analyzed by HPLC. Plasma concentration versus time data was analyzed by compartmental and noncompartmental methods. RIF PPs were thin walled porous particles with mass median aerodynamic diameter (MMAD) of 4.8±0.1 μm, GSD=1.29±0.03, and fine particle fraction below 5.8 μm of 52.9±2.0%. RIF content in the resulting particles was 91.8±0.1%. Plasma concentration vs time profiles revealed that the terminal slope of the iv group was different from that of the oral or pulmonary groups, indicating the possibility of flip-flop kinetics. RIF from IRPP appeared to be absorbed faster than that of ORPP or ORS as evidenced by higher RIF plasma concentrations up until 2 h. Notably, similar AUC (when corrected by dose), similar CL, λ, and half-life were obtained after oral administration of RIF at 40 mg/kg and pulmonary administration of RIF at 20 mg/kg. However, RIF in the IRPP group had a shorter Tmax and higher bioavailability than orally dosed groups. In addition, RIF concentrations in the BAL of animals in the IRPP group were 3-4-fold larger than those in the orally dosed groups. The disposition in ORS and ORPP were best described by a model with two sequential compartments, whereas the disposition of IRPP was best described by a two parallel compartment model. The advantages of delivering RIF by the pulmonary route are demonstrated in the present study. These include achieving higher RIF concentrations in the lungs and similar systemic levels after pulmonary delivery of one-half of the oral nominal dose. This is expected to result in a more effective treatment of pulmonary TB, as shown previously in published efficacy studies.

Strategies for the prevention of mother to child transmission in Western countries: an update

BACKGROUND

During the last decades remarkable scientific advances have been made toward the prevention of HIV mother-to-child transmission, in particular in developed nations. The aim of this review was to analyze the latest findings and available international recommendations on the prevention of HIV mother-to-child transmission in high-income countries.

METHODS

We performed a literature search of the Cochrane Library, MEDLINE by PubMed and EMBASE from database inception through June 2014, using the following terms: HIV, mother-to-child transmission and mother-to-child-transmission prevention. All types of articles in the English language were included. US and available European guidelines were searched and included in the analysis.

RESULTS

One hundred fifty articles were selected for inclusion in this review.

CONCLUSIONS

Global epidemiology of HIV infection is rapidly evolving, in particular in high-resource countries. The interpretation of clinical and epidemiological studies is crucial for the development of evidence-based recommendations to guide the management of HIV mother-to-child transmission. Although significant progress has been made, heterogeneity between countries in specific interventions still exists, which may address future research.

Attrition of TCR Vα7.2+ CD161++ MAIT cells in HIV-tuberculosis co-infection is associated with elevated levels of PD-1 expression

Mucosal-associated invariant T (MAIT) cells are evolutionarily conserved antimicrobial MR1-restricted CD8⁺ T cells co-expressing the semi-invariant TCR Vα7.2, and are numerous in the blood and mucosal tissues of humans. MAIT cells appear to undergo exhaustion in chronic viral infections. However, their role in human immunodeficiency virus type 1 (HIV-1) mono-infection and HIV/tuberculosis (TB) co-infection have seldom been elaborately investigated. We conducted a cross-sectional study to investigate the frequencies and phenotypes of CD161⁺⁺CD8⁺ T cells among anti-retroviral therapy (ART)/anti-TB therapy (ATT) treatment-naïve HIV/TB co-infected, ART/TB treated HIV/TB co-infected, ART naïve HIV-infected, ART-treated HIV-infected patients, and HIV negative healthy controls (HCs) by flow cytometry. Our data revealed that the frequency of MAIT cells was severely depleted in HIV mono- and HIV/TB co-infections. Further, PD-1 expression on MAIT cells was significantly increased in HIV mono- and HIV-TB co-infected patients. The frequency of MAIT cells did not show any significant increase despite the initiation of ART and/or ATT. Majority of the MAIT cells in HCs showed a significant increase in CCR6 expression as compared to HIV/TB co-infections. No marked difference was seen with expressions of chemokine co-receptor CCR5 and CD103 among the study groups. Decrease of CCR6 expression appears to explain why HIV-infected patients display weakened mucosal immune responses.

Evaluation of CD4+ CD25+ FoxP3+ Regulatory T cells and FoxP3 and CTLA-4 gene Expression in Patients wwith Newly Diagnosed Tuberculosis in Northeast of Iran

Background:

Tuberculosis (TB) is the world's second most common infectious disease after Human Immunodeficiency Virus Infection/Acquired Immunodeficiency Syndrome (HIV/AID) and the most frequent cause of mortality especially in developing countries. T regulatory (Treg) cells, which have suppressive activity and express forkhead winged-helix family transcriptional repressor p3 (FoxP3), suppress the immune responses against pathogens such as Mycobacterium tuberculosis. There are controversial results regarding the role of FoxP3 expressing cells in the blood of patients with TB.

Objectives:

The aim of this study was to evaluate the frequency CD4+ CD25+ Treg cells, and FoxP3 and Cytotoxic T Lymphocyte Antigen 4 (CTLA-4) gene expressions in peripheral blood of patients with tuberculosis and patients with positive tuberculin skin test before and after Peripheral Blood Mononuclear Cells (PBMCs) activation with Purified Protein Derivative (PPD).

Patients and Methods:

In this cross-sectional study, Peripheral Mononuclear Cells (PBMCs) were isolated from peripheral blood of 29 patients with newly diagnosed pulmonary TB and 19 patients with positive tuberculin skin test. The PBMCs were activated with PPD for 72 hours. Activated cells were harvested, RNA was extracted and cDNA was synthesized. A real-time Taqman method was designed and optimized for evaluation of Foxp3 gene expression and SYBR Green method was used and optimized for evaluation of CTLA-4 gene expression. A flow cytometry analysis was used to evaluate the frequency of CD4+ CD25+ Foxp3+ regulatory T cells in both groups.

Results:

There was no significant difference in the frequency of CD4+ CD25+ FoxP3+ regulatory T cells between the two groups. Expression of FoxP3 and CTLA-4 in peripheral blood of patients with newly diagnosed TB was significantly lower than the control group after and before activation with PPD.

Conclusions:

The expression of FoxP3 and CTLA-4 in PBMCs of patients with newly diagnosed TB was low, which might suggest that Treg cells may be sequestered in the lungs.

The effect of isoniazid preventive therapy on incidence of tuberculosis among HIV-infected clients under pre-ART care, Jimma, Ethiopia: a retrospective cohort study

Background

Tuberculosis (TB) is a major public health problem that accounts for almost half a million human immunodeficiency virus (HIV) associated deaths. Provision of isoniazid preventive therapy (IPT) is one of the public health interventions for the prevention of TB in HIV infected individuals. However, in Ethiopia, the coverage and implementation of IPT is limited. The objective of this study is to compare the incidence rate of TB, TB-free survival time and identify factors associated with development TB among HIV-infected individuals on pre-ART follow up.

Methods

A retrospective cohort study was conducted from January, 2008 to February 31, 2012 in Jimma hospital. Kaplan-Meier survival plots were used to calculate the crude effect in both groups on TB-free survival probabilities and compared using the log rank test. A Cox proportional hazard model was used to identify predictors of TB.

Result

A total of 588 patients on pre-ART care (294 IPT and 294 non-IPT group) were followed retrospectively for a median duration of 24.1 months. The median CD₄⁺ cell count was 422 cells/μl (IQR 344 – 589). During the follow up period, 49 individuals were diagnosed with tuberculosis, giving an overall incidence of 3.78 cases per 100 person year (PY). The incidence rate of TB was 5.06 per 100 PY in non-IPT group and 2.22 per 100 PY in IPT user group. Predictors of higher TB risk were: being on clinical WHO stage III/IV (adjusted hazard ratio (AHR = 3.05, 95% confidence interval (CI): 1.61, 5.81); non-IPT user (AHR = 2.02, 95% CI: 1.04, 3.92); having CD₄⁺ cell count less than 350 cells/μl (AHR = 3.16, 95% CI: 1.04, 3.92) and between 350–499 cells/μl, (AHR = 2.87; 95% CI: 1.37 - 6.03) and having episode of opportunistic infection (OI) in the past (AHR = 2.41, 95% CI: 1.33-4.34).

Conclusion

IPT use was associated with fifty percent reduction in new cases of tuberculosis and probability of developing TB was higher in non-IPT group. Implementing the widespread use of IPT has the potential to reduce TB rates substantially among HIV-infected individuals in addition to other tuberculosis prevention and control effort in resource limited settings.

A novel molecule with notable activity against multi-drug resistant tuberculosis

Multi-drug resistant tuberculosis (MDR-TB) is emerging as a serious global health problem, which has been elevated through co-infection involving HIV and MDR-Mtb. The discovery of new compounds with anti-MDR TB efficacy and favorable metabolism profiles is an important scientific challenge. Using computational biology and ligand docking data, we have conceived a multifunctional molecule, 2, as a potential anti-MDR TB agent. This compound was produced through a multi-step synthesis. It exhibited significant in vitro activity against MDR-TB (MIC 1.56μg/mL) and its half-life (t1/2) in human liver microsomes was 14.4h. The metabolic profiles of compound 2 with respect to human cytochrome P450 (CYP) and uridine 5'-diphospho-glucuronosyltransferase (UGT) isozymes were favorable. Compound 2 also had relatively low in vitro cytotoxicity in uninfected macrophages. It displayed synergistic behavior against MDR-TB in combination with PA-824. Interestingly, compound 2 also displayed in vitro anti-HIV activity.

Chronic infections of the small intestine

PURPOSE OF REVIEW

Chronic infections of the small intestine cause significant morbidity and mortality globally. This review focuses on the recent advances in the field of our understanding of selected intestinal infections.

RECENT FINDINGS

Primary and secondary immunodeficiency increase the susceptibility to many chronic intestinal infections. Endoscopy and intestinal biopsies are central to establishing a diagnosis of these conditions. Tuberculosis (TB) remains a major global health challenge. Emerging therapeutic agents to counteract multidrug-resistant strains have shown clinical efficacy, but concerns regarding mortality remain. PCR-based diagnostic TB tests have the potential to reduce diagnostic delays, but remain to be validated for intestinal infections. Adjunctive diagnostic imaging modalities can differentiate infections from Crohn's disease with increasing accuracy. Whipple's disease remains rare, but there have been substantial advances in our understanding of the causative organism Tropheryma whipplei. Extended treatment with broad-spectrum antibiotics is effective in most cases. The narrow therapeutic window and limited armamentarium for treating invasive filamentous fungal infections contribute to their significant morbidity and high rates of mortality.

SUMMARY

The speed and accuracy of diagnosing chronic intestinal infections have improved with recent imaging and laboratory methodologies. Significant research opportunities remain for clinicians and scientists to improve the diagnostic accuracy and clinical outcomes of chronic intestinal infections.

Tuberculosis and HIV Coinfection

Tuberculosis (TB) and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) constitute the main burden of infectious disease in resource-limited countries. In the individual host, the two pathogens, Mycobacterium tuberculosis and HIV, potentiate one another, accelerating the deterioration of immunological functions. In high-burden settings, HIV coinfection is the most important risk factor for developing active TB, which increases the susceptibility to primary infection or reinfection and also the risk of TB reactivation for patients with latent TB. M. tuberculosis infection also has a negative impact on the immune response to HIV, accelerating the progression from HIV infection to AIDS. The clinical management of HIV-associated TB includes the integration of effective anti-TB treatment, use of concurrent antiretroviral therapy (ART), prevention of HIV-related comorbidities, management of drug cytotoxicity, and prevention/treatment of immune reconstitution inflammatory syndrome (IRIS).

Development and evaluation of a new interferon-gamma release assay for the diagnosis of tuberculosis infection in HIV-infected individuals in China

BACKGROUND

Human immunodeficiency virus (HIV)-infected individuals are at high risk of contracting tuberculosis (TB) disease, and current methods for diagnosing TB infection are less effective in this population. We developed and evaluated a new interferon-gamma release assay (IGRA), named A.TB, in HIV-infected individuals, with and without active TB, in a setting of high TB burden and low HIV prevalence.

METHODS

A total of 255 subjects were divided into 3 groups according to their HIV and TB status: HIV+ without active TB (n = 123), HIV+/TB+ (n = 79), and HIV-/TB+ (n = 65). The A.TB assay was performed in parallel with the QuantiFERON-TB Gold In-Tube (QFT-GIT) and tuberculin skin test (TST).

RESULTS

The positive rate was 59.3% (n = 123) by A.TB and 53.8% (n = 106) by QFT-GIT. We observed a strong concordance of 81.2% (k = 0.612) between the two IGRAs. The QFT-GIT results were affected by low CD4(+) cell count (p = 0.013), while A.TB results were not. A.TB was also performed in patients with active TB (n = 65) and patients with active TB and HIV co-infection (n = 79). The sensitivity of A.TB in these groups was 80.0% and 81.0%, respectively.

CONCLUSION

The A.TB results were not affected by low CD4(+) cell count in the co-infected cohort. With further evaluation, A.TB may prove to be a valuable tool for diagnosing TB in HIV-infected patients.

Mechanistic insights on immunosenescence and chronic immune activation in HIV-tuberculosis co-infection

Immunosenescence is marked by accelerated degradation of host immune responses leading to the onset of opportunistic infections, where senescent T cells show remarkably higher ontogenic defects as compared to healthy T cells. The mechanistic association between T-cell immunosenescence and human immunodeficiency virus (HIV) disease progression, and functional T-cell responses in HIV-tuberculosis (HIV-TB) co-infection remains to be elaborately discussed. Here, we discussed the association of immunosenescence and chronic immune activation in HIV-TB co-infection and reviewed the role played by mediators of immune deterioration in HIV-TB co-infection necessitating the importance of designing therapeutic strategies against HIV disease progression and pathogenesis.

A double age-structured model of the co-infection of tuberculosis and HIV

After decades on the decline, it is believed that the emergence of HIV is responsible for an increase in the tuberculosis prevalence. The leading infectious disease in the world, tuberculosis is also the leading cause of death among HIV-positive individuals. Each disease progresses through several stages. The current model suggests modeling these stages through a time-since-infection tracking transmission rate function, which, when considering co-infection, introduces a double-age structure in the PDE system. The basic and invasion reproduction numbers for each disease are calculated and the basic ones established as threshold for the disease progression. Numerical results confirm the calculations and a simple treatment scenario suggests the importance of time-since-infection when introducing disease control and treatment in the model.

CRF19_cpx is an Evolutionary fit HIV-1 Variant Strongly Associated With Rapid Progression to AIDS in Cuba

Background

Clinicians reported an increasing trend of rapid progression (RP) (AIDS within 3 years of infection) in Cuba.

Methods

Recently infected patients were prospectively sampled, 52 RP at AIDS diagnosis (AIDS-RP) and 21 without AIDS in the same time frame (non-AIDS). 22 patients were sampled at AIDS diagnosis (chronic-AIDS) retrospectively assessed as > 3 years infected. Clinical, demographic, virological, epidemiological and immunological data were collected. Pol and env sequences were used for subtyping, transmission cluster analysis, and prediction of resistance, co-receptor use and evolutionary fitness. Host, immunological and viral predictors of RP were explored through data mining.

Findings

Subtyping revealed 26 subtype B strains, 6 C, 6 CRF18_cpx, 9 CRF19_cpx, 29 BG-recombinants and other subtypes/URFs. All patients infected with CRF19 belonged to the AIDS-RP group. Data mining identified CRF19, oral candidiasis and RANTES levels as the strongest predictors of AIDS-RP. CRF19 was more frequently predicted to use the CXCR4 co-receptor, had higher fitness scores in the protease region, and patients had higher viral load at diagnosis.

Interpretation

CRF19 is a recombinant of subtype D (C-part of Gag, PR, RT and nef), subtype A (N-part of Gag, Integrase, Env) and subtype G (Vif, Vpr, Vpu and C-part of Env). Since subtypes D and A have been associated with respectively faster and slower disease progression, our findings might indicate a fit PR driving high viral load, which in combination with co-infections may boost RANTES levels and thus CXCR4 use, potentially explaining the fast progression. We propose that CRF19 is evolutionary very fit and causing rapid progression to AIDS in many newly infected patients in Cuba.

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We propose that CRF19 is evolutionary very fit, causing rapid progression to AIDS in many newly infected patients in Cuba.

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CRF19 is a recombinant of subtype D, subtype A and subtype G, with a subtype D protease estimated to be particularly fit.

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A fit protease with high viral load and co-infections, may boost RANTES levels and thus CXCR4 use, hence fast progression.

Absence of Annexin A1 impairs host adaptive immunity against Mycobacterium tuberculosis in vivo

The role of Annexin A1 (ANXA1) in counter-regulating the activities of innate immune cells, such as the migration of neutrophils and monocytes, and the generation of pro-inflammatory mediators in various models of inflammatory and autoimmune diseases is well documented. However, while ANXA1 has been proposed as an important mediator of the adaptive immune response, its involvement in this respect has been less studied. Furthermore, while there have been numerous studies on the role of ANXA1 in inflammatory diseases, less has been reported on its influence in immunity against infection. A recent study reported a link between ANXA1 and tuberculosis, and proposed a model in which Mycobacterium tuberculosis exerts its virulence by manipulating the ANXA1-mediated host apoptotic response. This has prompted us to further investigate the role of ANXA1 in the pathogenesis of tuberculosis in vivo. Here, we show that ANXA1(-/-) mice are more susceptible to M. tuberculosis infection, as evidenced by a transient increase in the pulmonary bacterial burden, and exacerbated and disorganized granulomatous inflammation. These pathological manifestations correlated with an impaired ability of ANXA1(-/-) dendritic cells to activate naïve T cells, thereby supporting a role for ANXA1 in shaping the adaptive immunity against M. tuberculosis.

The demographic determinants of human microbiome health

The human microbiome is a vast reservoir of microbial diversity and increasingly recognized to have a fundamental role in human health. In polymicrobial communities, the presence of one species can modulate the demography (i.e., growth and distribution) of other species. These demographic impacts generate feedbacks in multispecies interactions, which can be magnified in spatially structured populations (e.g., host-associated communities). Here, we argue that demographic feedbacks between species are central to microbiome development, shaping whether and how potential metabolic interactions come to be realized between expanding lineages of bacteria. Understanding how demographic feedbacks tune metabolic interactions and in turn shape microbiome structure and function is now a key challenge to our abilities to better manage microbiome health.

Measuring glutathione redox potential of HIV-1-infected macrophages

Redox signaling plays a crucial role in the pathogenesis of human immunodeficiency virus type-1 (HIV-1). The majority of HIV redox research relies on measuring redox stress using invasive technologies, which are unreliable and do not provide information about the contributions of subcellular compartments. A major technological leap emerges from the development of genetically encoded redox-sensitive green fluorescent proteins (roGFPs), which provide sensitive and compartment-specific insights into redox homeostasis. Here, we exploited a roGFP-based specific bioprobe of glutathione redox potential (E_GSH; Grx1-roGFP2) and measured subcellular changes in E_GSH during various phases of HIV-1 infection using U1 monocytic cells (latently infected U937 cells with HIV-1). We show that although U937 and U1 cells demonstrate significantly reduced cytosolic and mitochondrial E_GSH (approximately −310 mV), active viral replication induces substantial oxidative stress (E_GSH more than −240 mV). Furthermore, exposure to a physiologically relevant oxidant, hydrogen peroxide (H₂O₂), induces significant deviations in subcellular E_GSH between U937 and U1, which distinctly modulates susceptibility to apoptosis. Using Grx1-roGFP2, we demonstrate that a marginal increase of about ∼25 mV in E_GSH is sufficient to switch HIV-1 from latency to reactivation, raising the possibility of purging HIV-1 by redox modulators without triggering detrimental changes in cellular physiology. Importantly, we show that bioactive lipids synthesized by clinical drug-resistant isolates of Mycobacterium tuberculosis reactivate HIV-1 through modulation of intracellular E_GSH. Finally, the expression analysis of U1 and patient peripheral blood mononuclear cells demonstrated a major recalibration of cellular redox homeostatic pathways during persistence and active replication of HIV.

Survival rates of human immunodeficiency virus and tuberculosis co-infected patients

Background:

At present, limited clinical data is available regarding survival rates of patients co-infected with human immunodeficiency virus (HIV)/tuberculosis (TB) in developing countries.

Objectives:

The present study aimed to evaluate the effect of HIV infection on the survival chances of active TB adults who disclosed their symptoms of TB in this part of Iran.

Patients and Methods:

The records and data of 807 patients only infected with TB and 21 co-infected patients with HIV/TB, who were admitted to primary health care units in Iran, were evaluated. Their survival time was analyzed using the Kaplan-Meier Estimator, Log-rank test and SPSS version 16.

Results:

Cox regression analysis showed that co-infection with HIV significantly affects the survival rate of TB patients so that the rate of death was 20.7 (8.1-53) times more than TB infected patients alone. Also, married patients with tuberculosis were 2.7 times more at risk of death than single subjects. We also confirmed that in HIV/TB positive patients, married individuals were more prone to death than single subjects (P value < 0.001).

Conclusions:

Our results denote the need to progress diagnostic and preventive measures in this part of Iran.

A derived network-based interferon-related signature of human macrophages responding to Mycobacterium tuberculosis

Network analysis of transcriptional signature typically relies on direct interaction between two highly expressed genes. However, this approach misses indirect and biological relevant interactions through a third factor (hub). Here we determine whether a hub-based network analysis can select an improved signature subset that correlates with a biological change in a stronger manner than the original signature. We have previously reported an interferon-related transcriptional signature (THP1r2Mtb-induced) from Mycobacterium tuberculosis (M. tb)-infected THP-1 human macrophage. We selected hub-connected THP1r2Mtb-induced genes into the refined network signature TMtb-iNet and grouped the excluded genes into the excluded signature TMtb-iEx. TMtb-iNet retained the enrichment of binding sites of interferon-related transcription factors and contained relatively more interferon-related interacting genes when compared to THP1r2Mtb-induced signature. TMtb-iNet correlated as strongly as THP1r2Mtb-induced signature on a public transcriptional dataset of patients with pulmonary tuberculosis (PTB). TMtb-iNet correlated more strongly in CD4(+) and CD8(+) T cells from PTB patients than THP1r2Mtb-induced signature and TMtb-iEx. When TMtb-iNet was applied to data during clinical therapy of tuberculosis, it resulted in the most pronounced response and the weakest correlation. Correlation on dataset from patients with AIDS or malaria was stronger for TMtb-iNet, indicating an involvement of TMtb-iNet in these chronic human infections. Collectively, the significance of this work is twofold: (1) we disseminate a hub-based approach in generating a biologically meaningful and clinically useful signature; (2) using this approach we introduce a new network-based signature and demonstrate its promising applications in understanding host responses to infections.

Severity of bovine tuberculosis is associated with co-infection with common pathogens in wild boar

Co-infections with parasites or viruses drive tuberculosis dynamics in humans, but little is known about their effects in other non-human hosts. This work aims to investigate the relationship between Mycobacterium bovis infection and other pathogens in wild boar (Sus scrofa), a recognized reservoir of bovine tuberculosis (bTB) in Mediterranean ecosystems. For this purpose, it has been assessed whether contacts with common concomitant pathogens are associated with the development of severe bTB lesions in 165 wild boar from mid-western Spain. The presence of bTB lesions affecting only one anatomic location (cervical lymph nodes), or more severe patterns affecting more than one location (mainly cervical lymph nodes and lungs), was assessed in infected animals. In addition, the existence of contacts with other pathogens such as porcine circovirus type 2 (PCV2), Aujeszky's disease virus (ADV), swine influenza virus, porcine reproductive and respiratory syndrome virus, Mycoplasma hyopneumoniae, Actinobacillus pleuropneumoniae, Haemophilus parasuis and Metastrongylus spp, was evaluated by means of serological, microbiological and parasitological techniques. The existence of contacts with a structured community of pathogens in wild boar infected by M. bovis was statistically investigated by null models. Association between this community of pathogens and bTB severity was examined using a Partial Least Squares regression approach. Results showed that adult wild boar infected by M. bovis had contacted with some specific, non-random pathogen combinations. Contact with PCV2, ADV and infection by Metastrongylus spp, was positively correlated to tuberculosis severity. Therefore, measures against these concomitant pathogens such as vaccination or deworming, might be useful in tuberculosis control programmes in the wild boar. However, given the unexpected consequences of altering any community of organisms, further research should evaluate the impact of such measures under controlled conditions. Furthermore, more research including other important pathogens, such as gastro-intestinal nematodes, will be necessary to complete this picture.

The present and future of tuberculosis vaccinations

The clinical, social, and economic burden of tuberculosis (TB) remains high worldwide, thereby highlighting the importance of TB prevention. The bacilli Calmette-Guérin (BCG) vaccine that is currently available can protect younger children but is less effective in adults, the major source of TB transmission. In addition, the emergence of drug-resistant Mycobacterium tuberculosis (Mtb) strains and the high prevalence of HIV infection have significantly complicated TB prognosis and treatment. Together, these data highlight the need for new and more effective vaccines. Recently, several vaccines containing multiple antigens, including some of those specific for dormant Mtb strains, have been developed. These vaccines appear to be the best approach for satisfactory Mtb prevention. However, until a new vaccine is proven more effective and safe than BCG, BCG should remain part of the immunization schedules for neonates and children at risk for TB as a fundamental prophylactic measure.

Thioridazine for treatment of tuberculosis: promises and pitfalls

The articles by De Knegt et al. and Singh et al. in a recent issue of this Journal address one of the current debates regarding the potential role of thioridazine in the treatment of tuberculosis. This commentary presents a summary of the available evidence, and, emphasizing the need for further research, asks the question: "How far can we go in repurposing thioridazine?"

Modeling tuberculosis in nonhuman primates

Nonhuman primates have emerged as an excellent model of human tuberculosis, in large part because they recapitulate the full spectrum of infection outcome and pathology seen in humans. Several variables inherent to the nonhuman primate models of tuberculosis are discussed in this review, including the monkey species, Mycobacterium tuberculosis strains, and routes of infection, all of which can influence the model to be chosen for various studies. New technologies for studying the microbiology, immunology, and pathogenesis of tuberculosis in nonhuman primates have greatly expanded the capabilities of this model for basic and translational studies, including the development and testing of new treatment and prevention strategies for tuberculosis.

Isoniazid induces apoptosis of activated CD4+ T cells: implications for post-therapy tuberculosis reactivation and reinfection

Tuberculosis (TB) remains the second highest killer from a single infectious disease worldwide. Current therapy of TB is lengthy and consists of multiple expensive antibiotics, in a strategy referred to as Directly Observed Treatment, Short Course (DOTS). Although this therapy is effective, it has serious disadvantages. These therapeutic agents are toxic and are associated with the development of a variety of drug-resistant TB strains. Furthermore, patients treated with DOTS exhibit enhanced post-treatment susceptibility to TB reactivation and reinfection, suggesting therapy-related immune impairment. Here we show that Isoniazid (INH) treatment dramatically reduces Mycobacterium tuberculosis antigen-specific immune responses, induces apoptosis in activated CD4⁺ T cells, and renders treated animals vulnerable to TB reactivation and reinfection. Consequently, our findings suggest that TB treatment is associated with immune impairment.

Dissemination of multidrug-resistant tuberculosis in a patient with acute HIV infection

Background

Opportunistic infections are relatively rare in early human immunodeficiency virus infection, especially infection with Mycobacterium tuberculosis. Here, we report a patient who presented with acute human immunodeficiency virus and multidrug-resistant M. tuberculosis co-infections.

Case presentation

A 27-year-old homosexual male was admitted for fever, cough, and hepatitis. At the time of admission, the p24 antigen was detected in his serum, indicating that he had an acute human immunodeficiency virus infection. He was also diagnosed with disseminated tuberculosis spreading to the lung and skin. Anti-tuberculosis medication had been started earlier with one-week intervals of highly active antiretroviral therapy. Despite prolonged anti-tuberculosis treatment, the patient developed tuberculous meningitis on the 50^th day of admission. Multidrug-resistant tuberculosis was cultured from his sputum and cerebrospinal fluid. The patient was successfully treated with second line anti-tuberculosis medication and antiretroviral treatment.

Conclusion

This is the first case of acute human immunodeficiency virus and multi drug-resistance tuberculosis co-infections. This case indicates that tuberculosis infection should be considered even in patients with acute human immunodeficiency virus infection.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-462) contains supplementary material, which is available to authorized users.

Manipulation of the mononuclear phagocyte system by Mycobacterium tuberculosis

Over the past 20 years, there has been an emerging appreciation about the role of the mononuclear phagocyte system (MPS) to control and eradicate pathogens. Likewise, there have been significant advances in dissecting the mechanisms involved in the microbial subversion of MPS cells, mainly affecting their differentiation and effector functions. Mycobacterium tuberculosis is a chronic bacterial pathogen that represents an enigma to the field because of its remarkable ability to thrive in humans. One reason is that M. tuberculosis renders a defective MPS compartment, which is perhaps the most ingenious strategy for survival in the host given the prominence of these cells to modulate microenvironments, their function as sentinels and orchestrators of the immune response, and their pathogenic role as reservoirs for microbial persistence. In this article, the principal strategies used by M. tuberculosis to subvert the MPS compartment are presented along with emerging concepts.

Mycobacterial and HIV infections up-regulated human zinc finger protein 134, a novel positive regulator of HIV-1 LTR activity and viral propagation

BACKGROUND

Concurrent occurrence of HIV and Tuberculosis (TB) infections influence the cellular environment of the host for synergistic existence. An elementary approach to understand such coalition at the molecular level is to understand the interactions of the host and the viral factors that subsequently effect viral replication. Long terminal repeats (LTR) of HIV genome serve as a template for binding trans-acting viral and cellular factors that regulate its transcriptional activity, thereby, deciding the fate of HIV pathogenesis, making it an ideal system to explore the interplay between HIV and the host.

METHODOLOGY/PRINCIPAL FINDINGS

In this study, using biotinylated full length HIV-1 LTR sequence as bait followed by MALDI analyses, we identified and further characterized human-Zinc-finger-protein-134 (hZNF-134) as a novel positive regulator of HIV-1 that promoted LTR-driven transcription and viral production. Over-expression of hZNF-134 promoted LTR driven luciferase activity and viral transcripts, resulting in increased virus production while siRNA mediated knockdown reduced both the viral transcripts and the viral titers, establishing hZNF-134 as a positive effector of HIV-1. HIV, Mycobacteria and HIV-TB co-infections increased hZNF-134 expressions in PBMCs, the impact being highest by mycobacteria. Corroborating these observations, primary TB patients (n = 22) recorded extraordinarily high transcript levels of hZNF-134 as compared to healthy controls (n = 16).

CONCLUSIONS/SIGNIFICANCE

With these observations, it was concluded that hZNF-134, which promoted HIV-1 LTR activity acted as a positive regulator of HIV propagation in human host. High titers of hZNF-134 transcripts in TB patients suggest that up-regulation of such positive effectors of HIV-1 upon mycobacterial infection can be yet another mechanism by which mycobacteria assists HIV-1 propagation during HIV-TB co-infections. hZNF-134, an uncharacterized host protein, thus assumes a novel regulatory role during HIV-host interactions. Our study provides new insights into the emerging role of zinc finger proteins in HIV-1 pathogenesis.

Long-acting antituberculous therapeutic nanoparticles target macrophage endosomes

Eradication of Mycobacterium tuberculosis (MTB) infection requires daily administration of combinations of rifampin (RIF), isoniazid [isonicotinylhydrazine (INH)], pyrazinamide, and ethambutol, among other drug therapies. To facilitate and optimize MTB therapeutic selections, a mononuclear phagocyte (MP; monocyte, macrophage, and dendritic cell)-targeted drug delivery strategy was developed. Long-acting nanoformulations of RIF and an INH derivative, pentenyl-INH (INHP), were prepared, and their physicochemical properties were evaluated. This included the evaluation of MP particle uptake and retention, cell viability, and antimicrobial efficacy. Drug levels reached 6 μg/10(6) cells in human monocyte-derived macrophages (MDMs) for nanoparticle treatments compared with 0.1 μg/10(6) cells for native drugs. High RIF and INHP levels were retained in MDM for >15 d following nanoparticle loading. Rapid loss of native drugs was observed in cells and culture fluids within 24 h. Antimicrobial activities were determined against Mycobacterium smegmatis (M. smegmatis). Coadministration of nanoformulated RIF and INHP provided a 6-fold increase in therapeutic efficacy compared with equivalent concentrations of native drugs. Notably, nanoformulated RIF and INHP were found to be localized in recycling and late MDM endosomal compartments. These were the same compartments that contained the pathogen. Our results demonstrate the potential of antimicrobial nanomedicines to simplify MTB drug regimens.

Safety and immunogenicity of the M72/AS01 candidate tuberculosis vaccine in HIV-infected adults on combination antiretroviral therapy: a phase I/II, randomized trial

OBJECTIVE

Tuberculosis (TB) is highly prevalent among HIV-infected people, including those receiving combination antiretroviral therapy (cART), necessitating a well tolerated and efficacious TB vaccine for these populations. We evaluated the safety and immunogenicity of the candidate TB vaccine M72/AS01 in adults with well controlled HIV infection on cART.

DESIGN

A randomized, observer-blind, controlled trial (NCT00707967).

METHODS

HIV-infected adults on cART in Switzerland were randomized 3 : 1 : 1 to receive two doses, 1 month apart, of M72/AS01, AS01 or 0.9% physiological saline (N = 22, N = 8 and N = 7, respectively) and were followed up to 6 months postdose 2 (D210). Individuals with CD4⁺ cell counts below 200 cells/μl were excluded. Adverse events (AEs) including HIV-specific and laboratory safety parameters were recorded. Cell-mediated (ICS) and humoral (ELISA) responses were evaluated before vaccination, 1 month after each dose (D30, D60) and D210.

RESULTS

Thirty-seven individuals [interquartile range (IQR) CD4⁺ cell counts at screening: 438-872 cells/μl; undetectable HIV-1 viremia] were enrolled; 73% of individuals reported previous BCG vaccination, 97.3% tested negative for the QuantiFERON-TB assay. For M72/AS01 recipients, no vaccine-related serious AEs or cART-regimen adjustments were recorded, and there were no clinically relevant effects on laboratory safety parameters, HIV-1 viral loads or CD4⁺ cell counts. M72/AS01 was immunogenic, inducing persistent and polyfunctional M72-specific CD4⁺ T-cell responses [medians 0.70% (IQR 0.37-1.07) at D60] and 0.42% (0.24-0.61) at D210, predominantly CD40L⁺IL-2⁺TNF-α⁺, CD40L⁺IL-2⁺ and CD40L⁺IL-2⁺TNF-α⁺IFN-γ⁺]. All M72/AS01 vaccines were seropositive for anti-M72 IgG after second vaccination until study end.

CONCLUSION

M72/AS01 was clinically well tolerated and immunogenic in this population, supporting further clinical evaluation in HIV-infected individuals in TB-endemic settings.

Factors associated with tuberculosis by HIV status in the Brazilian national surveillance system: a cross sectional study

Background

Over the last decade tuberculosis (TB) incidence and mortality in Brazil have been steadily declining. However, this downward trend has not been observed among HIV-infected patients. We describe the epidemiological and clinical profile of TB patients by HIV status using the Brazilian National Surveillance System.

Methods

All TB diagnoses with HIV status information between January 1, 2007 and December 31, 2011 were categorized as either HIV or non-HIV at time of TB diagnosis. Co-infected patients (TB-HIV) were compared to TB patients with no HIV-infection using a hierarchical logistic regression model using Stata 13.0.

Results

The prevalence of TB-HIV co-infection was 19% among adults ≥ 15 years of age. We analyzed data from 243,676 individuals, of whom 46,466 were TB-HIV and 197,210 were only TB cases. The following factors increased risk of co-infection: male sex (OR: 1.06, 95% CI 1.03-1.10), 20 to 39 years of age (OR = 4.82, 95% CI 4.34-5.36), black (OR = 1.08, 95% CI 1.04-1.13), 4–7 years of education (OR = 1.13, 95% CI 1.19-1.28), diagnosed following default (OR = 2.65, 95% CI 1.13-6.25), presenting with pulmonary and extra-pulmonary forms of TB simultaneously (OR = 2.80, 95% CI 1.56-5.02), presenting with histopathologic examination suggestive of TB (OR = 2.15, 95% CI 1.13-4.07). Co-infected patients were less likely to live in rural areas (OR = 0.45, 95% CI 0.42-0.48), have diabetes (OR = 0.45, 95% CI 0.40-0.50) and be smear positive (OR = 0.55, 95% CI 0.32-0.95), and co-infected patients had higher risk of default (OR = 2.96, 95% CI 2.36-3.71) and death from TB (OR = 5.16, 95% CI 43.04-5.77).

Conclusions

The prevalence of co-infection with HIV among TB patients is 19% in Brazil. By identifying predictors of co-infection targeted interventions can be developed to prevent both TB and HIV, and to diagnose each disease earlier and ultimately decrease poor treatment outcomes and death.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2334-14-415) contains supplementary material, which is available to authorized users.

Circulating mycobacterial-reactive CD4+ T cells with an immunosuppressive phenotype are higher in active tuberculosis than latent tuberculosis infection

BACKGROUND

Previous studies suggest that control of Mycobacterium tuberculosis infection is compromised by the activity of regulatory T cells, including those that express CD39, an ectonucleotidase with immunosuppressive properties. Here, we examine the role of CD39 on CD4+ T cells reacting to M. tuberculosis antigens.

METHODS

Cryopreserved PBMC from patients with active TB (n = 31) or individuals with LTBI (n = 30) were cultured with PPD, ESAT-6 or CFP-10 and antigen-reactive CD4+ T cells assessed by: A) intracellular expression of interferon-gamma (IFN-γ), tumour necrosis factor alpha (TNF-α) and interleukin (IL)-2, B) co-expression of CD25 and CD134 with or without CD39, and C) production of IFN-γ, TNF-α and IL-10 in culture supernatants.

RESULTS

Active TB patients were not differentiated from individuals with LTBI by intracellular expression of IFN-γ, TNF-α or IL-2 (alone or together), nor by co-expression of CD25 and CD134. However, active TB patients exhibited higher proportions of CD25+, CD134+, CD4+ T cells expressing CD39 in response to all antigens (p ≤ 0.022). Furthermore, in response to PPD, CD39 expression on CD25+, CD134+, CD4+ T cells correlated with IL-10 production (r = 0.41, p = 0.005) and inhibition of CD39 decreased IL-10 production.

CONCLUSIONS

Antigen-reactive CD4+ T cells expressing CD39 are more abundant in active TB than LTBI and are associated with production of the immunosuppressive cytokine IL-10. Modulating the effects of CD39 might enhance cellular immune responses against M. tuberculosis.