Relationship between chemokine receptor expression, chemokine levels and HIV-1 replication in the lungs of persons exposed to Mycobacterium tuberculosis

Burden of mortality and its predictors among TB-HIV co-infected patients in Ethiopia: Systematic review and meta-analysis

BACKGROUND

Human immunodeficiency virus (HIV) and tuberculosis (TB) are still the two major deadly pandemics globally, causes 167,000 deaths in 2022. The two lethal combinations pose a substantial challenge to public health, especially in areas with high burden of both diseases such as Sub-Saharan Africa including Ethiopia. However, there is no study that showed national figure on mortality of TB/HIV co-infected patients. Hence, this review intended to provide pooled mortality rate and its predictors among patients co- infected with twin pandemics.

METHODS

Using reputable electronic data bases, primary studies were searched from January 25 to February 5, 2024. The review included papers published in English language conducted between 2004 and 2024. Heterogeneity between included studies was evaluated using Cochrane Q-test and the I2 statistics. Sub-group analysis was done to mitigate significant heterogeneity. Sensitivity analysis was also done to evaluate the effect of single studies on pooled estimated result.

RESULTS

In this systematic review and meta-analysis a total of 5,210 study participants were included from 15 primary studies. The review disclosed that the pooled proportion and incidence of mortality were 18.73% (95% CI: 15.92-20.83) and 4.94 (95% CI: 2.98-6.89) respectively. Being bedridden and ambulatory functional status, poor ART adherence, CD4 count below the threshold (<200 cells/mm3), advanced WHO clinical staging, not provision of cotrimoxazole and isoniazid preventing therapy, anemia and extra pulmonary TB were significant predictors of mortality.

CONCLUSION AND RECOMMENDATIONS

The analyzed data of this systematic review and meta-analysis depicted that the national pooled proportion and incidence of mortality among TB-HIV co-infected patients were considered to be still high. The authors strongly recommended scale up and continuous provision of cotrimoxazole and isoniazid preventive therapy. In addition, early identification and treatment of anemia will greatly halt the high burden of mortality. Generally, to reduce mortality and improve survival, a collaborative effort is mandatory to emphasize close follow up of patients with identified predictors.

Modeling Survival Time to Death Among TB and HIV Co-infected Adult Patients: an Institution-Based Retrospective Cohort Study

BACKGROUND

Tuberculosis is a serious health threat, particularly for people living with human immunodeficiency virus (HIV), and HIV-positive people are more likely than others to contract the disease. Globally, tuberculosis (TB) is one of the leading causes of death among people living with HIV. The purpose of the current study was to identify factors associated with survival rates of TB/HIV co-infected patients using survival models.

METHODS

A retrospective study was conducted on TB/HIV co-infected adult patients registered and under follow-up at Tepi General Hospital (TGH) and Mizan-Tepi University Teaching Hospital (MTUTH), southwest Ethiopia. All TB/HIV co-infection patients who were registered and under follow-up from 1st January 2015 through 1st January 2020 were considered. The global Schoenfeld test was used to test the proportional hazard (PH) assumption. Various accelerated failure time (AFT) models were compared to determine the best model for the time to death of TB/HIV co-infected patients' data set. Among the most commonly used accelerated failure time models (AFT models), the study used exponential, Weibull, log-logistic, and log-lognormal AFT models. AIC and BIC were used to compare the performance of fitted models. The data were analyzed with the statistical software R.

RESULTS

Of 363 TB/HIV co-infected patients followed for 60 months, 79 (21.8%) died, while the remaining 284 (78.2%) were censored. The overall median survival time was 15.6 months. The proportional hazard assumption was checked and it was violated. In comparison to other models, the lognormal AFT model performed better. The results of the multivariable lognormal AFT model showed that age, residence, substance use, educational status, clinical stages of the disease, cluster of differentiation 4 (CD4 count/mm³), functional status, cotrimoxazole prophylactic therapy use (CPT use), and INH were all found to be significant factors, while gender, illness other than TB, and disclosure of status were insignificant variables at 5% level of significance.

CONCLUSION

Current study results revealed that older age, substance use, advanced WHO clinical stages of the disease (stage IV), bedridden functional status, and CD4 less than 200 count/mm³ were significantly associated with shorter survival time to death of HIV/TB co-infected patients while having advanced educational status, being from urban residence, CPT use, and INH significantly increase the survival time to death of TB/HIV co-infected patients. Patients with TB/HIV co-infection should be given special attention based on these important factors to improve their health and prolong their lives. HIV-positive patients are more likely than others to contract the TB disease. The risk of death among TB/HIV co-infected patients was found to be high. Out of all patients, 79 (21.8%) died. Accelerated failure time models are good alternatives for scenario Cox proportional hazard assumptions not met.

Dysregulation of the Immune Environment in the Airways During HIV Infection

HIV-1 increases susceptibility to pulmonary infection and disease, suggesting pathogenesis in the lung. However, the lung immune environment during HIV infection remains poorly characterized. This study examined T cell activation and the cytokine milieu in paired bronchoalveolar lavage (BAL) and blood from 36 HIV-uninfected and 32 HIV-infected participants. Concentrations of 27 cytokines were measured by Luminex, and T cells were phenotyped by flow cytometry. Blood and BAL had distinct cytokine profiles (p=0.001). In plasma, concentrations of inflammatory cytokines like IFN-γ (p=0.004) and TNF-α (p=0.004) were elevated during HIV infection, as expected. Conversely, BAL cytokine concentrations were similar in HIV-infected and uninfected individuals, despite high BAL viral loads (VL; median 48,000 copies/ml epithelial lining fluid). HIV-infected individuals had greater numbers of T cells in BAL compared to uninfected individuals (p=0.007); and BAL VL positively associated with CD4+ and CD8+ T cell numbers (p=0.006 and p=0.0002, respectively) and CXCL10 concentrations (p=0.02). BAL T cells were highly activated in HIV-infected individuals, with nearly 2-3 fold greater frequencies of CD4+CD38+ (1.8-fold; p=0.007), CD4+CD38+HLA-DR+ (1.9-fold; p=0.0006), CD8+CD38+ (2.8-fold; p=0.0006), CD8+HLA-DR+ (2-fold; p=0.022) and CD8+CD38+HLA-DR+ (3.6-fold; p<0.0001) cells compared to HIV-uninfected individuals. Overall, this study demonstrates a clear disruption of the pulmonary immune environment during HIV infection, with readily detectable virus and activated T lymphocytes, which may be driven to accumulate by local chemokines.

The pattern of comorbidity and its prevalence among drug-resistant tuberculosis patients at treatment initiation in Lagos, Nigeria

BACKGROUND

Multimorbidity is increasingly being recognized as a serious public health concern in the control of both drug-susceptible and drug-resistant tuberculosis (DR-TB). This study assessed the pattern of comorbidities and their prevalence in DR-TB patients at treatment initiation in Lagos, Nigeria.

METHODS

A cross-sectional study was conducted. The baseline laboratory records (human immunodeficiency virus [HIV] status, fasting blood sugar, audiometry, thyroid function tests, serum electrolyte, haemoglobin level and pregnancy test) of DR-TB patients initiated on treatment in Lagos, Nigeria between 1 August 2014 and 31 March 2017 were reviewed.

RESULTS

A total of 565 DR-TB patients' laboratory records were reviewed, of which 397 (70.3%) had comorbidities. The proportion with one, two, three and four comorbidities was 60.2%, 29.7%, 8.1% and 2.0%, respectively. Anaemia was the most common (48.1%) comorbid condition, while anaemia and hypokalaemia (7.3%), anaemia and hypothyroidism (6.5%) and anaemia and HIV (5%) were most common among patients with more than one comorbid condition. DR-TB patients with comorbidity were significantly older (34.8±12.3 y) than those without comorbidity (32.0±12.8 y) (p=0.038). Of the 176 females in the reproductive age group, 8 (4.5%) were pregnant at baseline.

CONCLUSIONS

The prevalence of comorbidity among DR-TB patients was high. There is a need for the national TB program to expand its DR-TB council of experts and also integrate reproductive health services into DR-TB management in Nigeria.

CCR5 Promoter Polymorphisms Associated With Pulmonary Tuberculosis in a Chinese Han Population

Background

Tuberculosis (TB), an infectious disease caused by Mycobacterium tuberculosis, is a major public health concern. Chemokines and their receptors, such as RANTES, CXCR3, and CCR5, have been reported to play important roles in cell activation and migration in immune responses against TB infection.

Methods

To understand the correlations involving CCR5 gene variations, M. tuberculosis infection, and TB disease progression, a case-control study comprising 450 patients with TB and 306 healthy controls from a Chinese Han population was conducted, along with the detection of polymorphisms in the CCR5 promoter using a sequencing method.

Results

After adjustment for age and gender, the results of logistic analysis indicated that the frequency of rs2734648-G was significantly higher in the TB patient group (P = 0.002, OR = 1.38, 95% CI: 1.123-1.696); meanwhile, rs2734648-GG showed notable susceptibility to TB (P = 6.32E-06, OR = 2.173, 95% CI: 1.546-3.056 in a recessive model). The genotypic frequency of rs1799987 also varied between the TB and control groups (P = 0.008). In stratified analysis, rs2734648-GG significantly increased susceptibility to pulmonary TB in a recessive model (P < 0.0001, OR = 2.382, 95% CI: 1.663-3.413), and the rs2734648-G allele significantly increased susceptibility to TB recurrence in a dominant model (P = 0.0032, OR = 1.936, 95% CI: 1.221-3.068), whereas rs1799987-AA was associated with susceptibility to pulmonary TB (P = 0.0078, OR = 1.678, 95% CI: 1.141-2.495 in a recessive model) but not with extra-pulmonary TB and TB recurrence. A haplotype constructed with the major alleles of the eight SNPs in the CCR5 promoter (rs2227010-rs2856758-rs2734648-rs1799987-rs1799988-rs41469351-rs1800023-rs1800024: A-A-G-G-T-C-G-C) exhibited extraordinarily increased risk of susceptibility to TB and pulmonary TB (P = 6.33E-11, OR = 24.887, 95% CI: 6.081-101.841).

Conclusion

In conclusion, CCR5 promoter polymorphisms were found to be associated with pulmonary TB and TB progression in Chinese Han people.

T cell-tropic HIV efficiently infects alveolar macrophages through contact with infected CD4+ T cells

Alveolar macrophages (AMs) are critical for defense against airborne pathogens and AM dysfunction is thought to contribute to the increased burden of pulmonary infections observed in individuals living with HIV-1 (HIV). While HIV nucleic acids have been detected in AMs early in infection, circulating HIV during acute and chronic infection is usually CCR5 T cell-tropic (T-tropic) and enters macrophages inefficiently in vitro. The mechanism by which T-tropic viruses infect AMs remains unknown. We collected AMs by bronchoscopy performed in HIV-infected, antiretroviral therapy (ART)-naive and uninfected subjects. We found that viral constructs made with primary HIV envelope sequences isolated from both AMs and plasma were T-tropic and inefficiently infected macrophages. However, these isolates productively infected macrophages when co-cultured with HIV-infected CD4+ T cells. In addition, we provide evidence that T-tropic HIV is transmitted from infected CD4+ T cells to the AM cytosol. We conclude that AM-derived HIV isolates are T-tropic and can enter macrophages through contact with an infected CD4+ T cell, which results in productive infection of AMs. CD4+ T cell-dependent entry of HIV into AMs helps explain the presence of HIV in AMs despite inefficient cell-free infection, and may contribute to AM dysfunction in people living with HIV.

Risk factors for mortality among drug-resistant tuberculosis patients registered for drug-resistant treatment in Amhara region, Ethiopia: a historical cohort study

Background

The emergency of drug resistant tuberculosis is a major public health concern worldwide including Ethiopia. However, little is known about risk factors of mortality among drug resistant tuberculosis patients in the study site. Thus, this study was aimed to estimate the risks factors for mortality among drug resistant tuberculosis patients registered for drug-resistant treatment in Amhara region, Ethiopia.

Methods

An institutional-based retrospective cohort study was carried out among laboratory-confirmed drug-resistant tuberculosis patients (n = 498) who were initiated treatment for drug-resistant tuberculosis between September 1, 2010, and December 31, 2017. The demographic and clinical characteristics of the patients were obtained from the register of patients treated for drug-resistant tuberculosis. The data were entered using EpiData version 4.2 and exported to Stata Version 14.1 for further analysis. Descriptive measures were used to characterize the study participants. Kaplan-Meier was used to estimate the survival time of the patients. Cox proportional hazard model was used to identify risk factors for mortality. Hazard Ratio (HR) with 95% confidence interval was used to report the strength of association between risk factors and mortality.

Results

Death was observed among 14.2% (n = 70) of the 498 patients who met the inclusion criteria. The incidence rate of death was 8.20 (95% CI: 7.62, 20.50) per 1000 Person-months in the course of follow-up. The median age was 29.30 years (IQR:23–41). Age 45 years and above (adjusted hazard ratio (AHR) = 1.28: 95% CI: 1.10, 1.68), smoking cigarette (AHR = 1.39: 95% CI:1.27,3.18), tuberculosis related complication (AHR = 9.31:95% CI:5.11,16.97), anemia (AHR = 3.04:95% CI:1.14, 9.20), HIV/AIDS (AHR = 1.34:95% CI:1.25, 3.35), previous tuberculosis treatment history (AHR = 1.37:95% CI:1.16, 1.86), and diabetes mellitus (AHR = 1.85:95% CI:1.24,5.71) were identified risk factors for mortality.

Conclusions

This study concluded that drug-resistant tuberculosis mortality remains high in the study site. Age 45 years and above, smoking cigarette, tuberculosis related clinical complication, being anemic at baseline, HIV/AID, previous tuberculosis treatment history, and diabetes mellitus were identified risk factors for mortality. Continual support of the integration of TB/HIV service with emphasis and working on identified risk factors may help in reducing drug-resistant tuberculosis mortality.

Mapping the extent of heterogeneity of human CCR5+ CD4+ T cells in peripheral blood and lymph nodes

BACKGROUND

CD4 T cells that express the chemokine receptor, CCR5, are the most important target of HIV-1 infection, but their functions, phenotypes and anatomical locations are poorly understood. We aimed to use multiparameter flow cytometry to better define the full breadth of these cells.

METHODS

High-parameter fluorescence flow and mass cytometry were optimized to analyse subsets of CCR5 memory CD4 T cells, including CD25CD127 Tregs, CXCR3CCR6- Th1-like, CCR6CD161CXCR3- Th17-like, integrins α4ß7 gut-homing, CCR4 skin-homing, CD62L lymph node-homing, CD38HLA-DR activated cells, and CD27-CD28- cytotoxic T lymphocytes, in a total of 22 samples of peripheral blood, ultrasound-guided fine needle biopsies of lymph nodes and excised tonsils. CCR5 antigen-specific CD4 T cells were studied using the OX40 flow-based assay.

RESULTS

10-20% of CCR5 memory CD4 T cells were Tregs, 10-30% were gut-homing, 10-30% were skin-homing, 20-40% were lymph node-homing, 20-50% were Th1-like and 20-40% were Th17-like cells. Up to 30% were cytotoxic T lymphocytes in CMV-seropositive donors, including cells that were either CCR5Granzyme K or CCR5Granzyme B. When all possible phenotypes were exhaustively analysed, more than 150 different functional and trafficking subsets of CCR5 CD4 T cells were seen. Moreover, a small population of resident CD69Granzyme KCCR5 CD4 T cells was found in lymphoid tissues. CMV- and Mycobacterium tuberculosis-specific CD4 T cells were predominantly CCR5.

CONCLUSION

These results reveal for the first time the prodigious heterogeneity of function and trafficking of CCR5 CD4 T cells in blood and in lymphoid tissue, with significant implications for rational approaches to prophylaxis for HIV-1 infection and for purging of the HIV-1 reservoir in those participants already infected.

Effect of tuberculosis infection on mortality of HIV-infected patients in Northern Tanzania

Background

TB and HIV are public health problems, which have a synergistic effect to each other. Despite the decreasing burden of these two diseases they still make a significant contribution to mortality. Tanzania is among the 30 high TB and HIV burden countries.

Methods

Routine data over 6 years from people living with HIV (PLHIV) attending health facilities in three regions of Northern Tanzania were analyzed, showing mortality trends from 2012 to 2017 for HIV and HIV/TB subpopulations. Poisson regression with frailty model adjusting for clustering at health facility level was used to analyze the data to determine mortality rate ratios (RR) and 95% confidence intervals (95%CI).

Results

Among all PLHIV the overall mortality rate was 28.4 (95% CI 27.6–29.2) deaths per 1000 person-years. For PLHIV with no evidence of TB the mortality rates was 26.2 (95% CI 25.4–27.0) per 1000 person-years, and for those with HIV/TB co-infection 57.8 (95% CI 55.6–62.3) per 1000 person-years. After adjusting for age, sex, residence, WHO stage, and bodyweight, PLHIV with TB co-infection had 40% higher mortality than those without TB (RR 1.4; 95% CI 1.24–1.67).

Conclusions

Over the 6-year period mortality rates for HIV/TB patients were consistently higher than for PLHIV who have no TB. More efforts should be directed into improving nutritional status among HIV patients, as it has destructive interaction with TB for mortality. This will improve patients’ body weight and CD4 counts which are protective against mortality. Among PLHIV attention should be given to those who are in WHO HIV stage 3 or 4 and having TB co-infection.

The role of miR-146a in viral infection

Cellular microRNAs (miRNAs) were identified as a key player in the posttranscriptional regulation of cellular-genes regulatory pathways. They also emerged as a significant regulator of the immune response. In particular, miR-146a acts as an importance modulator of function and differentiation cells of the innate and adaptive immunity. It has been associated with disorder including cancer and viral infections. Given its significance in the regulation of key cellular processes, it is not surprising which virus infection have found ways to dysregulation of miRNAs. miR-146a has been identified in exosomes (exosomal miR-146a). After the exosomes release from donor cells, they are taken up by the recipient cell and probably the exosomal miR-146a is able to modulate the antiviral response in the recipient cell and result in making them more susceptible to virus infection. In this review, we discuss recent reports regarding miR-146a expression levels, target genes, function, and contributing role in the pathogenesis of the viral infection and provide a clue to develop the new therapeutic and preventive strategies for viral disease in the future.

Effect of HIV on the Frequency and Number of Mycobacterium tuberculosis-Specific CD4+ T Cells in Blood and Airways During Latent M. tuberculosis Infection

Human immunodeficiency virus type 1 (HIV) infection substantially increases the risk of developing tuberculosis. There is extensive depletion of Mycobacterium tuberculosis-specific CD4+ T cells in blood during early HIV infection, but little is known about responses in the lungs at this stage. Given that mucosal organs are a principal target for HIV-mediated CD4+ T-cell destruction, we investigated M. tuberculosis-specific responses in bronchoalveolar lavage (BAL) from persons with latent M. tuberculosis infection and untreated HIV coinfection with preserved CD4+ T-cell counts. M. tuberculosis-specific CD4+ T-cell cytokine (interferon γ, tumor necrosis factor α, and interleukin 2) responses were discordant in frequency and function between BAL and blood. Responses in BAL were 15-fold lower in HIV-infected persons as compared to uninfected persons (P = .048), whereas blood responses were 2-fold lower (P = .006). However, an increase in T cells in the airways in HIV-infected persons resulted in the overall number of M. tuberculosis-specific CD4+ T cells in BAL being similar. Our study highlights the important insights gained from studying M. tuberculosis immunity at the site of disease during HIV infection.

HIV-1-Induced miR-146a Attenuates Monocyte Migration by Targeting CCL5 in Human Primary Macrophages

MicroRNAs (miRNAs) are widely involved in immune regulation during virus infection. Several studies showed that the expression of miR-146a was increased in human immunodeficiency virus type I (HIV-1)-infected cells, but the definitive function of miR-146a in HIV-1 infection remains obscure. The production of chemokine (C-C motif) ligand 5 (CCL5) in macrophages has been reported to play an important role in HIV/AIDS-associated pathogenesis. In this study, we examined the effects of miR-146a on CCL5 regulation in HIV-1-infected macrophages. Gain and loss of function studies showed that CCL5 might be one of the miR-146a targets, as miR-146a mimic reduced, while miR-146a inhibitor increased CCL5 production in HIV-1-infected macrophages. In addition, we demonstrated that miR-146a reduced CCL5-induced monocyte migration. Our study provided evidence that miR-146a targets CCL5 3' untranslated regions, downregulates its release from macrophages, and affects monocyte migration consequently. These findings drew a novel layer of posttranscriptional control of the chemokine CCL5 by miR-146a during HIV infection, which might contribute to HIV pathogenesis.

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

Globally, about 36.7 million people were living with HIV infection at the end of 2015. The most frequent infection co-occurring with HIV-1 is Mycobacterium tuberculosis-374,000 deaths per annum are attributable to HIV-tuberculosis, 75% of those occurring in Africa. HIV-1 infection increases the risk of tuberculosis by a factor of up to 26 and alters its clinical presentation, complicates diagnosis and treatment, and worsens outcome. Although HIV-1-induced depletion of CD4⁺ T cells underlies all these effects, more widespread immune deficits also contribute to susceptibility and pathogenesis. These defects present a challenge to understand and ameliorate, but also an opportunity to learn and optimize mechanisms that normally protect people against tuberculosis. The most effective means to prevent and ameliorate tuberculosis in HIV-1-infected people is antiretroviral therapy, but this may be complicated by pathological immune deterioration that in turn requires more effective host-directed anti-inflammatory therapies to be derived.

Predictors for Mortality among Multidrug-Resistant Tuberculosis Patients in Tanzania

PROBLEM

Factors related to MDRTB mortality in Tanzania have not been adequately explored and reported.

OBJECTIVES

To determine demographic, clinical, radiographic, and laboratory factors associated with MDRTB mortality in a Tanzanian TB Referral Hospital.

METHODOLOGY

This was a cross-sectional study with 193 participants. Demographic, clinical, laboratory, and radiological data were collected, and their associations with mortality among MDRTB patients were determined.

RESULTS AND CONCLUSIONS

Cough was the commonest finding among these MDRTB patients, with 179 (92.75%) of them presenting with cough, followed by chest X-ray consolidation in 156 patients (80.83%) and history of previous TB treatment in 151 patients (78.24%). Cigarette smoking, HIV positivity, and low CD4 counts were significantly associated with MDRTB mortality, p values of 0.034, 0.044, and 0.048, respectively. Fever on the other hand was at the borderline with p value of 0.059. We conclude that cigarette smoking and HIV status are significant risk factors for mortality among MDRTB patients. HIV screening should continually be emphasized among patients and the general community for early ARTs initiation. Based on the results from our study, policy makers and public health personnel should consider addressing tobacco cessation as part of national TB control strategy.

Interleukin-10 promoter gene polymorphisms and susceptibility to tuberculosis: a meta-analysis

Objective

As an update to other recent meta-analyses, the purpose of this study was to explore whether interleukin-10 (IL-10) polymorphisms and their haplotypes contribute to tuberculosis (TB) susceptibility.

Methods

We searched for published case-control studies examining IL-10 polymorphisms and TB in PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Wanfang databases and the Chinese National Knowledge Infrastructure (CNKI). Odds ratios (ORs) with 95% confidence intervals (CIs) were used to calculate the strengths of the associations.

Results

A total of 28 studies comprising 8,242 TB patients and 9,666 controls were included in the present study. There were no significant associations between the -1082G/A, -819C/T, and -592A/C polymorphisms and TB in the pooled samples. Subgroup analyses revealed that the -819T allele was associated with an increased TB risk in Asians in all genetic models (T vs. C: OR=1.17, 95% CI=1.05-1.29, P=0.003; TT vs. CC: OR=1.37, 95% CI=1.09-1.72, P=0.006; CT+TT vs. CC: OR=1.33, 95% CI=1.09-1.63, P=0.006; TT vs. CT+CC: OR=1.17, 95% CI=1.02-1.35, P=0.03) and that the -592A/C polymorphism was significantly associated with TB in Europeans under two genetic models (A vs. C: OR=0.77, 95% CI=0.60-0.98, P=0.03; AA vs. CC: OR=0.53, 95% CI=0.30-0.95, P=0.03). Furthermore, the GCC IL-10 promoter haplotype was associated with an increased risk of TB (GCC vs. others: P=1.42, 95% CI=1.02-1.97, P=0.04). Subgroup analyses based on ethnicity revealed that the GCC haplotype was associated with a higher risk of TB in Europeans, whereas the ACC haplotype was associated with a lower TB risk in both Asians and Europeans.

Conclusions

This meta-analysis suggests that the IL-10-819T/C polymorphism is associated with the risk of TB in Asians and that the IL-10-592A/C polymorphism may be a risk factor for TB in Europeans. Furthermore, these data indicate that IL-10 promoter haplotypes play a vital role in the susceptibility to or protection against the development of TB.

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.

Multifaceted Impact of Host C-C Chemokine CCL2 in the Immuno-Pathogenesis of HIV-1/M. tuberculosis Co-Infection

Active tuberculosis remains the leading cause of death among the HIV-1 seropositive individuals. Although significant success has been achieved in bringing down the number of HIV/AIDS-related mortality and morbidity following implementation of highly active anti-retroviral therapy (HAART). Yet, co-infection of Mycobacterium tuberculosis (Mtb) has posed severe clinical and preventive challenges in our efforts to eradicate the virus from the body. Both HIV-1 and Mtb commonly infect macrophages and trigger production of host inflammatory mediators that subsequently regulate the immune response and disease pathogenesis. These inflammatory mediators can impose beneficial or detrimental effects on each pathogen and eventually on host. Among these, inflammatory C–C chemokines play a central role in HIV-1 and Mtb pathogenesis. However, their role in lung-specific mechanisms of HIV-1 and Mtb interaction are poorly understood. In this review we highlight current view on the role of C–C chemokines, more precisely CCL2, on HIV-1: Mtb interaction, potential mechanisms of action and adverse clinical consequences in a setting HIV-1/Mtb co-infection. Targeting common chemokine regulators of HIV-1/Mtb pathogenesis can be an attractive and potential anti-inflammatory intervention in HIV/AIDS-related comorbidities.