Strategies to limit immune-activation in HIV patients

In vitro antibacterial activity of antiretroviral drugs on key commensal bacteria from the human microbiota

Introduction

Antiretroviral therapy has improved life expectancy in HIV-infected patients. However, people living with HIV under antiretroviral therapy are at higher risks of developing chronic complications and acquiring multidrug resistant bacteria than healthy population. These factors have been associated with shifts in gut microbiome composition and immune activation. It is unclear how antiretroviral drugs affect gut microbiota composition, but it has been observed that antiretroviral treatment is not able to fully restore gut health after HIV infection. Additionally, some antiretroviral drugs have shown antibacterial activity suggesting that these drugs could have a direct impact on the human microbiome composition.

Methods

We determined the in vitro antibacterial activity of 16 antiretroviral drugs against a set of key clinically relevant and human commensal bacterial strains.

Results

Our results demonstrate that 5 antiretroviral drugs have in vitro antibacterial activity against gut and vaginal human commensal bacteria. Zidovudine has antibacterial activity against Escherichia coli, Klebsiella pneumoniae and Prevotella bivia, abacavir against Gardnerella vaginalis, efavirenz against G. vaginalis and P. bivia and bictegravir against Enterococcus spp. and G. vaginalis. Moreover, we describe for the first time that elvitegravir has antibacterial activity against G. vaginalis and P. bivia and, most importantly, against vancomycin-resistant Enterococcus spp. and methicillin-resistant Staphylococcus aureus strains with MIC values of 4-16 and 4 µg/mL, respectively showing high level of effectiveness against the tested multidrug-resistant bacteria.

Discussion

Our results underscore that some antiretroviral drugs may influence the human microbiota composition. In addition, we report the potential use of elvitegravir to treat multidrug-resistant Gram-positive bacteria warranting the need of clinical studies to repurpose this antiretroviral drug.

Incomplete immune reconstitution and its predictors in people living with HIV in Wuhan, China

OBJECTIVE

This study aimed to build and validate a nomogram model to predict the risk of incomplete immune reconstitution in people living with HIV (PLWH).

METHODS

Totally 3783 individuals with a confirmed diagnosis of HIV/AIDS were included. A predictive model was developed based on a retrospective set (N = 2678) and was validated using the remaining cases (N = 1105). Univariate and multivariate logistic regression analyses were performed to determine valuable predictors among the collected clinical and laboratory variables. The predictive model is presented in the form of a nomogram, which is internally and externally validated with two independent datasets. The discrimination of nomograms was assessed by calculating the area under the curve (AUC). Besides, calibration curve and decision curve (DCA) analyses were performed in the training and validation sets.

RESULTS

The final model comprised 5 predictors, including baseline CD4, age at ART initiation, BMI, HZ and TBIL. The AUC of the nomogram model was 0.902, 0.926, 0.851 in the training cohort, internal validation and external cohorts. The calibration accuracy and diagnostic performance were satisfactory in both the training and validation sets.

CONCLUSIONS

This predictive model based on a retrospective study was externally validated using 5 readily available clinical indicators. It showed high performance in predicting the risk of incomplete immune reconstitution in people living with HIV.

Identification of CD8+ T cell subsets that normalize in early-treated people living with HIV receiving antiretroviral therapy

Background

Although combined antiretroviral therapy (cART) has decreased the mortality associated with HIV infection, complete immune reconstitution is not achieved despite viral suppression. Alterations of CD8⁺ T cells and some of their subpopulations, such as interleukin (IL)-17-producing cells, are evidenced in treated individuals and are associated with systemic inflammation and adverse disease outcomes. We sought to evaluate if different CD8⁺ T cell subsets are differentially normalized during a clinical follow-up of people living with HIV (PLWH) receiving suppressive cART.

Methods

We explored the changes in the frequencies, activation/exhaustion phenotypes (HLA-DR, CD38, PD-1, and TIM-3), and function (total and HIV-specific cells expressing CD107a, perforin, granzyme B, interferon [IFN]-γ and IL-17) of CD8⁺ T cells from early-treated PLWH receiving cART in a 1-year follow-up, using a multidimensional flow cytometry approach.

Results

Despite continuous cART-induced viral suppression and recovery of CD4⁺ T cells, after a 1-year follow-up, the CD8⁺ T cell counts, CD4:CD8 ratio, PD-1 expression, and IL-17 production by CD8⁺ T cells exhibited incomplete normalization compared with seronegative controls. However, the proportion of CD8⁺ T cells with an exhausted phenotype (co-expressing PD-1 andTIM-3), and cells co-expressing cytotoxic molecules (Perforin and Granzyme B), reached normalization.

Conclusions

Although suppressive cART achieves normalization of CD4⁺ T cell counts, only particular subsets of CD8⁺ T cells are more rapidly normalized in PLWH receiving cART, which could be routinely used as biomarkers for therapy efficiency in these patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12981-022-00465-0.

Human umbilical cord mesenchymal stem cell transfusion in immune non-responders with AIDS: a multicenter randomized controlled trial

We examined the safety and efficacy of human umbilical cord mesenchymal stem cell (hUC-MSC) infusion for immune non-responder (INR) patients with chronic HIV-1 infection, who represent an unmet medical need even in the era of efficient antiretroviral therapy (ART). Seventy-two INR patients with HIV were enrolled in this phase II randomized, double-blinded, multicenter, placebo-controlled, dose-determination trial (NCT01213186) from May 2013 to March 2016. They were assigned to receive high-dose (1.5 × 10⁶/kg body weight) or low-dose (0.5 × 10⁶/kg body weight) hUC-MSC, or placebo. Their clinical and immunological parameters were monitored during the 96-week follow-up study. We found that hUC-MSC treatment was safe and well-tolerated. Compared with baseline, there was a statistical increase in CD4+ T counts in the high-dose (P < 0.001) and low-dose (P < 0.001) groups after 48-week treatment, but no change was observed in the control group. Kaplan–Meier analysis revealed a higher cumulative probability of achieving an immunological response in the low-dose group compared with the control group (95.8% vs. 70.8%, P = 0.004). However, no significant changes in CD4/CD8+ T counts and CD4/CD8 ratios were observed among the three groups. In summary, hUC-MSC treatment is safe. However, the therapeutic efficacy of hUC-MSC treatment to improve the immune reconstitution in INR patients still needs to be further investigated in a large cohort study.

Safety and efficacy of allogeneic natural killer cell immunotherapy on human immunodeficiency virus type 1 immunological non-responders: a brief report

BACKGROUND

Allogeneic natural killer (NK) cell immunotherapy is recognized as a promising anti-tumor strategy, but whether it plays a role in poor CD4 recovery among human immunodeficiency virus type 1 (HIV-1) infected patients is unknown. This study aimed to investigate the safety and effectiveness of allogeneic NK cells immunotherapy on HIV-1 immunological non-responders (INRs) receiving antiretroviral therapy (ART).

METHODS

From February to April 2018, a prospective, randomized, controlled, open-label clinical trial, which enrolled 20 HIV-1 INRs following specific inclusion criteria, was conducted at Nankai University Second People's Hospital. Participants were randomly allocated (simple randomization 1:1) to either the combined treatment (NK + ART) group (n = 10) or the control (ART) group (n = 10). The allogenic highly activated NK cells from killer cell immunoglobulin-like receptor (KIR)/human leukocyte antigen (HLA)-Cw mismatched healthy donor were prepared (10 cells in each injection) and intravenously infused to each recruited patient of NK+ART group in three courses. Key immune parameters (CD4 count, CD8 count, CD4/CD8 ratio), laboratory tests (count of blood cells, biochemistry panel) and symptoms at baseline and at month 1, 3, 6, 9, 12, and 24 were measured/collected to analyze the safety and efficacy of the therapy. Comparisons were between the seven time-points of both groups using repeated measurement analysis of variance (ANOVA) test. Generalized estimating equations (GEE) model was performed to evaluate the overall effect of the NK+ART group vs. the ART group.

RESULTS

From baseline to 24 months, we noted a mean CD4 count augmentation (139 to 243 cells/μL) in the NK + ART group and (144 to 176 cells/μL) in the ART group (difference, 67; 95% CI, 10 to 124; P = 0.024). Our estimations revealed that NK+ART group could improve CD4 level (β = 54.59, P = 0.006) and CD8 level (β = 322.47, P = 0.010) on average among the six measurements compared with the ART group. Only two (2/10, 20%) participants in the NK+ART group developed a transient mild fever after the first course.

CONCLUSIONS

This preliminary study informs that HIV-1 INRs, allogenic NK cells immunotherapy is safe and could significantly improve CD4 recovery but not CD4/CD8 ratio. The practical effects, however, need long-term follow-up observations. Further study on the potential underlying mechanism is warranted. REGISTRATION INFO:: www.chictr.org.cn/showproj.aspx?proj=34912 (No. ChiCTR1900020634).

Adherence predictor variables in AIDS patients: an empirical study using the data mining-based RFM model

Background

Highly active antiretroviral therapy (ART) is still the only effective method to stop the disease progression in acquired immunodeficiency syndrome (AIDS) patients. However, poor adherence to the therapy makes it ineffective. In this work, we construct an adherence prediction model of AIDS patients using the classical recency, frequency and monetary value (RFM) model in the data mining-based customer relationship management model to obtain adherence predictor variables.

Methods

We cleaned 257,305 diagnostic data elements of AIDS outpatients in Shanghai from August 2009 to December 2019 to obtain 16,440 elements. We tested the RFM and RFm (R: recent consultation month, F: consultation frequency, M/m: total/average medical costs per visit) models, three clustering methods (K-means, Kohonen and two-step clustering) and four decision algorithms (C5.0, the classification and regression tree, Chi-square Automatic Interaction Detector and Quick, Unbiased, Efficient, Statistical Tree) to select the optimal combination. The optimal model and clustering analysis were used to divide the patients into two groups (good and poor adherence), then the optimal decision algorithm was used to construct the prediction model of adherence and obtain its predictor variables.

Results

The results revealed that the RFm model, K-means clustering analysis and C5.0 algorithm were optimal. After three rounds of k-means clustering analysis, the optimal RFm clustering model quality was 0.8, 10,614 elements were obtained, including 9803 and 811 from patients with good or poor adherence, respectively, and five types of patients were identified. The prediction model had an accuracy of 100% with the recent consultation month as an important adherence predictor variable.

Conclusions

This work presented a prediction model for medication adherence in AIDS patients at the designated AIDS center in Shanghai, using the RFm model and the k-means and C5.0 algorithms. The model can be expanded to include patients from other centers in China and worldwide.

Infection with multiple HIV-1 founder variants is associated with lower viral replicative capacity, faster CD4+ T cell decline and increased immune activation during acute infection

HIV-1 transmission is associated with a severe bottleneck in which a limited number of variants from a pool of genetically diverse quasispecies establishes infection. The IAVI protocol C cohort of discordant couples, female sex workers, other heterosexuals and men who have sex with men (MSM) present varying risks of HIV infection, diverse HIV-1 subtypes and represent a unique opportunity to characterize transmitted/founder viruses (TF) where disease outcome is known. To identify the TF, the HIV-1 repertoire of 38 MSM participants' samples was sequenced close to transmission (median 21 days post infection, IQR 18-41) and assessment of multivariant infection done. Patient derived gag genes were cloned into an NL4.3 provirus to generate chimeric viruses which were characterized for replicative capacity (RC). Finally, an evaluation of how the TF virus predicted disease progression and modified the immune response at both acute and chronic HIV-1 infection was done. There was higher prevalence of multivariant infection compared with previously described heterosexual cohorts. A link was identified between multivariant infection and replicative capacity conferred by gag, whereby TF gag tended to be of lower replicative capacity in multivariant infection (p = 0.02) suggesting an overall lowering of fitness requirements during infection with multiple variants. Notwithstanding, multivariant infection was associated with rapid CD4+ T cell decline and perturbances in the CD4+ T cell and B cell compartments compared to single variant infection, which were reversible upon control of viremia. Strategies aimed at identifying and mitigating multivariant infection could contribute toward improving HIV-1 prognosis and this may involve strategies that tighten the stringency of the transmission bottleneck such as treatment of STI. Furthermore, the sequences and chimeric viruses help with TF based experimental vaccine immunogen design and can be used in functional assays to probe effective immune responses against TF.

Effect of Structured Physical Activity on Inflammation and Immune Activation Profile of Antiretroviral Therapy-Experienced Children Living With HIV

AIM

To compare the markers of inflammation and immune activation in virally suppressed HIV-infected children on antiretroviral therapy, who practiced regular structured exercise comprising running and yoga to those who did not over a 2-year period.

METHODS

This retrospective cohort study included 72 children aged 8 to 16 years divided into 2 groups, exercisers (n = 36) and the nonexercisers (n = 36) based on their intentional physical activity. The analyses were carried out at baseline and after 2 years (Y2) for the soluble biomarkers of inflammation and immune activation (tumor necrosis factor alpha, interleukin-6, interleukin-10, interferon gamma, sCD14, and sCD163). In addition, cell-associated biomarker (CD38), lipopolysaccharides, and the gene expression of interleukin-2 and brain-derived neurotrophic factor were also measured at Y2.

RESULTS

Reduction in levels of sCD14 (effect size [ES], -0.6; 95% confidence interval [CI], -1.08 to -0.14), tumor necrosis factor alpha (ES, -0.7; 95% CI, -1.18 to -0.23), interferon gamma (ES, -0.7; 95% CI, -1.17 to -0.22), and interleukin-10 (ES, -0.6; 95% CI, -1.08 to -0.14) was observed among exercisers as compared with nonexercisers at Y2. In addition, CD38+ expressing CD4+ T cells were found to be lower among exercisers (P = .01) at Y2. However, the differences in levels of interleukin-6, sCD163, lipopolysaccharides, interleukin-2, and brain-derived neurotrophic factor were not significantly different among the 2 groups.

CONCLUSION

The study result suggests that regular structured physical activity improves the inflammatory profile of antiretroviral therapy-treated HIV-infected children.

Physical Activity and HIV: Effects on Fitness Status, Metabolism, Inflammation and Immune-Activation

Several studies evidenced that a sedentary lifestyle is related with higher levels of systemic inflammation and highlighted that physical activity can trigger anti-inflammatory effects. To evaluate the impact of self-prescribed physical activity on fitness status, metabolism, inflammation and immune-activation in people living with HIV, an interim analysis of the results of the clinical trial PRIMO (NCT03392805) was performed. Patients enrolled were divided in 2 groups on the basis of self-prescribed physical activity: a physically active group (self-prescribed physical activity) and a sedentary group. Physical fitness was evaluated by sport medicine specialists and related to nutritional status, anthropometric variables, adipokines levels (adiponectin, leptin, resistin), peripheral immune-activation (CD38, HLA-DR on CD4 and CD8), and plasma inflammatory markers (IL-6 and TNF-α). The physically active group had a better profile in anthropometric measures and aerobic fitness but did not show lower levels of immune-activation compared to sedentary group. Also serum IL-6, TNF-α, and adipokines levels showed no statistical differences. On the basis of these data, a regular self-organized physical activity seems useful to improve cardio-respiratory fitness, but unable to control HIV-related immune-activation.

Incomplete immune reconstitution in HIV/AIDS patients on antiretroviral therapy: Challenges of immunological non-responders

The morbidity and mortality of HIV type-1 (HIV-1)-related diseases were dramatically diminished by the grounds of the introduction of potent antiretroviral therapy, which induces persistent suppression of HIV-1 replication and gradual recovery of CD4⁺ T-cell counts. However, ∼10-40% of HIV-1-infected individuals fail to achieve normalization of CD4⁺ T-cell counts despite persistent virological suppression. These patients are referred to as "inadequate immunological responders," "immunodiscordant responders," or "immunological non-responders (INRs)" who show severe immunological dysfunction. Indeed, INRs are at an increased risk of clinical progression to AIDS and non-AIDS events and present higher rates of mortality than HIV-1-infected individuals with adequate immune reconstitution. To date, the underlying mechanism of incomplete immune reconstitution in HIV-1-infected patients has not been fully elucidated. In light of this limitation, it is of substantial practical significance to deeply understand the mechanism of immune reconstitution and design effective individualized treatment strategies. Therefore, in this review, we aim to highlight the mechanism and risk factors of incomplete immune reconstitution and strategies to intervene.

Cardiovascular disease risk and its determinants in people living with HIV across different settings in South Africa

Objectives

Socio‐economic factors and lifestyle are known to differ across geographies and populations, which may result in distinct risk profiles for cardiovascular disease (CVD). This study assessed carotid intima‐media thickness (CIMT), a proxy for CVD, and its determinants in two groups of people living with HIV (PLHIV) in two different settings in South Africa.

Methods

A cross‐sectional analysis was conducted comparing data from the Ndlovu Cohort Study in the Limpopo Province (group 1) and from three clinical trials in Johannesburg (group 2). The association between demographics, conventional CVD risk factors, HIV‐related factors and CIMT in groups 1 and 2 was analysed with two separate multivariable linear regression models.

Results

Group 1 consisted of 826 participants (mean age 42.2 years) and mean (± standard deviation) CIMT was 0.626 ± 0.128 mm. In this group, sex, age, body mass index (BMI), cholesterol, glucose and antiretroviral therapy (ART) duration (β = 0.011 mm per 5 years; P = 0.02) were associated with higher CIMT. There were positive interactions between age and ART duration and age and cholesterol. Group 2 consisted of 382 participants (mean age 39.5 years) and mean (± standard deviation) CIMT was 0.560 ± 0.092 mm. In this group, only sex, education level, BMI and cholesterol were associated with higher CIMT, albeit with weaker associations than in group 1.

Conclusions

Conventional CVD risk factors were the main drivers of CIMT. The impact of some of these risk factors appeared to increase with age. Differences in sample size, age and viral suppression might explain why an effect of ART was observed in group 1 but not in group 2.

CD8+ T-Cell Response to HIV Infection in the Era of Antiretroviral Therapy

Although the combined antiretroviral therapy (cART) has decreased the deaths associated with the immune deficiency acquired syndrome (AIDS), non-AIDS conditions have emerged as an important cause of morbidity and mortality in HIV-infected patients under suppressive cART. Since these conditions are associated with a persistent inflammatory and immune activation state, major efforts are currently made to improve the immune reconstitution. CD8⁺ T-cells are critical in the natural and cART-induced control of viral replication; however, CD8⁺ T-cells are highly affected by the persistent immune activation and exhaustion state driven by the increased antigenic and inflammatory burden during HIV infection, inducing phenotypic and functional alterations, and hampering their antiviral response. Several CD8⁺ T-cell subsets, such as interleukin-17-producing and follicular CXCR5⁺ CD8⁺ T-cells, could play a particular role during HIV infection by promoting the gut barrier integrity, and exerting viral control in lymphoid follicles, respectively. Here, we discuss the role of CD8⁺ T-cells and some of their subpopulations during HIV infection in the context of cART-induced viral suppression, focusing on current challenges and alternatives for reaching complete reconstitution of CD8⁺ T-cells antiviral function. We also address the potential usefulness of CD8⁺ T-cell features to identify patients who will reach immune reconstitution or have a higher risk for developing non-AIDS conditions. Finally, we examine the therapeutic potential of CD8⁺ T-cells for HIV cure strategies.

Immune Activation, Inflammation, and Non-AIDS Co-Morbidities in HIV-Infected Patients under Long-Term ART

Despite effective antiretroviral therapy (ART), people living with HIV (PLWH) still present persistent chronic immune activation and inflammation. This condition is the result of several factors including thymic dysfunction, persistent antigen stimulation due to low residual viremia, microbial translocation and dysbiosis, caused by the disruption of the gut mucosa, co-infections, and cumulative ART toxicity. All of these factors can create a vicious cycle that does not allow the full control of immune activation and inflammation, leading to an increased risk of developing non-AIDS co-morbidities such as metabolic syndrome and cardiovascular diseases. This review aims to provide an overview of the most recent data about HIV-associated inflammation and chronic immune exhaustion in PLWH under effective ART. Furthermore, we discuss new therapy approaches that are currently being tested to reduce the risk of developing inflammation, ART toxicity, and non-AIDS co-morbidities.

A Low Frequency of IL-17-Producing CD8+ T-Cells Is Associated With Persistent Immune Activation in People Living With HIV Despite HAART-Induced Viral Suppression

Immune activation is the hallmark of HIV infection, even in patients with highly active anti-retroviral therapy (HAART)-induced viral suppression. A major cause of immune activation during HIV infection is the intestinal microbial translocation as a consequence, among other factors, of the decrease and/or dysfunction of interleukin (IL)-17-producing T-cells, due to their role promoting the integrity of the intestinal barrier. A population of IL-17-producing CD8⁺ T-cells (Tc17 cells), characterized by the expression of CD161, has been described, but its relation with the persistent immune activation in non-viremic people living with HIV (PLWH) on HAART is unclear. By flow cytometry, we characterized the activation phenotype (evaluated by the expression of HLA-DR and CD38) of circulating CD161-expressing CD8⁺ T-cells; in addition, we explored the functionality of polyclonally-stimulated Tc17 cells in PLWH under HAART-induced viral suppression, and in healthy individuals. Finally, we determined the association of Tc17 cells with the expression of cellular and soluble activation markers. Circulating CD161-expressing CD8⁺ T-cells were decreased in PLWH compared with healthy individuals, despite their similar basal activation state. After polyclonal stimulation, IL-17 production was higher in CD8⁺ T-cells co-expressing HLA-DR and CD38 in healthy individuals. In contrast, although PLWH had a higher frequency of HLA-DR⁺ CD38⁺ CD8⁺ T-cells after stimulation, they had a lower production of IL-17. Interferon (IFN)-γ-producing CD8⁺ T-cells (Tc1 cells) were increased in PLWH. The low Tc17 cells response was associated with a high expression of CD38 and programmed death 1 protein, high levels of soluble CD14 and the treatment duration. Finally, to explore potential immunomodulatory strategies, the in vitro effect of the anti-inflammatory agent sulfasalazine was assessed on Tc17 cells. Interestingly, a decreased inflammatory environment, death of activated CD8⁺ T-cells, and an increased frequency of Tc17 cells were observed with sulfasalazine treatment. Thus, our findings suggest that activated CD8⁺ T-cells have a marked capacity to produce IL-17 in healthy individuals, but not in PLWH, despite HAART. This dysfunction of Tc17 cells is associated with the persistent immune activation observed in these patients, and can be partially restored by anti-inflammatory agents.

Multimorbidity, age-related comorbidities and mortality: association of activation, senescence and inflammation markers in HIV adults

BACKGROUND

The widespread introduction of combination antiretroviral therapy (cART) has increased survival of HIV-infected patients. However, the prevalence of age-related comorbidities remains higher than that of the general population, suggesting that individuals with HIV suffer from accelerated aging. Immune activation, senescence and inflammation could play an important role in this process.

METHODS

The CIADIS (Chronic Immune Activation anD Senescence) sub-study analyzed biomarkers of activation, differentiation and senescence of T cells in a cellular-CIADIS-weighted score, whereas biomarkers of inflammation were analyzed in a soluble CIADIS-weighted score using principal component analysis. Adjusted logistic regression and Cox proportional hazard models were used to determine the association between CIADIS-weighted scores and the presence of multimorbidity, time to occurrence of the first new age-related comorbidity and time to death, over a 3-year follow-up period.

RESULTS

Of 828 patients with an undetectable viral load, a higher cellular-CIADIS-weighted score and higher TNFRI levels were independently associated with the presence of multimorbidity (OR 1.3; 95% CI 1.0-1.6; P = 0.02), but the soluble CIADIS-weighted score was not (OR = 1.1; 95% CI 0.9-1.3; P = 0.33). A higher cellular CIADIS-weighted score (hazard ratio 2.2; P < 0.01), higher levels of CD8 activation and a lower CD4/CD8 ratio were associated with a higher risk of age-related comorbidities. Only TNFRI was associated with mortality in a 3-year period.

CONCLUSION

The cellular CIADIS-weighted score was independently associated with both multimorbidity at inclusion and the risk of new age-related comorbidity during a 3- year follow-up. TNFRI was associated a higher risk for mortality.

Altered gut microbiome composition in HIV infection: causes, effects and potential intervention

PURPOSE OF REVIEW

Aim of this review is to summarize the alterations occurring in gut microbiome composition after HIV infection, and to underline how intestinal dysbiosis can affect immune homeostasis, immune recovery, and persisting immune activation under antiretroviral therapy (ART). Many interventions have been suggested, mostly with inconclusive results.

RECENT FINDINGS

Recent evidence showed that gut microbiota from HIV-infected patients harbor reproducible differences compared to uninfected individuals. In this line, there is growing evidence that alterations in gut ecology during HIV infection correlate with persistence of immune defects and chronic inflammation. A reduced microbial diversity in feces of HIV-infected patients is highly associated with microbial translocation and monocyte activation markers; moreover, changes in mucosa-associated bacteria correlate with inflammation and T-cell activation.

SUMMARY

Studying the human host-microbiota interaction suggests that the consequences of HIV infection on microbial composition can influence immune status in HIV patients. ART induces microbiome changes that are independent of HIV infection, and some imply that ART may enhance dysbiosis. Studies and trials evaluated the effects of administering probiotics and prebiotics, finding a potential benefit on inflammation markers and immune cell activation. Emerging data on fecal microbial transplantation need to be assessed with further studies.

Effect of ready-to-use supplementary food on mortality in severely immunocompromised HIV-infected individuals in Africa initiating antiretroviral therapy (REALITY): an open-label, parallel-group, randomised controlled trial

BACKGROUND

In sub-Saharan Africa, severely immunocompromised HIV-infected individuals have a high risk of mortality during the first few months after starting antiretroviral therapy (ART). We hypothesise that universally providing ready-to-use supplementary food (RUSF) would increase early weight gain, thereby reducing early mortality compared with current guidelines recommending ready-to-use therapeutic food (RUTF) for severely malnourished individuals only.

METHODS

We did a 2 × 2 × 2 factorial, open-label, parallel-group trial at inpatient and outpatient facilities in eight urban or periurban regional hospitals in Kenya, Malawi, Uganda, and Zimbabwe. Eligible participants were ART-naive adults and children aged at least 5 years with confirmed HIV infection and a CD4 cell count of fewer than 100 cells per μL, who were initiating ART at the facilities. We randomly assigned participants (1:1) to initiate ART either with (RUSF) or without (no-RUSF) 12 weeks' of peanut-based RUSF containing 1000 kcal per day and micronutrients, given as two 92 g packets per day for adults and one packet (500 kcal per day) for children aged 5-12 years, regardless of nutritional status. In both groups, individuals received supplementation with RUTF only when severely malnourished (ie, body-mass index [BMI] <16-18 kg/m2 or BMI-for-age Z scores <-3 for children). We did the randomisation with computer-generated, sequentially numbered tables with different block sizes incorporated within an online database. Randomisation was stratified by centre, age, and two other factorial randomisations, to 12 week adjunctive raltegravir and enhanced anti-infection prophylaxis (reported elsewhere). Clinic visits were scheduled at weeks 2, 4, 8, 12, 18, 24, 36, and 48, and included nurse assessment of vital status and symptoms and dispensing of all medication including ART and RUSF. The primary outcome was mortality at week 24, analysed by intention to treat. Secondary outcomes included absolute changes in weight, BMI, and mid-upper-arm circumference (MUAC). Safety was analysed in all randomly assigned participants. Follow-up was 48 weeks. This trial is registered with ClinicalTrials.gov (NCT01825031) and the ISRCTN registry (43622374).

FINDINGS

Between June 18, 2013, and April 10, 2015, we randomly assigned 1805 participants to treatment: 897 to RUSF and 908 to no-RUSF. 56 (3%) were lost-to-follow-up. 96 (10·9%, 95% CI 9·0-13·1) participants allocated to RUSF and 92 (10·3%, 8·5-12·5) to no-RUSF died within 24 weeks (hazard ratio 1·05, 95% CI 0·79-1·40; log-rank p=0·75), with no evidence of interaction with the other randomisations (both p>0·7). Through 48 weeks, adults and adolescents aged 13 years and older in the RUSF group had significantly greater gains in weight, BMI, and MUAC than the no-RUSF group (p=0·004, 0·004, and 0·03, respectively). The most common type of serious adverse event was specific infections, occurring in 90 (10%) of 897 participants assigned RUSF and 87 (10%) of 908 assigned no-RUSF. By week 48, 205 participants had serious adverse events in both groups (p=0·81), and 181 had grade 4 adverse events in the RUSF group compared with 172 in the non-RUSF group (p=0·45).

INTERPRETATION

In severely immunocompromised HIV-infected individuals, providing RUSF universally at ART initiation, compared with providing RUTF to severely malnourished individuals only, improved short-term weight gain but not mortality. A change in policy to provide nutritional supplementation to all severely immunocompromised HIV-infected individuals starting ART is therefore not warranted at present.

FUNDING

Joint Global Health Trials Scheme (UK Medical Research Council, UK Department for International Development, and Wellcome Trust).

Deciphering natural control of HIV-1: A valuable strategy to achieve antiretroviral therapy termination

Antiretroviral therapy (ART) has dramatically reduced HIV-1-associated morbidity and mortality, and has transformed HIV-1 infection into a manageable chronic condition by suppressing viral replication. However, despite recent patient care improvements, ART still fails to cure HIV-1 infection due to the inability to counteract immune defects and metabolic disturbances that are associated with residual inflammation alongside viral persistence. Life-long drug administration also results in multiple side-effects in patients including lipodystrophy and insulin resistance. Thus, it is critical to find new ways to reduce the length of treatment and facilitate the termination of ART, for example by boosting protective immunity. The rare ability of some individuals to naturally control HIV-1 infection despite residual inflammation could be exploited to identify molecular mechanisms involved in host protection that may function as potential therapeutic targets. In this review, we highlight evidence illustrating the molecular and metabolic advantages of HIV-1 controllers over ART treated patients that contribute to the maintenance of effective antiviral immunity.

Impact of antiretroviral drugs on the microbiome: unknown answers to important questions

PURPOSE OF REVIEW

Little is known on how different antiretroviral (ARV) drugs affect the gut microbiome in HIV infection; and conflicting data exists on the effect of ARV drugs on residual inflammation/immune activation and microbial translocation.

RECENT FINDINGS

Gut microbiome involvement in the transmission and pathogenesis of HIV infection is increasingly being recognized. Various studies have shown that antiretroviral therapy (ART) is unable to restore gut health despite effective suppression of plasma HIV viremia. Indeed, the resolution of residual inflammation and gut microbial translocation is partial under ART. Very recent studies have provided new evidence that ARV combinations can differentially affect the gut microbiome, immune activation and microbial translocation. Furthermore, a recent article uncovered a link between drug metabolism and specific microbial species indicating that microbes can directly metabolically degrade ARV drugs when administered topically.

SUMMARY

There are still many unanswered questions regarding ARVs and the gut microbiome. It is, therefore, critical for researchers to address the effect of distinct ARV drugs on the microbiome and vice versa: the effects of the microbiome on ARV drug metabolism, and speculate about possible therapeutic avenues.

Host genetic variation and HIV disease: from mapping to mechanism

This review aims to provide a summary of current knowledge of host genetic effects on human immunodeficiency virus (HIV) disease. Mapping of simple single nucleotide polymorphisms (SNP) has been largely successful in HIV, but more complex genetic associations involving haplotypic or epigenetic variation, for example, remain elusive. Mechanistic insights explaining SNP associations are incomplete, but continue to be forthcoming. The number of robust immunogenetic correlates of HIV is modest and their discovery mostly predates the genome-wide era. Nevertheless, genome-wide evaluations have nicely validated the impact of HLA and CCR5 variants on HIV disease, and importantly, made clear the many false positive associations that were previously suggested by studies using the candidate gene approach. We describe how multiple HIV outcome measures such as acquisition, viral control, and immune decline have been studied in adults and in children, but that collectively these identify only the two replicable loci responsible for modifying HIV disease, CCR5, and HLA. Recent heritability estimates in this disease corroborate the modest impact of genetic determinants and their oligogenic nature. While the mechanism of protection afforded by genetic variants that diminish CCR5 expression is clear, new aspects of HLA class I-mediated protection continue to be uncovered. We describe how these genetic findings have enhanced insights into immunobiology, been clinically translated into CCR5 antagonists, allowed prioritization of antigens for vaccination efforts, and identified targets for genome-editing interventions. Finally, we describe how studies of genetically complex parts of the genome using new tools may begin revealing additional correlates.