Plasma levels of bacterial DNA correlate with immune activation and the magnitude of immune restoration in persons with antiretroviral-treated HIV infection

Persistent T Cell Repertoire Perturbation and T Cell Activation in HIV After Long Term Treatment

Objective

In people living with HIV (PLHIV), we sought to test the hypothesis that long term anti-retroviral therapy restores the normal T cell repertoire, and investigate the functional relationship of residual repertoire abnormalities to persistent immune system dysregulation.

Methods

We conducted a case-control study in PLHIV and HIV-negative volunteers, of circulating T cell receptor repertoires and whole blood transcriptomes by RNA sequencing, complemented by metadata from routinely collected health care records.

Results

T cell receptor sequencing revealed persistent abnormalities in the clonal T cell repertoire of PLHIV, characterized by reduced repertoire diversity and oligoclonal T cell expansion correlated with elevated CD8 T cell counts. We found no evidence that these expansions were driven by cytomegalovirus or another common antigen. Increased frequency of long CDR3 sequences and reduced frequency of public sequences among the expanded clones implicated abnormal thymic selection as a contributing factor. These abnormalities in the repertoire correlated with systems level evidence of persistent T cell activation in genome-wide blood transcriptomes.

Conclusions

The diversity of T cell receptor repertoires in PLHIV on long term anti-retroviral therapy remains significantly depleted, and skewed by idiosyncratic clones, partly attributable to altered thymic output and associated with T cell mediated chronic immune activation. Further investigation of thymic function and the antigenic drivers of T cell clonal selection in PLHIV are critical to efforts to fully re-establish normal immune function.

Changes of Gut-Microbiota-Liver Axis in Hepatitis C Virus Infection

Simple Summary

Gut microbiota alteration is linked to many health disorders including hepatitis C virus (HCV) infection. This dysbiosis in turn impacts the coordination between the gut and the liver that is known as the gut–liver-axis. Here, we discuss the latest findings regarding the changes in gut microbiota structure and functionality post HCV infection and its treatment regimens. In addition, we underline the contribution of the microbiota alterations to HCV associated liver complications.

Abstract

The gut–liver-axis is a bidirectional coordination between the gut, including microbial residents, the gut microbiota, from one side and the liver on the other side. Any disturbance in this crosstalk may lead to a disease status that impacts the functionality of both the gut and the liver. A major cause of liver disorders is hepatitis C virus (HCV) infection that has been illustrated to be associated with gut microbiota dysbiosis at different stages of the disease progression. This dysbiosis may start a cycle of inflammation and metabolic disturbance that impacts the gut and liver health and contributes to the disease progression. This review discusses the latest literature addressing this interplay between the gut microbiota and the liver in HCV infection from both directions. Additionally, we highlight the contribution of gut microbiota to the metabolism of antivirals used in HCV treatment regimens and the impact of these medications on the microbiota composition. This review sheds light on the potential of the gut microbiota manipulation as an alternative therapeutic approach to control the liver complications post HCV infection.

Rigorous Plasma Microbiome Analysis Method Enables Disease Association Discovery in Clinic

Blood microbiome is important to investigate microbial-host interactions and the effects on systemic immune perturbations. However, this effort has met with major challenges due to low microbial biomass and background artifacts. In the current study, microbial 16S DNA sequencing was applied to analyze plasma microbiome. We have developed a quality-filtering strategy to evaluate and exclude low levels of microbial sequences, potential contaminations, and artifacts from plasma microbial 16S DNA sequencing analyses. Furthermore, we have applied our technique in three cohorts, including tobacco-smokers, HIV-infected individuals, and individuals with systemic lupus erythematosus (SLE), as well as corresponding controls. More than 97% of total sequence data was removed using stringent quality-filtering strategy analyses; those removed amplicon sequence variants (ASVs) were low levels of microbial sequences, contaminations, and artifacts. The specifically enriched pathobiont bacterial ASVs have been identified in plasmas from tobacco-smokers, HIV-infected individuals, and individuals with SLE but not from control subjects. The associations between these ASVs and disease pathogenesis were demonstrated. The pathologic activities of some identified bacteria were further verified in vitro. We present a quality-filtering strategy to identify pathogenesis-associated plasma microbiome. Our approach provides a method for studying the diagnosis of subclinical microbial infection as well as for understanding the roles of microbiome-host interaction in disease pathogenesis.

Altered gut microbiota correlate with different immune responses to HAART in HIV-infected individuals

Background

Although gut microbiota dysbiosis has been reported in HIV infected individuals recently, the relationship between the gut microbiota and immune activation in patients with different immune responses to highly active antiretroviral therapy (HAART) is still not well understood. Gut microbiota and immune activation were studied in 36 non-HIV-infected subjects (healthy controls) and 58 HIV-infected individuals, including 28 immunological responders (IR) and 30 immunological non-responders (INR) (≥500 and < 200 CD4+ T-cell counts/μl after 2 years of HIV-1 viral suppression respectively) without comorbidities.

Results

Metagenome sequencing revealed that HIV-infected immunological responders and immunological non-responders could not recover completely from the gut microbiota dysbiosis. At a 97% similarity level, the relative abundances of Fusobacterium, Ruminococcus gnavus and Megamonas were greater, whereas Faecalibacterium, Alistipes, Bifidobacterium, Eubacterium rectale and Roseburia were more depleted in the IR and INR groups than those in the healthy controls. Ruminococcaceae and Alistipes were positively correlated with nadir and current CD4+ T-cell counts, but negatively correlated with CD8 + CD57+ T-cell counts. Inflammation markers and translocation biomarkers (LPS) levels were positively correlated with the abundances of genera Ruminococcus and Fusobacterium but were negatively correlated with the genus Faecalibacterium. The relative abundances of Escherichia-Shigella and Blautia were significantly higher in the IR than those in the INR group. Escherichia-Shigella were negatively correlated with the CD4/CD8 ratio but positively correlated with the amount of CD8 + CD57+ T-cells. Roseburia and Blautia were negatively associated with nadir CD4+ T-cell and positively associated with CD8 + CD57+ T-cell counts.

Conclusions

Gut microbiota dysbiosis may be one of the factors contributing to different immune responses and treatment outcomes to HAART.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-020-02074-1.

Association of Plasma Soluble Vascular Cell Adhesion Molecule-1 and sCD14 With Mortality in HIV-1-Infected West African Adults With High CD4 Counts

BACKGROUND

Several biomarkers of inflammation and coagulation were reported to be associated with HIV disease progression in different settings. In this article, we report the association between 11 biomarkers and medium-term mortality in HIV-infected West African adults.

METHODS

In Temprano ANRS 12136, antiretroviral therapy (ART)-naive HIV-infected adults with high CD4 counts were randomly assigned either to start ART immediately or defer ART until the World Health Organization criteria were met. Participants who completed the 30-month trial follow-up were invited to participate in a posttrial phase. The posttrial phase end point was all-cause death. We used multivariate Cox proportional models to analyze the association between baseline plasma biomarkers [IL-1ra, IL-6, soluble vascular cell adhesion molecule 1 (sVCAM-1), sCD14, D-dimer, fibrinogen, IP-10, sCD163, albumin, high-sensitivity C-reactive protein, and 16S rDNA] and all-cause death in the Temprano participants randomized to defer ART.

RESULTS

Four hundred seventy-seven patients (median age 35 years, 78% women, and median CD4 count: 379 cells/mm) were randomly assigned to defer starting ART until the World Health Organization criteria were met. The participants were followed for 2646 person-years (median 5.8 years). In the follow-up, 89% of participants started ART and 30 died. In the multivariate analysis adjusted for the study center, sex, baseline CD4 count, isoniazid preventive therapy, plasma HIV-1 RNA, peripheral blood mononuclear cell HIV-1 DNA, and ART, the risk of death was significantly associated with baseline sVCAM-1 (≥1458 vs. <1458: adjusted hazard ratio 2.57, 95% confidence interval: 1.13 to 5.82) and sCD14 (≥2187 vs. <2187: adjusted hazard ratio 2.79, interquartile range 1.29-6.02) levels.

CONCLUSIONS

In these sub-Saharan African adults with high CD4 counts, pre-ART plasma sVCAM-1 and sCD14 levels were independently associated with mortality.

Residual immune dysfunction under antiretroviral therapy

The usage of combination antiretroviral therapy in people with HIV (PWH) has incited profound improvement in morbidity and mortality. Yet, PWH may not experience full restoration of immune function which can manifest with non-AIDS comorbidities that frequently associate with residual inflammation and can imperil quality of life or longevity. In this review, we discuss the pathogenesis underlying chronic inflammation and residual immune dysfunction in PWH, as well as potential therapeutic interventions to ameliorate them and prevent incidence or progression of non-AIDS comorbidities. Current evidence advocates that early diagnosis and prompt initiation of therapy at high CD4 counts may represent the best available approach for an improved immune recovery in PWH.

Targeting Cannabinoid Receptor 2 on Peripheral Leukocytes to Attenuate Inflammatory Mechanisms Implicated in HIV-Associated Neurocognitive Disorder

HIV infection affects an estimated 38 million people. Approximately 50% of HIV patients exhibit neurocognitive dysfunction termed HIV-Associated Neurocognitive Disorder (HAND). HAND is a consequence of chronic low-level neuroinflammation due to HIV entry into the brain. Initially, monocytes become activated in circulation and traffic to the brain. Monocytes, when activated, become susceptible to infection by HIV and can then carry the virus across the blood brain barrier. Once in the brain, activated monocytes secrete chemokines, which recruit virus-specific CD8+ T cells into the brain to further promote neuroinflammation. HAND is closely linked to systemic inflammation driven, in part, by HIV but is also due to persistent translocation of microorganisms across the GI tract. Persistent anti-viral responses in the GI tract compromise microbial barrier integrity. Indeed, HIV patients can exhibit remarkably high levels of activated (CD16+) monocytes in circulation. Recent studies, including our own, show that HIV patients using medical marijuana exhibit lower levels of circulating CD16+ monocytes than non-cannabis using HIV patients. Cannabis is a known immune modulator, including anti-inflammatory properties, mediated, in part, by ∆9-tetrahydrocannabinol (THC), as well as less characterized minor cannabinoids, such as cannabidiol (CBD), terpenes and presumably other cannabis constituents. The immune modulating activity of THC is largely mediated through cannabinoid receptors (CB) 1 and 2, with CB1 also responsible for the psychotropic properties of cannabis. Here we discuss the anti-inflammatory properties of cannabinoids in the context of HIV and propose CB2 as a putative therapeutic target for the treatment of neuroinflammation. Graphical Abstract HIV-associated neurocognitive disorder is a systemic inflammatory disease leading to activation of plasmacytoid dendritic cells, monocytes and T cells. Monocyte and CD8 T cell migration across the BBB and interaction with astrocytes promotes neurotoxic inflammatory mediators release. CB2 ligands are proposed as therapeutics capable of suppressing systemic and localized inflammation.

Regulation of Gut Microbiota on Immune Reconstitution in Patients With Acquired Immunodeficiency Syndrome

Human immunodeficiency virus type 1 (HIV-1) infection of CD4⁺ T cells in the gut plays an insidious role in acquired immunodeficiency syndrome (AIDS) pathogenesis. Host immune function is closely related to gut microbiota. Changes in the gut microbiota cause a different immune response. Previous studies revealed that HIV-1 infection caused changes in gut microbiota, which induced immune deficiency. HIV-1 infection results in an abnormal composition and function of the gut microbiota, which may disrupt the intestinal epithelial barrier and microbial translocation, leading to long-term immune activation, including inflammation and metabolic disorders. At the same time, an abnormal gut microbiota also hinders the effect of antiviral therapy and affects the immune reconstruction of patients. However, studies on the impact of the gut microbiota on immune reconstitution in patients with HIV/AIDS are still limited. In this review, we focus on changes in the gut microbiota caused by HIV infection, as well as the impact and regulation of the gut microbiota on immune function and immune reconstitution, while we also discuss the potential impact of probiotics/prebiotics and fecal microbiota transplantation (FMT) on immune reconstitution.

Short Communication: Circulating Mitochondrial DNA and Lipopolysaccharide-Binding Protein but Not Bacterial DNA Are Increased in Acute Human Immunodeficiency Virus Infection

Microbial translocation has been suggested as a major driver of chronic immune activation HIV infection. Thus, we compared the extent of microbial translocation in patients with acute HIV infection and patients followed after CD4-guided structured treatment interruption (STI) by measuring different circulating markers: (1) lipopolysaccharide (LPS)-binding protein (LBP), (2) bacterial DNA, (3) soluble CD14 (sCD14), and (4) mitochondrial DNA (mtDNA). Bacterial DNA and sCD14 levels were similar in all groups. Patients in acute phase showed higher levels of LBP and mtDNA. In STI, we found a positive correlation between the percentage of CD8+ T cells and bacterial DNA levels. Considering all patients, LBP was positively correlated with the percentage and the absolute count of CD8+ T cells, and with mtDNA stressing the importance of mitochondrial products in sustaining chronic immune activation.

Endothelial Dysfunction Is Related to Monocyte Activation in Antiretroviral-Treated People With HIV and HIV-Negative Adults in Kenya

BACKGROUND

Residual monocyte activation may contribute to increased risk for endothelial dysfunction and subsequent atherosclerotic cardiovascular diseases (CVDs) among people with HIV (PWH) on antiretroviral therapy (ART). We examined the relationship between monocyte activation and endothelial activation in PWH in Kenya.

METHODS

Serum levels of markers of endothelial activation (soluble/circulating intercellular [sICAM-1] and vascular [sVCAM-1] cell adhesion molecule-1), intestinal barrier dysfunction (intestinal fatty acid binding protein [I-FABP]), and monocyte activation (soluble CD14 [sCD14]) were measured in 275 PWH on ART and 266 HIV-negative persons. Linear regression was used to evaluate associations, adjusting for demographic and traditional CVD risk factors.

RESULTS

Among 541 participants, the median age was 43 years, 50% were female, and most PWH were virally suppressed (97%). sICAM-1 and sVCAM-1 levels were significantly higher in PWH than in HIV-negative participants (P < .001 for both). After further adjustment for traditional CVD risk factors, HIV infection remained associated with 49% (95% CI, 33% to 67%) greater sICAM-1 and 30% (95% CI, 14% to 48%) greater sVCAM-1 relative to uninfected controls. Adjustment for sCD14 substantially attenuated the difference between PWH and HIV-negative individuals. In a stratified analysis of PWH, both sICAM-1 and sVCAM-1 were positively associated with sCD14 (P < .001).

CONCLUSIONS

Despite viral suppression, African PWH have evidence of enhanced endothelial activation associated with sCD14, suggesting that monocyte activation plays a role in atherosclerotic plaque development. Future studies are needed to determine mechanistic pathways leading to monocyte activation in this population.

High microbial translocation limits gut immune recovery during short-term HAART in the area with high prevalence of foodborne infection

BACKGROUND

Individuals residing in areas with high prevalence of foodborne infection could have a higher risk of gut microbial translocation which may affect monocyte activation, gut immune recovery and intestinal epithelial cell damage. We aimed to measure alterations in microbial translocation, monocyte activation, gut immune recovery, and intestinal epithelial cell damage in HAART treated individuals.

METHODS

A prospective, single-arm, longitudinal, cohort study was conducted among antiretroviral naïve HIV-1 infected Thai participants. All participants were in chronic stage of HIV-1 infection before starting HAART. Data and samples were collected prior to initiation of HAART and then after 24 and 48 weeks of HAART. Plasma biomarkers for microbial translocation (16S rDNA and LBP), monocyte activation (sCD14) and intestinal epithelial cell damage (I-FABP) were evaluated. We measured circulating gut-homing CD4⁺ T cells and circulating gut-homing Th17 cells to assess recoveries of gut immunity and gut immunity to microbial pathogens.

RESULTS

The kinetic studies showed no reduction in the levels of plasma 16S rDNA, sCD14 or I-FABP, significant decrease of plasma LBP level, and slow but significant increases in the frequencies of circulating gut-homing CD4⁺ T cells and circulating gut-homing Th17 cells during 48 weeks of HAART. Dividing participants into low and high microbial translocation (low and high MT) groups at baseline, both groups showed persistent plasma levels of 16S rDNA, sCD14 and I-FABP, and significantly decreased plasma level of LBP. The low MT group had significantly increased frequencies of circulating gut-homing CD4⁺ T cells and circulating gut-homing Th17 cells during 48 weeks of HAART but this was not observed in the high MT group.

CONCLUSIONS

We demonstrated persistent high microbial translocation, monocyte activation and intestinal epithelial cell damage with slow gut immune recovery during successful short-term HAART. Additionally, gut immune recovery was apparently limited by high microbial translocation. Our findings emphasize the adverse impact of high microbial translocation on gut immune recovery and the necessity of establishing a novel therapeutic intervention to inhibit microbial translocation.

Persistent high levels of immune activation and their correlation with the HIV-1 proviral DNA and 2-LTR circles loads, in a cohort of Mexican individuals following long-term and fully suppressive treatment

OBJECTIVES

The aim of this study was to investigate the correlation between the HIV-1 reservoir and the levels of immune activation in chronic patients under fully suppressive cART.

METHODS

We quantified the HIV proviral DNA and 2-LTR circles loads from PBMCs, the levels of CD38+ and Ki-67+ T-cells, and the levels of IL-7 in a cohort of patients with more than 5 years of ART at enrollment and after 1 year.

RESULTS

In 29 participants with a median of 8 years (IQR, 6.9-9.4) under suppressive cART we found higher levels of CD8+ CD38+ T-cells after 1-year (P = .000). There was a non-statistically significant poor correlation between the levels of immune activation and the proviral DNA of CD4+ and CD8+ T-cells. Ki-67+ T-cells declined without significant differences, and there was no significant correlation with the proportion of CD38+. IL-7 decreased at the follow-up observation (P = .094), but there was no correlation with the levels of CD38+ and Ki-67+ T-cells.

CONCLUSIONS

We found a weak but non-statistically significant correlation of the levels of T-cell activation with the proviral DNA and 2-LTR circles. This suggests the likely occurrence of further mechanisms driving chronic versus early immune activation other than viral replication by itself in chronic patients.

Blood Bacterial Profiles Associated With Human Immunodeficiency Virus Infection and Immune Recovery

Human immunodeficiency virus (HIV) infection impairs mucosal immunity and leads to bacterial translocation, fueling chronic inflammation and disease progression. While this is well established, questions remain about the compositional profile of the translocated bacteria, and to what extent it is influenced by antiretroviral therapy (ART). Using 16S ribosomal DNA targeted sequencing and shotgun proteomics, we showed that HIV increases bacterial translocation from the gut to the blood. HIV increased alpha diversity in the blood, which was dominated by aerobic bacteria belonging to Micrococcaceae (Actinobacteria) and Pseudomonadaceae (Proteobacteria) families, and the number of circulating bacterial proteins was also increased. Forty-eight weeks of ART attenuated this phenomenon. We found that enrichment with Lactobacillales order, and depletion of Actinobacteria class and Moraxellaceae and Corynebacteriacae families, were significantly associated with greater immune recovery and correlated with several inflammatory markers. Our findings suggest that the molecular cross talk between the host and the translocated bacterial products could influence ART-mediated immune recovery.

Biomarkers of Cellular Stress Do Not Associate with sCD14 in Progressive HIV and SIV Infections in Vivo

Background

Microbial translocation occurs after damage to the structural and/or immunological barrier of the gastrointestinal (GI) tract into circulation. Microbial components that trans-locate from the lumen of the GI tract directly stimulate the immune system and contribute to inflammation. When microbial translocation becomes chronic, the inflammation has detrimental consequences. Given that microbial translocation is an important phenomenon in many diseases, defining biomarkers that reliably reflect microbial translocation is critical. Measurement of systemic microbial products is difficult since: 1) robust assays to measure microbial antigens simultaneously are lacking; 2) confounding factors influence assays used to detect microbial products; and 3) biological clearance mechanisms limit their detection in circulation. Thus, host proteins produced in response to microbial stimulation are used as surrogates for microbial translocation; however, many of these proteins are also produced in response to host proteins expressed by dying cells.

Methods

We measured plasma levels of biomarkers associated with GI tract damage, immune responses to microbial products, and cell-death in people living with HIV before and after antiretroviral administration, and in macaque nonhuman primates before and after SIV infection.

Results

Proteins secreted during cellular stress (receptor for advanced glycation endproducts-RAGE and high motility group box 1-HMGB1), which can induce sCD14 production in vitro and in vivo, do not associate with elevated levels of biomarkers associated with microbial translocation in progressively HIV-infected individuals and SIV-infected NHPs.

Conclusions

Bystander cell death and generalized inflammation do not contribute to elevated levels of sCD14 observed in HIV/SIV-infected individuals.

HIV-associated gut dysbiosis is independent of sexual practice and correlates with noncommunicable diseases

Loss of gut mucosal integrity and an aberrant gut microbiota are proposed mechanisms contributing to chronic inflammation and increased morbidity and mortality during antiretroviral-treated HIV disease. Sexual practice has recently been uncovered as a major source of microbiota variation, potentially confounding prior observations of gut microbiota alterations among persons with HIV (PWH). To overcome this and other confounding factors, we examine a well-powered subset of AGEhIV Cohort participants comprising antiretroviral-treated PWH and seronegative controls matched for age, body-mass index, sex, and sexual practice. We report significant gut microbiota differences in PWH regardless of sex and sexual practice including Gammaproteobacteria enrichment, Lachnospiraceae and Ruminococcaceae depletion, and decreased alpha diversity. Men who have sex with men (MSM) exhibit a distinct microbiota signature characterized by Prevotella enrichment and increased alpha diversity, which is linked with receptive anal intercourse in both males and females. Finally, the HIV-associated microbiota signature correlates with inflammatory markers including suPAR, nadir CD4 count, and prevalence of age-associated noncommunicable comorbidities.

Antibiotic-induced microbiome perturbations are associated with significant alterations to colonic mucosal immunity in rhesus macaques

The diverse bacterial communities that colonize the gastrointestinal tract play an essential role in maintaining immune homeostasis through the production of critical metabolites such as short-chain fatty acids (SCFAs) and this can be disrupted by antibiotic use. However, few studies have addressed the effects of specific antibiotics longitudinally on the microbiome and immunity. We evaluated the effects of four specific antibiotics: enrofloxacin, cephalexin, paromomycin, and clindamycin, in healthy female rhesus macaques. All antibiotics disrupted the microbiome, including reduced abundances of fermentative bacteria and increased abundances of potentially pathogenic bacteria, including Enterobacteriaceae in the stool, and decreased Helicobacteraceae in the colon. This was associated with decreased SCFAs, indicating altered bacterial metabolism. Importantly, antibiotic use also substantially altered local immune responses, including increased neutrophils and Th17 cells in the colon. Furthermore, we observed increased soluble CD14 in plasma, indicating microbial translocation. These data provide a longitudinal evaluation of antibiotic-induced changes to the composition and function of colonic bacterial communities associated with specific alterations in mucosal and systemic immunity.

The Opioid Epidemic: Impact on Inflammation and Cardiovascular Disease Risk in HIV

PURPOSE OF REVIEW

People infected with HIV through injection drug use are more likely to experience progression to AIDS, death due to AIDS, and all-cause mortality even when controlling for access to care and antiretroviral therapy. While high-risk behavior and concurrent infections most certainly are contributors, chronic immune activation, downstream metabolic comorbidities may play an important role.

RECENT FINDINGS

Altered intestinal integrity plays a major role in HIV-related immune activation and microbial translocation markers are heightened in active heroin users. Additionally, greater injection frequency drives systemic inflammation and is associated with HIV viral rebound. Finally, important systemic inflammation markers have been linked with frailty and mortality in people who inject drugs with and without concurrent HIV infection. Heroin use may work synergistically with HIV infection to cause greater immune activation than either factor alone. Further research is needed to understand the impact on downstream metabolic comorbidities including cardiovascular disease. Medication-assisted treatment for opioid use disorder with methadone or buprenorphine may ameliorate some of this risk; however, there is presently limited research in humans, including in non-HIV populations, describing changes in immune activation on these treatments which is of paramount importance for those with HIV infection.

Presence of Inflammatory Group I and III Innate Lymphoid Cells in the Colon of Simian Immunodeficiency Virus-Infected Rhesus Macaques

Chronic, low-grade, systemic, and mucosal inflammation correlates with increased morbidity and poor clinical outcomes among patients living with human immunodeficiency virus (HIV). These long-term complications are linked to the disruption of gastrointestinal (GI) tract epithelial barrier integrity and subsequent microbial translocation. However, the mechanisms responsible for these downstream effects of infection are unknown. Here, we demonstrate that during the disruption of the GI tract and increased microbial translocation, we find inflammatory cytokines (e.g., interferon gamma [IFN-γ] and tumor necrosis factor alpha [TNF-α]) produced by innate lymphoid cells (ILCs) located in the colon secondary to simian immunodeficiency virus (SIV) infection. To do this, we used viably cryopreserved colon cells from SIV-infected and uninfected rhesus macaque monkeys and determined the make-up of the ILC subpopulations and the cytokines they expressed constitutively. Our studies revealed that the interleukin-22 (IL-22)/IL-17-producing ILCS was not altered during SIV infection. However, the percentage of IFN-γ+ ILCs in infected colons was 5- to 10-fold higher than that in uninfected colons. ILCs from infected tissue that produced IFN-γ also expressed TNF-α and IL-22. The coexpression of inflammatory cytokines with IL-22 is linked to the ability of ILCs to coexpress T-bet and RORγT/Ahr. The expression of IFN-γ/TNF-α by ILCs and NK cells combined likely triggers a pathway that contributes to chronic mucosal inflammation, GI barrier breakdown, and microbial translocation within the context of SIV/HIV infection.IMPORTANCE There is a slow yet significant uptick in systemic inflammation secondary to HIV infection that has long-term consequences for the infected host. The systemic inflammation most likely occurs as a consequence of the disruption of the gut epithelial barrier, leading to the translocation of gut microbial products. This disruption may result from mucosal inflammation. Here, we show in an animal model of HIV that chronic SIV-infected gut contains innate lymphoid cells producing inflammatory cytokines.

Myeloid Cells Enriched for a Dendritic Cell Population From People Living With HIV Have Altered Gene Expression Not Restored by Antiretroviral Therapy

Antiretroviral therapy (ART) for human immunodeficiency virus (HIV) infections has been designed to optimize CD4 T-cell survival and limit HIV replication. Cell types other than CD4 T cells such as monocytes/macrophage, dendritic cells, and granulocytes (collectively known as myeloid cells), are generally not considered in the development of ART protocols. Myeloid dendritic cells (mDCs) are the most potent inducers of CD4 T-cell activation and central to the regulation of immune responses. mDCs in the blood are decreased in number, altered in function, and implicated in promoting HIV latency in people living with HIV (PLWH). We found that cells enriched for mDC in PLWH had transcriptional changes compared to mDC from HIV uninfected individuals, some of which were not completely restored by ART. In contrast, other mDC functions such as interleukin-1 signaling and type I interferon pathways were restored by ART. Some of the transcriptional changes in mDC not completely reversed by ART were enriched in genes that are classically associated with cells of the monocyte/macrophage lineage, but new single-cell RNA sequencing studies show that they are also expressed by a subset of mDC. A cellular enzyme, acyloxyacyl hydrolase (AOAH), important for lipopolysaccharide (LPS) detoxification, had increased transcription in mDC of PLWH, not restored by ART. It is possible that one reason ART is not completely successful in PLWH is the failure to phenotypically change the mDCs. Thus, inability of ART to be completely effective might involve myeloid cells and the failure to restore mDC function as measured by gene transcription. We suggest that mDC and myeloid cells should be considered in future combination ART development.

Immune effects of Lactobacillus casei Shirota in treated HIV-infected patients with poor CD4+ T-cell recovery

BACKGROUND

HIV infection leads to depletion of intestinal CD4+ T cells, mucosal barrier dysfunction, increased gut permeability and microbial translocation even among patients on suppressive ART. Previous studies suggest probiotics may help restore intestinal function.

METHODS

In this double-blind, placebo-controlled pilot study, we enrolled HIV-infected patients on suppressive ART with poor CD4+ recovery to address the effect of daily oral use of Lactobacillus casei Shirota (LcS) on CD4+ T-cell count and CD4+/CD8+ ratio at 6 and 12 weeks after treatment initiation; immune activation and intestinal microbiome composition were addressed as secondary outcomes.

RESULTS

From January 2015 to July 2016, 48 patients were randomized (1 : 1) to active intervention or placebo. Groups had comparable demographic and clinical characteristics; only CD4+ T-cell nadir was statistically different between groups. All participants were virologically suppressed under ART. At week 6, the increment in CD4+ T-cell count was 17 cells/μl [interquartile range (IQR) -33 to 74] in the active intervention arm and 4 cells/μl (IQR -43 to 51) in the placebo arm (P = 0.291); at week 12, the change in CD4+ T-cell count was 8 cells//μl (IQR -30 to 70) in the active arm and 10 cells//μl (IQR -50 to 33) among participants allocated to placebo (P = 0.495). Median change in CD4+/CD8+ ratio at week 6 compared with baseline was 0 (IQR -0.04 to 0.05) in the active intervention arm and -0.01 in the placebo arm (IQR -0.06 to 0.03; P = 0.671). At week 12, the change in CD4+/CD8+ ratio was higher in the active product group compared with placebo (respectively 0.07 and 0.01), but this difference failed to reach statistical significance (P = 0.171). We found no significant effects of LcS on immune activation markers, CD4+ and CD8+ subpopulations, sCD14 levels or NK cells at week 12. Finally, we found no statistically significant differences between groups in the change of enteric microbiome at week 12.

CONCLUSION

In this pilot study, we found no statistically significant effect of LcS probiotic on CD4+ T-cell counts, CD4+/CD8+ ratio, immune activation or intestinal microbiome among HIV-infected patients on suppressive ART with poor CD4+ recovery.

Impact of Aging and HIV Infection on the Function of the C-Type Lectin Receptor MINCLE in Monocytes

Both aging and HIV infection are associated with an enhanced pro-inflammatory environment that contributes to impaired immune responses and is mediated in part by innate immune pattern-recognition receptors. MINCLE is a C-type lectin receptor that recognizes trehalose-6,6'-dimycolate or "cord factor," the most abundant glycolipid in Mycobacterium tuberculosis. Here, we evaluated MINCLE function in monocytes in a cohort of HIV-infected and uninfected young (21-35 years) and older adults (≥60 years) via stimulation of peripheral blood mononuclear cells with trehalose-6,6-dibehenate, a synthetic analog of trehalose-6,6'-dimycolate and measurement of cytokine production (interleukin [IL]-10, IL-12, IL-6, tumor necrosis factor-α) by multicolor flow cytometry. Our studies show an age- and HIV-associated increase in cytokine multifunctionality of monocytes both at the population and single cell level that was dominated by IL-12, IL-10, and IL-6. These findings provide insight into the host response to M. tuberculosis and possible sources for the pro-inflammatory environment seen in aging and HIV infection.

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.

Method comparison for the direct enumeration of bacterial species using a chemostat model of the human colon

BACKGROUND

Clostridioides difficile infection (CDI) has a high recurrent infection rate. Faecal microbiota transplantation (FMT) has been used successfully to treat recurrent CDI, but much remains unknown about the human gut microbiota response to replacement therapies. In this study, antibiotic-mediated dysbiosis of gut microbiota and bacterial growth dynamics were investigated by two quantitative methods: real-time quantitative PCR (qPCR) and direct culture enumeration, in triple-stage chemostat models of the human colon. Three in vitro models were exposed to clindamycin to induce simulated CDI. All models were treated with vancomycin, and two received an FMT. Populations of total bacteria, Bacteroides spp., Lactobacillus spp., Enterococcus spp., Bifidobacterium spp., C. difficile, and Enterobacteriaceae were monitored using both methods. Total clostridia were monitored by selective culture. Using qPCR analysis, we additionally monitored populations of Prevotella spp., Clostridium coccoides group, and Clostridium leptum group.

RESULTS

Both methods showed an exacerbation of disruption of the colonic microbiota following vancomycin (and earlier clindamycin) exposure, and a quicker recovery (within 4 days) of the bacterial populations in the models that received the FMT. C. difficile proliferation, consistent with CDI, was also observed by both qPCR and culture. Pearson correlation coefficient showed an association between results varying from 98% for Bacteroides spp., to 62% for Enterobacteriaceae.

CONCLUSIONS

Generally, a good correlation was observed between qPCR and bacterial culture. Overall, the molecular assays offer results in real-time, important for treatment efficacy, and allow the monitoring of additional microbiota groups. However, individual quantification of some genera (e.g. clostridia) might not be possible without selective culture.

The impact of substance abuse on HIV-mediated neuropathogenesis in the current ART era

Approximately 37 million people worldwide are infected with human immunodeficiency virus (HIV). One highly significant complication of HIV infection is the development of HIV-associated neurocognitive disorders (HAND) in 15-55% of people living with HIV (PLWH), that persists even in the antiretroviral therapy (ART) era. The entry of HIV into the central nervous system (CNS) occurs within 4-8 days after peripheral infection. This establishes viral reservoirs that may persist even in the presence of ART. Once in the CNS, HIV infects resident macrophages, microglia, and at low levels, astrocytes. In response to chronic infection and cell activation within the CNS, viral proteins, inflammatory mediators, and host and viral neurotoxic factors produced over extended periods of time result in neuronal injury and loss, cognitive deficits and HAND. Substance abuse is a common comorbidity in PLWH and has been shown to increase neuroinflammation and cognitive disorders. Additionally, it has been associated with poor ART adherence, and increased viral load in the cerebrospinal fluid (CSF), that may also contribute to increased neuroinflammation and neuronal injury. Studies have examined mechanisms that contribute to neuroinflammation and neuronal damage in PLWH, and how substances of abuse exacerbate these effects. This review will focus on how substances of abuse, with an emphasis on methamphetamine (meth), cocaine, and opioids, impact blood brain barrier (BBB) integrity and transmigration of HIV-infected and uninfected monocytes across the BBB, as well as their effects on monocytes/macrophages, microglia, and astrocytes within the CNS. We will also address how these substances of abuse may contribute to HIV-mediated neuropathogenesis in the context of suppressive ART. Additionally, we will review the effects of extracellular dopamine, a neurotransmitter that is increased in the CNS by substances of abuse, on HIV neuropathogenesis and how this may contribute to neuroinflammation, neuronal insult, and HAND in PLWH with active substance use. Lastly, we will discuss some potential therapies to limit CNS inflammation and damage in HIV-infected substance abusers.

A Link Between Plasma Microbial Translocation, Microbiome, and Autoantibody Development in First-Degree Relatives of Systemic Lupus Erythematosus Patients

OBJECTIVE

Systemic lupus erythematosus (SLE) is characterized by the production of antibodies against self antigens. However, the events underlying autoantibody formation in SLE remain unclear. This study was undertaken to investigate the role of plasma autoantibody levels, microbial translocation, and the microbiome in SLE.

METHODS

Plasma samples from 2 cohorts, one with 18 unrelated healthy controls and 18 first-degree relatives and the other with 19 healthy controls and 21 SLE patients, were assessed for autoantibody levels by autoantigen microarray analysis, measurement of lipopolysaccharide (LPS) levels by Limulus amebocyte assay, and determination of microbiome composition by microbial 16S ribosomal DNA sequencing.

RESULTS

First-degree relatives and SLE patients exhibited increased plasma autoantibody levels compared to their control groups. Parents and children of lupus patients exhibited elevated plasma LPS levels compared to controls (P = 0.02). Plasma LPS levels positively correlated with plasma anti-double-stranded DNA IgG levels in first-degree relatives (r = 0.51, P = 0.03), but not in SLE patients. Circulating microbiome analysis revealed that first-degree relatives had significantly reduced microbiome diversity compared to their controls (observed species, P = 0.004; Chao1 index, P = 0.005), but this reduction was not observed in SLE patients. The majority of bacteria that were differentially abundant between unrelated healthy controls and first-degree relatives were in the Firmicutes phylum, while differences in bacteria from several phyla were identified between healthy controls and SLE patients. Bacteria in the Paenibacillus genus were the only overlapping differentially abundant bacteria in both cohorts, and were reduced in first-degree relatives (adjusted P [Padj ] = 2.13 × 10-12 ) and SLE patients (Padj = 0.008) but elevated in controls.

CONCLUSIONS

These results indicate a possible role of plasma microbial translocation and microbiome composition in influencing autoantibody development in SLE.

Microbial Translocation Is Linked to a Specific Immune Activation Profile in HIV-1-Infected Adults With Suppressed Viremia

Persistent immune activation in virologically suppressed HIV-1 patients, which may be the consequence of various factors including microbial translocation, is a major cause of comorbidities. We have previously shown that different profiles of immune activation may be distinguished in virological responders. Here, we tested the hypothesis that a particular profile might be the consequence of microbial translocation. To this aim, we measured 64 soluble and cell surface markers of inflammation and CD4+ and CD8+ T-cell, B cell, monocyte, NK cell, and endothelial activation in 140 adults under efficient antiretroviral therapy, and classified patients and markers using a double hierarchical clustering analysis. We also measured the plasma levels of the microbial translocation markers bacterial DNA, lipopolysaccharide binding protein (LBP), intestinal-fatty acid binding protein, and soluble CD14. We identified five different immune activation profiles. Patients with an immune activation profile characterized by a high percentage of CD38+CD8+ T-cells and a high level of the endothelial activation marker soluble Thrombomodulin, presented with higher LBP mean (± SEM) concentrations (33.3 ± 1.7 vs. 28.7 ± 0.9 μg/mL, p = 0.025) than patients with other profiles. Our data are consistent with the hypothesis that the immune activation profiles we described are the result of different etiological factors. We propose a model, where particular causes of immune activation, as microbial translocation, drive particular immune activation profiles responsible for particular comorbidities.

Monocyte activation, HIV, and cognitive performance in East Africa

Chronic inflammation associated with monocyte activation has been linked to HIV-related cognitive outcomes in resource-rich settings. Few studies have investigated this relationship in the African context where endemic non-HIV infections may modulate effects. We characterized immune activation biomarkers in Kenyan and Ugandan participants in relation to neuropsychological testing performance (NTP) from the African Cohort Study (AFRICOS). We focused on activation markers associated with monocytes (sCD14, sCD163, neopterin), T cells (HLA-DR⁺CD38⁺ on CD4⁺ and CD8⁺ T lymphocytes), and microbial translocation (intestinal fatty acid-binding protein, I-FABP). The HIV-infected (n = 290) vs. HIV-uninfected (n = 104) groups were similar in age with mean (SD) of 41 (9.5) vs. 39 (9.9) years, respectively (p = 0.072). Among HIV-infected participants, the mean (SD) current CD4⁺ count was 402 (232); 217 (75%) were on combination antiretroviral therapy (cART) and 199 (69%) had suppressed plasma HIV RNA. sCD14 was inversely correlated to NTP (r = - 0.14, p = 0.037) in models that included both HIV-infected and uninfected individuals, adjusted for HIV status and research site, whereas sCD163 was not (r = 0.041, p = 0.938). Neither of the T cell activation markers correlated with NTP. In the HIV-infected group, I-FABP was inversely associated with NTP (r = - 0.147, p = 0.049), even among those with suppressed plasma virus (r = - 0.0004, p = 0.025). Among the full group, HIV status did not appear to modulate the effects observed. In this cohort from East Africa, sCD14, but not sCD163, is associated with cognitive performance regardless of HIV status. Findings among both HIV-infected and HIV-uninfected groups is supportive that HIV and non-HIV-related inflammatory sources contribute to cognitive performance in this setting.

Antiretroviral therapy partially improves the abnormalities of dendritic cells and lymphoid and myeloid regulatory populations in recently infected HIV patients

This study aimed to evaluate the effects of antiretroviral therapy on plasmacytoid (pDC) and myeloid (mDC) dendritic cells as well as regulatory T (Treg) and myeloid-derived suppressor (MDSC) cells in HIV-infected patients. Forty-five HIV-infected patients (20 of them with detectable HIV load −10 recently infected and 10 chronically infected patients-, at baseline and after antiretroviral therapy, and 25 with undetectable viral loads) and 20 healthy controls were studied. The influence of HIV load, bacterial translocation (measured by 16S rDNA and lipopolysaccharide-binding protein) and immune activation markers (interleukin –IL- 6, soluble CD14, activated T cells) was analyzed. The absolute numbers and percentages of pDC and mDC were significantly increased in patients. Patients with detectable viral load exhibited increased intracellular expression of IL-12 by mDCs and interferon -IFN- α by pDCs. Activated population markers were elevated, and the proportion of Tregs was significantly higher in HIV-infected patients. The MDSC percentage was similar in patients and controls, but the intracellular expression of IL-10 was significantly higher in patients. The achievement of undetectable HIV load after therapy did not modify bacterial translocation parameters, but induce an increase in pDCs, mDCs and MDSCs only in recently infected patients. Our data support the importance of early antiretroviral therapy to preserve dendritic and regulatory cell function in HIV-infected individuals.

Inflammatory and immunometabolic consequences of gut dysfunction in HIV: Parallels with IBD and implications for reservoir persistence and non-AIDS comorbidities

The gastrointestinal mucosa is critical for maintaining the integrity and functions of the gut. Disruption of this barrier is a hallmark and a risk factor for many intestinal and chronic inflammatory diseases. Inflammatory bowel disease (IBD) and HIV infection are characterized by microbial translocation and systemic inflammation. Despite the clinical overlaps between HIV and IBD, significant differences exist such as the severity of gut damage and mechanisms of immune cell homeostasis. Studies have supported the role of metabolic activation of immune cells in promoting chronic inflammation in HIV and IBD. This inflammatory response persists in HIV+ persons even after long-term virologic suppression by antiretroviral therapy (ART). Here, we review gut dysfunction and microbiota changes during HIV infection and IBD, and discuss how this may induce metabolic reprogramming of monocytes, macrophages and T cells to impact disease outcomes. Drawing from parallels with IBD, we highlight how factors such as lipopolysaccharides, residual viral replication, and extracellular vesicles activate biochemical pathways that regulate immunometabolic processes essential for HIV persistence and non-AIDS metabolic comorbidities. This review highlights new mechanisms and support for the use of immunometabolic-based therapeutics towards HIV remission/cure, and treatment of metabolic diseases.

Contribution of Liver Fibrosis and Microbial Translocation to Immune Activation in Persons Infected With HIV and/or Hepatitis C Virus

Background

The independent contributions of microbial translocation and liver fibrosis to immune activation in human immunodeficiency virus (HIV) and/or hepatitis C virus (HCV)-infected persons are unclear.

Methods

Multivariable linear regression was used to evaluate whether intestinal fatty acid binding protein (I-FABP: a marker of gut epithelial integrity) and transient elastography-measured liver fibrosis might mediate the association of HIV and HCV with the soluble CD14 (sCD14) level in 120 individuals with HIV and HCV coinfection, 262 with HIV monoinfection, 72 with HCV monoinfection, and 170 without infection.

Results

Coinfected individuals, HIV-monoinfected individuals, and HCV-monoinfected individuals had 37%, 21%, and 12% higher sCD14 levels, respectively, than uninfected individuals, after multivariable adjustment. Additional adjustment for I-FABP level modestly attenuated the association of HIV infection, but attenuation occurred to a lesser extent in the HCV-monoinfected group. Adjustment for liver fibrosis substantially attenuated the association of HCV infection, but attenuation occurred to a lesser extent in the HIV-monoinfected group. Relative to the uninfected group, the primary mediator of the sCD14 level was the I-FABP level in the HIV-infected groups and liver fibrosis in the HCV-monoinfected group.

Conclusion

HIV and HCV are independently and additively associated with higher a sCD14 level. Our findings suggest that microbial translocation contributes to an increased sCD14 level during HIV infection, whereas liver fibrosis plays a stronger role during HCV monoinfection. Coinfected persons may be at greatest risk for progression, because of the independent effects of microbial translocation and liver fibrosis on immune activation.

How Monocytes Contribute to Increased Risk of Atherosclerosis in Virologically-Suppressed HIV-Positive Individuals Receiving Combination Antiretroviral Therapy

Combination antiretroviral therapy (ART) is effective at suppressing HIV viremia to achieve persistently undetectable levels in peripheral blood in the majority of individuals with access and ability to maintain adherence to treatment. However, evidence suggests that ART is less effective at eliminating HIV-associated inflammation and innate immune activation. To the extent that residual inflammation and immune activation persist, virologically suppressed people living with HIV (PLWH) may have increased risk of inflammatory co-morbidities, and adjunctive therapies may need to be considered to reduce HIV-related inflammation and fully restore the health of virologically suppressed HIV+ individuals. Cardiovascular disease (CVD) is the single leading cause of death in the developed world and is becoming more important in PLWH with access to ART. Arterial disease due to atherosclerosis, leading to acute myocardial infarction (AMI) and stroke, is a major component of CVD. Atherosclerosis is an inflammatory disease, and epidemiological comparisons of atherosclerosis and AMI show a higher prevalence and suggest a greater risk in PLWH compared to the general population. The reasons for greater prevalence of CVD in PLWH can be broadly grouped into four categories: (a) the higher prevalence of traditional risk factors e.g., smoking and hypertension (b) dyslipidemia (also a traditional risk factor) caused by off-target effects of ART drugs (c) HIV-related inflammation and immune activation and (d) other undefined HIV-related factors. Management strategies aimed at reducing the impact of traditional risk factors in PLWH are similar to those for the general population and their effectiveness is currently being evaluated. Together with improvements in ART regimens and guidelines for treatment, and a greater awareness of its impact on CVD, the HIV-related risk of AMI and stroke is decreasing but remains elevated compared to the general community. Monocytes are key effector cells which initiate the formation of atherosclerotic plaques by migrating into the intima of coronary arteries and accumulating as foam cells full of lipid droplets. This review considers the specific role of monocytes as effector cells in atherosclerosis which progresses to AMI and stroke, and explores mechanisms by which HIV may promote an atherogenic phenotype and function independent of traditional risk factors. Altered monocyte function may represent a distinct HIV-related factor which increases risk of CVD in PLWH.

Laboratory surrogate markers of residual HIV replication among distinct groups of individuals under antiretroviral therapy

BACKGROUND

Residual HIV-1 replication among individuals under antiretroviral therapy (ART) relates to HIV micro-inflammation.

OBJECTIVES

To determine the levels of residual HIV replication markers among distinct subgroups of antiretroviral-treated individuals.

METHODS

One hundred sixteen patients were distributed into 5 treatment groups: first-line suppressive ART with a non-nucleoside analog reverse-transcriptase inhibitor (NNRTI) (n = 26), first-line suppressive ART with boosted protease inhibitors (PI-r) (n = 25), salvage therapy using PI-r (n = 27), salvage therapy with PI-r and raltegravir (n = 22) and virologic failure (n = 16). Episomal and total DNA quantitation was evaluated. ELISA was used for HIV antibody and LPS quantitation.

RESULTS

Episomal DNA was positive in 26% to 38% of individuals under suppressive ART, and it was higher among individuals experiencing ART virologic failure (p = 0.04). The HIV proviral load was higher among patients with detectable episomal DNA (p = 0.01). Individuals receiving initial PI-r treatment presented lower HIV antibody (p = 0.027) and LPS (p = 0.029) levels than individuals receiving NNRTI. There was a negative correlation between episomal DNA quantitation and the duration of suppressive ART (p = 0.04), CD4+ T-cell count (p = 0.08), and CD8+ T-cell count (p = 0.07).

CONCLUSIONS

Residual HIV replication has been inferred among individuals under suppressive ART according to episomal DNA detection. Residual replication may decrease with longer periods of suppressive ART and higher levels of CD4+ and CD8+ T cells. The relationship between episomal DNA and total DNA suggests there is a replenishment of the proviral reservoir with impacts on HIV persistence. Lower antibody and LPS levels among patients with initial PI-r ART suggest these regimens may more effectively suppress HIV and have a higher capacity to decrease the HIV antigenic component.

Progesterone decreases gut permeability through upregulating occludin expression in primary human gut tissues and Caco-2 cells

Progesterone plays a protective role in preventing inflammation and preterm delivery during pregnancy. However, the mechanism involved is unknown. Microbial product translocation from a permeable mucosa is demonstrated as a driver of inflammation. To study the mechanism of the protective role of progesterone during pregnancy, we investigated the effect of physiologic concentrations of progesterone on tight junction protein occludin expression and human gut permeability in vitro and systemic microbial translocation in pregnant women in vivo. Plasma bacterial lipopolysaccharide (LPS), a representative marker of in vivo systemic microbial translocation was measured. We found that plasma LPS levels were significantly decreased during 24 to 28 weeks of gestation compared to 8 to 12 weeks of gestation. Moreover, plasma LPS levels were negatively correlated with plasma progesterone levels but positively correlated with plasma tumor necrosis factor-alpha (TNF-α) levels at 8 to 12 weeks of gestation but not at 24 to 28 weeks of gestation. Progesterone treatment increased intestinal trans-epithelial electrical resistance (TEER) in primary human colon tissues and Caco-2 cells in vitro through upregulating tight junction protein occludin expression. Furthermore, progesterone exhibited an inhibitory effect on nuclear factor kappa B (NF-κB) activation following LPS stimulation in Caco-2 cells. These results reveal a novel mechanism that progesterone may play an important role in decreasing mucosal permeability, systemic microbial translocation, and inflammation during pregnancy.

Morphine Potentiates Dysbiotic Microbial and Metabolic Shifts in Acute SIV Infection

Human Immunodeficiency Virus (HIV) pathogenesis has been closely linked with microbial translocation, which is believed to drive inflammation and HIV replication. Opioid drugs have been shown to worsen this symptom, leading to a faster progression of HIV infection to Acquired Immunodeficiency Syndrome (AIDS). The interaction of HIV and opioid drugs has not been studied at early stages of HIV, particularly in the gut microbiome where changes may precede translocation events. This study modeled early HIV infection by examining Simian Immunodeficiency Virus (SIV)-infected primates at 21 days or less both independently and in the context of opioid use. Fecal samples were analyzed both for 16S analysis of microbial populations as well as metabolite profiles via mass spectrometry. Our results indicate that changes are minor in SIV treated animals in the time points examined, however animals treated with morphine and SIV had significant changes in their microbial communities and metabolic profiles. This occurred in a time-independent fashion with morphine regardless of how long the animal had morphine in its system. Globally, the observed changes support that microbial dysbiosis is occurring in these animals at an early time, which likely contributes to the translocation events observed later in SIV/HIV pathogenesis. Additionally, metabolic changes were predictive of specific treatment groups, which could be further developed as a diagnostic tool or future intervention target to overcome and slow the progression of HIV infection to AIDS.

Fungal Translocation Is Associated with Immune Activation and Systemic Inflammation in Treated HIV

The mechanisms causing HIV-associated immune activation remain incompletely understood. Alteration of intestinal integrity with subsequent translocation of bacterial products appears to play an important role; however, little is known about the impact of fungal translocation. We assessed the effect of fungal translocation and its association with immune activation in people living with HIV (PLWH) compared with uninfected controls. We measured serum levels of β-D-glucan (BDG) and anti-Saccharomyces cerevisiae antibodies (ASCA) immunoglobulin G (IgG) and immunoglobulin A (IgA) and markers of systemic inflammation and immune activation in virally suppressed PLWH on antiretroviral therapy (ART) and uninfected controls. T-test and Mann-Whitney tests were used to compare markers by HIV status and correlation and regression analyses were used to assess associations of fungal translocation markers with markers of inflammation. One hundred seventy-six participants were included (128 HIV+ and 48 HIV-); 72% male, 65% African American, median age was 50 years, and CD4 was 710 cells/cm³. Levels of BDG tended to be lower in HIV+ when compared with controls (p = .05). No significant difference in levels of ASCA IgG and IgA was seen between groups (p > .75). There was a significant correlation between BDG and several markers of inflammation and immune activation in PLWH, not seen in uninfected controls. In contrast, no correlations were seen between levels of ASCA IgG and IgA with inflammatory markers. PLWH on ART do not have higher levels of BDG or ASCA when compared with uninfected controls, however, the association found between BDG and several inflammation markers suggests a potential role of fungal translocation in the heightened immune activation seen in treated HIV.

Microbial Translocation and Immune Activation in HIV-1 Infected Pregnant Women

BACKGROUND

Immune Activation (IA) has been previously documented in both pregnant (PG) and non-PG HIV-1 infected (HIV+) women as well as in HIV- uninfected PG women; the latter as a result of the fetal allograft. To determine whether the combined effects of HIV and pregnancy result in increased IA and whether IA is associated with Microbial Translocation (MT), we performed a prospective, longitudinal, controlled study during pregnancy and the postpartum (PP) period.

METHODS

HIV+ PG women had biomarkers of IA and MT tested at 12-20 weeks (T1), and 24-36 weeks (T2) of pregnancy and at 6-8 weeks Postpartum (T3). HIV+, non-PG women were tested at comparable time points. HIV- PG women were tested at T1 only. HIV+ women were not started on antiretroviral therapy (ART) until T1. Biomarkers of IA assessed included: CD4DR+, CD4CD38+, CD4DR+CD38+, CD8DR+, CD8CD38+, and CD8DR+CD38+. Biomarkers of MT included LPS, sCD14, and 16SrDNA.

RESULTS

30 HIV+PG women, 18 HIV+ non-PG and 10 HIV-PG were enrolled. In the HIV+ women, there were no differences in median age, viral load, % or absolute CD4 at entry. Significant differences between T1 and T2 and between T1 and T3 were noted in CD8DR+CD38+ in HIV+PG women after ART. CD4DR+, CD4DR+CD38+, and CD8DR+ decreased post ART in HIV+PG women but a decline in IA was less evident in HIV+ non-PG. LPS decreased post ART by T3 in both HIV+PG and HIV+ non-PG groups; 16SrDNA was elevated at all time points in both groups when compared to control values, and declined post ART in the HIV+PG group. A subgroup of HIV-PG at T1 had IA and MT as evidenced by several IA markers and increased LPS.

CONCLUSION

The degree of IA and MT was similar among HIV+PG and HIV+ non-PG women followed longitudinally. There was no incremental increase due to the combined effects of HIV and pregnancy. Several markers of IA and MT (LPS, 16SrDNA) decreased post ART. IA and MT occurred in a subgroup of HIV-PG women during the 1st trimester. Further study must be done to confirm whether MT consistently occurs in some healthy women during PG.

Biomarkers of aging in HIV: inflammation and the microbiome

PURPOSE

HIV-infected subjects present increased levels of inflammatory cytokines and T cell activation in the peripheral blood despite suppressive combination antiretroviral therapy which renders them susceptible to premature aging. The purpose of the present work was to review existing evidence on the ways in which the anatomical and microbiological abnormalities of the gastrointestinal tract can represent a major cause of organ disease in HIV infection.

METHODS

We conducted a systematic review of the Pubmed database for articles published from 2014 to 2018. We included studies on inflammatory/activation biomarkers associated with cardiovascular and bone disease, neurocognitive impairment and serious non-AIDS events in HIV-infected subjects. We also included researches which linked peripheral inflammation/activation to the anatomical, immune and microbiological alterations of the gastrointestinal tract.

RESULTS

Recent literature data confirm the association between non-infectious comorbidities and inflammation in HIV infection which may be driven by gastrointestinal tract abnormalities, specifically microbial translocation and dysbiosis. Furthermore, there is mounting evidence on the possible role of metabolic functions of the microbiota in the pathogenesis of premature aging in the HIV-infected population.

CONCLUSIONS

Biomarkers need to be validated for their use in the management of HIV infection. Compounds which counteract microbial translocation, inflammation and dysbiosis have been investigated as alternative therapeutic strategies in viro-suppressed HIV-infected individuals, but appear to have limited efficacy, probably due to the multifactorial pathogenesis of non-infectious comorbidities in this setting.

TLR9 polymorphism correlates with immune activation, CD4 decline and plasma IP10 levels in HIV patients

Background

The mechanism behind HIV mediated immune activation remains debated, although the role of virus replication in this process is increasingly evident. Toll like Receptor 9 (TLR9) has been implicated in HIV mediated immune activation via sensing of viral CpG DNA. Polymorphisms in the TLR9 gene and promoter region including TLR9 1635A/G and 1486C/T have been found to be associated with multiple infectious diseases and cancers.

Methods

In the current study, we looked at the correlation of TLR9 polymorphisms 1635A/G and 1486C/T with key hallmarks of HIV disease in a cohort of 50 HIV infected patients. We analyzed CD4 counts, T cell immune activation characterized by upregulation of CD38 and HLA-DR and upregulation of plasma biomarkers of inflammation like LPS, sCD14, IL-6 and IP10 in the HIV patient cohort and compared it to healthy controls.

Results

We found that TLR9 1635AA genotype was associated with lower CD4 counts and significantly higher immune activation in both CD4+ and CD8+ T cells. Analysis of HIV associated plasma biomarkers including LPS, sCD14, IL-6 and IP10 revealed a strong correlation between IP10 and immune activation. Interestingly, IP10 levels were also found to be higher in HIV patients with the 1635AA genotype. Furthermore, the TLR9 1486C/T polymorphism that is in linkage disequilibrium with 1635A/G was weakly associated with lower CD4 counts, higher CD8 immune activation and higher IP10 levels.

Conclusions

As TLR9 stimulation is known to induce IP10 production by dendritic cells, our findings provide new insights into HIV mediated immune activation and CD4 loss. TLR9 stimulation by viral CpG DNA may be important to HIV immunopathogenesis and the TLR9 polymorphisms 1635A/G and 1486C/T may be associated with disease progression.

Microbial Translocation Does Not Drive Immune Activation in Ugandan Children Infected With HIV

Objective

Immune activation is associated with morbidity and mortality during human immunodeficiency virus (HIV) infection, despite receipt of antiretroviral therapy (ART). We investigated whether microbial translocation drives immune activation in HIV-infected Ugandan children.

Methods

Nineteen markers of immune activation and inflammation were measured over 96 weeks in HIV-infected Ugandan children in the CHAPAS-3 Trial and HIV-uninfected age-matched controls. Microbial translocation was assessed using molecular techniques, including next-generation sequencing.

Results

Of 249 children included, 142 were infected with HIV; of these, 120 were ART naive, with a median age of 2.8 years (interquartile range [IQR], 1.7-4.0 years) and a median baseline CD4+ T-cell percentage of 20% (IQR, 14%-24%), and 22 were ART experienced, with a median age of 6.5 years (IQR, 5.9-9.2 years) and a median baseline CD4+ T-cell percentage of 35% (IQR, 31%-39%). The control group comprised 107 children without HIV infection. The median increase in the CD4+ T-cell percentage was 17 percentage points (IQR, 12-22 percentage points) at week 96 among ART-naive children, and the viral load was <100 copies/mL in 76% of ART-naive children and 91% of ART-experienced children. Immune activation decreased with ART use. Children could be divided on the basis of immune activation markers into the following 3 clusters: in cluster 1, the majority of children were HIV uninfected; cluster 2 comprised a mix of HIV-uninfected children and HIV-infected ART-naive or ART-experienced children; and in cluster 3, the majority were ART naive. Immune activation was low in cluster 1, decreased in cluster 3, and persisted in cluster 2. Blood microbial DNA levels were negative or very low across groups, with no difference between clusters except for Enterobacteriaceae organisms (the level was higher in cluster 1; P < .0001).

Conclusion

Immune activation decreased with ART use, with marker clustering indicating different activation patterns according to HIV and ART status. Levels of bacterial DNA in blood were low regardless of HIV status, ART status, and immune activation status. Microbial translocation did not drive immune activation in this setting.

Clinical Trials Registration

ISRCTN69078957.

Applications of liquid biopsy in lung cancer-diagnosis, prognosis prediction, and disease monitoring

Lung cancer is the most common cancer in both the developing and developed countries, which has an unoptimistic outcome. As a result of high rates in mortality and considerable difficulties in treatment, early detection of lung cancer is thought as one of the potential solutions for this stigma. Tissue biopsy has been widely used for cancer diagnosis, but the invasive nature limits their application, especially when repeated biopsies are needed. Liquid biopsy, a minimally invasive procedure aiming to primarily analyze circulating tumor cells (CTCs) and/or circulating tumor DNA (ctDNA) for diagnosing and profiling cancer, has gained interest from oncologists and basic researchers. A great number of achievements in the field of liquid biopsy has been developed, thus liquid biopsy is more feasible in clinical practice than before. More importantly, liquid biopsy is being used, in addition to the diagnosis of lung cancer, to predict prognosis according to genetic alterations and monitor disease based on signature molecular markers. In this review, we briefly summarize techniques in liquid biopsy and focus on its applications in disease diagnosis, prognosis prediction, and condition monitoring of lung cancer.

I-FABP Is Higher in People With Chronic HIV Than Elite Controllers, Related to Sugar and Fatty Acid Intake and Inversely Related to Body Fat in People With HIV

Background

Intestinal fatty acid binding protein (I-FABP) has been shown to be a marker of intestinal damage among people living with HIV. We hypothesized that I-FABP would be increased in chronically HIV-infected patents more than elite controllers and would relate to specific nutrient intake and body composition.

Methods

In an observational study, serum I-FABP was measured by enzyme-linked immunosorbent assay. Anthropometric measurements, dual-energy x-ray absorptiometry, and single-slice abdominal computed tomography were obtained to assess body composition, as well as visceral and subcutaneous adipose tissue areas (VAT and SAT). Dietary intake was assessed using 4-day food records.

Results

One hundred forty-nine people with chronic HIV (65% male, 47 ± 7 years of age, 54.7% white, and 14 ± 6 years of known HIV), 10 elite controllers (60% male, 53 ± 8 years, 60% white, and 20 ± 7 years of known HIV), and 69 HIV-negative controls (59.4% male, 46 ± 7 years, and 52.2% white) were included in the analysis. I-FABP was significantly higher in HIV progressors relative to HIV-negative controls and elite controllers. In the chronic HIV group, I-FABP was positively associated with dietary intake of added sugar and with saturated fatty acids. I-FABP was inversely associated with body mass index, VAT, and SAT. I-FABP also correlated with MCP-1, CXCL10, sCD163, and lipopolysaccharide (LPS) among all participants.

Conclusions

I-FABP was increased among chronically HIV-infected patients to a greater degree than in elite controllers and was related to nutrient intake and body composition in HIV progressors. Future studies to investigate the role of intestinal damage on nutrient absorption are needed to elucidate the mechanisms of these relationships.

Trial Registration Identifier

NCT00455793.

Prevalence, incidence, predictors, treatment, and control of hypertension among HIV-positive adults on antiretroviral treatment in public sector treatment programs in South Africa

BACKGROUND

One of the key risk factors for cardiovascular disease is hypertension. Hypertension, which leads to heart attacks and strokes, already affects one billion people worldwide, making it a global public health issue. Incidence and prevalence of the condition is on the rise in low- and middle-income countries, with the biggest increase in sub-Saharan Africa and South Africa at the forefront. We examined the prevalence, incidence, predictors, treatment, and control of hypertension among HIV-positive patients on ART in a large South African observational cohort.

METHODS

We conducted a prospective study of ART naïve adults initiating ART at a public sector HIV clinic in South Africa between April 2004-2017. Patients with diagnosed hypertension at ART initiation were excluded from the incidence analysis. Log-binomial regression was used to estimate predictors of hypertension at ART initiation, while competing risks regression was used to evaluate the relationship between predictors of incident hypertension, accounting for death as a competing risk.

RESULTS

Among 77,696 eligible patients, 22.0% had prevalent hypertension at ART initiation. Of the remaining patients with no hypertension at ART initiation, 8,125 incident hypertension cases were diagnosed over the period of follow-up, corresponding to an incident rate of 5.4 per 100 person-years (95% confidence interval (CI): 5.3-5.6). We found patients ≥40 years of age and patients with a body mass index (BMI) ≥25kg/m2 were at increased risk of both prevalent and incident hypertension. Male patients and those with pre-hypertension at ART initiation had increased hazards of hypertension over the period of follow-up. When assessing the choice of antiretroviral drug in first-line ART, patients initiated on nevirapine were at 27% increased risk of developing hypertension compared to those initiated on efavirenz, while patients who initiated on either zidovudine or stavudine had a 40% increased risk of developing hypertension compared to patients initiated on tenofovir. Patientswith poorer health status at ART initiation (i.e. WHO III/IV stage, low CD4 count, low hemoglobin levels and low BMI) had a decrease risk of prevalent hypertension. We found an inverse relationship in patients with a CD4 count <50 cells/mm3 at ART initiation who had a 25% increased risk of incident hypertension compared to those with a CD4 count ≥350 cells/mm3.

CONCLUSION

Over 20% of patients in our cohort had hypertension at ART initiation, and 13% of those with normal blood pressure at ART initiation developed hypertension while on ART. Older patients, males, those on nevirapine, zidovudine or stavudine, and those who are overweight/obese should be targeted for frequent blood pressure monitoring and the identification of other cardiovascular risk factors to encourage lifestyle modifications. Additionally, these groups should be offered pharmaceutical therapy to help prevent myocardial infarction, heart failure, stroke, and kidney disease. Further research is needed to determine the level of access and adherence to pharmaceutical treatment for hypertension in this population. Additionally, an HIV-negative comparison population is needed to assess the association of the HIV virus itself with hypertension.

Intestinal macrophages in mucosal immunity and their role in systemic lupus erythematosus disease

Monocytes play an important role in inducing host systemic immunity against invading pathogens and inflammatory responses. After activation, monocytes migrate to tissue sites, where they initiate both innate and adaptive immune responses, and become macrophages. Although mucosal macrophages produce inflammatory cytokines in response to pathogens, the perturbations in innate immune signaling pathway have been implicated in autoimmune diseases such as systemic lupus erythematosus (SLE). In this review, we focus on the role of human macrophages in intestinal innate immune responses, homeostasis, and SLE disease. We further discuss sex differences in the intestinal macrophages and their role in the physiology and pathogenesis of SLE.

HIV infection and care pathway: From guidelines to clinical practice

OBJECTIVES

To quantify within a cohort of HIV-infected individuals the number of medical visits and procedures to be carried out according to comorbidities and risk factors to implement a personalized care pathway.

PATIENTS AND METHODS

Retrospective study of 915 patients consulting from January 1 to December 31, 2016 at an outpatient unit of multidisciplinary consultations, using an electronic patient record. We built an algorithm using parameters required for the application of the national guidelines for the management of HIV-infected individuals. The frequency of comorbidities was measured according to gender, transmission risk group, and nadir CD4 (<or>200/mm³).

RESULTS

Patients were mostly men (median age: 52 years), of whom 16% were aged≥60 years. Viral load was<40 copies/mL in 93.5% of treated patients and CD4 cell count≥500/mm³ for 73%. Overall, 74.5% of patients had at least one comorbidity. The number of comorbidities was similar in men and women but was significantly higher in patients with a nadir CD4 <200/mm3 and increased with age (irrespective of gender). The minimum number of consultations to be scheduled per year was 8123: 70% for the management of comorbidities with an average of six consultations/year/patient. Overall, 53% of patients should attend a proctology consultation. The minimum number of paramedical procedures to be performed was 5115.

CONCLUSION

The implementation of a personalized multidisciplinary management within a single facility seems to be a suitable care model to address the needs of HIV-infected individuals.

Distinct systemic microbiome and microbial translocation are associated with plasma level of anti-CD4 autoantibody in HIV infection

Microbial signals have been linked to autoantibody induction. Recently, we found that purified anti-CD4 autoantibodies from the plasma of chronic HIV-1-infected patients under viral-suppressed antiretroviral therapy (ART) play a pathologic role in poor CD4+ T cell recovery. The purpose of the study was to investigate the association of systemic microbiome and anti-CD4 autoantibody production in HIV. Plasma microbiome from 12 healthy controls and 22 HIV-infected subjects under viral-suppressed ART were analyzed by MiSeq sequencing. Plasma level of autoantibodies and microbial translocation (LPS, total bacterial 16S rDNA, soluble CD14, and LPS binding protein) were analyzed by ELISA, limulus amebocyte assay, and qPCR. We found that plasma level of anti-CD4 IgGs but not anti-CD8 IgGs was increased in HIV+ subjects compared to healthy controls. HIV+ subjects with plasma anti-CD4 IgG > 50 ng/mL (high) had reduced microbial diversity compared to HIV+ subjects with anti-CD4 IgG ≤ 50 ng/mL (low). Moreover, plasma anti-CD4 IgG level was associated with elevated microbial translocation and reduced microbial diversity in HIV+ subjects. The Alphaproteobacteria class was significantly enriched in HIV+ subjects with low anti-CD4 IgG compared to patients with high anti-CD4 IgG even after controlling for false discovery rate (FDR). The microbial components were different from the phylum to genus level in HIV+ subjects with high anti-CD4 IgGs compared to the other two groups, but these differences were not significant after controlling for FDR. These results suggest that systemic microbial translocation and microbiome may associate with anti-CD4 autoantibody production in ART-treated HIV disease.

Enhanced preservation of the human intestinal microbiota by ridinilazole, a novel Clostridium difficile-targeting antibacterial, compared to vancomycin

Ridinilazole, a novel targeted antibacterial being developed for the treatment of C. difficile infection (CDI) and prevention of recurrence, was shown in a recent Phase 2 study to be superior to vancomycin with regard to the primary efficacy measure, sustained clinical response (SCR), with the superiority being driven primarily by marked reductions in the rates of CDI recurrence within 30 days. Tolerability of ridinilazole was comparable to that of vancomycin. The current nested cohort study compared the effects of ridinilazole and vancomycin on fecal microbiota during and after treatment among participants in the Phase 2 study. Changes in the microbiota were assessed using qPCR and high-throughput sequencing on participants' stools collected at multiple time-points (baseline [Day 1], Day 5, end-of-treatment [EOT; Day 10], Day 25, end-of-study [EOS; Day 40], and at CDI recurrence). qPCR analyses showed profound losses of Bacteroides, C. coccoides, C. leptum, and Prevotella groups at EOT with vancomycin treatment, while ridinilazole-treated participants had a modest decrease in C. leptum group levels at EOT, with levels recovering by Day 25. Vancomycin-treated participants had a significant increase in the Enterobacteriaceae group, with this increase persisting beyond EOT. At EOT, alpha diversity decreased with both antibiotics, though to a significantly lesser extent with ridinilazole (p <0.0001). Beta diversity analysis showed a significantly larger weighted Unifrac distance from baseline-to-EOT with vancomycin. Taxonomically, ridinilazole had a markedly narrower impact, with modest reductions in relative abundance in Firmicutes taxa. Microbiota composition returned to baseline sooner with ridinilazole than with vancomycin. Vancomycin treatment resulted in microbiome-wide changes, with significant reductions in relative abundances of Firmicutes, Bacteroidetes, Actinobacteria, and a profound increase in abundance of Proteobacteria. These findings demonstrate that ridinilazole is significantly less disruptive to microbiota than vancomycin, which may contribute to the reduced CDI recurrence observed in the Phase 2 study.

Microbial translocation: translating simian immunodeficiency virus to HIV

PURPOSE OF REVIEW

The article describes recent advances in understanding the causes and consequences of microbial translocation in HIV and simian immunodeficiency virus infections.

RECENT FINDINGS

Persistent microbial translocation contributes to aberrant immune activation in immunodeficiency lentiviral infections and thereby, pathogenesis and mortality. Efforts to delineate the circumstances surrounding translocation have benefited from use of simian immunodeficiency virus-infected nonhuman primates and highlight the overwhelming immunologic diversion caused by translocating microbes. The use of therapeutics aimed at reducing microbial translocation show promise and will benefit from continued research into the mechanisms that promote systemic microbial dissemination in treated and untreated infections.

SUMMARY

Insights into the source and identity of translocating microbes in lentiviral infections continue to enhance the development of adjunct therapeutics.

Nonhuman primate models of human viral infections

Humans have a close phylogenetic relationship with nonhuman primates (NHPs) and share many physiological parallels, such as highly similar immune systems, with them. Importantly, NHPs can be infected with many human or related simian viruses. In many cases, viruses replicate in the same cell types as in humans, and infections are often associated with the same pathologies. In addition, many reagents that are used to study the human immune response cross-react with NHP molecules. As such, NHPs are often used as models to study viral vaccine efficacy and antiviral therapeutic safety and efficacy and to understand aspects of viral pathogenesis. With several emerging viral infections becoming epidemic, NHPs are proving to be a very beneficial benchmark for investigating human viral infections.