Systemic effects of inflammation on health during chronic HIV infection

Comparing the care needs of people living with and without HIV in Canadian home and long-term care settings

Background

With the advent of highly active antiretroviral therapy (HAART), HIV has become a manageable chronic infection and individuals with it are living longer. Older individuals with HIV will begin to seek services across the continuum of health care. Whether their care needs differ from those who are HIV negative has not been well-characterized.

Objectives

To compare the demographic characteristics, chronic conditions, presence of infections, and mental health issues among HIV-positive versus HIV-negative individuals in home care, long-term care and complex continuing care settings across Canada.

Methods

This cross-sectional study used interRAI data to compare characteristics of HIV-positive and HIV-negative individuals in long-term care, complex continuing care and home care settings. Chi-square analyses explored differences between groups on co-infections, chronic disease and mental health issues.

Results

Data from 1,200,073 people were analyzed of whom 1,608 (0.13%) had HIV. Overall, HIV-positive individuals had more co-infections but fewer chronic diseases than their HIV-negative counterparts. Depression, social isolation and the use of psychotropic medications were generally more prevalent in the HIV-positive cohort.

Conclusion

People living with HIV make up a small cohort of people with complex needs in home care and institutional settings and their care needs differ from those who are HIV negative. As HIV-positive people age, a better understanding of the context in which these issues are experienced will support appropriate interventions.

Human immunodeficiency virus-associated disruption of mucosal barriers and its role in HIV transmission and pathogenesis of HIV/AIDS disease

Oral, intestinal and genital mucosal epithelia have a barrier function to prevent paracellular penetration by viral, bacterial and other pathogens, including human immunodeficiency virus (HIV). HIV can overcome these barriers by disrupting the tight and adherens junctions of mucosal epithelia. HIV-associated disruption of epithelial junctions may also facilitate paracellular penetration and dissemination of other viral pathogens. This review focuses on possible molecular mechanisms of HIV-associated disruption of mucosal epithelial junctions and its role in HIV transmission and pathogenesis of HIV and acquired immune deficiency syndrome (AIDS).

Soluble endothelial protein C receptor (sEPCR) as an inflammatory biomarker in naive HIV-infected patients during ART

BACKGROUND

After the advent of ART, non-AIDS-related comorbidities are the main causes of death in HIV patients. Multiple biomarkers have been studied as markers of disease. We wanted to test soluble endothelial protein C receptor (sEPCR) in an HIV setting.

OBJECTIVES

The primary objective was to determine whether sEPCR decreases after 48 weeks of ART in naive HIV patients. Secondary objectives were to compare sEPCR levels between patients with chronic HIV infection (CHI) and primary HIV infection (PHI) and to analyse if there is a correlation between sEPCR and both immunovirological parameters and different markers of inflammation.

PATIENTS AND METHODS

We analysed sEPCR in 33 patients with CHI and 19 patients with PHI naive to ART. sEPCR was compared together with immunovirological parameters (HIV RNA and CD4 cell count) and IL-6 or D-dimer (DD).

RESULTS AND CONCLUSIONS

After 48 weeks of ART, in CHI, the sEPCR decrease was significant (P = 0.0006) and sEPCR at baseline was correlated with both CD4 cell increase (r = +0.463, P = 0.007) and HIV RNA decrease (r = -0.363, P = 0.038). In PHI, sEPCR was stable (P = 0.35); there was a correlation between 48 week DD change and IL-6 change (r = +0.696, P = 0.0009) and also between 48 week DD change and sEPCR change (r = +0.553, P = 0.014). Despite the small sample size, we hypothesize that sEPCR levels reflect coagulant pathway activation caused by the endothelial damage during chronic infection more than a marker of the cytokine storm that occurs during PHI. Alternatively, in PHI, the link found between sEPCR and DD secondary to IL-6 suggests sEPCR is an indirect marker of inflammation.

Untangling the Gordian knot of HIV, stress, and cognitive impairment

As individuals live longer with HIV, this "graying of the HIV epidemic" has introduced a new set of challenges including a growing number of age and inflammation-related diseases such as cardiovascular disease, type II diabetes, cancer, and dementia. The biological underpinnings of these complex and co-morbid diseases are not fully understood and become very difficult to disentangle in the context of HIV and aging. In the current review we examine the contributions and interactions of HIV, stress, and cognitive impairment and query the extent to which inflammation is the linchpin in these dynamic interactions. Given the inter-relatedness of stress, inflammatory mechanisms, HIV, and cognitive impairment, future work will either need to address multiple dimensions simultaneously or embrace the philosophy that breaking the aberrant cycle at any one point will subsequently remedy the other related systems and processes. Such a single-point intervention may be effective in early disease states, but after perpetuation of an aberrant cycle, adaptations in an attempt to internally resolve the issue will likely lead to the need for multifaceted interventions. Acknowledging that HIV, inflammation, and stress may interact with one another and collectively impact cognitive ability is an important step in fully understanding an individual's complete clinical picture and moving towards personalized medicine.

Reduced Levels of D-dimer and Changes in Gut Microbiota Composition After Probiotic Intervention in HIV-Infected Individuals on Stable ART

BACKGROUND

Microbial translocation and chronic inflammation may contribute to non-AIDS morbidity in patients with HIV. This study assessed the impact of probiotic intervention on microbial translocation and inflammation in patients on antiretroviral therapy with viral suppression and subnormal CD4 count.

METHODS

Thirty-two patients receiving antiretroviral therapy (CD4 <500 cells/μL) were randomized in a double-blind fashion to multistrain daily probiotics (n = 15), placebo (n = 9), or controls (n = 8) for 8 weeks. Soluble inflammation markers, D-dimer, lipopolysaccharide (LPS), sCD14, T-cell activation, tryptophan metabolites, and gut microbiota composition were analyzed at baseline and end of study. Nonparametric statistics were applied.

RESULTS

Twenty-four participants completed the study and were included in as-treated analyses. In patients receiving probiotics, there was a significant reduction in D-dimer levels (median change 33%, P = 0.03) and a tendency to reduced levels of C-reactive protein (CRP) (P = 0.05) and interleukin (IL)-6 (P = 0.06). The changes in CRP and IL-6 were highly correlated (r = 0.95, P < 0.01), whereas changes in D-dimer did not correlate with changes in CRP or IL-6. Increases in Bifidobacteria (P = 0.04) and Lactobacilli (P = 0.06) were observed in the probiotic group, whereas the relative abundance of Bacteroides decreased (P ≤ 0.01). No significant changes were seen in markers of microbial translocation or T-cell activation. However, the expansion of Bifidobacteria correlated negatively with differences in LPS (r = -0.77, P = 0.01), whereas the reduction in Bacteroides correlated positively with changes in LPS during the study period (r = 0.72, P = 0.02).

CONCLUSIONS

Probiotic intervention seemed to reduce markers of coagulation and inflammation without overt changes in microbial translocation. These findings warrant further studies in larger cohorts with long-term follow-up.

Loss of Function of Intestinal IL-17 and IL-22 Producing Cells Contributes to Inflammation and Viral Persistence in SIV-Infected Rhesus Macaques

In HIV/SIV-infected humans and rhesus macaques (RMs), a severe depletion of intestinal CD4(+) T-cells producing interleukin IL-17 and IL-22 associates with loss of mucosal integrity and chronic immune activation. However, little is known about the function of IL-17 and IL-22 producing cells during lentiviral infections. Here, we longitudinally determined the levels and functions of IL-17, IL-22 and IL-17/IL-22 producing CD4(+) T-cells in blood, lymph node and colorectum of SIV-infected RMs, as well as how they recover during effective ART and are affected by ART interruption. Intestinal IL-17 and IL-22 producing CD4(+) T-cells are polyfunctional in SIV-uninfected RMs, with the large majority of cells producing four or five cytokines. SIV infection induced a severe dysfunction of colorectal IL-17, IL-22 and IL-17/IL-22 producing CD4(+) T-cells, the extent of which associated with the levels of immune activation (HLA-DR(+)CD38(+)), proliferation (Ki-67+) and CD4(+) T-cell counts before and during ART. Additionally, Th17 cell function during ART negatively correlated with residual plasma viremia and levels of sCD163, a soluble marker of inflammation and disease progression. Furthermore, IL-17 and IL-22 producing cell frequency and function at various pre, on, and off-ART experimental points associated with and predicted total SIV-DNA content in the colorectum and blood. While ART restored Th22 cell function to levels similar to pre-infection, it did not fully restore Th17 cell function, and all cell types were rapidly and severely affected--both quantitatively and qualitatively--after ART interruption. In conclusion, intestinal IL-17 producing cell function is severely impaired by SIV infection, not fully normalized despite effective ART, and strongly associates with inflammation as well as SIV persistence off and on ART. As such, strategies able to preserve and/or regenerate the functions of these CD4(+) T-cells central for mucosal immunity are critically needed in future HIV cure research.

Curing HIV: Moving Forward Faster

There is enormous enthusiasm in the scientific community for finding a cure for HIV. Although much remains to be discovered regarding the mechanisms of viral persistence and how it may be disrupted, some assumptions regarding the goals of a cure, applicability to target populations, and what is required of the assays we employ, may lead to missed opportunities and discoveries and hamper the discovery of a product that will safely cure tens of millions of HIV-infected people around the world. The field will benefit from an awareness and critical interrogation of assumptions that may be implicit in their scientific pursuits.

Animal Models for HIV Cure Research

The HIV-1/AIDS pandemic continues to spread unabated worldwide, and no vaccine exists within our grasp. Effective antiretroviral therapy (ART) has been developed, but ART cannot clear the virus from the infected patient. A cure for HIV-1 is badly needed to stop both the spread of the virus in human populations and disease progression in infected individuals. A safe and effective cure strategy for human immunodeficiency virus (HIV) infection will require multiple tools, and appropriate animal models are tools that are central to cure research. An ideal animal model should recapitulate the essential aspects of HIV pathogenesis and associated immune responses, while permitting invasive studies, thus allowing a thorough evaluation of strategies aimed at reducing the size of the reservoir (functional cure) or eliminating the reservoir altogether (sterilizing cure). Since there is no perfect animal model for cure research, multiple models have been tailored and tested to address specific quintessential questions of virus persistence and eradication. The development of new non-human primate and mouse models, along with a certain interest in the feline model, has the potential to fuel cure research. In this review, we highlight the major animal models currently utilized for cure research and the contributions of each model to this goal.

Antiretroviral therapy induces a rapid increase in bone resorption that is positively associated with the magnitude of immune reconstitution in HIV infection

OBJECTIVE

Antiretroviral therapy (ART) paradoxically intensifies bone loss in the setting of HIV infection. Although the extent of bone loss varies, it occurs with virtually all ART types, suggesting a common pathway that may be aligned with HIV disease reversal. Using an animal model of immunodeficiency we recently demonstrated that immune activation associated with CD4 T-cell reconstitution induces increased production of the osteoclastogenic cytokines RANKL and TNFα by immune cells, driving enhanced bone resorption and loss in bone mineral density.

DESIGN

To confirm these findings in humans, we investigated the early kinetics of CD4 T-cell recovery in relation to biomarkers of bone turnover and osteoclastogenic regulators in a prospective 24-week cohort study.

METHODS

Clinical data and blood sampling for HIV-RNA PCR, CD4 T-cell counts, bone turnover biomarkers, and osteoclastogenic regulators were obtained from ART-naïve HIV-infected study participants initiating standard doses of lopinavir/ritonavir plus tenofovir disoproxil fumarate/emtricitabine at baseline and at weeks 2, 8, 12, and 24 post ART.

RESULTS

C-terminal telopeptide of collagen (CTx) a sensitive biomarker of bone resorption rose by 200% above baseline at week 12, remaining elevated through week 24 (α<0.01), and was associated with significant increases in plasma levels of osteoclastogenic regulators [receptor activator of NF-kB ligand (RANKL), tumor necrosis factor alpha, (TNFα)]. Importantly, the magnitude of CD4 T-cell recovery correlated significantly with CTx (rs = 0.387, α=0.01).

CONCLUSION

Our data suggest that ART-induced bone loss occurs early, is aligned with early events of immune reconstitution, and these immune changes provide a unifying mechanism to explain in part the skeletal decline common to all ART.

Elevated Abundance, Size, and MicroRNA Content of Plasma Extracellular Vesicles in Viremic HIV-1+ Patients: Correlations With Known Markers of Disease Progression

BACKGROUND

Because of factors only partly understood, the generalized elevated immune activation and inflammation characterizing HIV-1-infected patients are corrected incompletely with antiretroviral therapy (ART). Extracellular vesicles (EVs) including exosomes and microvesicles released by several cell types may contribute to immune activation and dysfunction. EV size, abundance, and content appear to differ according to infection phase, disease progression, and ART.

METHODS

We examined whether the size of EVs and the abundance of exosomes in plasma are associated with cell and tissue activation as well as with viral production. Acetylcholinesterase-bearing (AChE+) exosomes in plasma were quantified using an AChE assay. EV size was analyzed using dynamic light scattering. Proteins and microRNAs present in EVs were detected by Western blot and real-time polymerase chain reaction, respectively.

RESULTS

Exosomes were found more abundant in the plasma of ART-naive patients. EV size was larger in ART-naive than in ART-suppressed patients, elite controllers, or healthy control subjects. Both exosome abundance and EV sizes were inversely correlated with CD4/CD8 T-cell ratio and neutrophil, platelet, and CD4 T-cell counts and positively correlated with CD8 T-cell counts. A negative correlation was found between CD4 T-cell nadir and exosome abundance, but not EV size. Levels of miR-155 and miR-223 but not miR-92 were strongly correlated negatively with EV abundance and size in ART-naive patients.

CONCLUSIONS

Monitoring of circulating EVs and EV-borne microRNA is possible and may provide new insight into HIV-1 pathogenesis, disease progression, and the associated inflammatory state, as well as the efficacy of ART and the treatments intended to reduce immune activation.

Effects of Combined CCR5/Integrase Inhibitors-Based Regimen on Mucosal Immunity in HIV-Infected Patients Naïve to Antiretroviral Therapy: A Pilot Randomized Trial

Whether initiation of antiretroviral therapy (ART) regimens aimed at achieving greater concentrations within gut associated lymphoid tissue (GALT) impacts the level of mucosal immune reconstitution, inflammatory markers and the viral reservoir remains unknown. We included 12 HIV- controls and 32 ART-naïve HIV patients who were randomized to efavirenz, maraviroc or maraviroc+raltegravir, each with fixed-dose tenofovir disoproxil fumarate/emtricitabine. Rectal and duodenal biopsies were obtained at baseline and at 9 months of ART. We performed a comprehensive assay of T-cell subsets by flow cytometry, T-cell density in intestinal biopsies, plasma and tissue concentrations of antiretroviral drugs by high-performance liquid chromatography/mass spectroscopy, and plasma interleukin-6 (IL-6), lipoteichoic acid (LTA), soluble CD14 (sCD14) and zonulin-1 each measured by ELISA. Total cell-associated HIV DNA was measured in PBMC and rectal and duodenal mononuclear cells. Twenty-six HIV-infected patients completed the follow-up. In the duodenum, the quadruple regimen resulted in greater CD8+ T-cell density decline, greater normalization of mucosal CCR5+CD4+ T-cells and increase of the naïve/memory CD8+ T-cell ratio, and a greater decline of sCD14 levels and duodenal HIV DNA levels (P = 0.004 and P = 0.067, respectively), with no changes in HIV RNA in plasma or tissue. Maraviroc showed the highest drug distribution to the gut tissue, and duodenal concentrations correlated well with other T-cell markers in duodenum, i.e., the CD4/CD8 ratio, %CD4+ and %CD8+ HLA-DR+CD38+ T-cells. Maraviroc use elicited greater activation of the mucosal naïve CD8+ T-cell subset, ameliorated the distribution of the CD8+ T-cell maturational subsets and induced higher improvement of zonulin-1 levels. These data suggest that combined CCR5 and integrase inhibitor based combination therapy in ART treatment naïve patients might more effectively reconstitute duodenal immunity, decrease inflammatory markers and impact on HIV persistence by cell-dependent mechanisms, and show unique effects of MVC in duodenal immunity driven by higher drug tissue penetration and possibly by class-dependent effects.

Neurological immune reconstitution inflammatory response: riding the tide of immune recovery

PURPOSE OF REVIEW

This manuscript reviews current reports about clinical aspects of immune reconstitution inflammatory syndrome (IRIS), with a particular emphasis on IRIS in the setting of progressive multifocal leukoencephalopathy (PML) and to a lesser extent on cryptococcal meningitis and HIV.

RECENT FINDINGS

PML prognosis has been radically improved, as it has become possible to provide immune reconstitution, although some remaining morbidity and mortality results from excess inflammation. Similar pathologic responses are seen less often, but remain clinically important in cryptococcal meningitis, and HIV. Early diagnosis and active management of PML results in optimal outcomes with survival of 75% or higher in multiple recent series. These finding apply both to natalizumab and HIV-associated PML. Cryptococcal meningitis is frequently complicated by IRIS, and early treatment with antifungal therapy preceding HIV therapy provides optimal outcomes. HIV IRIS is reduced by early therapy, which is now recommended, but even on therapy, chronic dysregulated immune responses may play important roles in ongoing HIV-associated neurocognitive disease (HAND), which is common, as well as rare but more dramatic subacute encephalopathies.

SUMMARY

The clinician must actively monitor and treat both opportunistic infection and the inflammatory response that is essential to recovery but may itself augment disease and injury.

Antibiotic and Antiinflammatory Therapy Transiently Reduces Inflammation and Hypercoagulation in Acutely SIV-Infected Pigtailed Macaques

Increased chronic immune activation and inflammation are hallmarks of HIV/SIV infection and are highly correlated with progression to AIDS and development of non-AIDS comorbidities, such as hypercoagulability and cardiovascular disease. Intestinal dysfunction resulting in microbial translocation has been proposed as a lead cause of systemic immune activation and hypercoagulability in HIV/SIV infection. Our goal was to assess the biological and clinical impact of a therapeutic strategy designed to reduce microbial translocation through reduction of the microbial content of the intestine (Rifaximin-RFX) and of gut inflammation (Sulfasalazine-SFZ). RFX is an intraluminal antibiotic that was successfully used in patients with hepatic encephalopathy. SFZ is an antiinflammatory drug successfully used in patients with mild to moderate inflammatory bowel disease. Both these clinical conditions are associated with increased microbial translocation, similar to HIV-infected patients. Treatment was administered for 90 days to five acutely SIV-infected pigtailed macaques (PTMs) starting at the time of infection; seven untreated SIVsab-infected PTMs were used as controls. RFX+SFZ were also administered for 90 days to three chronically SIVsab-infected PTMs. RFX+SFZ administration during acute SIVsab infection of PTMs resulted in: significantly lower microbial translocation, lower systemic immune activation, lower viral replication, better preservation of mucosal CD4⁺ T cells and significantly lower levels of hypercoagulation biomarkers. This effect was clear during the first 40 days of treatment and was lost during the last stages of treatment. Administration of RFX+SFZ to chronically SIVsab–infected PTMs had no discernible effect on infection. Our data thus indicate that early RFX+SFZ administration transiently improves the natural history of acute and postacute SIV infection, but has no effect during chronic infection.

We report that administration of the intraluminal antibiotic Rifaximin and the gut-focused anti-inflammatory drug Sulfasalazine to acutely SIV-infected pigtailed macaques is associated with a transient disruption of the vicious circle of inflammation-microbial translocation-immune activation which is pathognomonic to pathogenic HIV/SIV infection and drives HIV disease progression and non-AIDS comorbidities in HIV-infected patients. This therapeutic approach resulted in transient lower microbial translocation, lower systemic immune activation, lower viral replication, better preservation of mucosal CD4⁺ T cells and lower levels of hypercoagulation biomarkers throughout acute SIV infection. Our results thus support the use of therapeutic approaches to reduce microbial translocation, improve the clinical outcome of HIV-infected patients receiving antiretroviral therapy and prevent non-AIDS comorbidities. Our results also reinforce the importance of early therapeutic management of HIV infection.

Using the pathogenic and nonpathogenic nonhuman primate model for studying non-AIDS comorbidities

With the advent of antiretroviral therapy that can control virus replication below the detection levels of conventional assays, a new clinical landscape of AIDS emerged, in which non-AIDS complications prevail over AIDS-defining conditions. These comorbidities are diverse and affect multiple organs, thus resulting in cardiovascular, kidney, neurocognitive and liver disease, osteopenia/osteoporosis, and cancers. A common feature of these conditions is that they are generally associated with accelerated aging. The mechanism behind these comorbidities is chronic excessive inflammation induced by HIV infection, which persists under antiretroviral therapy. Progressive simian immunodeficiency virus (SIV) infection of nonhuman primates (NHPs) closely reproduces these comorbidities and offers a simplified system in which most of the traditional human risk factors for comorbidities (i.e., smoking, hyperlipidemia) are absent. Additionally, experimental conditions can be properly controlled during a shorter course of disease for SIV infection. As such, NHPs can be employed to characterize new paradigms of AIDS pathogenesis and to test the efficacy of interventions aimed at alleviating non-AIDS-related comorbidities.

Increased levels of inflammatory cytokines in the female reproductive tract are associated with altered expression of proteases, mucosal barrier proteins, and an influx of HIV-susceptible target cells

Elevated inflammatory cytokines (EMCs) at mucosal surfaces have been associated with HIV susceptibility, but the underlying mechanisms remain unclear. We characterized the soluble mucosal proteome associated with elevated cytokine expression in the female reproductive tract. A scoring system was devised based on the elevation (upper quartile) of at least three of seven inflammatory cytokines in cervicovaginal lavage. Using this score, HIV-uninfected Kenyan women were classified as either having EMC (n=28) or not (n=68). Of 455 proteins quantified in proteomic analyses, 53 were associated with EMC (5% false discovery rate threshold). EMCs were associated with proteases, cell motility, and actin cytoskeletal pathways, whereas protease inhibitor, epidermal cell differentiation, and cornified envelope pathways were decreased. Multivariate analysis identified an optimal signature of 16 proteins that distinguished the EMC group with 88% accuracy. Three proteins in this signature were neutrophil-associated proteases that correlated with many cytokines, especially GM-CSF (granulocyte-macrophage colony-stimulating factor), IL-1β (interleukin-1β), MIP-3α (macrophage inflammatory protein-3α), IL-17, and IL-8. Gene set enrichment analyses implicated activated immune cells; we verified experimentally that EMC women had an increased frequency of endocervical CD4(+) T cells. These data reveal strong linkages between mucosal cytokines, barrier function, proteases, and immune cell movement, and propose these as potential mechanisms that increase risk of HIV acquisition.

HIV infection is independently associated with frailty in middle-aged HIV type 1-infected individuals compared with similar but uninfected controls

BACKGROUND

Frailty is an age-related syndrome of decreased physiological reserve and resistance to stressors, associated with increased morbidity and mortality in the general elderly population. An increased prevalence of frailty has been reported amongst HIV-infected individuals.

METHODS

Fried frailty phenotype was systematically assessed in predominantly virologically suppressed HIV type 1 (HIV-1)-infected and otherwise comparable HIV-uninfected participants aged at least 45 at enrollment into the AGEhIV Cohort Study. Multivariable ordinal logistic regression was used to investigate associations between HIV- and antiretroviral therapy-related covariates, markers of inflammation and body composition and prefrailty/frailty.

RESULTS

Data were available for 521 HIV-infected and 513 HIV-uninfected individuals. Prevalence of frailty (10.6 versus 2.7%) and prefrailty (50.7 versus 36.3%) were significantly higher in HIV-infected individuals (Ptrend < 0.001). HIV infection remained statistically significantly associated with prefrailty/frailty after adjustment for age, sex, race/ethnicity, smoking, hepatitis C infection, comorbidities and depression [adjusted odds ratio (ORadj) 2.16, P < 0.001]. A higher waist-to-hip ratio attenuated the coefficient of HIV-infected status (ORadj 1.93, P < 0.001), but not waist- or hip-circumference individually or markers of inflammation. Within the HIV-infected group, parameters related to body composition were most strongly and independently associated with prefrailty/frailty: current BMI less than 20 kg/m2 (OR 2.83, P = 0.01), nadir BMI less than 20 kg/m2 (OR 2.51, P = 0.001) and waist-to-hip ratio (OR 1.79 per 0.1 higher, P < 0.001).

CONCLUSION

HIV infection was independently associated with prefrailty/frailty in middle-aged HIV-infected patients compared with HIV-uninfected controls. This partly may be mediated by the higher waist- and lower hip-circumference in the HIV-infected individuals, potentially partially caused by lipodystrophy, and in part be a consequence of historic weight loss associated with advanced HIV-disease.

Dysregulated Immune Activation in Second-Line HAART HIV+ Patients Is Similar to That of Untreated Patients

Background

Successful highly active antiretroviral therapy (HAART) has changed the outcome of AIDS patients worldwide because the complete suppression of viremia improves health and prolongs life expectancy of HIV-1+ patients. However, little attention has been given to the immunological profile of patients under distinct HAART regimens. This work aimed to investigate the differences in the immunological pattern of HIV-1+ patients under the first- or second-line HAART in Brazil.

Methods

CD4+ T cell counts, Viral load, and plasma concentration of sCD14, sCD163, MCP-1, RANTES, IP-10, IL-1β, IL-6, TNF-α, IL-12, IFN-α, IFN-γ, IL-4, IL-5, and IL-10 were assessed for immunological characterization of the following clinical groups: Non-infected individuals (NI; n = 66), HIV-1+ untreated (HIV; n = 46), HIV-1+ treated with first-line HAART (HAART 1; n = 15); and HIV-1+ treated with second-line HAART (HAART 2; n = 15).

Results

We found that the immunological biosignature pattern of HAART 1 is similar to that of NI individuals, especially in patients presenting slow progression of the disease, while patients under HAART 2 remain in a moderate inflammatory state, which is similar to that of untreated HIV patients pattern. Network correlations revealed that differences in IP-10, TNF-α, IL-6, IFN-α, and IL-10 interactions were primordial in HIV disease and treatment. Heat map and decision tree analysis identified that IP-10>TNF-α>IFN-α were the best respective HAART segregation biomarkers.

Conclusion

HIV patients in different HAART regimens develop distinct immunological biosignature, introducing a novel perspective into disease outcome and potential new therapies that consider HAART patients as a heterogeneous group.

[Key role played by the gut associated lymphoid tissue during human immunodeficiency virus infection]

The gut associated lymphoid tissue (GALT) is the site of numerous immunological disturbances during HIV-1 infection. It constitutes the largest reservoir for HIV, not or very poorly susceptible to antiretroviral therapy (ART), making it a major obstacle to HIV cure. Moreover, the GALT is involved in systemic immune activation in HIV-infected individuals: intestinal damage due to viral replication and severe CD4(+) T cell depletion in the GALT leads to microbial translocation, a key driver of immune activation, and in turn, disease progression. In this review, we describe the role of the GALT in HIV infection and we discuss therapeutic options to decrease the intestinal viral reservoir and to preserve immune function in the gut of HIV-infected people. Achieving these goals is necessary for a long-term infection control after the interruption of ART.

The α7-nicotinic receptor is upregulated in immune cells from HIV-seropositive women: consequences to the cholinergic anti-inflammatory response

Antiretroviral therapy partially restores the immune system and markedly increases life expectancy of HIV-infected patients. However, antiretroviral therapy does not restore full health. These patients suffer from poorly understood chronic inflammation that causes a number of AIDS and non-AIDS complications. Here we show that chronic inflammation in HIV+ patients may be due to the disruption of the cholinergic anti-inflammatory pathway by HIV envelope protein gp120_IIIB. Our results demonstrate that HIV gp120_IIIB induces α7 nicotinic acetylcholine receptor (α7) upregulation and a paradoxical proinflammatory phenotype in macrophages, as activation of the upregulated α7 is no longer capable of inhibiting the release of proinflammatory cytokines. Our results demonstrate that disruption of the cholinergic-mediated anti-inflammatory response can result from an HIV protein. Collectively, these findings suggest that HIV tampering with a natural strategy to control inflammation could contribute to a crucial, unresolved problem of HIV infection: chronic inflammation.

Elevated Biomarkers of Inflammation and Coagulation in Patients with HIV Are Associated with Higher Framingham and VACS Risk Index Scores

Background

Biomarkers of inflammation and altered coagulation are of increasing interest as predictors of chronic disease and mortality in HIV patients, as well as the use of risk stratification scores such as the Framingham index and the Veterans Aging Cohort Study (VACS) score.

Methods

Demographic and laboratory data for 252 HIV patients were assessed for their relationship with 5 biomarkers: hsCRP, D-dimer, Cystatin C, IL-6 and TNF-alpha. Analysis of variance was used to model the association between the number of elevated biomarkers patients had and their Framingham 10 year cardiovascular risk and VACS scores.

Results

87% of patients were male and 75.7% were virally suppressed (HIV RNA <48 copies/ml). The median and interquartile ranges for each biomarker were: hsCRP 1.65 ug/mL (0.73, 3.89), D-dimer 0.17 ug/mL (0.09, 0.31), Cystatin C 0.87 mg/L (0.78, 1.01), IL-6 2.13 pg/mL (1.3, 3.59), TNF-alpha 4.65 pg/mL (3.5, 5.97). 62.6% of patients had more than one biomarker >75^th percentile, while 18.6% had three or more elevated biomarkers. Increased age, cigarette smoking, CD4 counts of <200 cells/mm³, Framingham scores and VACS scores were most strongly associated with elevations in biomarkers. When biomarkers were used to predict the Framingham and VACS scores, those with a higher number of elevated biomarkers had higher mean VACS scores, with a similar but less robust finding for Framingham scores.

Conclusions

Despite viral suppression and immunological stability, biomarkers of inflammation and coagulation remain elevated in a significant number of patients with HIV and are associated with higher scores on risk stratification indices.

Interleukin-21 combined with ART reduces inflammation and viral reservoir in SIV-infected macaques

Despite successful control of viremia, many HIV-infected individuals given antiretroviral therapy (ART) exhibit residual inflammation, which is associated with non-AIDS-related morbidity and mortality and may contribute to virus persistence during ART. Here, we investigated the effects of IL-21 administration on both inflammation and virus persistence in ART-treated, SIV-infected rhesus macaques (RMs). Compared with SIV-infected animals only given ART, SIV-infected RMs given both ART and IL-21 showed improved restoration of intestinal Th17 and Th22 cells and a more effective reduction of immune activation in blood and intestinal mucosa, with the latter maintained through 8 months after ART interruption. Additionally, IL-21, in combination with ART, was associated with reduced levels of SIV RNA in plasma and decreased CD4(+) T cell levels harboring replication-competent virus during ART. At the latest experimental time points, which were up to 8 months after ART interruption, plasma viremia and cell-associated SIV DNA levels remained substantially lower than those before ART initiation in IL-21-treated animals but not in controls. Together, these data suggest that IL-21 supplementation of ART reduces residual inflammation and virus persistence in a relevant model of lentiviral disease and warrants further investigation as a potential intervention for HIV infection.

Can We Repurpose FDA-Approved Alefacept to Diminish the HIV Reservoir?

Current anti-retroviral treatment (ART) for HIV is effective in maintaining HIV at undetectable levels. However, cessation of ART results in immediate and brisk rebound of viremia to high levels. This rebound is driven by an HIV reservoir mainly enriched in memory CD4+ T cells. In order to provide any form of functional HIV Cure, elimination of this viral reservoir has become the focus of current HIV cure strategies. Alefacept was initially developed for the treatment of chronic plaque psoriasis. Alefacept is a chimeric fusion protein consisting of the CD2-binding portion of human leukocyte function antigen-3 (LFA3) linked to the Fc region of human IgG1 (LFA3-Fc). Alefacept was designed to inhibit memory T cell activation that contributes to the chronic autoimmune disease psoriasis by blocking the CD2 coreceptor. However, it was found to deplete memory T cells that express high levels of CD2 via NK cell-mediated antibody dependent cell cytotoxicity (ADCC) in vivo. Phase II and phase III clinical trials of alefacept with psoriasis patients demonstrated promising results and an excellent safety profile. Subsequently, alefacept has been successfully repurposed for other memory T cell-mediated autoimmune diseases including skin diseases other than psoriasis, organ transplantation and type I diabetes (T1D). Herein, we review our specific strategy to repurpose the FDA approved biologic alefacept to decrease and hopefully someday eliminate the HIV reservoir, for which CD2hi memory CD4+ T cells are a significant contributor.

Progress Toward HIV Eradication: Case Reports, Current Efforts, and the Challenges Associated with Cure

An estimated 35 million people worldwide are infected with HIV, yet a widely applicable cure strategy remains elusive. Recent case reports have suggested that curing HIV infection is possible, renewing excitement about research efforts. We describe those cases and discuss their relevance to the global HIV epidemic. We also review ongoing cure strategies that are transitioning from the lab to the clinic, and the assays and clinical assessments that can be used to evaluate cure interventions.

Association of immune-activation and senescence markers with non-AIDS-defining comorbidities in HIV-suppressed patients

OBJECTIVES

We studied the link between T-cell activation, differentiation and senescence phenotypes and non-AIDS-related comorbidities in HIV-suppressed patients.

DESIGN

Patients included in the ANRS CO3 Aquitaine Cohort were consecutively enrolled in this cross-sectional study between October 2011 and May 2013 called Chronic Immune Activation and Senescence (CIADIS) study.

METHODS

We summarized immune markers [CD4 and CD8 activation (DR), differentiation (naive and terminally differentiated memory T cells), and senescence (CD57CD28)] in a weighted immune score by principal component analysis called CIADIS. Previously described Veterans Aging Cohort Study (VACS) index and immune risk profile (IRP) scores were calculated. We used adjusted logistic regression to assess the association between the CIADIS score and the presence of at least three non-AIDS-defining comorbidities.

RESULTS

Of 876 patients with an undetectable viral load, 73.4% were men and median age was 50.5 years [interquartile range (IQR) 44.7-56.7 years]. Median CD4 T-cell count was 579/μl (IQR 429-759 cells/μl), and median duration of HIV viral suppression was 5.3 years (IQR 2.3-8.7). The weighted CIADIS score was associated with at least three comorbidities (odds ratio 1.3 for 1 SD more, 95% confidence interval 1.0, 1.6) independently of age, sex, AIDS stage, and the Veterans Aging Cohort Study score. The CIADIS and the immune risk profile scores were significantly associated with at least three comorbidities in adjusted models restricted to patients younger than 60 years. None of the tested scores were associated with at least three comorbidities in patients older than 60 years.

CONCLUSIONS

The weighted CIADIS score based on activation, senescence, and differentiation markers might help physicians identifying patients at a higher risk for non-AIDS-related comorbidities.

Obesity is associated with greater inflammation and monocyte activation among HIV-infected adults receiving antiretroviral therapy

OBJECTIVES

Among virally suppressed HIV-infected persons, we examined the relationship between obesity and alterations in key clinical markers of immune activation and inflammation. These markers have also been associated with excess HIV-related cardiovascular disease and mortality.

METHODS

We evaluated data from virally suppressed participants in the Study to Understand the Natural History of HIV/AIDS in the Era of Effective Therapy, including inflammatory biomarkers (interleukin-6 and highly sensitive C-reactive protein), monocyte biomarkers [soluble CD163 (sCD163), sCD14], and monocyte immunophenotypes. We assessed associations with these immunologic measures and obesity, via logistic regression preadjustment and postadjustment for demographic and clinical factors, homeostatic model assessment of insulin resistance, and leptin levels.

RESULTS

Among 452 evaluable participants, median (interquartile range) age was 41 (36-48) years, CD4 cell count was 475 (308-697) cells/μl, and 21% were obese (BMI ≥ 30 kg/m). In univariable models, obesity, smoking, and lower CD4 cell count were associated with higher measures of inflammation and monocyte activation. After adjustment, obesity remained independently associated with elevated levels (highest vs. lower two tertiles) of interleukin-6 [odds ratio (OR) 1.96; P = 0.02], highly sensitive C-reactive protein (OR 2.79; P < 0.001) and sCD163 (OR 1.94; P = 0.02), and elevated frequency of CD14CD16 (OR 1.77; P = 0.03) and CD14dimCD16 (OR 1.97; P = 0.01). Adjusting for homeostatic model assessment of insulin resistance and leptin modestly affected associations for obesity with inflammation and monocyte activation.

CONCLUSION

Obesity was prevalent and independently associated with greater monocyte activation and systemic inflammation. Research is needed to determine how adipose tissue excess is functionally related to persistent immunologic abnormalities among HIV-infected persons with viral suppression.

Increased susceptibility of CD4+ T cells from elderly individuals to HIV-1 infection and apoptosis is associated with reduced CD4 and enhanced CXCR4 and FAS surface expression levels

Background

Elderly HIV-1 infected individuals progress to AIDS more frequently and rapidly than people becoming infected at a young age. To identify possible reasons for these differences in clinical progression, we performed comprehensive phenotypic analyses of CD4+ T cells from uninfected young and elderly individuals, and examined their susceptibility to HIV-1 infection and programmed death.

Results

Peripheral blood mononuclear cells (PBMCs) from older people contain an increased percentage of central memory and Th17 CD4+ T cells that are main target cells of HIV-1 and strongly reduced proportions of naïve T cells that are poorly susceptible to HIV-1. Unstimulated T cells from elderly individuals expressed higher levels of activation markers, death receptors, and the viral CXCR4 co-receptor than those from young individuals but responded poorly to stimulation. CD4+ T cells from older individuals were highly susceptible to CXCR4- and CCR5-tropic HIV-1 infection but produced significantly lower quantities of infectious virus than cells from young individuals because they were highly prone to apoptosis and thus presumably had a very short life span. The increased susceptibility of T cells from the elderly to HIV-1 infection correlated directly with CXCR4 and inversely with CD4 expression. The levels of apoptosis correlated with the cell surface expression of FAS but not with the expression of programmed death receptor 1 (PD1) or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL).

Conclusions

Increased levels of activated and highly susceptible HIV-1 target cells, reduced CD4 and enhanced CXCR4 cell surface expression, together with the high susceptibility to FAS-induced programmed cell death may contribute to the rapid CD4+ T cell depletion and accelerated clinical course of infection in elderly HIV-1-infected individuals.

Electronic supplementary material

The online version of this article (doi:10.1186/s12977-015-0213-1) contains supplementary material, which is available to authorized users.

HIV infection

More than 75 million people worldwide have been infected with human immunodeficiency virus (HIV), and there are now approximately 37 million individuals living with the infection. Untreated HIV replication causes progressive CD4(+) T cell loss and a wide range of immunological abnormalities, leading to an increased risk of infectious and oncological complications. HIV infection also contributes to cardiovascular disease, bone disease, renal and hepatic dysfunction and several other common morbidities. Antiretroviral drugs are highly effective at inhibiting HIV replication, and for individuals who can access and adhere to these drugs, combination antiretroviral therapy leads to durable (and probably lifelong) suppression of viral replication. Viral suppression enables immune recovery and the near elimination of the risk for developing acquired immune deficiency syndrome (AIDS). Despite effective treatment, HIV-infected individuals have a higher than expected risk of heart, bone, liver, kidney and neurological disease. When used optimally by an infected (or by an uninfected) person, antiretroviral drugs can virtually eliminate the risk of HIV transmission. Despite major advances in prevention sciences, HIV transmission remains common in many vulnerable populations, including men who have sex with men, injection drug users and sex workers. Owing to a lack of widespread HIV testing and the costs and toxicities associated with antiretroviral drugs, the majority of the infected population is not on effective antiretroviral therapy. To reverse the pandemic, improved prevention, treatment and implementation approaches are necessary.

Adipose Tissue Is a Neglected Viral Reservoir and an Inflammatory Site during Chronic HIV and SIV Infection

Two of the crucial aspects of human immunodeficiency virus (HIV) infection are (i) viral persistence in reservoirs (precluding viral eradication) and (ii) chronic inflammation (directly associated with all-cause morbidities in antiretroviral therapy (ART)-controlled HIV-infected patients). The objective of the present study was to assess the potential involvement of adipose tissue in these two aspects. Adipose tissue is composed of adipocytes and the stromal vascular fraction (SVF); the latter comprises immune cells such as CD4+ T cells and macrophages (both of which are important target cells for HIV). The inflammatory potential of adipose tissue has been extensively described in the context of obesity. During HIV infection, the inflammatory profile of adipose tissue has been revealed by the occurrence of lipodystrophies (primarily related to ART). Data on the impact of HIV on the SVF (especially in individuals not receiving ART) are scarce. We first analyzed the impact of simian immunodeficiency virus (SIV) infection on abdominal subcutaneous and visceral adipose tissues in SIVmac251 infected macaques and found that both adipocytes and adipose tissue immune cells were affected. The adipocyte density was elevated, and adipose tissue immune cells presented enhanced immune activation and/or inflammatory profiles. We detected cell-associated SIV DNA and RNA in the SVF and in sorted CD4+ T cells and macrophages from adipose tissue. We demonstrated that SVF cells (including CD4+ T cells) are infected in ART-controlled HIV-infected patients. Importantly, the production of HIV RNA was detected by in situ hybridization, and after the in vitro reactivation of sorted CD4+ T cells from adipose tissue. We thus identified adipose tissue as a crucial cofactor in both viral persistence and chronic immune activation/inflammation during HIV infection. These observations open up new therapeutic strategies for limiting the size of the viral reservoir and decreasing low-grade chronic inflammation via the modulation of adipose tissue-related pathways.

Role of T-cell reconstitution in HIV-1 antiretroviral therapy-induced bone loss

HIV infection causes bone loss. We previously reported that immunosuppression-mediated B-cell production of receptor activator of NF-κB ligand (RANKL) coupled with decline in osteoprotegerin correlate with decreased bone mineral density (BMD) in untreated HIV infection. Paradoxically, antiretroviral therapy (ART) worsens bone loss although existing data suggest that such loss is largely independent of specific antiretroviral regimen. This led us to hypothesize that skeletal deterioration following HIV disease reversal with ART may be related to T-cell repopulation and/or immune reconstitution. Here we transplant T cells into immunocompromised mice to mimic ART-induced T-cell expansion. T-cell reconstitution elicits RANKL and TNFα production by B cells and/or T cells, accompanied by enhanced bone resorption and BMD loss. Reconstitution of TNFα- or RANKL-null T-cells and pharmacological TNFα antagonist all protect cortical, but not trabecular bone, revealing complex effects of T-cell reconstitution on bone turnover. These findings suggest T-cell repopulation and/or immune reconstitution as putative mechanisms for bone loss following ART initiation.

Vitamin D status in Well-Controlled Caucasian HIV Patients in Relation to Inflammatory and Metabolic Markers--A Cross-Sectional Cohort Study in Sweden

To study vitamin D (25OH D₃) in relation to (i) microbial translocation (ii) systemic inflammation and (iii) blood lipid markers, in Caucasian, well-controlled HIV patients and healthy controls, plasma and serum samples from n = 97 male, HIV patients on HAART with immeasurable viral load (<20 copies/ml) since median 6.5 years and no concurrent inflammatory or infectious disease and n = 30 healthy controls were analysed for (i) LPS; (ii) sCD14, hsCRP, IL-4, IL-6, IL-10, IL-17, MCP-1 and IFN-γ; as well as (iii) blood lipids. Vitamin D levels were similarly distributed and equally low in both HIV patients and controls. There was no association between vitamin D levels and markers of microbial translocation, systemic inflammation or dyslipidemia. LPS levels were similar in both groups but HIV patients expressed higher levels of sCD14 and hsCRP, with HIV as an independent risk factor. HIV patients had higher cholesterol and Apo B levels. Notably, more HIV patients smoked and smoking was associated with lower vitamin D levels. In conclusion; these well-treated Caucasian HIV patients had similar vitamin D levels as healthy controls. However, despite perfect virological control, they exhibited slightly increased inflammatory markers and disturbed blood lipids. However, neither of these parameters were associated with low vitamin D levels but appeared to be linked to the HIV-disease per se. Thus, the rationale for vitamin D substitution as a way to improve microbial translocation and systemic inflammation is not fully supported in this HIV population.

The simultaneous occurrence of both hypercoagulability and hypofibrinolysis in blood and serum during systemic inflammation, and the roles of iron and fibrin(ogen)

Although the two phenomena are usually studied separately, we summarise a considerable body of literature to the effect that a great many diseases involve (or are accompanied by) both an increased tendency for blood to clot (hypercoagulability) and the resistance of the clots so formed (hypofibrinolysis) to the typical, 'healthy' or physiological lysis. We concentrate here on the terminal stages of fibrin formation from fibrinogen, as catalysed by thrombin. Hypercoagulability goes hand in hand with inflammation, and is strongly influenced by the fibrinogen concentration (and vice versa); this can be mediated via interleukin-6. Poorly liganded iron is a significant feature of inflammatory diseases, and hypofibrinolysis may change as a result of changes in the structure and morphology of the clot, which may be mimicked in vitro, and may be caused in vivo, by the presence of unliganded iron interacting with fibrin(ogen) during clot formation. Many of these phenomena are probably caused by electrostatic changes in the iron-fibrinogen system, though hydroxyl radical (OH˙) formation can also contribute under both acute and (more especially) chronic conditions. Many substances are known to affect the nature of fibrin polymerised from fibrinogen, such that this might be seen as a kind of bellwether for human or plasma health. Overall, our analysis demonstrates the commonalities underpinning a variety of pathologies as seen in both hypercoagulability and hypofibrinolysis, and offers opportunities for both diagnostics and therapies.

Early Initiation Rather Than Prolonged Duration of Antiretroviral Therapy in HIV Infection Contributes to the Normalization of CD8 T-Cell Counts

BACKGROUND

CD8 T-cell counts remain elevated in human immunodeficiency virus (HIV) infection even after long-term antiretroviral therapy (ART), which is associated with an increased risk of non-AIDS-related events. We assessed the impact of ART initiation in early versus chronic HIV infection on trajectories of CD8 cell counts over time.

METHODS

Of 280 individuals enrolled during primary HIV infection (PHI), 251 were followed up for 24 months; 84 started ART before 6 months of infection (eART), 49 started between 6 and 24 months, and 118 remained untreated. Plasma HIV viral load (VL), CD4 and CD8 cell counts were assessed at each study visit. CD8 counts were also examined in 182 age-matched HIV-infected individuals who started ART during chronic infection and maintained undetectable plasma VL for ≥5 years.

RESULTS

At PHI baseline, higher CD8 cell counts were associated with more recent infection (P = .02), higher CD4 cell counts (P < .001), and higher VL (P < .001). The CD8 count in the eART group decreased from 797 to 588 cells/µL over 24 months (P < .001), to a level lower than that in untreated PHI (834 cells/µL; P = .004) or in long-term-treated patients with chronic HIV infection (743 cells/µL; P = .047). More prominent CD4 T-cell recovery was observed in the eART group than in the delayed ART group.

CONCLUSIONS

ART initiated in early HIV infection is associated with improved resolution of CD8 T-cell elevation compared with long-term ART initiated in chronic infection. Early ART may help reduce the risk of non-AIDS-related events by alleviating this elevation.

Impairment of T cell development and acute inflammatory response in HIV-1 Tat transgenic mice

Immune activation and chronic inflammation are hallmark features of HIV infection causing T-cell depletion and cellular immune dysfunction in AIDS. Here, we addressed the issue whether HIV-1 Tat could affect T cell development and acute inflammatory response by generating a transgenic mouse expressing Tat in lymphoid tissue. Tat-Tg mice showed thymus atrophy and the maturation block from DN4 to DP thymic subpopulations, resulting in CD4⁺ and CD8⁺ T cells depletion in peripheral blood. In Tat-positive thymus, we observed the increased p65/NF-κB activity and deregulated expression of cytokines/chemokines and microRNA-181a-1, which are involved in T-lymphopoiesis. Upon LPS intraperitoneal injection, Tat-Tg mice developed an abnormal acute inflammatory response, which was characterized by enhanced lethality and production of inflammatory cytokines. Based on these findings, Tat-Tg mouse could represent an animal model for testing adjunctive therapies of HIV-1-associated inflammation and immune deregulation.

Palliative HIV care: opportunities for biomedical and behavioral change

Advances in treatment are contributing to substantial increases in life expectancy for individuals living with HIV, prompting a need to develop care models for the effective management of HIV as a chronic illness. With many individuals continuing to experience symptoms and complications that add to the disease burden across the spectrum of HIV disease, the discussion herein explores the complementary role that early palliative care can play in HIV primary care as a strategy for enhancing long-term quality of life. After first defining the concept of early palliative care, its scope in the context of current clinical realities in HIV treatment and implications for HIV care models is described. After reviewing the emerging extant research literature on HIV palliative care outcomes, a program description is offered as an illustration of how palliative care integration with HIV primary care can be achieved.

Plasma and Cerebrospinal Fluid Biomarkers Predict Cerebral Injury in HIV-Infected Individuals on Stable Combination Antiretroviral Therapy

OBJECTIVES

HIV-associated brain injury persists despite combination antiretroviral therapy, but contributing factors remain poorly understood. We postulated that inflammation-associated biomarkers will be associated with cerebral injury on proton magnetic resonance spectroscopy in chronically HIV-infected subjects.

METHODS

Five biomarkers were measured in 197 HIV-infected subjects: soluble CD14, MCP-1, IP-10, MIP-1β, and fractalkine. Levels of N-acetyl aspartate (NAA), Choline (Cho), Myoinositol (MI), Glutamate + Glutamine (Glx), and Creatine (Cr) were acquired in the midfrontal cortex (MFC), frontal white matter, and basal ganglia (BG). Predictive models were built through linear regression, and the best models were chosen using the Akaike Information Criterion.

RESULTS

Increases in plasma or CSF MCP-1 were associated with lower NAA/Cr in the MFC and BG, whereas metabolite changes in the frontal white matter for NAA/Cr, GlxCr, and Cho/Cr were explained almost exclusively by a single factor, sCD14. Plasma and CSF levels of this factor were also significantly associated with Glx/Cr in MFC and BG. Higher CSF FKN was associated with higher NAA/Cr in BG. Best predictors for higher Cho/Cr in BG and MFC were CSF sCD14 and CSF MIP-1β. Plasma and CSF IP-10 were only associated with Cho/Cr in MFC. Of the 3 models that simultaneously accounted for both plasma and CSF, there were more associations between CSF biomarkers and magnetic resonance spectroscopy metabolites.

CONCLUSIONS

Markers of inflammation and immune activation, in particular MCP-1 and sCD14, predominantly reflecting CNS sources, contribute to the persistence of brain injury in a metabolite and region-dependent manner in chronically HIV-infected patients on stable combination antiretroviral therapy.

Critical Role for the Adenosine Pathway in Controlling Simian Immunodeficiency Virus-Related Immune Activation and Inflammation in Gut Mucosal Tissues

The role of the adenosine (ADO) pathway in human immunodeficiency virus type 1/simian immunodeficiency virus (HIV-1/SIV) infection remains unclear. We compared SIVsab-induced changes of markers related to ADO production (CD39 and CD73) and breakdown (CD26 and adenosine deaminase) on T cells from blood, lymph nodes, and intestine collected from pigtailed macaques (PTMs) and African green monkeys (AGMs) that experience different SIVsab infection outcomes. We also measured ADO and inosine (INO) levels in tissues by mass spectrometry. Finally, we assessed the suppressive effect of ADO on proinflammatory cytokine production after T cell receptor stimulation. The baseline level of both CD39 and CD73 coexpression on regulatory T cells and ADO levels were higher in AGMs than in PTMs. Conversely, high INO levels associated with dramatic increases in CD26 expression and adenosine deaminase activity were observed in PTMs during chronic SIV infection. Immune activation and inflammation markers in the gut and periphery inversely correlated with ADO and directly correlated with INO. Ex vivo administration of ADO significantly suppressed proinflammatory cytokine production by T cells in both species. In conclusion, the opposite dynamics of ADO pathway-related markers and contrasting ADO/INO levels in species with divergent proinflammatory responses to SIV infection support a key role of ADO in controlling immune activation/inflammation in nonprogressive SIV infections. Changes in ADO levels predominately occurred in the gut, suggesting that the ADO pathway may be involved in sparing natural hosts of SIVs from developing SIV-related gut dysfunction. Focusing studies of the ADO pathway on mucosal sites of viral replication is warranted.

IMPORTANCE

The mechanisms responsible for the severe gut dysfunction characteristic of progressive HIV and SIV infection in humans and macaques are not completely elucidated. We report that ADO may play a key role in controlling immune activation/inflammation in nonprogressive SIV infections by limiting SIV-related gut inflammation. Conversely, in progressive SIV infection, significant degradation of ADO occurs, possibly due to an early increase of ADO deaminase complexing protein 2 (CD26) and adenosine deaminase. Our study supports therapeutic interventions to offset alterations of this pathway during progressive HIV/SIV infections. These potential approaches to control chronic immune activation and inflammation during pathogenic SIV infection may prevent HIV disease progression.

Altered metabolism of gut microbiota contributes to chronic immune activation in HIV-infected individuals

Altered interplay between gut mucosa and microbiota during treated HIV infection may possibly contribute to increased bacterial translocation and chronic immune activation, both of which are predictors of morbidity and mortality. Although a dysbiotic gut microbiota has recently been reported in HIV+ individuals, the metagenome gene pool associated with HIV infection remains unknown. The aim of this study is to characterize the functional gene content of gut microbiota in HIV+ patients and to define the metabolic pathways of this bacterial community, which is potentially associated with immune dysfunction. We determined systemic markers of innate and adaptive immunity in a cohort of HIV-infected individuals on successful antiretroviral therapy without comorbidities and in healthy non-HIV-infected subjects. Metagenome sequencing revealed an altered functional profile, with enrichment of the genes involved in various pathogenic processes, lipopolysaccharide biosynthesis, bacterial translocation, and other inflammatory pathways. In contrast, we observed depletion of genes involved in amino acid metabolism and energy processes. Bayesian networks showed significant interactions between the bacterial community, their altered metabolic pathways, and systemic markers of immune dysfunction. This study reveals altered metabolic activity of microbiota and provides novel insight into the potential host-microbiota interactions driving the sustained inflammatory state in successfully treated HIV-infected patients.

Myocardial Infarction, Stroke, and Mortality in cART-Treated HIV Patients on Statins

Despite combination antiretroviral therapy (cART), people living with HIV (PLWH) continue to have more systemic inflammation and metabolic disturbances than the general population. These risk factors for atherosclerosis and organ dysfunction may be ameliorated by statins. We retrospectively analyzed 438 cART treated PLWH from the Nutrition For Healthy Living (NFHL) cohort to determine the association between statins and myocardial infarction (MI), stroke, and all-cause mortality as a composite. We used Cox proportional hazards regression as our main analysis. The average age was 44 years, 32% were women, and 67 of the 438 subjects used statins. There was no association between statins and our composite endpoint in two separate models [1.26 (0.57-2.79) in statin history model and 0.93 (0.65-1.32) per year in statin duration model]. The composite outcome was significantly associated with CD4 count, age, and smoking status in both models. CD4 count remained significant even after exclusion of mortality from the composite (HR=0.88, p=0.02). Confounding control via propensity scoring and multiple imputations did not change the results. Statins did not have an effect on MI, stroke, and mortality. Interestingly, CD4 count appears to be an important predictor of these outcomes, even after exclusion of death from the composite.

Viremic and Virologically Suppressed HIV Infection Increases Age-Related Changes to Monocyte Activation Equivalent to 12 and 4 Years of Aging, Respectively

BACKGROUND

Chronic inflammation and immune activation occur in both HIV infection and normal aging and are associated with inflammatory disease. However, the degree to which HIV influences age-related innate immune changes, and the biomarkers which best reflect them, remains unclear.

METHODS AND RESULTS

We measured established innate immune aging biomarkers in 309 individuals including 88 virologically suppressed (VS) and 52 viremic (viral load ≤ and >50 copies per milliliter, respectively) HIV-positive individuals. Levels of soluble (ie, CXCL10, soluble CD163, neopterin) and cellular (ie, proportions of inflammatory CD16 monocytes) biomarkers of monocyte activation were increased in HIV-positive individuals and were only partially ameliorated by viral suppression. Viremic and VS HIV-positive individuals show levels of age-related monocyte activation biomarkers that are similar to uninfected controls aged 12 and 4 years older, respectively. Viremic HIV infection was associated with an accelerated rate of change of some monocyte activation markers (eg, neopterin) with age, whereas in VS individuals, subsequent age-related changes occurred at a similar rate as in controls, albeit at a higher absolute level. We further identified CXCL10 as a robust soluble biomarker of monocyte activation, highlighting the potential utility of this chemokine as a prognostic marker.

IMPLICATIONS

These findings may partially explain the increased prevalence of inflammatory age-related diseases in HIV-positive individuals and potentially indicate the pathological mechanisms underlying these diseases, which persist despite viral suppression.

Dispelling myths and focusing on notable concepts in HIV pathogenesis

Since the discovery of HIV over three decades ago, major efforts have been made to control and perhaps eliminate HIV infection worldwide. During these studies, certain myths or misconceptions about this infectious disease have been emphasized and other potentially beneficial concepts have received less attention. A true long-term solution to HIV infection merits an appreciation of alternative ideas and findings that could be beneficial in the ultimate control of HIV/AIDS. Here, I discuss six issues and call for more attention to the science of HIV and well-designed clinical trials.

Unique cytokine and chemokine patterns in bronchoalveolar lavage are associated with specific causative pathogen among HIV infected patients with pneumonia, in Medellin, Colombia

We wanted to investigate the pro-inflammatory cytokine/chemokine profile associated with the etiological agents identified in HIV patients. Immunosuppressed patients admitted to two hospitals in Medellin, Colombia, with clinical and radiographic diagnosis of pneumonia were enrolled in the study. After consent, bronchoalveolar lavage (BAL) was collected for bacterial, mycobacterial and fungal diagnosis. All patients were followed for a year. A stored BAL sample was used for cytokine/chemokine detection and measurement using commercial, magnetic human cytokine bead-based 19-plex assays. Statistical analysis was performed by assigning cytokine/chemokine concentrations levels into <25 percentile (lower), 25-75 percentile (normal) and >75 percentile (higher). Principal component analysis (PCA) and Kruskal-Wallis analysis were conducted to identify the clustering of cytokines with the various infectious etiologies (fungi, Mycobacterium tuberculosis - MTB, and bacteria). Average age of patients was 35, of whom 77% were male, and the median CD4 count of 33cells/μl. Of the 57 HIV infected patients, in-hospital mortality was 12.3% and 33% died within a year of follow up. The PCA revealed increased IL-10, IL-12, IL-13, IL-17, Eotaxin, GCSF, MIP-1α, and MIP-1β concentrations to be associated with MTB infection. In patients with proven fungal infection, low concentrations of IL-1RA, IL-8, TNF-α and VEGF were identified. Bacterial infections displayed a distinct cytokine pattern and were not misclassified using the MTB or fungi cytokine patterns (p-value<0.0001). Our results indicate a unique pattern of pro-inflammatory cytokine/chemokine, allowing differentiation between bacterial and non-bacterial pathogens. Moreover, we found distinct, if imperfectly discriminatory, cytokine/chemokine patterns associated with MTB and fungal infections.

Abdominal obesity contributes to neurocognitive impairment in HIV-infected patients with increased inflammation and immune activation

OBJECTIVE

We tested our hypothesis that abdominal obesity when associated with increased levels of systemic and central nervous system immunoinflammatory mediators contributes to neurocognitive impairment (NCI).

DESIGN

Cross-sectional.

SETTING

Six Academic Centers.

PARTICIPANTS

One hundred fifty-two patients with plasma HIV RNA <1000 copies per milliliter had clinical evaluations and cognitive function quantified by global deficit scores (GDS).

OUTCOME MEASURES

GDS, waist circumference (WC) and plasma IL-6, sCD163, and sCD14 and CSF sCD40L, sTNFrII, MCP-1, sICAM, and MMP-9.

RESULTS

WC and plasma IL-6 levels positively correlated with GDS; the WC correlation was strongest in the high tertile of IL-6 (ρ = 0.39, P = 0.005). IL-6 correlated with GDS only if WC was ≥99 cm. In the high tertile of CSF sCD40L, a biomarker of macrophage and microglial activation, the correlation of IL-6 to GDS was strongest (ρ = 0.60, P < 0.0001). Across 3-5 visits within ±1 year of the index visit, GDS remained worse in patients with IL-6 levels in the high versus low tertile (P = 0.02). Path analysis to explore potential mediators of NCI produced a strong integrated model for patients in the high CSF sCD40L tertile. In this model, WC affected GDS both directly and through a second path that was mediated by IL-6. Inclusion of plasma sCD14 levels strengthened the model. NCI was more common in men and for individuals with components of the metabolic syndrome.

CONCLUSIONS

Neurocognitive function was significantly linked to abdominal obesity, systemic inflammation (high IL-6), and immune activation in plasma (high sCD14) and CSF (high sCD40L). Abdominal obesity, inflammation, and central nervous system immune activation are potential therapeutic targets for NCI in HIV-positive patients.

Acupuncture to Reduce HIV-Associated Inflammation

Background. HIV infection is associated with systemic inflammation that can increase risk for cardiovascular events. Acupuncture has been shown to have immunomodulatory effects and to improve symptoms in persons with inflammatory conditions. Objective. To test the anti-inflammatory effects of an acupuncture protocol that targets the cholinergic anti-inflammatory pathway (CAIP), a neural mechanism whose activation has been shown to reduce the release of proinflammatory cytokines, in persons with HIV-associated inflammation. Design, Setting, Participants, and Interventions. Double-blind, placebo-controlled clinical trial conducted in an outpatient clinic located in a medically underserved urban neighborhood. Twenty-five clinically-stable HIV-infected persons on antiretroviral therapy were randomized to receive once weekly CAIP-based acupuncture or sham acupuncture. Main Outcome Measures. Outcomes included plasma concentrations of high sensitivity C-reactive protein and D-dimer and fasting lipids. Results. Twenty-five participants completed the protocol (treatment group n = 12, control group n = 13). No adverse events related to the acupuncture protocol were observed. Compared to baseline values, the two groups did not significantly differ in any outcome measures at the end of the acupuncture protocol. Conclusions. CAIP-based acupuncture did not favorably modulate inflammatory or lipid parameters. Additional studies are warranted of CAIP-based protocols of different frequencies/durations.

HIV and the gut microbiota, partners in crime: breaking the vicious cycle to unearth new therapeutic targets

The gut microbiota plays a key role in health and immune system education and surveillance. The delicate balance between microbial growth and containment is controlled by the immune system. However, this balance is disrupted in cases of chronic viral infections such as HIV. This virus is capable of drastically altering the immune system and gastrointestinal environment leading to significant changes to the gut microbiota and mucosal permeability resulting in microbial translocation from the gut into the peripheral blood. The changes made locally in the gut have far-reaching consequences on the other organs of the body starting in the liver, where microbes and their products are normally filtered out, and extending to the blood and even brain. Microbial translocation and their downstream effects such as increased indolamine 2,3-dioxygenase (IDO) enzyme expression and activity create a self-sustaining feedback loop which enhances HIV disease progression and constitute a vicious cycle of inflammation and immune activation combining viral and bacterial factors. Understanding this self-perpetuating cycle could be a key element in developing new therapies aimed at the gut microbiota and its fallout after infection.

Investigating the role of ankyrin-rich membrane spanning protein in human immunodeficiency virus type-1 Tat-induced microglia activation

Long-term persistence of human immunodeficiency virus type-1 (HIV) in the central nervous system (CNS) results in mild to severe neurocognitive impairment in a significant proportion of the HIV-infected population. These neurological deficits are known as HIV-associated neurocognitive disorders (HAND). Microglia are CNS-resident immune cells that are directly infected by HIV and consequently secrete proinflammatory molecules that contribute to HIV-induced neuroinflammation. Indeed, the number of activated macrophage and microglia in the brain is more highly correlated with cognitive impairment than the amount of neuronal apoptosis. Ankyrin-rich membrane spanning protein (ARMS/Kidins220) is a multidomain transmembrane protein that is involved with neurotrophin signaling in the CNS. We have previously established the role of ARMS in mediating neuronal survival via a neurotrophin-dependent mechanism. Recent reports also have suggested that ARMS is involved with cell signaling in multiple immune cell types. In this study, we aim to investigate the role of ARMS in HIV Tat-mediated microglial cell activation by employing in vitro methods. Following ARMS depletion by a lentivirus encoding ARMS-specific short hairpin RNA (shRNA), we observed a marked reduction in the HIV Tat-induced proinflammatory response, associated with loss of tumor necrosis factor alpha production and nuclear factor-kappa B (NF-κB) activation. Furthermore, co-immunoprecipitation studies suggested that ARMS physically interacts with inhibitory kappa B kinase subunits in order to facilitate NF-κB activation. Our results establish the role of ARMS in microglial activation by HIV Tat and warrant additional studies to better understand these molecular mechanisms, which may uncover novel therapeutic targets for the treatment of HAND.

HIV enteropathy and aging: gastrointestinal immunity, mucosal epithelial barrier, and microbial translocation

PURPOSE OF REVIEW

Despite decreases in morbidity and mortality as a result of antiretroviral therapy, gastrointestinal dysfunction remains common in HIV infection. Treated patients are at risk for complications of 'premature' aging, such as cardiovascular disease, osteopenia, neurocognitive decline, malignancies, and frailty. This review summarizes recent observations in this field.

RECENT FINDINGS

Mucosal CD4 lymphocytes, especially Th17 cells, are depleted in acute HIV and simian immune deficiency virus (SIV) infections, although other cell types also are affected. Reconstitution during therapy often is incomplete, especially in mucosa. Mucosal barrier function is affected by both HIV infection and aging and includes paracellular transport via tight junctions and uptake through areas of apoptosis; other factors may affect systemic antigen exposure. The resultant microbial translocation is associated with systemic immune activation in HIV and SIV infections. There is evidence of immune activation and microbial translocation in the elderly. The immune phenotypes of immunosenescence in HIV infection and aging appear similar. There are several targets for intervention; blockage of residual mucosal virus replication, preventing antigen uptake, modulating the microbiome, improving T cell recovery, combining therapies aimed at mucosal integrity, augmenting mucosal immunity, and managing traditional risk factors for premature aging in the general population.

SUMMARY

Aging may interact with HIV enteropathy to enhance microbial translocation and immune activation.

Patient-centered care for people living with multimorbidity

PURPOSE OF REVIEW

The purpose of this review is to consider a patient-centred approach to the care of people living with HIV (PLWH) who have multimorbidity, irrespective of the specific conditions.

RECENT FINDINGS

Interdisciplinary care to achieve patient-centred care for people with multimorbidity is recognized as important, but the evaluation of models designed to achieve this goal are needed. Key elements of such approaches include patient preferences, interpretation of the evidence, prognosis as a tool to inform patient-centred care, clinical feasibility and optimization of treatment regimens.

SUMMARY

Developing and evaluating the best models of patient-centred care for PLWH who also have multimorbidity is essential. This challenge represents an opportunity to leverage the lessons learned from the care of people with multimorbidity in general, and vice versa.

Biologic aging, frailty, and age-related disease in chronic HIV infection

PURPOSE OF REVIEW

Effective therapies have transformed HIV infection into a chronic disease, and new problems are arising related to aging. This article reviews the aging process, age-related deficit accumulation and frailty, and how these might be affected by chronic HIV infection.

RECENT FINDINGS

Aging is characterized by acceleration in the rate of unrepaired physiologic damage an organism accumulates. HIV infection is associated with many factors that might affect the aging process, including extrinsic behavioral risk factors and co-infections, and multiple intrinsic factors, including intercellular communication, inflammation, and coagulation pathways. Whether each factor affects the aging process, they likely result in an increase in the risk of adverse health outcomes, and so give rise to frailty, likely with several clinical manifestations.

SUMMARY

Age-related deficit accumulation is influenced by both the background or environmental rate of insults an organism sustains and the efficacy of intrinsic damage control and repair mechanisms. Both processes are likely affected in people living with HIV infection.

Immunosuppressive Tryptophan Catabolism and Gut Mucosal Dysfunction Following Early HIV Infection

BACKGROUND

Tryptophan (Trp) catabolism into kynurenine (Kyn) contributes to immune dysfunction in chronic human immunodeficiency virus (HIV) infection. To better define the relationship between Trp catabolism, inflammation, gut mucosal dysfunction, and the role of early antiretroviral therapy (ART), we prospectively assessed patients early after they acquired HIV.

METHODS

Forty patients in the early phase of infection were longitudinally followed for 12 months after receiving a diagnosis of HIV infection; 24 were untreated, and 16 were receiving ART. Kyn/Trp ratio, regulatory T-cells (Tregs) frequency, T-cell activation, dendritic cell counts, and plasma levels of gut mucosal dysfunction markers intestinal-type fatty acid-binding protein, soluble suppression of tumorigenicity 2, and lipopolysaccharide were assessed.

RESULTS

Compared with healthy subjects, patients in the early phase of infection presented with elevated Kyn/Trp ratios, which further increased in untreated patients but normalized in ART recipients. Accordingly, in untreated subjects, the elevated Treg frequency observed at baseline continued to increase over time. The highest CD8(+) T-cell activation was observed during the early phase of infection and decreased in untreated patients, whereas activation normalized in ART recipients. The Kyn/Trp ratio was positively associated with CD8(+) T-cell activation and levels of inflammatory cytokines (interleukin 6, interferon γ-inducible protein 10, interleukin 18, and tumor necrosis factor α) and negatively associated with dendritic cell frequencies at baseline and in untreated patients. However, ART did not normalize plasma levels of gut mucosal dysfunction markers.

CONCLUSIONS

Early initiation of ART normalized enhanced Trp catabolism and immune activation but did not improve plasma levels of gut mucosal dysfunction markers.

HIV infection Worsens Age-Associated Defects in Antibody Responses to Influenza Vaccine

BACKGROUND

Antibody responses to seasonal influenza vaccines are defective during older age and human immunodeficiency virus (HIV) infection. The effect of HIV on immune function in aging is relatively unknown.

METHODS

HIV-infected and HIV-uninfected young women (age, 19-54 years) and older women (age, >55 years) were evaluated for B-cell and T-cell responses before and 4 weeks after influenza vaccination.

RESULTS

Frequencies of seroprotection pre-vaccination and vaccine responsiveness (≥4-fold increase in antibody titer) were lower in HIV-infected participants than in age-matched HIV-uninfected participants. A subgroup of vaccine nonresponders were compared to responders and found to have reduced frequencies of memory B cells and antigen-specific antibody-secreting cells after vaccination. Frequencies of peripheral T-follicular helper (pTfh) cells correlated with memory B-cell function and influenza A(H1N1) antibody titers. Serologic and immunologic deficits were most frequent in older HIV-infected participants. Underlying CD4(+) T-cell immune activation and inflammation correlated negatively with antibody titers and B-cell function, which was not enhanced by exogenous interleukin 21 supplementation in HIV-infected, older vaccine nonresponders.

CONCLUSIONS

Immune activation associated with HIV infection and impaired pTfh function heighten deficiencies in antibody responses to influenza vaccine in older individuals. Strategies to reduce immune activation or augment pTfh function may enhance antibody responses in the aging HIV-infected population.