Cytomegalovirus Seropositivity Is Associated With Increased Microbial Translocation in People Living With Human Immunodeficiency Virus and Uninfected Controls

Anti-cytomegalovirus antibody levels stratify human immune profiles across the lifespan

Human cytomegalovirus (hCMV) is a ubiquitous latent persistent herpesvirus infecting 60-90% of the population worldwide. hCMV carriage in immunocompetent people is asymptomatic; thus, hCMV can be considered a component of normative aging. However, hCMV powerfully modulates many features of the immune, and likely other, systems and organs. Questions remain as to how hCMV carriage affects the human host. We used anti-CMV antibody titers as a stratifying criterion to examine the impact of "intensity" of hCMV infection as a potential biomarker of aging, inflammation, and immune homeostasis in a cohort of 247 participants stratified into younger (21-40 years) and older (> 65 years of age) groups. We showed that anti-CMV antibody titers increased with age and directly correlated to increased levels of soluble tumor necrosis factor (sTNFR) I in younger but not older participants. CD8 + cell numbers were reduced in the older group due to the loss in CD8 + T naïve (Tn) cells. In CMV carriers and, in particular, in anti-CMV Ab-high participants, this loss was mitigated or reversed by an increase in the numbers of CD8 + T effector memory (Tem) and T effector memory reexpressing CD45RA (Temra) cells. Analysis of CD38, HLA-DR, and CD57 expression revealed subset (CD4 or CD8)-specific changes that correlated with anti-CMV Ab levels. In addition, anti-CMV Ab levels predicted anti-CMV CD8 T cell responsiveness to different CMV open reading frames (ORFs) selectively in older participants, which correlated to the transcriptional order of expression of specific CMV ORFs. Implications of these results for the potential predictive value of anti-CMV Ab titers during aging are discussed.

Persistence of a Skewed Repertoire of NK Cells in People with HIV-1 on Long-Term Antiretroviral Therapy

HIV-1 infection greatly alters the NK cell phenotypic and functional repertoire. This is highlighted by the expansion of a rare population of FcRγ- NK cells exhibiting characteristics of traditional immunologic memory in people with HIV (PWH). Although current antiretroviral therapy (ART) effectively controls HIV-1 viremia and disease progression, its impact on HIV-1-associated NK cell abnormalities remains unclear. To address this, we performed a longitudinal analysis detailing conventional and memory-like NK cell characteristics in n = 60 PWH during the first 4 y of ART. Throughout this regimen, a skewed repertoire of cytokine unresponsive FcRγ- memory-like NK cells persisted and accompanied an overall increase in NK surface expression of CD57 and KLRG1, suggestive of progression toward immune senescence. These traits were linked to elevated serum inflammatory biomarkers and increasing Ab titers to human CMV, with human CMV viremia detected in approximately one-third of PWH at years 1-4 of ART. Interestingly, 40% of PWH displayed atypical NK cell subsets, representing intermediate stages of NK-poiesis based on single-cell multiomic trajectory analysis. Our findings indicate that NK cell irregularities persist in PWH despite long-term ART, underscoring the need to better understand the causative mechanisms that prevent full restoration of immune health in PWH.

COPD in People with HIV: Epidemiology, Pathogenesis, Management, and Prevention Strategies

Chronic obstructive pulmonary disease (COPD) is a progressive respiratory disorder characterized by airflow limitation and persistent respiratory symptoms. People with HIV (PWH) are particularly vulnerable to COPD development; PWH have demonstrated both higher rates of COPD and an earlier and more rapid decline in lung function than their seronegative counterparts, even after accounting for differences in cigarette smoking. Factors contributing to this HIV-associated difference include chronic immune activation and inflammation, accelerated aging, a predilection for pulmonary infections, alterations in the lung microbiome, and the interplay between HIV and inhalational toxins. In this review, we discuss what is known about the epidemiology and pathobiology of COPD among PWH and outline screening, diagnostic, prevention, and treatment strategies.

Effect of Immune-Modulatory Interventions on Asymptomatic Cytomegalovirus Shedding During Suppressive Antiretroviral Therapy

Long-term consequences of human immunodeficiency virus (HIV) are likely the result of persistent inflammation and immune dysfunction of which cytomegalovirus (CMV) is a known contributor. We leveraged 2 AIDS Clinical Trials Group clinical trials exploring the effects of immune modulators (ruxolitinib and sirolimus) on inflammation in people with HIV on antiretroviral therapy to determine whether these interventions affected CMV shedding at various mucosal sites. Analyzing 635 mucosal samples collected, we found no significant difference in CMV levels across study arms or time points. Men had more CMV shedding than women. We did confirm an association between higher CMV DNA and immune markers associated with HIV persistence and HIV-associated mortality rates.

Cytomegalovirus Immunoglobulin G (IgG) Titer and Coronary Artery Disease in People With Human Immunodeficiency Virus (HIV)

BACKGROUND

Cytomegalovirus (CMV) infection is thought to result in increased immune activation in people with human immunodeficiency virus (HIV, PWH). Although some data have linked asymptomatic CMV infection to cardiovascular disease among PWH, it remains unknown whether CMV is associated with increased or high-risk coronary plaque.

METHODS

The Randomized Trial to Prevent Vascular Events in HIV (REPRIEVE) enrolled PWH aged 40-75 years on stable antiretroviral therapy (ART) with low-to-moderate atherosclerotic cardiovascular disease (ASCVD) risk. Among a subset of US REPRIEVE participants, coronary plaque was assessed by coronary computed tomography angiography. Here, we assessed the relationship between CMV immunoglobulin G (IgG) titer and (1) levels of immune activation, (2) inflammatory biomarkers, and (3) coronary plaque phenotypes at study entry.

RESULTS

Of 672 participants, mean age was 51 years, 83% were men, median ASCVD risk score was 4.5%, and 66% had current CD4+ T-cell count ≥500 cells/mm3. Higher CMV IgG quartile group was associated with older age and lower current and nadir CD4+ T-cell counts. CMV IgG titer was associated with specific inflammatory biomarkers (sCD163, MCP-1, interleukin [IL]-6, hsCRP) in univariate analysis, but not after controlling for HIV-specific factors. In contrast, CMV IgG titer was not associated with coronary artery disease indexes, including presence of plaque, coronary artery calcium (CAC) score >0, vulnerable plaque presence, or Leaman score >5.

CONCLUSIONS

No meaningful association was seen between CMV IgG titer and coronary artery disease indexes among ART-treated PWH at study enrollment. Longitudinal assessments in REPRIEVE will determine the relationship of CMV IgG titer to plaque progression and cardiovascular events.

CLINICAL TRIALS REGISTRATION

NCT02344290.

Influence of letermovir treatment on gut inflammation in people living with HIV on antiretroviral therapy: protocol of the open-label controlled randomised CIAO study

INTRODUCTION

Chronic cytomegalovirus (CMV) infection is very frequent in people living with HIV (PLWH). High anti-CMV IgG titres, which may be linked to transient CMV replication, have been associated with earlier mortality, CD8 T-cell expansion, lower CD4/CD8 ratio and increased T-cell senescence. We previously showed that anti-CMV IgG titres correlated with gut permeability in PLWH on antiretroviral therapy (ART), which was associated with microbial translocation, systemic inflammation and non-infectious/non-AIDS comorbidities. Letermovir, a novel anti-CMV drug with a good safety profile, was recently approved for anti-CMV prophylaxis in allogeneic haematopoietic stem cell transplant recipients. A drastic and selective reduction of both low-grade replication and clinically significant CMV infections, combined with an improved immune reconstitution have been reported. In vitro, letermovir prevented CMV-induced epithelial disruption in intestinal tissues. Based on these findings, we aim to assess whether letermovir could inhibit CMV subclinical replication in CMV-seropositive PLWH receiving ART and, in turn, decrease CMV-associated gut damage and inflammation.

METHOD AND ANALYSIS

We will conduct a multi-centre, open-label, randomised, controlled clinical trial, including a total of 60 CMV-seropositive ART-treated PLWH for at least 3 years, with a viral load <50 copies/mL and CD4+ count >400 cells/µL. Forty participants will be randomised to receive letermovir for 14 weeks and 20 participants will receive standard of care (ART) alone. Plasma, pheripheral blood mononuclear cells (PBMCs), and stool samples will be collected. Colon biopsies will be collected in an optional substudy. We will assess the effect of letermovir on gut damage, microbial translocation, inflammation and HIV reservoir size.

ETHICS AND DISSEMINATION

The study was approved by Health Canada and the Research Ethics Boards of the McGill University Health Centre (MUHC-REB, protocol number: MP37-2022-8295). Results will be made available through publications in open access peer-reviewed journals and through the CIHR/CTN website.

TRIAL REGISTRATION NUMBER

NCT05362916.

HIV but Not CMV Replication Alters the Blood Cytokine Network during Early HIV Infection in Men

OBJECTIVE

CMV coinfection contributes to sustained immune activation in people with chronic HIV. In particular, asymptomatic CMV shedding in semen has been associated with increased local and systemic immune activation, even during suppressive antiretroviral therapy (ART). However, the effect of seminal CMV shedding in people with HIV in the earliest phase of HIV infection is not known.

METHODS

Using Luminex, we measured the concentration of 34 cytokines in the blood plasma of sixty-nine men who had sex with men with or without HIV and in subgroups of CMV shedders vs. non-shedders. Differences in blood plasma cytokines between groups were investigated using the multivariate supervised partial least squares discriminant analysis method.

RESULTS

Independently of CMV, we found that concentrations of IP-10, MIG, MCP-1, I-TAC 10, IL-16, and MIP-1β were modulated in the earliest phase of HIV infection compared with control individuals without HIV. In people with HIV, there was no difference in blood cytokines among CMV shedders vs. non-shedders.

CONCLUSION

In early/acute HIV infection, asymptomatic CMV shedding in semen does not drive additional cytokine changes in blood. Early ART initiation should remain the priority, while the added benefit of CMV suppression during the various stages of HIV infection needs to be further investigated.

Etiology of Persistent Microalbuminuria in Nigeria (P_MICRO study): protocol and study design

BACKGROUND

Microalbuminuria is an independent risk factor for cardiovascular and kidney disease and a predictor of end organ damage, both in the general population and in persons with HIV (PWH). Microalbuminuria is also an important risk factor for mortality in PWH treated with antiretroviral therapy (ART). In the ongoing Renal Risk Reduction (R3) study in Nigeria, we identified a high prevalence of microalbuminuria confirmed by two measurements 4-8 weeks apart in ART-experienced, virologically suppressed PWH. Although Stage 1 or 2 hypertension and exposure to potentially nephrotoxic antiretroviral medications were common in R3 participants, other traditional risk factors for albuminuria and kidney disease, including diabetes, APOL1 high-risk genotype, and smoking were rare. Co-infection with endemic pathogens may also be significant contributors to albuminuria, but co-infections were not evaluated in the R3 study population.

METHODS

In Aim 1, we will cross-sectionally compare the prevalence of albuminuria and established kidney disease risk factors in a cohort of PWH to age- and sex-matched HIV-negative adults presenting for routine care at the Aminu Kano Teaching Hospital in Kano, Nigeria. We will leverage stored specimens from 2500 R3 participants and enroll an additional 500 PLWH recently initiated on ART (≤ 24 months) and 750 age- and sex-matched HIV-negative adults to determine the contribution of HIV, hypertension, and other comorbid medical conditions to prevalent albuminuria. In Aim 2, we will follow a cohort of 1000 HIV-positive, ART-treated and 500 HIV-negative normoalbuminuric adults for 30 months to evaluate the incidence and predictors of albuminuria.

DISCUSSION

The findings from this study will support the development of interventions to prevent or address microalbuminuria in PWH to reduce kidney and cardiovascular morbidity and mortality. Such interventions might include more intensive monitoring and treatment of traditional risk factors, the provision of renin-angiotensin aldosterone system or sodium-glucose cotransporter-2 inhibitors, consideration of changes in ART regimen, and screening and treatment for relevant co-infections.

Plasma d-amino acids are associated with markers of immune activation and organ dysfunction in people with HIV

BACKGROUND

d-Amino acids (d-AAs) have been associated with age-associated conditions in the general population but their relevance in people with HIV (PWH), who experience accentuated/accelerated aging has not been studied. We compared d-AA levels in HIV-infected and uninfected controls and explored their association with markers of immune activation, gut permeability and organ dysfunction.

DESIGN

Case-control analysis.

METHOD

Plasma samples from 60 antiretroviral therapy-treated HIV-infected individuals and 59 uninfected controls were analysed. A three-dimensional HPLC system was used to measure d-and l-asparagine, serine, alanine and proline and presented as %d-AA. Additionally, cell-associated and soluble markers of immune activation and senescence were characterized. Kidney and liver functions were expressed as estimated glomerular filtration rate and fibrosis-4 scores, respectively. Mann-Whitney and Spearman rank correlation coefficients were used for statistical analysis.

RESULTS

d-Asparagine, d-serine, d-alanine and d-proline were detectable in all plasma samples and correlated with age in HIV-infected and uninfected but not different between groups. Kynurenine/tryptophan ratio was positively correlated with all %d-AAs in PWH and with %d-serine and %d-proline in controls. %d-AAs were not consistently correlated with markers of gut permeability in both groups. All %d-AAs were also correlated with kidney function in both groups whereas age-associated accumulation of %d-asparagine, %d-serine and %d-proline were correlated with liver function and the VACS score in controls.

CONCLUSION

Plasma d-AAs are associated with chronological age and correlated with markers of immune activation and organ decline, though variably, in PWH and controls. Their role in the biology of aging warrants further investigation.

A novel prediction model to evaluate the probability of CD4+/CD8+ cell ratio restoration in HIV-infected individuals

BACKGROUND

Our study aimed to develop a clinical prediction model to evaluate the possibility of CD4+/CD8+ ratio restoration in HIV-positive individuals.

METHODS

About 1980, HIV/AIDS patients initiated with antiretroviral treatment from 1 January 2013, to 30 December 2016, at Beijing Ditan Hospital and achieved persistent virological suppression during the 4 years follow-up were included in this study. Multivariate Cox proportional regression analysis was used to identify the independent risk factors and establish a predictive model. The model's performance was assessed using the area under the receiver operating characteristic and calibration plots.

RESULTS

Overall, after 4 years of treatment, a total of 455 individuals (22.98%) restored their CD4+/CD8+ ratio (≥1). The area under the receiver operating characteristic was 0.782 and 0.743 in the deriving and validation cohort, respectively. The ultimate model included five indexes: age at AIDS diagnosis, albumin, and syphilis status, and baseline CD4+ and CD8+ values. A nomogram further visualized the model, and the calibration plots indicated high agreement of predicted and observed outcomes.

CONCLUSION

Our prediction model might be practical and easily applied to recognize HIV/AIDS individuals most likely to benefit from modern antiretroviral therapy.

Cytomegalovirus Viremia and Clinical Outcomes in Kenyan Children Diagnosed With Human Immunodeficiency Virus (HIV) in Hospital

BACKGROUND

Cytomegalovirus (CMV) viremia is common in human immunodeficiency virus (HIV) infection and is associated with worse long-term outcomes. To date, no studies have assessed CMV viremia in children diagnosed with HIV in hospital.

METHODS

We studied CMV viremia and clinical outcomes in 163 Kenyan children aged 2 months to 12 years, diagnosed with HIV in hospital. CMV DNA levels in plasma were measured using quantitative polymerase chain reaction (PCR). Regression models were used to assess associations between CMV viremia ≥1000 IU/mL and the risk of continued hospitalization or death at 15 days, duration of hospitalization, and 6-month mortality.

RESULTS

At enrollment, 62/114 (54%) children had CMV viremia, and 20 (32%) were ≥1000 IU/mL. Eleven CMV reactivations were observed after admission. The prevalence and level of CMV viremia were highest in children <2 years and lowest in children ≥5 years old. CMV viremia ≥1000 IU/mL was independently associated with age <2 years (P = .03), higher log10 HIV RNA level (P = .01), and height-for-age z score >-2 (P = .02). Adjusting for age and log10 HIV RNA, the relative risk of death or continued hospitalization at 15 days was 1.74 (95% confidence interval [CI] = 1.04, 2.90), and the hazard ratio of 6-month mortality was 1.97 (95% CI = .57, 5.07) for children with CMV DNA ≥1000 IU/mL compared to lower-level or undetectable CMV DNA. Children with CMV DNA ≥1000 IU/mL were hospitalized a median ~5 days longer than children with lower-level or undetectable CMV DNA (P = .002).

CONCLUSIONS

In this nested observational study, CMV viremia was common in hospitalized children with HIV, and levels ≥1000 IU/mL were associated with increased risk of mortality and longer hospitalization.

Distinct Plasma Concentrations of Acyl-CoA-Binding Protein (ACBP) in HIV Progressors and Elite Controllers

HIV elite controllers (ECs) are characterized by the spontaneous control of viral replication, and by metabolic and autophagic profiles which favor anti-HIV CD4 and CD8 T-cell responses. Extracellular acyl coenzyme A binding protein (ACBP) acts as a feedback inhibitor of autophagy. Herein, we assessed the circulating ACBP levels in ECs, compared to people living with HIV (PLWH) receiving antiretroviral therapy (ART) or not. We found lower ACBP levels in ECs compared to ART-naïve or ART-treated PLWH (p < 0.01 for both comparisons), independently of age and sex. ACBP levels were similar in ECs and HIV-uninfected controls. The expression of the protective HLA alleles HLA-B*27, *57, or *58 did not influence ACBP levels in ECs. ACBP levels were not associated with CD4 or CD8 T-cell counts, CD4 loss over time, inflammatory cytokines, or anti-CMV IgG titers in ECs. In ART-treated PLWH, ACBP levels were correlated with interleukin (IL)-1β levels, but not with other inflammatory cytokines such as IL-6, IL-8, IL-32, or TNF-α. In conclusion, ECs are characterized by low ACBP plasma levels compared to ART-naïve or ART-treated PLWH. As autophagy is key to anti-HIV CD4 and CD8 T-cell responses, the ACBP pathway constitutes an interesting target in HIV cure strategies.

Aging With Grace for People Living With HIV: Strategies to Overcome Leaky Gut and Cytomegalovirus Coinfection

ABSTRACT

The intestinal epithelial layer acts as a mechanical and functional barrier between the intraluminal microbiota and the immunologically active submucosa. A progressive loss of gut barrier function (leaky gut) leads to enhanced translocation of microbial products, which in turn contributes as endotoxins to inflammaging. Th17 T cell represents the main immune sentinels in the gut epithelium, preventing aggression from commensal and pathogenic microbes. As HIV infection deeply affects gut Th17 function and increases gut permeability, microbial translocation occurs at high level in people living with HIV (PLWH) and has been associated with the development of non-AIDS comorbidities. Although the inflammatory role of endotoxins like lipopolysaccharide produced by Gram-negative bacteria is well-established, fungal products such as β-D-glucan emerge as new contributors. In addition, PLWH are more frequently infected with cytomegalovirus (CMV) than the general population. CMV infection is a well-described accelerator of immune aging, through the induction of expansion of dysfunctional CD8 T-cells as well as through enhancement of gut microbial translocation. We critically review immune mechanisms related to bacterial and fungal translocation, with a focus on the contribution of CMV coinfection in PLWH. Improving gut barrier dysfunction, microbial composition, and reducing microbial translocation constitute emerging strategies for the prevention and treatment of HIV-associated inflammation and may be relevant for age-related inflammatory conditions.

Microbiota-Meditated Immunity Abnormalities Facilitate Hepatitis B Virus Co-Infection in People Living With HIV: A Review

Hepatitis B virus (HBV) co-infection is fairly common in people living with HIV (PLWH) and affects millions of people worldwide. Identical transmission routes and HIV-induced immune suppression have been assumed to be the main factors contributing to this phenomenon. Moreover, convergent evidence has shown that people co-infected with HIV and HBV are more likely to have long-term serious medical problems, suffer more from liver-related diseases, and have higher mortality rates, compared to individuals infected exclusively by either HIV or HBV. However, the precise mechanisms underlying the comorbid infection of HIV and HBV have not been fully elucidated. In recent times, the human gastrointestinal microbiome is progressively being recognized as playing a pivotal role in modulating immune function, and is likely to also contribute significantly to critical processes involving systemic inflammation. Both antiretroviral therapy (ART)-naïve HIV-infected subjects and ART-treated individuals are now known to be characterized by having gut microbiomic dysbiosis, which is associated with a damaged intestinal barrier, impaired mucosal immunological functioning, increased microbial translocation, and long-term immune activation. Altered microbiota-related products in PLWH, such as lipopolysaccharide (LPS) and short-chain fatty acids (SCFA), have been associated with the development of leaky gut syndrome, favoring microbial translocation, which in turn has been associated with a chronically activated underlying host immune response and hence the facilitated pathogenesis of HBV infection. Herein, we critically review the interplay among gut microbiota, immunity, and HIV and HBV infection, thus laying down the groundwork with respect to the future development of effective strategies to efficiently restore normally diversified gut microbiota in PLWH with a dysregulated gut microbiome, and thus potentially reduce the prevalence of HBV infection in this population.

Seroprevalence of Epstein-Barr virus and cytomegalovirus infections in Presidente Figueiredo, Amazonas, Brazil

Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infections affect around 95% of the world's population. In Brazil, there are few epidemiological reports related to EBV and CMV infection, especially in the western Amazon region. This study aimed to estimate the seroprevalence of EBV and CMV infection in individuals residents in Presidente Figueiredo, Amazonas, Brazil. Blood samples of 443 individuals were tested for the presence of anti-EBV and anti-CMV IgG antibodies through an enzyme-linked immunosorbent assay. EBV (95.9%; 95% CI: 0.94;0.98), CMV (96.8%; 95% CI: 0.95;0.98) and CMV/EBV (93%;95% CI: 0.91-0.95) coinfection were highly prevalent in the study population. Children (1 to 5 years) not attending school were less susceptible to EBV (OR 0.15; 95% CI: 0.05-0.52; p = 0.017) and CMV infections (OR 0.05; 95% CI: 0.02 - 0.17; p < 0.0001). Teenagers at high school showed increased susceptibility to CMV infection (OR 4.65; 95%CI: 1.43-15.08; p = .013) and EBV/CMV co-infection (OR 3.04; 95%CI: 1.44-6.45; p = 0.005). The seroprevalence of CMV and EBV infections were preeminent and tend to increase with age in the study population. Either attendance to a daycare facility or primary school before the age of 5 years may increase the susceptibility to EBV or CMV infection.

More than a Gender Issue: Testis as a Distinctive HIV Reservoir and Its Implication for Viral Eradication

Early establishment of HIV reservoir represents the main impediment to an HIV cure. Mainly composed of infected memory CD4 T-cells and macrophages, HIV reservoirs are found in several organs including lymph nodes, gut, and testes. In men, and as seen in brain and eyes, testes represent a distinctive organ characterized by an immune privilege, allowing the tolerance of spermatozoa which only develop after puberty, long after the establishment of systemic immunity. The immune privilege of testes relies on a strict testis-blood barrier, and a local immunosuppressive environment. Testes has been described as reservoir for several viruses including Ebola, Zika, and HIV. Indeed, HIV reservoirs were detected in tested viremic and virally suppressed donor taking antiretroviral therapy (ART). Herein, we discuss the distinctive environment found in human testes and describe a validated method allowing the characterization and quantification of HIV-infected CD4 T-cells in human testes. Using mechanical and enzymatic treatment, cells can be extracted from human testis samples. Characterization of those cells can be performed by flow cytometry and HIV reservoir quantification performed by nested qPCR after flow cytometry sorting.

Glutathione Metabolism Is a Regulator of the Acute Inflammatory Response of Monocytes to (1→3)-β-D-Glucan

(1→3)-β-D-Glucan (BDG) represents a potent pathogen-associated molecular pattern (PAMP) in triggering the host response to fungal and some bacterial infections. Monocytes play a key role in recognizing BDG and governing the acute host response to infections. However, the mechanisms regulating monocyte's acute response to BDG are poorly understood. We sought to investigate the response of monocytes to BDG at the epigenetic, transcriptomic, and molecular levels. Response of human monocytes to 1, 4, and 24 hours of BDG exposure was investigated using RNA-seq, ATAC-seq, H3K27ac and H3K4me1 ChIP-seq. We show that pathways including glutathione metabolism, pentose phosphate pathway, and citric acid cycle were upregulated at the epigenetic and transcriptomic levels in response to BDG exposure. Strikingly, unlike bacterial lipopolysaccharides, BDG induced intracellular glutathione synthesis. BDG exposure also induced NADP synthesis, increased NADPH/NADP ratio, and increased expression of genes involved in the pentose phosphate pathway in a GSH-dependent manner. By inhibiting GSH synthesis with L-buthionine sulfoximine (BSO) before BDG exposure we show that the GSH pathway promotes cell survival and regulates monocyte's effector functions including NO production, phagocytosis, and cytokine production. In summary, our work demonstrates that BDG induces glutathione synthesis and metabolism in monocytes, which is a major promoter of the acute functional response of monocytes to infections.

Immunological age prediction in HIV-infected, ART-treated individuals

Anti-retroviral therapy (ART) improves life expectancy in people living with HIV (PWH), but it remains unclear how chronic HIV infection affects normal aging of the immune system. Plasma cell-free protein expression and immune phenotypes were assessed in blood from ART treated PWH (19-77yrs, n = 106) and age-matched, HIV-negative controls (HC, n = 103). Using univariate spearman correlation, we identified 277 and 491 age-associated parameters out of a total 1,357 in HC and PWH, respectively. PWH exhibited shared and distinct age-associated immune profiles compared to HC highlighting the effect of HIV infection on immunological aging. Our analysis resulted in an 8-parameter, plasma-detectable inflammatory index that correlated with chronological age of all study participants but was higher overall in PWH. Additionally, predictive modeling for age in HC participants and age-associated parameters generated a 25-parameter signature, IMAP-25, with 70% and 53% accuracy in HC and PWH, respectively. Applying the IMAP-25 signature to immunological data from PWH revealed accelerated aging in PWH by 5.6 yrs. Overall, our results demonstrate that immune signatures, easily monitored in human blood samples, can be used as an indicator of one’s ‘immunological age’ during ART-treated HIV infection and can be applied to other disease states that affect the immune system.

Cytomegalovirus viremia is associated with poor outcomes in AIDS patients with disseminated nontuberculous mycobacterial disease

Both cytomegalovirus (CMV) viremia and disseminated nontuberculous mycobacterial (NTM) disease are common opportunistic infections in AIDS patients. Whether concurrent CMV viremia is associated with mortality in patients with AIDS and disseminated NTM disease is unknown. Subjects were patients with AIDS and disseminated NTM disease seen at a single center from January 2015 to April 2021. Data were retrospectively collected. Differences in demographics and clinical characteristics and hospitalization survival rates were compared between patients with disseminated NTM and with CMV viremia or not. Subjects were 113 AIDS patients with disseminated NTM who were seen at this Hospital from January 2015 to April 2021. Twenty-six of the patients had CMV viremia and 87 did not. The median age was 36 years (interquartile range [IQR] 29-42) and 108 patients were male (96%). The median CD4 count was 7 cells/µL (IQR 3-17). The median plasma CMV viral load was 9,245 IU/mL (IQR 3147-45725). The serum albumin of patients with CMV viremia was significantly lower than that of patients without CMV viremia (P = 0.03). Compared to patients without CMV viremia (81.6%), patients with CMV viremia had a significantly poorer prognosis (P = 0.01). Cox regression analysis indicated that the risk of a poor prognosis in patients with CMV viremia was 4.7 times higher than that in patients without CMV viremia (P = 0.003), and patients with CD8 more than 250/μL had a better prognosis (P = 0.02). CMV viremia increases the risk of a poor prognosis in patients with AIDS and a disseminated NTM infection. A routine CMV DNA test should be performed on patients with AIDS and disseminated NTM disease in order to reduce the risk of death.

Immune Landscape of CMV Infection in Cancer Patients: From "Canonical" Diseases Toward Virus-Elicited Oncomodulation

Human Cytomegalovirus (HCMV) is an immensely pervasive herpesvirus, persistently infecting high percentages of the world population. Despite the apparent robust host immune responses, HCMV is capable of replicating, evading host defenses, and establishing latency throughout life by developing multiple immune-modulatory strategies. HCMV has coexisted with humans mounting various mechanisms to evade immune cells and effectively win the HCMV-immune system battle mainly through maintaining its viral genome, impairing HLA Class I and II molecule expression, evading from natural killer (NK) cell-mediated cytotoxicity, interfering with cellular signaling, inhibiting apoptosis, escaping complement attack, and stimulating immunosuppressive cytokines (immune tolerance). HCMV expresses several gene products that modulate the host immune response and promote modifications in non-coding RNA and regulatory proteins. These changes are linked to several complications, such as immunosenescence and malignant phenotypes leading to immunosuppressive tumor microenvironment (TME) and oncomodulation. Hence, tumor survival is promoted by affecting cellular proliferation and survival, invasion, immune evasion, immunosuppression, and giving rise to angiogenic factors. Viewing HCMV-induced evasion mechanisms will play a principal role in developing novel adapted therapeutic approaches against HCMV, especially since immunotherapy has revolutionized cancer therapeutic strategies. Since tumors acquire immune evasion strategies, anti-tumor immunity could be prominently triggered by multimodal strategies to induce, on one side, immunogenic tumor apoptosis and to actively oppose the immune suppressive microenvironment, on the other side.

CMV Infection Is Directly Related to the Inflammatory Status in Chronic Heart Failure Patients

High levels of inflammation play an important role in chronic heart failure (CHF). Patients with CHF have elevated levels of pro-inflammatory cytokines circulating systemically, mainly TNF and IL-6. However, there are almost no studies that relate these levels to the functional status of patients in CHF, much less to their CMV serostatus. In this study, patients with CHF (n=40; age=54.9 ± 6.3; New York Heart Association functional classification (NYHA, I-III) and healthy controls (n=40; age=53.5 ± 7.1) were analyzed. The serum concentrations of nine pro- and anti-inflammatory cytokines were measured by Luminex^® xMap Technology and the basal level of mRNA expression of some immune molecules was quantified by TaqMan™ Array in CD4+ T-lymphocytes. The concentration of these cytokines in culture supernatants in response to anti-CD3 and LPS was also measured. The percentage of CD28null T-cells was determined, as well as the antibody titer against CMV. We found a higher concentration of all cytokines studied in CHF serum compared to healthy controls, as well as a direct correlation between functional status in CHF patients and levels of inflammatory cytokines. Moreover, the highest cytokine concentrations were found in patients with higher concentrations of lymphocytes lacking CD28 molecule. The cytokine production was much higher in CMV+ patients, and the production of these cytokines was found mainly in the T-lymphocytes of CMV+ patients in response to anti-CD3. Anti-CMV antibody levels were positively correlated with cytokine levels. The baseline expression of specific mRNA of the main molecules involved in the Th1 response, as well as molecules related to the CD4+CD28 null subset was higher in CMV+ patients. The cytokine concentrations are higher in CHF CMV+ patients and these concentrations are related to the production of antibodies against CMV. These high levels of cytokines are also associated with the more differentiated CD28null lymphocyte populations. All this, together with the dynamics of the pathology itself, makes CMV+ patients present a worse functional status and possibly a worse evolution of the pathology.

Influence of NKG2C Genotypes on HIV Susceptibility and Viral Load Set Point

NKG2C is an activating NK cell receptor encoded by a gene having an unexpressed deletion variant. Cytomegalovirus (CMV) infection expands a population of NKG2C+ NK cells with adaptive-like properties. Previous reports found that carriage of the deleted NKG2C- variant was more frequent in people living with HIV (PLWH) than in HIV- controls unexposed to HIV. The frequency of NKG2C+ NK cells positively correlated with HIV viral load (VL) in some studies and negatively correlated with VL in others. Here, we investigated the link between NKG2C genotype and HIV susceptibility and VL set point in PLWH. NKG2C genotyping was performed on 434 PLWH and 157 HIV-exposed seronegative (HESN) subjects. Comparison of the distributions of the three possible NKG2C genotypes in these populations revealed that the frequencies of NKG2C+/+ and NKG2C+/- carriers did not differ significantly between PLWH and HESN subjects, while that of NKG2C-/- carriers was higher in PLWH than in HESN subjects, in which none were found (P = 0.03, χ2 test). We were unable to replicate that carriage of at least 1 NKG2C- allele was more frequent in PLWH. Information on the pretreatment VL set point was available for 160 NKG2C+/+, 83 NKG2C+/-, and 6 NKG2C-/- PLWH. HIV VL set points were similar between NKG2C genotypes. The frequency of NKG2C+ CD3- CD14- CD19- CD56dim NK cells and the mean fluorescence intensity (MFI) of NKG2C expression on NK cells were higher on cells from CMV+ PLWH who carried 2, versus 1, NKG2C+ alleles. We observed no correlations between VL set point and either the frequency or the MFI of NKG2C expression. IMPORTANCE We compared NKG2C allele and genotype distributions in subjects who remained HIV uninfected despite multiple HIV exposures (HESN subjects) with those in the group PLWH. This allowed us to determine whether NKG2C genotype influenced susceptibility to HIV infection. The absence of the NKG2C-/- genotype among HESN subjects but not PLWH suggested that carriage of this genotype was associated with HIV susceptibility. We calculated the VL set point in a subset of 252 NKG2C-genotyped PLWH. We observed no between-group differences in the VL set point in carriers of the three possible NKG2C genotypes. No significant correlations were seen between the frequency or MFI of NKG2C expression on NK cells and VL set point in cytomegalovirus-coinfected PLWH. These findings suggested that adaptive NK cells played no role in establishing the in VL set point, a parameter that is a predictor of the rate of treatment-naive HIV disease progression.

Plasma 1,3-β-d-glucan levels predict adverse clinical outcomes in critical illness

BACKGROUNDThe fungal cell wall constituent 1,3-β-d-glucan (BDG) is a pathogen-associated molecular pattern that can stimulate innate immunity. We hypothesized that BDG from colonizing fungi in critically ill patients may translocate into the systemic circulation and be associated with host inflammation and outcomes.METHODSWe enrolled 453 mechanically ventilated patients with acute respiratory failure (ARF) without invasive fungal infection and measured BDG, innate immunity, and epithelial permeability biomarkers in serially collected plasma samples.RESULTSCompared with healthy controls, patients with ARF had significantly higher BDG levels (median [IQR], 26 pg/mL [15-49 pg/mL], P < 0.001), whereas patients with ARF with high BDG levels (≥40 pg/mL, 31%) had higher odds for assignment to the prognostically adverse hyperinflammatory subphenotype (OR [CI], 2.88 [1.83-4.54], P < 0.001). Baseline BDG levels were predictive of fewer ventilator-free days and worse 30-day survival (adjusted P < 0.05). Integrative analyses of fungal colonization and epithelial barrier disruption suggested that BDG may translocate from either the lung or gut compartment. We validated the associations between plasma BDG and host inflammatory responses in 97 hospitalized patients with COVID-19.CONCLUSIONBDG measurements offered prognostic information in critically ill patients without fungal infections. Further research in the mechanisms of translocation and innate immunity recognition and stimulation may offer new therapeutic opportunities in critical illness.FUNDINGUniversity of Pittsburgh Clinical and Translational Science Institute, COVID-19 Pilot Award and NIH grants (K23 HL139987, U01 HL098962, P01 HL114453, R01 HL097376, K24 HL123342, U01 HL137159, R01 LM012087, K08HK144820, F32 HL142172, K23 GM122069).

Anti-cytomegalovirus Immunoglobulin G Is Linked to CD4 T-cell Count Decay in Human Immunodeficiency Virus (HIV) Elite Controllers

Elite controllers (ECs) are people living with human immunodeficiency virus (HIV) who spontaneously control viral replication without antiretroviral therapy. We observed that elevated anti-cytomegalovirus (CMV) immunoglobulin G (IgG) levels correlated with annual CD4 T-cell count decay in ECs independently of age, sex, and human leukocyte antigen (HLA) type. Elevated anti-CMV titers may favor disease progression in ECs.

Cytomegalovirus as an Uninvited Guest in the Response to Vaccines in People Living with HIV

In stark contrast to the rapid development of vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), an effective human immunodeficiency virus (HIV) vaccine is still lacking. Furthermore, despite virologic suppression and CD4 T-cell count normalization with antiretroviral therapy (ART), people living with HIV (PLWH) still exhibit increased morbidity and mortality compared to the general population. Such differences in health outcomes are related to higher risk behaviors, but also to HIV-related immune activation and viral coinfections. Among these coinfections, cytomegalovirus (CMV) latent infection is a well-known inducer of long-term immune dysregulation. Cytomegalovirus contributes to the persistent immune activation in PLWH receiving ART by directly skewing immune response toward itself, and by increasing immune activation through modification of the gut microbiota and microbial translocation. In addition, through induction of immunosenescence, CMV has been associated with a decreased response to infections and vaccines. This review provides a comprehensive overview of the influence of CMV on the immune system, the mechanisms underlying a reduced response to vaccines, and discuss new therapeutic advances targeting CMV that could be used to improve vaccine response in PLWH.

Clinical consequences of asymptomatic cytomegalovirus in treated human immunodeficency virus infection

PURPOSE OF REVIEW

Despite antiretroviral therapy (ART)-mediated viral suppression, people with human immunodeficiency virus (HIV) (PWH) have increased morbidity and mortality. Immune activation and inflammation persist on ART and predict these complications. Over 90% of PWH have cytomegalovirus (CMV) co-infection, and CMV is considered a plausible contributor to this persistent immune activation.

RECENT FINDINGS

A detailed understanding of the link between CMV and multimorbidity is needed, particularly as research moves toward identifying potential targeted therapeutics to attenuate inflammation-mediated morbidity and mortality in treated HIV. We review the literature on the association between CMV and immune activation as well as multiple end-organ complications including cardiovascular disease, venous thromboembolic disease, metabolic complications, gastrointestinal dysfunction, central nervous system involvement, birth sex-related differences, and the relation to the HIV reservoir. We conclude with a discussion of ongoing therapeutic efforts to target CMV.

SUMMARY

As CMV is a plausible driver of multiple comorbidities through persistent immune activation in treated HIV, future research is needed and planned to address its causal role as well as to test novel therapeutics in this setting.

Prevalence and Characterization of Subclinical Coronary Atherosclerotic Plaque with CT among Individuals with HIV: Results from the Canadian HIV and Aging Cohort Study

Background People living with HIV (PLWH) have a higher risk of myocardial infarction. Coronary atherosclerotic plaque CT characterization helps to predict cardiovascular risk. Purpose To measure CT characteristics of coronary plaque in PLWH without known cardiovascular disease and healthy volunteers without HIV. Materials and Methods In this prospective study, noncontrast CT (all participants, n = 265) was used for coronary artery calcium (CAC) scoring in asymptomatic PLWH and healthy volunteers without HIV, without known cardiovascular disease, from 2012 to 2019. At coronary CT angiography (n = 233), prevalence, frequency, and volume of calcified, mixed, and noncalcified plaque were measured. Poisson regressions were used with adjustment for cardiovascular risk factors. Results There were 181 PLWH (mean age, 56 years ± 7; 167 men) and 84 healthy volunteers (mean age, 57 years ± 8; 65 men) evaluated by using noncontrast CT. CT angiography was performed in 155 PLWH and 78 healthy volunteers. Median 10-year Framingham risk score was not different between PLWH and healthy volunteers (10% vs 9%, respectively; P = .45), as were CAC score (odds ratio [OR], 1.06; 95% CI: 0.58, 1.94; P = .85) and overall plaque prevalence (prevalence ratio, 1.07; 95% CI: 0.86, 1.32; P = .55) after adjustment for cardiovascular risk. Noncalcified plaque prevalence (prevalence ratio, 2.5; 95% CI: 1.07, 5.67; P = .03) and volume (OR, 2.8; 95% CI: 1.05, 7.40; P = .04) were higher in PLWH. Calcified plaque frequency was reduced in PLWH (OR, 0.6; 95% CI: 0.40, 0.91; P = .02). Treatment with protease inhibitors was associated with higher volume of overall (OR, 1.8; 95% CI: 1.09, 2.85; P = .02) and mixed plaque (OR, 1.6; 95% CI: 1.04, 2.45; P = .03). Conclusion Noncalcified coronary plaque burden at coronary CT angiography was two- to threefold higher in asymptomatic people living with HIV without known cardiovascular disease compared with healthy volunteers without HIV. © RSNA, 2021 Online supplemental material is available for this article. See also the editorial by Lai in this issue.

The Architecture of Circulating Immune Cells Is Dysregulated in People Living With HIV on Long Term Antiretroviral Treatment and Relates With Markers of the HIV-1 Reservoir, Cytomegalovirus, and Microbial Translocation

Long-term changes in the immune system of successfully treated people living with HIV (PLHIV) remain incompletely understood. In this study, we assessed 108 white blood cell (WBC) populations in a cohort of 211 PLHIV on stable antiretroviral therapy and in 56 HIV-uninfected controls using flow cytometry. We show that marked differences exist in T cell maturation and differentiation between PLHIV and HIV-uninfected controls: PLHIV had reduced percentages of CD4+ T cells and naïve T cells and increased percentages of CD8+ T cells, effector T cells, and T helper 17 (Th17) cells, together with increased Th17/regulatory T cell (Treg) ratios. PLHIV also exhibited altered B cell maturation with reduced percentages of memory B cells and increased numbers of plasmablasts. Determinants of the T and B cell composition in PLHIV included host factors (age, sex, and smoking), markers of the HIV reservoir, and CMV serostatus. Moreover, higher circulating Th17 percentages were associated with higher plasma concentrations of interleukin (IL) 6, soluble CD14, the gut homing chemokine CCL20, and intestinal fatty acid binding protein (IFABP). The changes in circulating lymphocytes translated into functional changes with reduced interferon (IFN)- γ responses of peripheral blood mononuclear cells to stimulation with Candida albicans and Mycobacterium tuberculosis. In conclusion, this comprehensive analysis confirms the importance of persistent abnormalities in the number and function of circulating immune cells in PLHIV on stable treatment.

Gut Leakage of Fungal-Related Products: Turning Up the Heat for HIV Infection

The intestinal epithelial layer serves as a physical and functional barrier between the microbiota in the lumen and immunologically active submucosa. Th17 T-cell function protects the gut epithelium from aggression from microbes and their by-products. Loss of barrier function has been associated with enhanced translocation of microbial products which act as endotoxins, leading to local and systemic immune activation. Whereas the inflammatory role of LPS produced by Gram-negative bacteria has been extensively studied, the role of fungal products such as β-D-glucan remains only partially understood. As HIV infection is characterized by impaired gut Th17 function and increased gut permeability, we critically review mechanisms of immune activation related to fungal translocation in this viral infection. Additionally, we discuss markers of fungal translocation for diagnosis and monitoring of experimental treatment responses. Targeting gut barrier dysfunction and reducing fungal translocation are emerging strategies for the prevention and treatment of HIV-associated inflammation and may prove useful in other inflammatory chronic diseases.

Circulating β-d-Glucan as a Marker of Subclinical Coronary Plaque in Antiretroviral Therapy-Treated People With Human Immunodeficiency Virus

Background

Despite antiretroviral therapy (ART), people with human immunodeficiency virus (PWH) have increased risk of inflammatory comorbidities, including cardiovascular diseases. Gut epithelial damage, and translocation of bacterial lipopolysaccharide (LPS) or fungal β-d-glucan (BDG) drive inflammation in ART-treated PWH. In this study, we investigated whether markers of gut damage and microbial translocation were associated with cardiovascular risk in asymptomatic ART-treated PWH.

Methods

We cross-sectionally analyzed plasma from 93 ART-treated PWH and 52 uninfected controls older than 40 years of age from the Canadian HIV and Aging Cohort. Participants were cardiovascular disease free and underwent a cardiac computed tomography (CT) to measure total coronary atherosclerotic plaque volume (TPV). Levels of bacterial LPS and gut damage markers REG3α and I-FABP were measured by enzyme-linked immunosorbent assay. Fungal BDG levels were analyzed using the Fungitell assay.

Results

β-d-glucan levels but not LPS were significantly elevated in ART-treated PWH with coronary artery plaque (P = .0007). Moreover, BDG but not LPS levels correlated with TPV (r = 0.26, P = .01). Intestinal fatty acid binding protein (I-FABP) but not REG3α levels correlated with TPV (r = 0.23, P = .03). However, BDG and LPS levels were not elevated in uninfected controls with plaque. In multivariable models, elevated BDG levels were independently associated with the presence of coronary atherosclerosis in PWH but not in uninfected controls.

Conclusions

Translocation of fungal BDG was associated with coronary atherosclerosis assessed by CT-scan imaging in ART-treated PWH, suggesting a human immunodeficiency virus-specific pathway leading to cardiovascular disease. Further investigation is needed to appraise causality of this association. Translocation of fungal products may represent a therapeutic target to prevent cardiovascular disease in ART-treated PWH.

Plasma levels of the fungal product β-D-Glucan, but not the bacterial product lipopolysaccharide, are associated with the presence and the size of subclinical coronary atherosclerosis plaque in people living with HIV taking antiretroviral therapy, independently of classical cardiovascular risk factors.

Fecal Calprotectin Is Elevated in HIV and Related to Systemic Inflammation

BACKGROUND

Fecal calprotectin (FC), a biomarker of gastrointestinal (GI) inflammation, is used in the diagnosis and management of inflammatory bowel disease. HIV infection severely damages gut-associated lymphoid and epithelial tissues leading to GI inflammation that drives systemic inflammation and increases subsequent risk of comorbidities. For the first time, we compared FC concentrations by HIV and antiretroviral therapy (ART) status and determined the relationship to systemic inflammation.

METHODS

People with and without HIV were enrolled and underwent a comprehensive clinical and laboratory assessment. Stool samples were collected, and FC was measured by enzyme-linked immunosorbent assay ELISA. Plasma biomarkers of inflammation were also measured.

RESULTS

One hundred one participants with HIV (83 ART-treated and 18 ART-naive) and 89 uninfected controls were enrolled. There were no significant differences between ART-naive and ART-treated participants, but both HIV groups had significantly higher FC concentrations than controls when FC was considered as a continuous variable or by cut-offs used in inflammatory bowel disease. The highest median and largest proportion of participants with FC >100 µg/g were seen in ART-naive, followed by ART-treated and then controls. Among HIV participants, FC concentrations were positively associated with high-sensitivity C-reactive protein, soluble tumor necrosis factor receptor II, and soluble vascular cellular adhesion molecule and inversely associated with CD4 counts.

CONCLUSIONS

FC concentrations are elevated in HIV regardless of ART status. ART and immune reconstitution seem to reduce FC but not to concentrations seen in uninfected controls. Our results suggest a role for FC as a noninvasive surrogate measurement of GI inflammation and associated systemic inflammation in HIV.

Chronic obstructive pulmonary disease in HIV

Introduction: Chronic obstructive pulmonary disease (COPD) is more prevalent in people with HIV (PWH) than in the general population and leads to an increased burden of morbidity and mortality in this population. The mechanisms behind COPD development and progression in PWH are not fully elucidated, and there are no PWH-specific guidelines for COPD management. Areas covered: The goal of this broad narrative review is to review the epidemiology of COPD in PWH globally, highlight proposed pathways contributing to increased COPD prevalence and progression in PWH, discuss structural and functional changes in the lungs in this population, assesses the excess mortality and comorbidities in PWH with COPD, and address management practices for this unique population. Expert opinion: Understanding how a chronic viral infection leads to COPD, independent of cigarette smoking, is of critical scientific importance. Further research should focus on the pathophysiology of the interaction between HIV and COPD, and determine the role of disease-modifying risk factors such as opportunistic pneumonia and air pollution, as well as generate data from randomized clinical trials on the safety and efficacy of specific therapies for this vulnerable patient population.

Antiretroviral therapy reduces but does not normalize immune and vascular inflammatory markers in adults with chronic HIV infection in Kenya

INTRODUCTION

Markers of monocyte/macrophage activation and vascular inflammation are associated with HIV-related cardiovascular diseases (CVD) and mortality. We compared these markers among African people living with HIV (PLWH) and HIV-negative adults, and examined risk factors associated with elevated biomarkers (>75th percentile) in PLWH on antiretroviral therapy (ART).

DESIGN

Cross-sectional study.

METHODS

We measured serum concentrations of a gut integrity biomarker (intestinal-fatty acid binding protein), monocyte/macrophage activation biomarkers (soluble CD14 and CD163), and vascular inflammation biomarkers [soluble intercellular adhesion molecule 1 (sICAM-1) and soluble vascular adhesion molecule 1 (sVCAM-1)]. We assessed the relationship of these inflammatory parameters with HIV, using logistic regression adjusting for traditional CVD risk factors.

RESULTS

Among the 541 participants, median age was 43 years and half were female. Among 275 PLWH, median CD4 T-cell count and duration of ART use was 509 cells/μl and 8 years, respectively. PLWH had significantly higher prevalence of elevated inflammatory biomarkers compared with HIV-negative individuals even after adjustment for traditional CVD risk factors. Compared with individuals without HIV, the prevalence of elevated biomarkers was highest among persons with detectable viral load and CD4 T-cell counts 200 cells/μl or less. In a subanalysis among PLWH, nadir CD4 T-cell count 200 cells/μl or less was associated with elevated soluble CD14 (sCD14); dyslipidemia with elevated sCD14, sICAM-1, and sVCAM-1; and overweight/obesity with reduced sCD14. Longer ART exposure (>4 years) was associated with reduced sVCAM-1 and sICAM-1.

CONCLUSION

HIV and not traditional CVD risk factors is a primary contributor of monocyte/macrophage activation and inflammation despite ART. Anti-inflammatory therapies in addition to ART may be necessary to reduce these immune dysregulations and improve health outcomes of African PLWH.

Specificity Influences in (1→3)-β-d-Glucan-Supported Diagnosis of Invasive Fungal Disease

(1→3)-β-glucan (BDG) testing as an adjunct in the diagnosis of invasive fungal disease (IFD) has been in use for nearly three decades. While BDG has a very high negative predictive value in this setting, diagnostic false positives may occur, limiting specificity and positive predictive value. Although results may be diagnostically false positive, they are analytically correct, due to the presence of BDG in the circulation. This review surveys the non-IFD causes of elevated circulating BDG. These are in the main, iatrogenic patient contamination through the use of BDG-containing medical devices and parenterally-delivered materials as well as translocation of intestinal luminal BDG due to mucosal barrier injury. Additionally, infection with Nocardia sp. may also contribute to elevated circulating BDG. Knowledge of the factors which may contribute to such non-IFD-related test results can improve the planning and interpretation of BDG assays and permit investigational strategies, such as serial sampling and BDG clearance evaluation, to assess the likelihood of contamination and improve patient care.

A Summary of the Fifth Annual Virology Education HIV Microbiome Workshop

In October of 2019, researchers and community members from around the world met at the NIH for the fifth annual International Workshop on Microbiome in HIV. New research was presented on the role of the microbiome on chronic inflammation and vaccine design, interactions of genetics, environment, sexual practice and HIV infection with the microbiome and the development and clinical trials of microbiome-based therapeutic approaches intended to decrease the probability of HIV acquisition/transmission or ameliorate sequelae of HIV. The keynote address by Dr. Jacques Ravel focused on his work on the vaginal microbiome and efforts to improve the analysis and resolution of microbiome data.

CD4+:CD8+ T Cell Ratio Normalization and the Development of AIDS Events in People with HIV Starting Antiretroviral Therapy

We identify factors associated with the normalization of the CD4+:CD8+ T cell ratio among UK Collaborative HIV Cohort study participants, and describe the association of the CD4+ and CD8+ T cell counts and the CD4+:CD8+ T cell ratio, with the risk of new AIDS events among individuals who achieve a suppressed viral load. Participants initiating combination antiretroviral therapy (cART) after 2006 with a CD4+:CD8+ T cell ratio <1, and viral suppression within 6 months were included. Cox proportional hazard models were used to examine associations with ratio normalization (ratio ≥1). Poisson regression models were used to investigate factors associated with the development of AIDS after viral load suppression. A total of 13,178 participants [median age: 37 (interquartile range: 31–44)] were followed for 75,336 person-years. Of the 4,042 (32.9%) who experienced ratio normalization, individuals with a high CD4+ T cell count [>500 vs. ≤200 cells/mm³, adjusted hazard ratio (95% confidence interval): 7.93 (6.97–9.01)], low CD8+ T cell count [>1,150 vs. ≤500 cells/mm³: 0.18 (0.16–0.21)], and low CD4+:CD8+ T cell ratio [>0.8 vs. <0.2: 12.36 (10.41–14.68)] at cART initiation were more likely to experience ratio normalization. Four hundred and nineteen people developed a new AIDS event. Most recent CD4+ T cell count [>500 vs. ≤200 cells/mm³: adjusted rate ratio 0.24 (0.16–0.34)] and CD4+:CD8+ T cell ratio [>0.8 vs. <0.2: 0.33 (0.21–0.52)] were independently associated with a new AIDS event. One third of study participants experienced ratio normalization after starting cART. CD4+ T cell count and CD4+:CD8+ T cell ratio are both individually associated with ratio normalization and the development of new AIDS events after cART.

The Presence of (1→3)-β-D-Glucan as Prognostic Marker in Patients After Major Abdominal Surgery

BACKGROUND

While the serological detection of (1→3)-β-D-glucan (BDG) can indicate invasive fungal disease (IFD), false positivity occurs. Nevertheless, the presence of BDG can still be recognized by the host's innate immune system and persistent BDG antigenemia, in the absence of IFD, can result in deleterious proinflammatory immune responses.

METHODS

During the XXX (INTENSE) study into the preemptive use of micafungin to prevent invasive candidiasis (IC) after abdominal surgery, the serum burden of BDG was determined to aid diagnosis of IC. Data from the INTENSE study were analyzed to determine whether BDG was associated with organ failure and patient mortality, while accounting for the influences of IC and antifungal therapy.

RESULTS

A BDG concentration >100 pg/mL was associated with a significantly increased Sequential Organ Failure Assessment score (≤100 pg/mL: 2 vs >100 pg/mL: 5; P < .0001) and increased rates of mortality (≤100 pg/mL: 13.7% vs >100 pg/mL: 39.0%; P = .0002). Multiple (≥2) positive results >100 pg/mL or a BDG concentration increasing >100 pg/mL increased mortality (48.1%). The mortality rate in patients with IC and a BDG concentration >100 pg/mL and ≤100 pg/mL was 42.3% and 25.0%, respectively. The mortality rate in patients without IC but a BDG concentration >100 pg/mL was 37.3%. The use of micafungin did not affect the findings.

CONCLUSIONS

The presence of persistent or increasing BDG in the patient's circulation is associated with significant morbidity and mortality after abdominal surgery, irrespective of IC. The potential lack of a specific therapeutic focus has consequences when trying to manage these patients, and when designing clinical trials involving patients where host-associated BDG concentrations may be elevated.

CLINICAL TRIALS REGISTRATION

NCT01122368.

Treating From the Inside Out: Relevance of Fecal Microbiota Transplantation to Counteract Gut Damage in GVHD and HIV Infection

The gastrointestinal (GI) tract is a complex and well-balanced milieu of anatomic and immunological barriers. The epithelial surface of the GI tract is colonized by trillions of microorganisms, known as the gut microbiota, which is considered an “organ” with distinctive endocrine and immunoregulatory functions. Dysregulation of the gut microbiota composition, termed dysbiosis, has been associated with epithelial damage and translocation of microbial products into the circulating blood. Dysbiosis, increased gut permeability and chronic inflammation play a major role on the clinical outcome of inflammatory bowel diseases, graft-vs.-host disease (GVHD) and HIV infection. In this review, we focus on GVHD and HIV infection, conditions sharing gut immune damage leading to dysbiosis. The degree of dysbiosis and level of epithelial gut damage predict poor clinical outcome in both conditions. Emerging interventions are therefore warranted to promote gut microbiota homeostasis and improve intestinal barrier function. Interventions such as anti-inflammatory medications, and probiotics have toxicity and/or limited transitory effects, justifying innovative approaches. Fecal microbiota transplantation (FMT) is one such approach where fecal microorganisms are transferred from healthy donors into the GI tract of the recipient to restore microbiota composition in patients with Clostridium difficile-induced colitis or inflammatory bowel diseases. Preliminary findings point toward a beneficial effect of FMT to improve GVHD and HIV-related outcomes through the engraftment of beneficial donor bacteria, notably those producing anti-inflammatory metabolites. Herein, we critically review the potential for FMT in alleviating dysbiosis and gut damage in patients with GVHD or HIV-infection. Understanding the underlying mechanism by which FMT restores gut function will pave the way toward novel scalable and targeted interventions.

The Bacterium Akkermansia muciniphila: A Sentinel for Gut Permeability and Its Relevance to HIV-Related Inflammation

Gut dysbiosis, namely dysregulation of the intestinal microbiota, and increased gut permeability lead to enhanced inflammation and are commonly seen in chronic conditions such as obesity and aging. In people living with HIV (PLWH), several lines of evidence suggest that a depletion of gut CD4 T-cells is associated with gut dysbiosis, microbial translocation and systemic inflammation. Antiretroviral therapy (ART) rapidly controls viral replication, which leads to CD4 T-cell recovery and control of the disease. However, gut dysbiosis, epithelial damage and microbial translocation persist despite ART, increasing risk of developing inflammatory non-AIDS comorbidities such as cardiovascular disease, diabetes mellitus, liver steatosis and cancer. In addition to ART, an emerging research priority is to discover strategies to improve the gut microbial composition and intestinal barrier function. Probiotic interventions have been extensively used with controversial benefits in humans. Encouragingly, within the last decade, the intestinal symbiotic bacterium Akkermansia muciniphila has emerged as the “sentinel of the gut.” A lower abundance of A. muciniphila has been shown in diabetic and obese people as well as in PLWH. Interventions with high levels of polyphenols such as tea or diets rich in fruit, the antibiotic vancomycin and the antidiabetic drug metformin have been shown to increase A. muciniphila abundance, contributing to improved metabolic function in diabetic and obese individuals. We hypothesize that gut microbiota rich in A. muciniphila can reduce microbial translocation and inflammation, preventing occurrences of non-AIDS comorbidities in PLWH. To this aim, we will discuss the protective effect of A. muciniphila and its potential applications, paving the way toward novel therapeutic strategies to improve gut health in PLWH.

Metformin effect on gut microbiota: insights for HIV-related inflammation

The gut microbiota is emerging as a prominent player in maintaining health through several metabolic and immune pathways. Dysregulation of gut microbiota composition, also known as dysbiosis, is involved in the clinical outcome of diabetes, inflammatory bowel diseases, cancer, aging and HIV infection. Gut dysbiosis and inflammation persist in people living with HIV (PLWH) despite receiving antiretroviral therapy, further contributing to non-AIDS comorbidities. Metformin, a widely used antidiabetic agent, has been found to benefit microbiota composition, promote gut barrier integrity and reduce inflammation in human and animal models of diabetes. Inspired by the effect of metformin on diabetes-related gut dysbiosis, we herein critically review the relevance of metformin to control inflammation in PLWH. Metformin may improve gut microbiota composition, in turn reducing inflammation and risk of non-AIDS comorbidities. This review will pave the way towards innovative strategies to counteract dysregulated microbiota and improve the lives of PLWH.