High soluble CD163 levels correlate with disease progression and inflammation in Kenyan children with perinatal HIV-infection

Distinct fecal microbial signatures are linked to sex and chronic immune activation in pediatric HIV infection

Introduction

Our understanding of HIV-associated gut microbial dysbiosis in children perinatally-infected with HIV (CLWH) lags behind that of adults living with HIV. Childhood represents a critical window for the gut microbiota. Any disturbances, including prolonged exposure to HIV, antiretroviral drugs, and antibiotics are likely to have a significant impact on long-term health, resulting in a less resilient gut microbiome. The objective of our study was to characterize the gut microbiota in CLWH, and compare it with HIV-unexposed and -uninfected children.

Methods

We enrolled 31 children aged 3 to 15 years; 15 were CLWH and 16 were HUU. We assessed dietary patterns and quality; quantified soluble and cellular markers of HIV disease progression by flow cytometry, enzyme-linked immunosorbent and multiplex-bead assays, and profiled the gut microbiota by 16S rRNA sequencing. We explored relationships between the gut microbiota, antibiotic exposure, dietary habits, soluble and cellular markers and host metadata.

Results

Children had a Western-type diet, their median health eating index score was 67.06 (interquartile range 58.76-74.66). We found no discernable impact of HIV on the gut microbiota. Alpha diversity metrics did not differ between CLWH and HUU. Sex impacted the gut microbiota (R-squared= 0.052, PERMANOVA p=0.024). Male children had higher microbial richness compared with female children. Two taxa were found to discriminate female from male children independently from HIV status: Firmicutes for males, and Bacteroides for females. Markers of HIV disease progression were comparable between CLWH and HUU, except for the frequency of exhausted CD4+ T cells (PD-1+) which was increased in CLWH (p=0.0024 after adjusting for confounders). Both the frequency of exhausted CD4+ and activated CD4+ T cells (CD38+ HLADR+) correlated positively with the relative abundance of Proteobacteria (rho=0.568. false discovery rate (FDR)-adjusted p= 0.029, and rho=0.62, FDR-adjusted p=0.0126, respectively).

Conclusion

The gut microbiota of CLWH appears similar to that of HUU, and most markers of HIV disease progression are normalized with long-term ART, suggesting a beneficial effect of the latter on the gut microbial ecology. The relationship between exhausted and activated CD4+ T cells and Proteobacteria suggests a connection between the gut microbiome, and premature aging in CLWH.

Cellular and molecular insights into incomplete immune recovery in HIV/AIDS patients

Highly active antiretroviral therapy (ART) can effectively inhibit virus replication and restore immune function in most people living with human immunodeficiency virus (HIV). However, an important proportion of patients fail to achieve a satisfactory increase in CD4⁺ T cell counts. This state is called incomplete immune reconstitution or immunological nonresponse (INR). Patients with INR have an increased risk of clinical progression and higher rates of mortality. Despite widespread attention to INR, the precise mechanisms remain unclear. In this review, we will discuss the alterations in the quantity and quality of CD4⁺ T as well as multiple immunocytes, changes in soluble molecules and cytokines, and their relationship with INR, aimed to provide cellular and molecular insights into incomplete immune reconstitution.

Characteristics and clinical significance of plasma IL-18, sCD14, and sCD163 levels in patients with HIV-1 infection

Biomarkers of monocyte-macrophages activation and inflammation in plasma such as interleukin-18 (IL-18), soluble leukocyte differentiation antigen 14 (sCD14), and sCD163 are associated with disease severity and prognosis in HIV-1 infected patients, however, their relationships with efficacy of antiretroviral therapy (ART) need further investigation. We aimed to characterize and explore the clinical significance of plasma IL-18, sCD14, and sCD163 in this population. This was a retrospective cohort study consisting of HIV-1 infected patients enrolled in a randomized, controlled, open-label, noninferiority trial (ALTERLL study), with follow-up time points including initiation of ART (baseline), 12-, 24- and 48-weeks of treatment. Plasma levels of IL-18, sCD14, and sCD163 were measured using the enzyme-linked immunosorbent assay method. Viral suppression was defined as HIV-1 RNA < 20 copies/ml. Among the 193 studied patients (median age of 29.0 years, 180 males), IL-18 and sCD163 had U-shaped regression curves and sCD14 had an inverted U-shaped regression curve while the virus was decreased and immune function recovered. Patients with higher levels of IL-18 or lower levels of sCD163 at baseline were less likely to achieve viral suppression at Week 12 or Week 24 of treatment, respectively. In multivariate analysis, baseline sCD163 ≤ 500 pg/ml (adjusted odds ratio 0.33, 95% confidence interval 0.16-0.68) was independently associated with a lower rate of viral suppression at Week 24 of treatment. In conclusion, we demonstrated different dynamic changes among IL-18, sCD14, and sCD163 after ART. Baseline sCD163 level could be a potential predictor of early virological response to ART. Further validation and mechanistic research are needed.

Coordination of inflammatory responses in children with perinatally-acquired HIV infection

OBJECTIVE

We investigated dynamics of inflammatory biomarkers in children with perinatally-acquired HIV (PHIV) who started antiretrovirals at age <3 years and achieved sustained virologic control (HIV plasma RNA<400 copies/mL).

DESIGN

This was a retrospective analysis of inflammatory biomarkers in children enrolled in a randomized trial of early (<3 years of age) PI-based versus NNRTI-based regimens (P1060), who achieved sustained virologic control and participated in a neurodevelopmental follow-up study (P1104 s) between ages 5-11 years.

METHODS

We measured 20 inflammatory biomarkers using ELISA or chemiluminescence at onset of sustained virologic control (Tc) and at P1104 s entry (Te).

RESULTS

The 213 participants had median ages of 1.2, 1.9, and 7.0 years at antiretroviral initiation, Tc, and Te, respectively, with 138 on PI-based and 74 on NNRTI-based regimens at Tc. Eighteen markers decreased and two increased from Tc to Te (Te-Tc). Biomarker subsets, particularly cytokines, the chemokine IP-10, and adhesion molecules sICAM-1 and sVCAM-1, correlated at Tc, Te, and Te-Tc. At Tc, higher biomarker levels were associated with younger age, female sex, HIV plasma RNA ≥750,000 copies/mL, lower nadir CD4+%, lower nadir weight z-scores, and NNRTI-based treatment. Greater Te-Tc biomarker declines were associated with younger age, male sex, higher Tc biomarker levels, lower nadir CD4+%, and NNRTI-based treatment. Duration of controlled viremia and nadir height Z-scores showed mixed associations.

CONCLUSIONS

Biomarker expression showed substantial coordination. Most markers decreased after virologic control. Demographic and clinical variables associated with biomarker patterns were identified. Mechanistic studies of these biomarker patterns are needed to inform interventions to control inflammation.

Biological Aging and Immune Senescence in Children with Perinatally Acquired HIV

Chronic HIV-infected children suffer from premature aging and aging-related diseases. Viral replication induces an ongoing inflammation process, with the release of pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), the activation of the immune system, and the production of proinflammatory cytokines. Although combined highly active antiretroviral therapy (ART) has significantly modified the natural course of HIV infection, normalization of T and B cell phenotype is not completely achievable; thus, many HIV-infected children display several phenotypical alterations, including higher percentages of activated cells, that favor an accelerated telomere attrition, and higher percentages of exhausted and senescent cells. All these features ultimately lead to the clinical manifestations related to premature aging and comorbidities typically observed in older general population, including non-AIDS-related malignancies. Therefore, even under effective treatment, the premature aging process of HIV-infected children negatively impacts their quality and length of life. This review examines the available data on the impact of HIV and ART on immune and biological senescence of HIV-infected children.