Determinants of B-Cell Compartment Hyperactivation in European Adolescents Living With Perinatally Acquired HIV-1 After Over 10 Years of Suppressive Therapy

Analytical treatment interruption in children living with HIV: position statement from the EPIICAL consortium

Analytical treatment interruption (ATI) is widely acknowledged as an essential component of studies to advance our understanding of HIV cure, but discussion has largely been focused on adults. To address this gap, we reviewed evidence related to the safety and utility of ATI in paediatric populations. Three randomised ATI trials using CD4 T-cell and clinical criteria to guide restart of antiretroviral therapy (ART) have been conducted. These trials found low risks associated with ATI in children, including reassuring findings pertaining to neurocognitive outcomes. Similar to adults treated during acute infection, infants treated early in life have shifts in virological and immunological parameters that increase their likelihood of achieving ART-free viral control. Early ART limits the size and diversity of the viral reservoir and shapes effective innate and HIV-specific humoral and cellular responses. Several cases of durable ART-free viral control in early treated children have been reported. We recommend that, where appropriate for the study question and where adequate monitoring is available, ATI should be integrated into ART-free viral control research in children living with HIV. Paediatric participants have the greatest likelihood of benefiting and potentially the most years to prospectively realise those benefits. Excluding children from ATI trials limits the evidence base and delays access to interventions.

Children with perinatally acquired HIV exhibit distinct immune responses to 4CMenB vaccine

Children with perinatally acquired HIV (PHIV) have special vaccination needs, as they make suboptimal immune responses. Here, we evaluated safety and immunogenicity of 2 doses of 4-component group B meningococcal vaccine in antiretroviral therapy-treated children with PHIV and healthy controls (HCs). Assessments included the standard human serum bactericidal antibody (hSBA) assay and measurement of IgG titers against capsular group B Neisseria meningitidis antigens (fHbp, NHBA, NadA). The B cell compartment and vaccine-induced antigen-specific (fHbp+) B cells were investigated by flow cytometry, and gene expression was investigated by multiplexed real-time PCR. A good safety and immunogenicity profile was shown in both groups; however, PHIV demonstrated a reduced immunogenicity compared with HCs. Additionally, PHIV showed a reduced frequency of fHbp+ and an altered B cell subset distribution, with higher fHbp+ frequency in activated memory and tissue-like memory B cells. Gene expression analyses on these cells revealed distinct mechanisms between PHIV and HC seroconverters. Overall, these data suggest that PHIV presents a diverse immune signature following vaccination. The impact of such perturbation on long-term maintenance of vaccine-induced immunity should be further evaluated in vulnerable populations, such as people with PHIV.

Emerging insights into atypical B cells in pediatric chronic infectious diseases and immune system disorders: T(o)-bet on control of B-cell immune activation

Repetitive or persistent cellular stimulation in vivo has been associated with the development of a heterogeneous B-cell population that exhibits a distinctive phenotype and, in addition to classical B-cell markers, often expresses the transcription factor T-bet and myeloid marker CD11c. Research suggests that this atypical population consists of B cells with distinct B-cell receptor specificities capable of binding the antigens responsible for their development. The expansion of this population occurs in the presence of chronic inflammatory conditions and autoimmune diseases where different nomenclatures have been used to describe them. However, as a result of the diverse contexts in which they have been investigated, these cells have remained largely enigmatic, with much ambiguity remaining regarding their phenotype and function in humoral immune response as well as their role in autoimmunity. Atypical B cells have garnered considerable interest because of their ability to produce specific antibodies and/or autoantibodies and because of their association with key disease manifestations. Although they have been widely described in the context of adults, little information is present for children. Therefore, the aim of this narrative review is to describe the characteristics of this population, suggest their function in pediatric immune-related diseases and chronic infections, and explore their potential therapeutic avenues.

Effective early antiretroviral therapy in perinatal-HIV infection reduces subsequent plasma inflammatory profile

BACKGROUND

The long-term immunologic effects of antiretroviral therapy (ART) in children with perinatally-acquired HIV (PHIV) have not been fully elucidated. Here, we investigated how the timing of ART initiation affects the long-term immune profile of children living with PHIV by measuring immunomodulatory plasma cytokines, chemokines, and adenosine deaminases (ADAs).

METHODS

40 PHIV participants initiated ART during infancy. 39 participant samples were available; 30 initiated ART ≤6 months (early-ART treatment); 9 initiated ART >6 months and <2 years (late-ART treatment). We compared plasma cytokine and chemokine concentrations and ADA enzymatic activities between early-ART and late-ART treatment 12.5 years later and measured correlation with clinical covariates.

RESULTS

Plasma concentrations of 10 cytokines and chemokines (IFNγ, IL-12p70, IL-13, IL-17A, IL-IRA, IL-5, IL-6, and IL-9 as well as CCL7, CXCL10), ADA1, and ADA total were significantly higher in late-ART compared to early-ART treatment. Furthermore, ADA1 was significantly positively correlated with IFNγ, IL-17A, and IL-12p70. Meanwhile, total ADA was positively correlated with IFNγ, IL-13, IL-17A, IL-1RA, IL-6, and IL-12p70 as well as CCL7.

CONCLUSIONS

Elevation of several pro-inflammatory plasma analytes in late-ART despite 12.5 years of virologic suppression compared to early-ART treatment suggests that early treatment dampens the long-term plasma inflammatory profile in PHIV participants.

IMPACT

This study examines differences in the plasma cytokine, chemokine, and ADA profiles 12.5 years after treatment between early (≤6months) and late (>6 months and <2 years) antiretroviral therapy (ART) treatment initiation in a cohort of European and UK study participants living with PHIV. Several cytokines and chemokines (e.g., IFNγ, IL-12p70, IL-6, and CXCL10) as well as ADA-1 are elevated in late-ART treatment in comparison to early-ART treatment. Our results suggest that effective ART treatment initiated within 6 months of life in PHIV participants dampens a long-term inflammatory plasma profile as compared to late-ART treatment.

B-cell immunity and vaccine induced antibody protection reveal the inefficacy of current vaccination schedule in infants with perinatal HIV-infection in Mozambique, Africa

BACKGROUND

Despite antiretroviral treatment (ART), immune dysfunction persists in children with perinatal HIV infection (HEI). Here we investigated the impact of HIV status on maternal antibody (Ab) passage, long-term vaccine induced immunity and B-cell maturation.

METHODS

46 HIV Exposed Uninfected (HEU), 43 HEI, and 15 HIV unexposed uninfected (HUU) infants were vaccinated with 3 doses of DTaP-HepB-Hib-PCV10-OP at 2, 3, and 4 months at Matola Provincial Hospital, Maputo, Mozambique. Tetanus toxoid specific (TT) IgG, HIV Ab and B-cell phenotype characteristics were evaluated at entry, pre-ART, 5, 10, and 18 months in this longitudinal cohort study.

FINDINGS

Baseline (maternal) plasma TT Ab levels were significantly lower in HEI compared to both HEU and HUU and a faster decay of TT Ab was observed in HEI compared to HEU with significantly lower TT Ab levels at 10 and 18 months of age. TT unprotected (UP) (≤0.1 IU/mL) HEI showed higher HIV-RNA at entry and higher longitudinal HIV viremia (Area Under the Curve) compared to TT protected (P) HEI. A distinct HIV-Ab profile was found at entry in HEI compared to HEU. B-cell phenotype showed a B-cell perturbation in HEI vs HEU infants at entry (mean age 40.8 days) with lower transitional CD10+CD19+ B-cells and IgD+CD27- naive B-cells and an overall higher frequency of IgD-CD27- double negative B-cell subsets in HEI.

INTERPRETATION

B-cell perturbation, presenting with higher double negative IgD-CD27- B-cells was observed in neonatal age and may play a major role in the B-cell exhaustion in HEI. The ability to maintain TT protective Ab titers over time is impaired in HEI with uncontrolled viral replication and the current vaccination schedule is insufficient to provide long-term protection against tetanus.

FUNDING

This work was supported by: NIH grant to SP (5R01AI127347-05); Children's Hospital Bambino Gesú (Ricerca corrente 2019) to NC, and Associazione Volontari Bambino Gesù to PP.

Neglected mycobiome in HIV infection: Alterations, common fungal diseases and antifungal immunity

Human immunodeficiency virus (HIV) infection might have effects on both the human bacteriome and mycobiome. Although many studies have focused on alteration of the bacteriome in HIV infection, only a handful of studies have also characterized the composition of the mycobiome in HIV-infected individuals. Studies have shown that compromised immunity in HIV infection might contribute to the development of opportunistic fungal infections. Despite effective antiretroviral therapy (ART), opportunistic fungal infections continue to be a major cause of HIV-related mortality. Human immune responses are known to play a critical role in controlling fungal infections. However, the effect of HIV infection on innate and adaptive antifungal immunity remains unclear. Here, we review recent advances in understanding of the fungal microbiota composition and common fungal diseases in the setting of HIV. Moreover, we discuss innate and adaptive antifungal immunity in HIV infection.

Clinical, Virological and Immunological Subphenotypes in a Cohort of Early Treated HIV-Infected Children

Background

Identifying subphenotypes within heterogeneous diseases may have an impact in terms of therapeutic options. In this study, we aim to assess different subphenotypes in children living with human immunodeficiency virus (HIV-1), according to the clinical, virological, and immunological characteristics.

Methods

We collected clinical and sociodemographic data, baseline viral load (VL), CD4 and CD8 count and percentage, age at initiation of ART, HIV DNA reservoir size in peripheral blood mononuclear cells (PBMCs), cell-associated RNA (CA-RNA), ultrasensitive VL, CD4 subsets (T effector CD25+, activated memory cells, Treg cells), humoral-specific HIV response (T-bet B cells), innate response (CD56dim natural killer (NK) cells, NKp46+, perforin), exhaustion markers (PD-1, PD-L1, DNAM), CD8 senescence, and biomarkers for T-lymphocyte thymic output (TREC) and endothelial activation (VCAM). The most informative variables were selected using an unsupervised lasso-type penalty selection for sparse clustering. Hierarchical clustering was performed using Pearson correlation as the distance metric and WARD.D2 as the clustering method. Internal validation was applied to select the best number of clusters. To compare the characteristics among clusters, boxplot and Kruskal Wallis test were assessed.

Results

Three subphenotypes were discovered (cluster1: n=18, 45%; cluster2: n=11, 27.5%; cluster3: n=11, 27.5%). Patients in cluster1 were treated earlier, had higher baseline %CD4, low HIV reservoir size, low western blot score, higher TREC values, and lower VCAM values than the patients in the other clusters. In contrast, cluster3 was the less favorable. Patients were treated later and presented poorer outcomes with lower %CD4, and higher reservoir size, along with a higher percentage of CD8 immunosenescent cells, lower TREC, higher VCAM cytokine, and a higher %CD4 PD-1. Cluster2 was intermediate. Patients were like those of cluster1, but had lower levels of t-bet expression and higher HIV DNA reservoir size.

Conclusions

Three HIV pediatric subphenotypes with different virological and immunological features were identified. The most favorable cluster was characterized by a higher rate of immune reconstitution and a slower disease progression, and the less favorable with more senescence and high reservoir size. In the near future therapeutic interventions for a path of a cure might be guided or supported by the different subphenotypes.