Dataset Information

Thymic Output and CD4 T-Cell Reconstitution in HIV-Infected Children on Early and Interrupted Antiretroviral Treatment: Evidence from the Children with HIV Early Antiretroviral Therapy Trial.

ABSTRACT:

Objectives

Early treatment of HIV-infected children and adults is important for optimal immune reconstitution. Infants' immune systems are more plastic and dynamic than older children's or adults', and deserve particular attention. This study aimed to understand the response of the HIV-infected infant immune system to early antiretroviral therapy (ART) and planned ART interruption and restart.

Methods

Data from HIV-infected children enrolled the CHER trial, starting ART aged between 6 and 12?weeks, were used to explore the effect of ART on immune reconstitution. We used linear and non-linear regression and mixed-effects models to describe children's CD4 trajectories and to identify predictors of CD4 count during early and interrupted ART.

Results

Early treatment arrested the decline in CD4 count but did not fully restore it to the levels observed in HIV-uninfected children. Treatment interruption at 40 or 96?weeks resulted in a rapid decline in CD4 T-cells, which on retreatment returned to levels observed before interruption. Naïve CD4 T-cell count was an important determinant of overall CD4 levels. A strong correlation was observed between thymic output and the stable CD4 count both before and after treatment interruption.

Conclusion

Early identification and treatment of HIV-infected infants is important to stabilize CD4 counts at the highest levels possible. Once stabilized, children's CD4 counts appear resilient, with good potential for recovery following treatment interruption. The naïve T-cell pool and thymic production of naive cells are key determinants of children's CD4 levels.

SUBMITTER: Lewis J

PROVIDER: S-EPMC5611383 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Thymic Output and CD4 T-Cell Reconstitution in HIV-Infected Children on Early and Interrupted Antiretroviral Treatment: Evidence from the Children with HIV Early Antiretroviral Therapy Trial.

Lewis Joanna J Payne Helen H Walker A Sarah AS Otwombe Kennedy K Gibb Diana M DM Babiker Abdel G AG Panchia Ravindre R Cotton Mark F MF Violari Avy A Klein Nigel N Callard Robin E RE

Frontiers in immunology 20170920

<h4>Objectives</h4>Early treatment of HIV-infected children and adults is important for optimal immune reconstitution. Infants' immune systems are more plastic and dynamic than older children's or adults', and deserve particular attention. This study aimed to understand the response of the HIV-infected infant immune system to early antiretroviral therapy (ART) and planned ART interruption and restart.<h4>Methods</h4>Data from HIV-infected children enrolled the CHER trial, starting ART aged betwe ...[more]

PMID: 28979264

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Project description:BackgroundLong-term immune reconstitution on antiretroviral therapy (ART) has important implications for HIV-infected children, who increasingly survive into adulthood. Children's response to ART differs from adults', and better descriptive and predictive models of reconstitution are needed to guide policy and direct research. We present statistical models characterising, qualitatively and quantitatively, patterns of long-term CD4 recovery.Methods and findingsCD4 counts every 12 wk over a median (interquartile range) of 4.0 (3.7, 4.4) y in 1,206 HIV-infected children, aged 0.4-17.6 y, starting ART in the Antiretroviral Research for Watoto trial (ISRCTN 24791884) were analysed in an exploratory analysis supplementary to the trial's pre-specified outcomes. Most (n?=?914; 76%) children's CD4 counts rose quickly on ART to a constant age-corrected level. Using nonlinear mixed-effects models, higher long-term CD4 counts were predicted for children starting ART younger, and with higher CD4 counts (p<0.001). These results suggest that current World Health Organization-recommended CD4 thresholds for starting ART in children ?5 y will result in lower CD4 counts in older children when they become adults, such that vertically infected children who remain ART-naïve beyond 10 y of age are unlikely ever to normalise CD4 count, regardless of CD4 count at ART initiation. CD4 profiles with four qualitatively distinct reconstitution patterns were seen in the remaining 292 (24%) children. Study limitations included incomplete viral load data, and that the uncertainty in allocating children to distinct reconstitution groups was not modelled.ConclusionsAlthough younger ART-naïve children are at high risk of disease progression, they have good potential for achieving high CD4 counts on ART in later life provided ART is initiated following current World Health Organization (WHO), Paediatric European Network for Treatment of AIDS, or US Centers for Disease Control and Prevention guidelines. In contrast, to maximise CD4 reconstitution in treatment-naïve children >10 y, ART should ideally be considered even if there is a low risk of immediate disease progression. Further exploration of the immunological mechanisms for these CD4 recovery profiles should help guide management of paediatric HIV infection and optimise children's immunological development. Please see later in the article for the Editors' Summary.

Project description:BackgroundInterim results from the children with HIV early antiretroviral (CHER) trial showed that early antiretroviral therapy (ART) was life-saving for infants infected with HIV. In view of the few treatment options and the potential toxicity associated with lifelong ART, in the CHER trial we compared early time-limited ART with deferred ART.MethodsCHER was an open-label randomised controlled trial of HIV-infected asymptomatic infants younger than 12 weeks in two South African trial sites with a percentage of CD4-positive T lymphocytes (CD4%) of 25% or higher. 377 infants were randomly allocated to one of three groups: deferred ART (ART-Def), immediate ART for 40 weeks (ART-40W), or immediate ART for 96 weeks (ART-96W), with subsequent treatment interruption. The randomisation schedule was stratified by clinical site with permuted blocks of random sizes to balance the numbers of infants allocated to each group. Criteria for ART initiation in the ART-Def group and re-initiation after interruption in the other groups were CD4% less than 25% in infancy; otherwise, the criteria were CD4% less than 20% or Centers for Disease Control and Prevention severe stage B or stage C disease. Combination therapy of lopinavir-ritonavir, zidovudine, and lamivudine was the first-line treatment regimen at ART initiation and re-initiation. The primary endpoint was time to failure of first-line ART (immunological, clinical, or virological) or death. Comparisons were done by intention-to-treat analysis, with use of time-to-event methods. This trial is registered with ClinicalTrials.gov, number NCT00102960.Findings377 infants were enrolled, with a median age of 7·4 weeks, CD4% of 35%, and HIV RNA log 5·7 copies per mL. Median follow-up was 4·8 years; 34 infants (9%) were lost to follow-up. Median time to ART initiation in the ART-Def group was 20 weeks (IQR 16-25). Time to restarting of ART after interruption was 33 weeks (26-45) in ART-40W and 70 weeks (35-109) in ART-96W; at the end of the trial, 19% of patients in ART-40W and 32% of patients in ART-96W remained off ART. Proportions of follow-up time spent on ART were 81% in the ART-Def group, 70% in the ART-40W group, and 69% in the ART-96W group. 48 (38%) of 125 children in the ART-Def group, 32 (25%) of 126 in the ART-40W group, and 26 (21%) of 126 in the ART-96W group reached the primary endpoint. The hazard ratio, relative to ART-Def, was 0·59 (95% CI 0·38-0·93, p=0·02) for ART-40W and 0·47 (0·27-0·76, p=0·002) for ART-96W. Three children in ART-Def, three in ART-40W, and one in ART-96W switched to second-line ART.InterpretationEarly time-limited ART had better clinical and immunological outcomes than deferred ART, with no evidence of excess disease progression during subsequent treatment interruption and less overall ART exposure than deferred ART. Longer time on primary ART permits longer subsequent interruption, with marginally better outcomes.FundingUS National Institutes of Health.

Dataset Information

Thymic Output and CD4 T-Cell Reconstitution in HIV-Infected Children on Early and Interrupted Antiretroviral Treatment: Evidence from the Children with HIV Early Antiretroviral Therapy Trial.

Objectives

Methods

Results

Conclusion

Publications

Thymic Output and CD4 T-Cell Reconstitution in HIV-Infected Children on Early and Interrupted Antiretroviral Treatment: Evidence from the Children with HIV Early Antiretroviral Therapy Trial.

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