Immune reconstitution in HAART-treated children with AIDS. Highly Active Anti-Retroviral Therapy

Effect of tuberculosis-HIV co-treatment on clinical and growth outcomes among hospitalized children newly initiating antiretroviral therapy

OBJECTIVE

Evaluate effects of tuberculosis (TB)-HIV co-treatment on clinical and growth outcomes in children with HIV (CHIV).

DESIGN

Longitudinal study among Kenyan hospitalized ART-naive CHIV in the PUSH trial (NCT02063880).

METHODS

CHIV started ART within 2 weeks of enrollment; Anti-TB therapy was initiated based on clinical and TB diagnostics. Children were followed for 6 months with serial viral load, CD4%, and growth assessments [weight-for-age z -score (WAZ), height-for-age z -score (HAZ), and weight-for-height z -score (WHZ)]. TB-ART treated and ART-only groups were compared at 6 months post-ART for undetectable viral load (<40 c/ml), CD4% change, and growth using generalized linear models, linear regression, and linear mixed-effects models, respectively.

RESULT

Among 152 CHIV, 40.8% (62) were TB-ART treated. Pre-ART, median age was 2.0 years and growth was significantly lower, and viral load significantly higher in the TB-ART versus ART-only group. After 6 months on ART, 37.2% of CHIV had undetectable viral load and median CD4% increased by 7.2% (IQR 2.0-11.6%) with no difference between groups. The TB-ART group had lower WAZ and HAZ over 6 month follow-up [WAZ -0.81 (95% CI: -1.23 to -0.38], P  < 0.001; HAZ -0.15 (95% CI: -0.29 to -0.01), P  = 0.030] and greater rate of WAZ increase in analyses unadjusted and adjusted for baseline WAZ [unadjusted 0.62 (95% CI: 0.18-1.07, P  = 0.006) or adjusted 0.58 (95% CI: 0.12-1.03, P  = 0.013)].

CONCLUSION

TB-HIV co-treatment did not adversely affect early viral suppression and CD4 + recovery post-ART. TB-ART-treated CHIV had more rapid growth reconstitution, but growth deficits persisted, suggesting need for continued growth monitoring.

Virological suppression in children and adolescents is not influenced by genotyping, but depends on optimal adherence to antiretroviral therapy

Objective

To evaluate the virological outcomes in children and adolescents infected with HIV-1 in Salvador, Bahia according to genotyping results.

Methods

We retrospectively evaluated the rates of virological suppression of children and adolescents submitted to HIV-1 genotyping test from January/2008 to December/2012. The participants were followed in the two referral centers for pediatric AIDS care, in Salvador, Brazil. Resistance mutations, drug sensitivity profiles, and viral subtypes were analyzed using the Stanford HIV-1 Drug Resistance Database. Adherence was estimated by drugs withdrawal at pharmacies of the two sites.

Results

101 subjects were included: 35 (34.6%) were drug-naïve, and the remaining 66 were failing ART. In drug-naïve group, 3 (8.6%), presented with NNRTIs resistance mutations, along with polymorphic mutations to PIs in most (82.8%) of them. Among the failing therapy group, we detected a high frequency (89.4%) of resistance mutations to PIs, NRTI (84.8%), and NNRTI (59.1%). Virological suppression after introduction/modification of genotyping-guided ART was achieved only for patients (53.1%) with drug withdrawal over 95%. Main detected HIV-1 subtypes were B (67.3%), F (7.9), C (1.9%), and recombinant forms (22.9%).

Conclusions

Despite the use of genotyping tests in guidance of a more effective antiretroviral regimen, poor adherence to ART seems to be the main determinant of low virological suppression rate for children and adolescents, in Salvador, Brazil.

Terapia antirretroviral em crianças e adolescentes infectados pelo HIV: o que sabemos após 30 anos de epidemia

Este estudo tem como objetivo avaliar o uso da terapia antirretroviral combinada em crianças e adolescentes com AIDS. Foram captados 247 resumos nos portais PubMed e LILACS, publicados entre 1983 e 2013, sendo utilizados 69 artigos para as referências bibliográficas. A atenção atribuída às pesquisas na faixa etária pediátrica durante os trinta anos de epidemia de AIDS se justifica por características imunológicas próprias, sendo a progressão da AIDS mais rápida em crianças que em adultos. Pesquisas recentes abordam estratégias de intervenção medicamentosa de alta potência antes do aparecimento dos sintomas iniciais. A introdução precoce da terapia antirretroviral combinada foi implantada com eficácia e segurança em populações com poucos recursos fixos, com melhora significativa da sobrevida desses pacientes. O desafio atual é lidar com uma doença crônica com intercorrências agudas. Novas pesquisas serão necessárias, atentando para as especificidades populacionais e particularizando as necessidades individuais dos pacientes pediátricos.

The clinical pattern, prevalence, and factors associated with immune reconstitution inflammatory syndrome in Ugandan children

OBJECTIVE

To determine clinical pattern, prevalence, and factors associated with pediatric immune reconstitution inflammatory syndrome (IRIS) in Uganda.

DESIGN

A prospective, multicenter cross-sectional study.

METHODS

We enrolled HIV-infected children receiving antiretroviral therapy (ART) between 0.5 and 6 months duration from December 2006 to October 2007 at three pediatric clinics in Uganda. Children were evaluated for IRIS at a one-time study visit by a standardized pediatric case definition.

RESULTS

The IRIS prevalence was 38% [95% confidence interval (CI) 31-46] among 162 children (57% female) with a median age of 6 years (interquartile range 2.5-11 years). Of the IRIS events, 77% were unmasking of a new opportunistic infection and 23% were probable paradoxical IRIS events toward prior opportunistic infections. The majority of IRIS events (55%) occurred in the first month of ART. The clinical events were diverse, with tuberculosis-IRIS (29%) being the most frequent presentation. Independent risk factors for IRIS were pre-ART CD4(+) cell percentage below 15% (odds ratio = 3.1, 95% CI 1.2-8.4, P = 0.027), current CD8(+) cell absolute count below 1000 cells/microl (odds ratio = 4.3, 95% CI 1.8-10.4, P = 0.001), male sex (odds ratio = 2.6, 95% CI 1.06-8.4, P = 0.01), and a cough of more than 1 week duration at the current clinic visit (odds ratio = 4.3, 95% CI 1.7-10.7, P = 0.002). A more than 25 CD4(+) T-cells increase at current study visit from the pre-ART baseline was associated with IRIS by univariate (P = 0.005) but not multivariate analysis.

CONCLUSION

IRIS events commonly occur early after ART initiation in children with advanced immunosuppression, as commonly seen in resource-limited areas. Both healthcare providers and caregivers of the children need awareness of IRIS to minimize ART nonadherence.

Clinical outcomes after an unstructured treatment interruption in children and adolescents with perinatally acquired HIV infection

OBJECTIVE

An unstructured treatment interruption in children with perinatally acquired HIV infection is an issue with unresolved significance. The objective of this study was to investigate the actual prevalence and clinical outcomes of a treatment interruption in children and adolescents with perinatally acquired HIV-1 infection.

METHODS

Clinical data were analyzed for 72 children and adolescents who had HIV-1 infection and stopped their medications at 4 academic centers in the United States between January 2000 and September 2004.

RESULTS

Among 405 patients with perinatal HIV-1 infection, 72 (17.8%) experienced a treatment interruption during the observation period. The mean age of patients at the time of the treatment interruption was 12.8 years, and the mean length of the treatment interruption was 14 months. Medication fatigue was the most common reason for a treatment interruption. The CD4+ T-cell percentage nadir before the treatment interruption did not predict CD4+ T-cell percentage declines during the treatment interruption; however, the CD4+ T-cell percentage gain from nadir to the time of the treatment interruption predicted CD4+ T-cell percentage declines during the treatment interruption. During the median follow-up of 19 months (range: 6-48 months), 48 (67%) patients resumed antiretroviral medications. As expected, there was a continuous CD4+ T-cell percentage decrease and plasma HIV-1 RNA increase during the observation period. Overall, 7 (10%) patients were admitted to the hospital; 2 (3%) patients experienced an AIDS-defining illness.

CONCLUSIONS

An unstructured treatment interruption seems to be a major issue for youth with perinatally acquired HIV-1 infection. Patients who experienced the greatest rise in CD4+ T-cell percentage on treatment had the largest CD4+ T-cell percentage decline after the treatment interruption. Close monitoring is required when a treatment interruption occurs in children and adolescents with HIV infection.

Natural history of HIV infected pediatric long-term or slow progressor population after the first decade of life

BACKGROUND

Perinatally infected long-term nonprogressors/slow progressors represent a select group of individuals. There is very limited information on this group of children beyond the first decade of life. A group of HIV-infected long-term nonprogressor/slow progressor children was studied.

METHODS

We enrolled 20 HIV-infected adolescents who were receiving no or minimal therapy (defined as single or dual nucleoside therapy) before the age of 10 years and who had maintained CD4 counts above 25% for the first decade of life. We analyzed immunologic and virologic characteristics. Thymic receptor excision circles (TREC) were measured on stored frozen peripheral blood mononuclear cells. CD4 count, viral load and other pertinent information including race and age were obtained from individual medical records.

RESULTS

Nine of the 20 patients recruited were noted to have developed falling CD4 counts at or around puberty, whereas the other 11 remained stable. There was no difference in TREC values or HIV RNA values before or after puberty between the 2 groups of patients. Those who remained stable, in terms of maintaining CD4 T cells as a group had falling viral loads with age. Those whose CD4 values declined after puberty had viral loads that did not decrease with age.

CONCLUSION

A select group of patients who never received HAART during their first decade of life will continue to maintain good CD4 associated with declining HIV RNA values. Thymic output is not predictive of those that don't maintain CD4 T cells.

Development of a macrophage-based nanoparticle platform for antiretroviral drug delivery

Complex dosing regimens, costs, side effects, biodistribution limitations, and variable drug pharmacokinetic patterns have affected the long-term efficacy of antiretroviral medicines. To address these problems, a nanoparticle indinavir (NP-IDV) formulation packaged into carrier bone marrow-derived macrophages (BMMs) was developed. Drug distribution and disease outcomes were assessed in immune-competent and human immunodeficiency virus type 1 (HIV-1)-infected humanized immune-deficient mice, respectively. In the former, NP-IDV formulation contained within BMMs was adoptively transferred. After a single administration, single-photon emission computed tomography, histology, and reverse-phase-high-performance liquid chromatography (RP-HPLC) demonstrated robust lung, liver, and spleen BMMs and drug distribution. Tissue and sera IDV levels were greater than or equal to 50 microM for 2 weeks. NP-IDV-BMMs administered to HIV-1-challenged humanized mice revealed reduced numbers of virus-infected cells in plasma, lymph nodes, spleen, liver, and lung, as well as, CD4(+) T-cell protection. We conclude that a single dose of NP-IDV, using BMMs as a carrier, is effective and warrants consideration for human testing.

Association of CD4+ T-lymphocyte counts and new thymic emigrants in HIV-infected children during successful highly active antiretroviral therapy

BACKGROUND

In a cohort of children receiving highly active antiretroviral therapy (HAART) with sustained plasma HIV-1 RNA < 50 copies/mL, children who reached undetectable RNA after week 8 (slow responders, median: week 20) had higher HIV-1 intracellular DNA (HIV-1 DNA) and equal or greater CD4+ T-lymphocyte counts compared with children who reached undetectable plasma HIV-1 RNA by week 8 (rapid responders) throughout HAART.

OBJECTIVE

To determine whether levels of T-cell receptor excision circles (TRECs) could explain the apparent inconsistency between the quantity of HIV-1 DNA and CD4+ T-lymphocyte counts in HIV-1-infected children receiving HAART with sustained virologic suppression.

METHODS

T-cell receptor excision circles and HIV-1 DNA and plasma HIV-1 RNA were quantified longitudinally by PCR in 31 children (median age, 5.6 years) with sustained undetectable plasma HIV-1 RNA for >104 weeks of HAART.

RESULTS

There was a positive correlation between TREC and HIV-1 DNA during HAART, notably at weeks 48 and 80 (P < .004). During the early stage of HAART, TREC levels positively correlated with CD4+ T-lymphocyte percentages (P < .02) and naive CD4+ T-lymphocyte counts (P < .001) and percentages (P = .05). Median TREC levels were consistently equal or higher in slow responders compared with rapid responders (P < .001) despite slow responders having consistently greater quantities of HIV-1 DNA.

CONCLUSION

To maintain adequate levels of CD4+ T-lymphocytes, children with high HIV-1 DNA maintain high levels of TREC while receiving HAART. Thus, a thymic control mechanism is required to maintain new CD4+ T lymphocytes in the presence of persistent virus.

CLINICAL IMPLICATIONS

The TREC level is a useful marker of thymic function in HIV-infected children.

An MDR1-3435 variant is associated with higher plasma nelfinavir levels and more rapid virologic response in HIV-1 infected children

OBJECTIVE

The multidrug-resistance transporter gene (MDR1) encoding for P-glycoprotein (P-gp) and genes encoding for isoenzymes of cytochrome P450 (CYP) have an important role in transport and metabolism of antiretroviral agents. This research examined the impact of single nucleotide polymorphisms (SNP) of MDR1 and CYP genes on nelfinavir and efavirenz pharmacokinetics and the response to highly active antiretroviral therapy (HAART) in HIV-1 infected children.

METHODS

Seventy-one HIV-1-infected children from PACTG 382 receiving nelfinavir, efavirenz and one or two nucleoside reverse transcriptase inhibitors had genomic DNA from PBMC evaluated for MDR1 and CYP SNP by real-time PCR. Plasma drug concentrations, CD4 lymphocyte counts and HIV-1 RNA were measured during HAART.

RESULTS

The frequencies of C/C, C/T and T/T genotypes in the MDR1-3435-C-->T polymorphisms were 44% (n = 31), 46% (n = 33) and 10% (n = 7), respectively. Ninety-one percent of children with the C/T genotype reached plasma HIV-1 RNA < 400 copies/ml by week 8 compared to 59% of children with the C/C genotype (P = 0.01). Children with the C/T genotypes had higher 8 h postdose concentration (P = 0.02) and lower clearance rate (P = 0.04) for nelfinavir compared to those with the C/C genotype. The seven children with the T/T genotype had nelfinavir pharmacokinetics and virologic response similar to those with the C/C genotype. No compensatory polymorphisms were observed between MDR1 and CYP genotypes.

CONCLUSIONS

HIV-1 infected children with the MDR1-3435-C/T genotype had more rapid virologic responses to HAART at week 8 with higher plasma nelfinavir concentrations compared to those with the C/C genotype. These findings suggest that P-gp may play an important role in the pharmacokinetics and virologic response to HAART containing nelfinavir.

Relationship between Changes in Thymic Emigrants and Cell-Associated HIV-1 Dna in HIV-1-Infected Children Initiating Antiretroviral Therapy

Objectives and methods

To investigate the relationship between cell-associated HIV-1 dynamics and recent thymic T-cell emigrants, HIV-1 DNA and T-cell receptor rearrangement excision circles (TREC, a marker of recent thymic emigrants) were measured in peripheral blood mononuclear cells in 181 samples from 33 HIV-1-infected children followed for 96 weeks after antiretroviral therapy (ART) initiation.

Results

At baseline, HIV-1 DNA was higher in children with higher TREC ( P=0.02) and was not related to age, CD4 or HIV-1 RNA in multivariate analyses ( P>0.3). Overall, TREC increased and HIV-1 DNA decreased significantly after ART initiation, with faster HIV-1 DNA declines in children with higher baseline TREC ( P=0.009). The greatest decreases in HIV-1 DNA occurred in children with the smallest increases in TREC levels during ART ( P=0.002). However, this inverse relationship between changes in HIV-1 DNA and TREC tended to vary according to the phase of HIV-1 RNA decline ( P=0.13); for the same increase in TREC, HIV-1 DNA decline was much smaller during persistent or transient viraemia compared with stable HIV-1 RNA suppression.

Conclusions

Overall, these findings indicate that TREC levels predict HIV-1 DNA response to ART and suggest that immune repopulation by thymic emigrants adversely affects HIV-1 DNA decline in the absence of persistent viral suppression, possibly by providing a cellular source for viral infection and replication.

Characterizing immune reconstitution after long-term highly active antiretroviral therapy in pediatric AIDS

In this study, we sought to characterize the T lymphocyte recovery in vertically HIV-1-infected children who respond to long-term highly active antiretroviral therapy (HAART). A 3-year longitudinal retrospective study was used to perform a cross-sectional study of 32 children rated according to the time course of CD4(+) T cell percentages in response to antiretroviral therapy and CDC clinical classification: (1) long-term asymptomatic (LTA group): 8 children in A1 during the whole follow-up period; (2) responsive to HAART (Rec group): 13 children in C3 before HAART who achieved CD4(+) T cell counts of > 500 cells/mm(3) after 3 years of HAART; and (3) nonresponsive to HAART (Non-Rec group): 11 children in C3 during the whole follow-up period despite 3 years of HAART. We also studied 17 healthy age-matched uninfected children as controls. Lymphoproliferative responses (LPRs) were evaluated by incorporation of [(3)H]thymidine, identification of T cell subsets by three-color flow cytometry, and determination of thymic production of T cells by quantification of T cell receptor rearrangement excision circles (TRECs). Interestingly, the Rec group showed an increase in percentage of CD4(+) T cells and a decrease in viral load, and recovered LPRs to mitogens and recall antigens, with values similar to those of the LTA group. Moreover, the Rec group produced similar percentages and absolute counts of naive (CD45RA(+)CD62L(+)) CD4(+) and CD8(+) T cells, and TRECs similar to those of the LTA group. In particular, the Rec group produced similar percentages of CD8(+)CD28(-)CD57(+) and CD8(+)CD28(-)CD57(-) T cell subsets compared with controls. Our data indicate that among children who have already progressed to AIDS and severe immunodeficiency but who respond to HAART, the immune system can recover and resemble those of nonprogressors or even uninfected children, in quantitative as well as in functional terms.

Immune reconstitution in HIV-1-infected children on antiretroviral therapy: role of thymic output and viral fitness

OBJECTIVE

To investigate the role of thymic output and viral fitness in immune reconstitution in HIV-1-infected children on antiretroviral therapy.

METHODS

Thymic output was studied by measuring levels of T-cell receptor rearrangement excision circles (TREC) in peripheral blood lymphocytes, using a real-time quantitative PCR assay. Recombinant viruses containing pre-therapy or post-therapy HIV-1 protease domains were evaluated for viral infectivity in a quantitative single-cycle assay.

RESULTS

Eighteen HIV-1-infected children who showed a significant increase in CD4 T-cell count after therapy were studied; HIV-1 plasma viraemia was substantially suppressed in 12 children (virological responders), but not in the other six (virological non-responders). TREC were quantified at baseline, and sequentially during the first 12 months of therapy. Both virological responders and non-responders showed an increase in TREC levels that was inversely correlated with baseline TREC and CD4 T cell counts. Changes in TREC positively correlated with CD4 T-cell count increases in virological responders, but not in non-responders; moreover, the ratios between TREC and CD4 T-cell count increases were higher in non-responders than in responders, suggesting a persistence of peripheral CD4 T-cell loss in the former. Drug-resistant viruses with reduced replicative capacity were documented in three out of six non-responders.

CONCLUSIONS

These findings indicate that recovery of thymic function is a pivotal event in immune reconstitution, and suggest that CD4 T-cell increase despite persistent viraemia is sustained by a continuous thymic output that compensates peripheral CD4 T-cell depletion which might be slowed down by emerging viruses with reduced fitness.

Identification of novel HLA-A2-restricted human immunodeficiency virus type 1-specific cytotoxic T-lymphocyte epitopes predicted by the HLA-A2 supertype peptide-binding motif

Virus-specific cytotoxic T-lymphocyte (CTL) responses are critical in the control of human immunodeficiency virus type 1 (HIV-1) infection and will play an important part in therapeutic and prophylactic HIV-1 vaccines. The identification of virus-specific epitopes that are efficiently recognized by CTL is the first step in the development of future vaccines. Here we describe the immunological characterization of a number of novel HIV-1-specific, HLA-A2-restricted CTL epitopes that share a high degree of conservation within HIV-1 and a strong binding to different alleles of the HLA-A2 superfamily. These novel epitopes include the first reported CTL epitope in the Vpr protein. Two of the novel epitopes were immunodominant among the HLA-A2-restricted CTL responses of individuals with acute and chronic HIV-1 infection. The novel CTL epitopes identified here should be included in future vaccines designed to induce HIV-1-specific CTL responses restricted by the HLA-A2 superfamily and will be important to assess in immunogenicity studies in infected persons and in uninfected recipients of candidate HIV-1 vaccines.

Correlation of clinical parameters and immunological function with human immunodeficiency virus plasma viremia in children

Studies of immune function in human immunodeficiency virus (HIV)-infected children are important, because functional abnormalities can precede CD4+ T-cell loss and are associated with the development of opportunistic and bacterial infections. We sought to correlate clinical parameters and immunological function with HIV RNA plasma levels in 20 children. HIV RNA levels were measured by a polymerase chain reaction assay. We analyzed T-cell responses to mitogens (phytohemagglutinin, concanavalin A, and pokeweed [PWM]) and antigens (tetanus toxoid and Candida albicans); T-cell suppressor activity; and humoral immunity to Haemophilus influenzae, hepatitis B, tetanus, and diphtheria vaccines. The median age of the children was 6 years. Eight children had HIV RNA levels less than 200 to 9621 copies per milliliter (group I). Four children had 37,970 to 82,630 copies per milliliter (group II). Eight children had 102,100 to 191,200 copies per milliliter (group III). There were no differences in the HIV-related complications between group I and II children. Group I/II children had significantly higher CD4+ T-cell counts (P = 0.02), less symptomatic HIV disease (P = 0.005), and more detectable protective vaccine immunity (P = 0.014) compared with group III children. Responses to mitogens were conserved in most children. Group I children tended to have higher responses to tetanus toxoid than group II children and significantly higher responses than group III children (P = 0.01). Group I had significantly higher responses to C. albicans than groups II (P = 0.016) and III (P = 0.001). Group I/II children tended to have lower suppressor activity compared with group III children (median, 0 vs 64%). We demonstrated that humoral and cellular immune dysfunction exists at all stages of disease in HIV-infected children but was most severe in children with greater than or equal to 100,000 HIV RNA copies per milliliter. Function was the most intact in children with less than 10,000 copies per milliliter.