Immunology and the REACH study: HIV immunology and preliminary findings. Reaching for Excellence in Adolescent Care and Health

Soluble CD14, CD163, and CD27 biomarkers distinguish ART-suppressed youth living with HIV from healthy controls

OBJECTIVE

To define inflammatory pathways in youth living with HIV infection (YLWH), assessments of biomarkers associated with lymphocyte and macrophage activation, vascular injury, or bone metabolism were performed in YLWH in comparison with healthy controls (HC).

DESIGN

Longitudinal multicenter study comparing biomarkers in YLWH suppressed on antiretroviral therapy (ART), those with ongoing viral replication, and HC were compared using single blood samples obtained at end of study.

METHODS

Twenty-three plasma proteins were measured by ELISA or multiplex assays. Principal component analysis (PCA) was used to define contributions of individual biomarkers to define outcome groups.

RESULTS

The study cohort included 129 predominantly African American, male participants, 21-25 years old at entry. Nine biomarkers of lymphocyte and macrophage activation and cardiovascular injury differed between HC and YLWH. Significant positive correlations were identified between lymphocyte and macrophage activation biomarkers among HC and YLWH. Correlations distinct to YLWH were predominantly between biomarkers of macrophage and vascular inflammation. PCA of outcome groups showed HC and suppressed YLWH clustering together for lymphocyte activation biomarkers, whereas macrophage activation markers showed all YLWH clustering distinct from HC. Cardiovascular biomarkers were indistinguishable across groups. Averaged variable importance projection to assess single biomarkers that maximally contribute to discriminate among outcome groups identified soluble CD27, CD14, and CD163 as the 3 most important with TNFα and LPS also highly relevant in providing separation.

CONCLUSIONS

Soluble inflammatory and lymphocyte biomarkers sufficiently distinguish YLWH from HC. Persistent macrophage activation biomarkers may provide a means to monitor consequences of HIV infection in fully suppressed YLWH.

Immune Reconstitution but Persistent Activation After 48 Weeks of Antiretroviral Therapy in Youth With Pre-Therapy CD4 >350 in ATN 061

BACKGROUND

Measures of immune outcomes in youth who initiate combination antiretroviral therapy (cART) early in HIV infection are limited.

DESIGN

Adolescent Trials Network 061 examined changes over 48 weeks of cART in T-cell subsets and markers of T-cell and macrophage activation in subjects with pre-therapy CD4 > 350 cells/mm. All subjects had optimal viral suppression from weeks 24 through 48.

METHODS

Subjects (n = 48) initiated cART with tenofovir/emtricitabine plus ritonavir-boosted atazanavir. Data were collected at baseline and weeks 12, 24, and 48. Trends were compared to uninfected controls.

RESULTS

Significant increases over 48 weeks were noted in all CD4 populations, including total, naive, central memory (CM), and effector memory RO (EM RO) and effector memory RA (EM RA), whereas numbers of CM and EM RO CD8 cells declined significantly. By week 48, CD4 naive cells were similar to controls, whereas CM CD4 cells remained significantly lower and EM RO and EM RA subsets were significantly higher. CD38 and HLA DR expression, both individually and when co-expressed, decreased over 48 weeks of cART on CD8 cells but remained significantly higher than controls at week 48. In contrast, markers of macrophage activation measured by sCD14 and sCD163 in plasma did not change with cART and were significantly higher than controls.

CONCLUSIONS

In youth initiating early cART, CD4 cell reconstitution is robust with decreases in CD8 cells. However, CD8 T-cell and macrophage activation persists at higher levels than uninfected controls.

Notification of HIV status disclosure and its related factors in HIV-infected adolescents in 2009 in the Aconda program (CePReF, CHU Yopougon) in Abidjan, Côte d'Ivoire, The PRADO-CI Study

Introduction

We studied the frequency of documentation of disclosure of HIV status in medical charts and its correlates among HIV-infected adolescents in 2009, in Abidjan, Côte d'Ivoire.

Methods

The PRADO-CI is a cross-sectional study aimed at studying HIV-infected adolescents’ social, psychological, and behavioural difficulties and their determinants in Abidjan, Côte d'Ivoire. In this study, we present specific analyses on disclosure. All HIV-infected adolescents aged 13–21 years and followed at least once in 2009 in two urban HIV-care centres in Abidjan (Cepref and Yopougon Teaching Hospital) were enrolled in the study. Standardized data were extracted from medical records to document if there was notification of disclosure of HIV status in the medical record. Frequency of notification of HIV disclosure was estimated with its 95% confidence interval (CI) and correlates were analyzed using logistic regression.

Results

In 2009, 229 adolescents were included: 126 (55%) males; 93% on antiretroviral therapy (ART), 61% on cotrimoxazole prophylaxis. Their median age was 15 years at the time of the study. Among the 193 patients for whom information on HIV status disclosure was documented (84%), only 63 (32.6%; 95% CI=26.0–39.3%) were informed of their status. The proportion of adolescents informed increased significantly with age: 19% for 13–15 years, 33% for 16–18 years and 86% for 19–21 years (p <0.0001). Adolescents on ART tended to be more likely to be informed of their HIV status (34.5%) than those not treated (13.3%) (p=0.11). Those on cotrimoxazole were significantly more likely to be informed (39.6%) than those not (21.9%) (p=0.01). Disclosure was significantly higher in adolescents with a history of ART regimen change (p=0.003) and in those followed in the Cepref (48.4%) compared to the Yopougon Teaching Hospital (24.8%), (p=0.001). In multivariate analyses, disclosed HIV status was significantly higher in those followed-up in the Cepref compared to the other centre: adjusted odds ratio (aOR)=3.5 (95% CI: 1.1–10.9), and among older adolescents compared to those aged 13–15 years: [16–18 years] aOR=4.2 (95% CI: 1.5–11.5) and [>18 years]: aOR=22.1 (95% CI: 5.2–93.5).

Conclusions

HIV disclosure rate was low among Ivoirian HIV adolescents and was site- and age-dependent. There is a need for practical interventions to support HIV disclosure to adolescents which provides age-appropriate information about the disease.

Assessment of biomarkers of cardiovascular risk among HIV type 1-infected adolescents: role of soluble vascular cell adhesion molecule as an early indicator of endothelial inflammation

Cardiovascular disease (CVD) biomarkers were examined in a cohort of HIV-infected and HIV-uninfected adolescents who participated in Adolescent Trials Network study 083 utilizing samples from the Reaching for Excellence in Adolescent Care cohort, a longitudinal study of youth infected through adult risk behavior. Nonfasting blood samples from 97 HIV-infected and 81 HIV-uninfected adolescents infected by adult risk behaviors were analyzed for total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), very low-density lipoprotein (VLDL), triglycerides, apolipoprotein A-I, high-sensitivity C-reactive protein (hsCRP), soluble vascular adhesion molecule-1 (sVCAM-1), myeloperoxidase, and neopterin at baseline and 18 months later. Results were analyzed using ANOVA, Wilcoxon signed-rank, and paired t tests. Among infected subjects 67 received antiretroviral therapy and 30 were treatment naive. The HIV-infected and HIV-uninfected subjects were similar in gender, ethnicity, and cardiovascular risk factors such as smoking and obesity. In all groups lipid parameters were within accepted guidelines for cardiovascular risk. Among HIV-infected youth on antiretroviral therapy (ART), HDL and apoprotein A-I were significantly lower when compared to uninfected youth. hsCRP was not elevated and thus not predictive for risk in any group. sVCAM-1 levels were significantly elevated in both HIV-infected groups: 1,435 ng/ml and 1,492 ng/ml in untreated and treated subjects, respectively, and 1,064 ng/ml in the uninfected group (p<0.0001). Across all groups neopterin correlated with sVCAM at 18 months (Spearman correlation coefficient 0.58, p<0.0001). Only 9% of ART-treated subjects fully suppressed virus. Lipid profiles and hsCRP, traditional markers of cardiovascular disease, are not abnormal among HIV-infected youth but elevated sVCAM may be an early marker of atherosclerosis.

Glutathione, glutathione peroxidase, and selenium status in HIV-positive and HIV-negative adolescents and young adults

BACKGROUND

Antioxidant nutrient deficiencies may hasten the progression of HIV disease by impairing antioxidant defenses.

OBJECTIVE

The objective of the study was to determine whether HIV infection is associated with poor selenium status and low antioxidant protection by glutathione and glutathione peroxidase (GPX).

DESIGN

In a cross-sectional study of 365 HIV-positive and HIV-negative adolescents and young adults, we examined the relation of plasma selenium, whole-blood glutathione, and whole-blood GPX to HIV status, disease severity, immune activation, and oxidative damage.

RESULTS

Selenium deficiency (plasma selenium < 0.070 microg/mL) was not seen in any subjects, and plasma selenium in 244 HIV-positive subjects (0.120 +/- 0.0013 microg/mL) did not differ significantly (P = 0.071) from that in 121 HIV-negative subjects (0.125 +/- 0.0020 microg/mL) . However, multiple regression analysis after adjustment for covariates showed a significant (P = 0.002) negative association between HIV-associated immune activation (plasma neopterin) and plasma selenium concentrations. GPX activity was highest in HIV-positive subjects taking antiretroviral therapy (median: 14.2; 25th, 75th percentiles: 11.1, 18.7 U/mL; n = 130), intermediate in HIV-positive subjects not taking antiretroviral therapy (11.8; 9.4, 15.1 U/mL; n = 114), and lowest in HIV-negative subjects (10.6; 8.6, 12.7 U/mL; n = 121; P < 0.05 for all comparisons). GPX was also positively associated with malondialdehyde, a marker of oxidative damage.

CONCLUSIONS

Subjects had adequate selenium status, although HIV-related immune activation was associated with lower plasma selenium concentrations. GPX activity appears to have been induced by the oxidative stress associated with HIV infection and use of antiretroviral therapy. Thus, young, well-nourished subjects can mount a compensatory antioxidant response to HIV infection.

Vitamin D status in adolescents and young adults with HIV infection

BACKGROUND

Vitamin D status affects immune function and thus may affect the progress of HIV infection.

OBJECTIVES

Our goals were to assess vitamin D intake and status in subjects with HIV infection and in matched control subjects and to determine whether HIV infection was associated with vitamin D insufficiency.

DESIGN

Plasma 25-hydroxyvitamin D [25(OH)D] concentrations and vitamin D intake were measured in a cross-sectional study of members of the Reaching for Excellence in Adolescent Health (REACH) cohort.

RESULTS

The subjects were aged 14-23 y; 74% were female, and 72% were black. Mean (+/-SE) vitamin D intake from food was 30% greater (P = 0.023) in HIV-positive subjects (295 +/- 18 IU/d; n = 237) than in HIV-negative subjects (227 +/- 26 IU/d; n = 121). The prevalence of vitamin D supplement use was 29% (104 of 358 subjects) and did not differ significantly by HIV status (P = 0.87). Mean plasma 25(OH)D did not differ significantly (P = 0.62) between the HIV-positive (20.3 +/- 1.1 nmol/L; n = 238) and HIV-negative (19.3 +/- 1.7 nmol/L; n = 121) subjects, nor was HIV status a significant predictor of plasma 25(OH)D when multiple regression analysis was used to adjust for other variables. The prevalence of vitamin D insufficiency [plasma 25(OH)D < or = 37.5 nmol/L] in the subjects was 87% (312 of 359 subjects).

CONCLUSIONS

HIV infection did not influence vitamin D status. The prevalence of vitamin D insufficiency in both HIV-positive and HIV-negative REACH subjects was high, perhaps because these disadvantaged, largely urban youth have limited sun exposure.

Vitamins C and E in adolescents and young adults with HIV infection

BACKGROUND

Oxidative stress during HIV infection may impair immune function, cause more rapid disease progression, and increase requirements for dietary antioxidants such as vitamins C and E.

OBJECTIVES

The study had 2 principal objectives. The first was to ascertain whether HIV infection and immune activation were associated with lower plasma concentrations of ascorbate, urate, and alpha- and gamma-tocopherols and with total antioxidant status (TAS). The second objective was to ascertain whether these antioxidants were associated with protection against oxidative damage.

DESIGN

This was a cross-sectional study involving 241 HIV-positive and 115 HIV-negative subjects aged 14-23 y. Subjects were primarily female (76%) and African American (70%), and 21% were Hispanic.

RESULTS

Plasma ascorbate was significantly lower, but gamma-tocopherol and TAS were significantly higher in subjects with HIV infection when the analysis was adjusted for dietary intake and sex. Plasma alpha-tocopherol did not differ significantly by HIV status. Plasma gamma-tocopherol also was higher in subjects with oxidative damage than in those without such damage. More than 90% of subjects had adequate plasma concentrations for both ascorbate and alpha-tocopherol, although alpha-tocopherol concentrations were lower than expected on the basis of third National Health and Nutrition Examination Survey data.

CONCLUSIONS

Low plasma ascorbate concentrations in HIV-positive subjects suggest that vitamin C requirements are significantly higher in those with HIV infection. Plasma tocopherol concentrations were not depressed by HIV infection and may be maintained by compensatory mechanisms such as the activity of alpha-tocopherol transfer protein.

HIV in adolescents

Adolescence is a time of dramatic physical, emotional, cognitive, and social change that brings new vulnerabilities. Youth represent half of all new HIV infections in the United States and the rest of the world. The number of newly infected adolescents who acquire the disease behaviorally and the number of perinatally infected children surviving into adolescence have both contributed to this growth. This article reviews the most recent epidemiology of HIV/AIDS in adolescents, gives guidance on clinical practice, including medical and psychosocial care, and examines prevention issues, including counseling and testing, which are needed to make programs effective for youth.

Immune activation and oxidative damage in HIV-positive and HIV-negative adolescents

In a cross-sectional study involving subjects from the Reaching for Excellence in Adolescent Health cohort, we examined the associations between HIV status, disease severity, immune activation, and oxidative damage. Subjects (265 HIV-positive and 127 HIV-negative) were young (range: 14-23 years of age) and primarily female (75%) and black (67%). Many subjects, particularly female subjects, were overweight or obese. Relatively few HIV-positive subjects had advanced HIV disease (13%), and 54% were taking antiretroviral therapy (ART). The 2 markers of oxidative damage used in this study (plasma malondialdehyde and protein carbonyl concentrations) did not correlate with each other, and neither was higher in HIV-positive subjects than in HIV-negative controls. Increased oxidative damage was seen in association with male gender, cigarette smoking, marijuana use, immune activation (as indicated by activated CD8 T-cell counts and plasma C-reactive protein concentration), and use of ART, however. Plasma ceruloplasmin was associated with decreased oxidative damage in HIV-positive subjects, although this association was not seen in those taking ART.

Perinatal antiretroviral treatment and hematopoiesis in HIV-uninfected infants

BACKGROUND

The perinatal prophylactic administration of zidovudine is associated with rapidly reversible macrocytic anemia in infants. However, a recent study suggests that there may be more persistent inhibition of hematopoïetic stem cells.

OBJECTIVE

To study hematopoiesis in uninfected infants, born to HIV-1 seropositive mothers, including those exposed and those not exposed to perinatal zidovudine alone or in combination.

METHODS

Longitudinal study, from 0 to 18 months, of hemoglobin, platelets, polynuclear neutrophils, total lymphocytes, and CD4+ and CD8+ lymphocytes in more than 4000 infants of the French Perinatal Study. Modeling of repeated measures and non-linear evolution with age, with models combining natural cubic B-splines and random effects.

RESULTS

The hemoglobin level was transiently reduced in newborns exposed to zidovudine. Multivariate analysis taking into account age, prematurity, geographical origin, maternal drug use and maternal CD4 cell count, indicated that levels of the three other lineages were slightly lower until age 18 months in exposed than not exposed infants (P < 0.0001 for each lineage). There was a negative relationship between the duration of exposure and each hematological variable. Combinations of antiretroviral treatments were associated with larger decreases than monotherapy up to 15 months of age. Similar, but less pronounced, patterns were found for the CD4+ and CD8+ subpopulations of lymphocytes.

CONCLUSIONS

Zidovudine administered during the perinatal period may result in a small but significant and durable effect on hematopoïesis up to the age of 18 months.

CD4+ and CD8+ T cell receptor repertoire perturbations with normal levels of T cell receptor excision circles in HIV-infected, therapy-naive adolescents

Our objective was to determine whether treatment-naive HIV-infected adolescents manifest abnormalities in thymus function and peripheral T cell repertoire, and to assess relationships of these immunologic characteristics with each other, with plasma HIV virus load, and T cell surface markers. TCR Vbeta repertoire was determined by CDR3 length spectratyping in purified CD4(+) and CD8(+) T cells of high-risk, HIV-negative adolescents and of treatment-naive, HIV-infected adolescents. Thymus function was investigated by the simultaneous examination of T cell receptor excision circles (TRECs) in the CD4(+) and CD8(+) T cell subsets. HIV-infected adolescents exhibited significantly greater perturbations in their TCR Vbeta repertoire in comparison with HIV-negative subjects. Perturbations in the CD8(+) T cell compartment were more profound in comparison with CD4(+) T cells. The CD4(+) TCR Vbeta perturbations were negatively correlated with the total and phenotypically naive CD4(+) T cells, and with CD4(+) TRECs. CD8(+) TRECs, although not correlated with CD8(+) TCR Vbeta perturbations, showed negative correlation with memory and activated CD8(+) T cells. Interestingly, TRECs in CD4(+) and CD8(+) T cells were not significantly different between HIV-infected and uninfected adolescents. The TCR Vbeta repertoire in adolescents is profoundly perturbed even in early stages of HIV infection, when total CD4(+) cell counts in most subjects are within normal limits. The correlative analyses demonstrating negative association of CD4(+) cell TRECs with CD4(+) TCR Vbeta perturbations and of CD8(+) TRECs with CD8(+) cell activation markers provide evidence of the intense activation of the central and peripheral immune compartments in this study population.

TH1 and TH2 cytokine mRNA and protein levels in human immunodeficiency virus (HIV)-seropositive and HIV-seronegative youths

The roles of cytokines in the progression of human immunodeficiency virus (HIV)-associated disease are controversial. The patterns of innate cytokine production have been postulated to shift from TH1- to TH2-type cytokines with the progression of HIV-associated disease. Although there have been studies of cytokines in children and adults, no data are available on cytokine production in healthy or HIV-infected adolescents. We analyzed and characterized cytokine mRNA and protein levels for gamma interferon, interleukin 2 (IL-2), IL-4, and tumor necrosis factor alpha and protein levels of IL-6 in both stimulated and unstimulated peripheral blood mononuclear cells obtained from a large longitudinal, observational cohort study of HIV-seropositive and -seronegative adolescents. We correlated cytokine results with viral load and CD4(+)-T-cell counts as critical markers of disease progression in HIV-infected adolescents. These data were used to examine hypotheses related to the TH1-to-TH2 cytokine shift in a sample of HIV-infected adolescents. Five hundred twenty subjects participating in the REACH (Reaching for Excellence in Adolescent Care and Health) Project of the Adolescent Medicine HIV/AIDS Research Network contributed blood samples. Samples selected for the cross-sectional data set analyzed had to meet selection criteria developed to minimize the potential confounding effects of acute intercurrent illnesses or infections, recent vaccination for hepatitis, and altered hormone status and to optimize congruence of cytokine measurements with assays of viral load and CD4(+)-T-cell counts. Group differences in the proportions of subjects with detectable levels of each cytokine marker were compared. In the subset of subjects with detectable cytokine values, differences in detected values were compared across subgroups defined by HIV serostatus and among HIV-seropositive subjects by three viral load classifications. The study sample was 65% HIV seropositive, 71% African-American, and 75% female with a mean age of 17.4 years. HIV-seropositive subjects were relatively healthy with mean and median CD4(+)-T-cell counts of 534 and 499 cells/mm(3), respectively. Only 8.1% of subjects had CD4(+)-T-cell counts below 200 cells/mm(3), and 25% had viral loads that were below the threshold of detection (<400 copies/ml). Detailed analyses of these data indicate that there were no differences in cytokines detected in HIV-seropositive and HIV-seronegative adolescents, and there was no apparent relationship between the cytokine measurements and the viral load or CD4(+)-T-cell categorization, the parameters selected as markers of HIV-associated disease status. These adolescents, including the HIV-seropositive subjects, were relatively healthy, and the HIV-infected subjects were at an early stage in the course of their HIV-associated disease. On the basis of our data, we conclude that, early in the course of HIV-associated disease in adolescents, there are no detectable shifts from TH1 to TH2 cytokine production.

Assessment of thymic activity in human immunodeficiency virus-negative and -positive adolescents by real-time PCR quantitation of T-cell receptor rearrangement excision circles

Circular DNA molecules known as T-cell receptor rearrangement excision circles (TREC) arise during T-cell development and are present in cells that have recently emigrated from the thymus. In cross-sectional studies, the number of peripheral blood lymphocytes bearing TREC decreases with age, consistent with an anatomically demonstrated loss of thymic epithelial tissue. TREC numbers increase following hematopoietic stem cell transplantation and during therapy for human immunodeficiency virus (HIV) infection. Quantitation of TREC has therefore been proposed as a parameter of thymic activity. In this study, we used real-time PCR to quantify TREC in peripheral blood samples obtained longitudinally from HIV-seronegative adolescents. TREC values in peripheral blood T cells were very stable throughout adolescence, once thought to be a time of rapid involution of the thymus. In addition, in a cross-sectional analysis, we examined TREC values in a cohort of HIV-positive adolescents and found evidence of ongoing thymopoiesis in perinatally infected individuals, despite lifelong infection. These data demonstrate the utility of TREC assessment in adolescents and that HIV infection does not uniformly result in accelerated thymic involution in childhood.