Relationship of CD4+ T cell counts and HIV type 1 viral loads in untreated, infected adolescents. Adolescent Medicine HIV/AIDS Research Network

Advanced in immunological monitoring of HIV infection: profile of immune cells and cytokines in people living with HIV-1 in Benin

BACKGROUND

Immune cells and cytokines have been linked to viremia dynamic and immune status during HIV infection. They may serve as useful biomarkers in the monitoring of people living with HIV-1 (PLHIV-1). The present work was aimed to assess whether cytokines and immune cell profiles may help in the therapeutic follow-up of PLHIV-1.

METHODS

Forty PLHIV-1 in treatment success (PLHIV-1s) and fifty PLHIV-1 in treatment failure (PLHIV-1f) followed at the University Hospital of Abomey-Calavi/Sô-Ava in Benin were enrolled. Twenty healthy persons were also recruited as control group. Circulating cytokines and immune cells were quantified respectively by ELISA and flow cytometry.

RESULTS

PLHIV-1 exhibited low proportions of CD4 + T cells, NK, NKT, granulocytes, classical and non-classical monocytes, and high proportions of CD8 + T cells, particularly in the PLHIV-1f group, compared to control subjects. Eosinophils, neutrophils and B cell frequencies did not change between the study groups. Circulating IFN-γ decreased whereas IL-4 significantly increased in PLHIV-1s compared to PLHIV-1f and control subjects even though the HIV infection in PLHIV-1s downregulated the high Th1 phenotype observed in control subjects. However, Th1/Th2 ratio remained biased to a Th1 phenotype in PLHIV-1f, suggesting that high viral load may have maintained a potential pro-inflammatory status in these patients. Data on inflammatory cytokines showed that IL-6 and TNF-α concentrations were significantly higher in PLHIV-1s and PLHIV-1f groups than in control subjects. Significant high levels of IL-5 and IL-7 were observed in PLHIV-1f compared to controls whereas PLHIV-1s presented only a high level of IL-5. No change was observed in IL-13 levels between the study groups.

CONCLUSION

Our study shows that, in addition to CD4/CD8 T cell ratio, NK and NKT cells along with IL-6, TNF-α, IL-5 and IL-7 cytokines could serve as valuable immunological biomarkers in the therapeutic monitoring of PLHIV-1 although a larger number of patients would be necessary to confirm these results.

Cytomegalovirus viral load and mortality after haemopoietic stem cell transplantation in the era of pre-emptive therapy: a retrospective cohort study

BACKGROUND

Although cytomegalovirus viral load is commonly used to guide pre-emptive therapy in the post-transplantation setting, few data are available correlating viraemia with clinical endpoints. We therefore investigated the association between cytomegalovirus viral load and mortality in the first year after haemopoietic stem cell transplantation.

METHODS

In this retrospective cohort study, we included patients from the Fred Hutchinson Cancer Research Center, WA, USA, who received an allogeneic haemopoietic stem cell transplantation between Jan 1, 2007, and Feb 28, 2013, were cytomegalovirus seropositive or had a seropositive donor, and underwent weekly plasma cytomegalovirus monitoring by PCR through to day 100 post-transplantation. Cox proportional hazards models were used to estimate the association of cytomegalovirus viral load at different thresholds with overall mortality by 1 year post-transplantation, adjusting for the use of pre-emptive therapy and other factors such as neutropenia, and graft-versus-host disease.

FINDINGS

Of the 1037 patients initially selected for inclusion in this cohort, 87 (8%) patients were excluded because of missing cytomegalovirus testing and 24 (2%) were excluded because of their participation in cytomegalovirus prophylaxis trials. In the remaining 926 patients included in this study, the cumulative overall mortality was 30·0% (95% CI 26·9-33·0) 1 year after haemopoietic stem cell transplantation. 95 patients developed cytomegalovirus disease; death was directly attributable to cytomegalovirus disease in three (1%) of 263 patients who died in the first year after transplantation. A cytomegalovirus viral load of 250 IU/mL or greater was associated with increased risk of early (day 0-60 post-transplantation) death (adjusted hazard ratio [HR] 19·8, 95% CI 9·6-41·1). The risk was attenuated after day 60 (adjusted HR 1·8, 95% CI 1·3-2·3). Similar associations were noted for higher cytomegalovirus viral load thresholds.

INTERPRETATION

Cytomegalovirus viraemia is associated with an increased risk of overall mortality in the first year after haemopoietic stem cell transplantation, independent of the use of pre-emptive therapy, and with evidence of a positive dose-response relationship. These data indicate the suitability of viral load as a surrogate clinical endpoint for clinical trials for cytomegalovirus vaccines, biologics, and drugs.

FUNDING

Merck and Co, National Institutes of Health.

Estimating minimum adult HIV prevalence: a cross-sectional study to assess the characteristics of people living with HIV in Italy

In 2012, we conducted a retrospective cross-sectional study to assess the number of people living with HIV linked to care and, among these, the number of people on antiretroviral therapy. The health authority in each of the 20 Italian Regions provided the list of Public Infectious Diseases Clinics providing antiretroviral therapy and monitoring people with HIV infection. We asked every Public Infectious Diseases Clinic to report the number of HIV-positive people diagnosed and linked to care and the number of those on antiretroviral therapy during 2012. In 2012, 94,146 people diagnosed with HIV and linked to care were reported. The majority were males (70.1%), Italians (84.4%), and aged between 25 and 49 years (63.4%); the probable route of transmission was heterosexual contact in 37.5% of cases, injecting drug use in 28.1%, and male-to-male contact in 27.9%. Among people in care, 20.1% had less than 350 CD4 cells/μl, 87.6% received antiretroviral therapy, and among these, 62.4% had a CD4 cell count higher than 350 cells/μl. The overall estimated prevalence of individuals diagnosed and linked to care in 2012 in Italy was 0.16 per 100 residents (all ages). Adding the estimated proportion of undiagnosed people, the estimated HIV prevalence would range between 0.19 and 0.26 per 100 residents. In Italy, the majority of people diagnosed and linked to care receive antiretroviral therapy. A higher prevalence of individuals diagnosed and linked to care was observed in Northern Italy and among males. More information for developing the HIV care continuum is necessary to improve the entire engagement in care, focusing on test-and-treat strategies to substantially reduce the proportion of people still undiagnosed or with a detectable viral load.

Immune markers predictive of neuropsychiatric symptoms in HIV-infected youth

The purpose of this study was to evaluate possible associations between systemic immune dysregulation (activated CD8(+) T lymphocytes and natural killer [NK] cell count/function) and symptoms of depression and anxiety in youth with horizontally (behaviorally) acquired HIV infection. This secondary analysis of a previously collected prospective cohort included 323 youth with horizontally acquired HIV infection enrolled in the Reaching for Excellence in Adolescent Care and Health (REACH) cohort of the NICHD/NIH. A multivariable linear regression model with generalized estimating equations for intraindividual repeated measures was used to examine the relationship between flow cytometry measurements of activated T lymphocytes (CD8(+) CD38(+)), NK cells (CD3(-) CD16(+) CD56(+)), and NK cell functional activity (lytic units per NK cell and per peripheral blood mononuclear cell) and their association with subsequent symptoms of depression (Center for Epidemiologic Studies depression scale) and anxiety (Revised Children's Manifest Anxiety Scale). Higher measures of NK cell functional activity were associated with fewer anxiety symptoms measured 12 months later in crude and adjusted analyses. Higher counts of activated T cells were associated with fewer depression symptoms measured 12 months later in adjusted analysis. NK cell function and activated T-lymphocyte count may be related to subsequent symptoms of depression and anxiety.

KIR2DS4 promotes HIV-1 pathogenesis: new evidence from analyses of immunogenetic data and natural killer cell function

BACKGROUND

KIR2DS4 gene variants encode full-length and truncated protein products, with only the former serving as membrane-bound receptors to activate natural killer (NK) cells. We have previously shown that full-length KIR2DS4 was associated with relatively high viral load and accelerated heterosexual HIV-1 transmission. Our objective here was to provide confirmatory data and to offer new insights about the potential mechanisms.

METHODOLOGY/PRINCIPAL FINDINGS

Mixed models for repeated (longitudinal) outcome measurements on 207 HIV-1 seropositive American youth revealed an association of full-length KIR2DS4 with relatively high viral load and low CD4+ T-cell count (p<0.01 for both). Depending on KIR2DS4 expression (presence or absence) on cell surface, NK cells from 43 individuals with untreated, chronic HIV-1 infection often differed in functional properties, including degranulation and secretion of IFN-γ and MIP-1β. In particular, polyfunctional NK cells were enriched in the KIR2DS4-positive subset.

CONCLUSIONS/SIGNIFICANCE

Full-length KIR2DS4 promotes HIV-1 pathogenesis during chronic infection, probably through the maintenance of an excessively pro-inflammatory state.

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.

Antiretroviral therapy restores diversity in the T-cell receptor Vbeta repertoire of CD4 T-cell subpopulations among human immunodeficiency virus type 1-infected children and adolescents

Human immunodeficiency virus (HIV) type 1 infection perturbs the T-cell receptor (TCR) Vbeta repertoire. The TCR CDR3 length diversity of individual Vbeta families was examined within CD45RA and CD45RO CD4 T cells to assess the impact of the virus on clonality throughout CD4 T-cell activation and differentiation. A cross-sectional and longitudinal cohort study of 13 HIV-infected and 8 age-matched healthy children and adolescents examined the Vbeta CDR3 length profiles within CD4 T-cell subsets by the use of spectratyping. HIV-infected subjects demonstrated higher numbers of perturbations in CD4 CD45RA T cells (5.8 +/- 4.9 Vbeta families) than healthy individuals (1.6 +/- 1.8 Vbeta families) (P = 0.04). Surprisingly, CD4 CD45RO central memory T cells from infected subjects showed no increased perturbations compared to the perturbations for the same cells from healthy subjects (2.9 +/- 3.1 and 1.1 +/- 1.8 Vbeta families, respectively; P = 0.11). CD4 CD45RA TCR perturbations were higher among infected subjects with >25% CD4 cells than healthy subjects (mean number of perturbed Vbeta families, 6.6 +/- 5.4; P = 0.04). No correlations between perturbations in CD4 subsets and pretherapy age or viral load were evident. In contrast to CD8 T cells, HIV induces TCR disruptions within CD45RA but not CD45RO CD4 T cells. Therapy-induced viral suppression resulted in increases in thymic output and the normalization of the diversity of TCR within CD45RA CD4 T cells after 2 months of treatment. Perturbations occur prior to CD4 T-cell attrition and normalize with effective antiretroviral therapy. The impact of HIV on the diversity of TCR within naïve, central memory, and effector memory CD4 T cells is distinctly different from that in CD8 T cells.

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.

Gender differences in lymphocyte populations, plasma HIV RNA levels, and disease progression in a cohort of children born to women infected with HIV

OBJECTIVE

We sought to document gender differences in lymphocyte subsets and plasma RNA levels in a pediatric cohort with presumed minimal hormonal differences (on the basis of age).

METHODS

Blood samples from antiretroviral therapy-treated, HIV-infected children (n = 158) and HIV-uninfected children (n = 1801) who were enrolled in the Women and Infants Transmission Study were analyzed at specified study intervals with consensus protocols, and various parameters were compared.

RESULTS

Antiretroviral therapy-treated, HIV-infected female children had, on average, 0.38 log10 copies per mL lower plasma RNA levels than did their male counterparts, but lymphocyte differences were not noted in this cohort. Despite their higher plasma RNA level, a greater proportion of male children survived through 8 years of age. There were no gender differences with respect to the age of diagnosis of HIV, time to antiretroviral therapy after diagnosis of HIV, or type of antiretroviral therapy. Lymphocyte differences were noted for uninfected children.

CONCLUSIONS

Plasma RNA levels differed among antiretroviral therapy-treated, HIV-infected children according to gender, in a manner similar to that noted in previous pediatric and adult studies. Lymphocyte subsets varied according to gender in a cohort of HIV-exposed but uninfected children. Most importantly, overall mortality rates for this cohort differed according to gender.

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.

Interleukin 18 and human immunodeficiency virus type I infection in adolescents and adults

Interleukin (IL)-18, a proinflammatory cytokine, has been recognized recently as an important factor in both treated and untreated patients with human immunodeficiency virus type 1 (HIV-1) infection. Consistent with all earlier reports, our quantification of serum IL-18 concentrations in 88 HIV-1 seropositive, North American adolescents (14-18 years old) revealed a positive correlation with cell-free HIV-1 viral load at two separate visits (Spearman's r = 0.31 and 0.50, respectively, P < 0.01 for both), along with a negative correlation with CD4+ T cell counts (r = -0.31 and -0.35, P < 0.01 for both). In additional analyses of 66 adults (21-58 years old) from Zambia, HIV-1 seroconversion was associated uniformly with elevated IL-18 production (P < 0.0001). These epidemiological relationships were independent of other population-related characteristics, including age, gender and ethnicity. In neither study population could serum IL-18 concentrations be associated with the IL-18 gene (IL18) promoter genotypes defined by five major single nucleotide polymorphisms. Collectively, these findings suggest that circulating IL-18 rather than the IL18 genotype may provide a useful biomarker for HIV-1-related events or outcomes.

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.

Cytokine and chemokine gene polymorphisms among ethnically diverse North Americans with HIV-1 infection

Twenty-four common single nucleotide polymorphisms (SNPs) in 10 cytokine and chemokine genes were defined in 579 North Americans at high risk of HIV-1 infection due to sexual behavior and injection drug use. Among the 3 major ethnic (African-American, Hispanic/Latino, and other) groups involved, HIV-1-seropositive individuals differed significantly from ethnically matched HIV-1-seronegative individuals (odds ratios = 2.13-4.82; P = 0.003-0.05) for several SNPs and haplotypes defined at the IL4, IL4R, IL6, IL10, CCL5 (RANTES), and CXCL12 (SDF1) loci. In addition, the homozygous IL4-590T/T genotype was associated with higher (+87-131 cells/microL) CD4 T-cell counts in HIV-1-infected and AIDS-free adolescents not receiving antiretroviral therapy (adjusted P = 0.004). No SNPs at IFNG, IL2, IL12B, TNF, or CCL2 (MCP1) showed any association with HIV-related outcomes. Additional typing for IL1A, IL1B, IL1R1, IL1RN, and TGFB1 SNPs also failed to demonstrate any influence on HIV-1 infection or virologic/immunologic control in more selected patient groups. Coupled with previous findings, our data suggest that heritable IL4 and IL10 variations may contribute to the acquisition or progression of HIV infection and that the effects of other targeted loci in the cytokine and chemokine system cannot be established unequivocally in the study populations.

Evaluation of two commercially available, inexpensive alternative assays used for assessing viral load in a cohort of human immunodeficiency virus type 1 subtype C-infected patients from South Africa

Although human immunodeficiency virus type 1 (HIV-1) RNA is the acknowledged "gold standard" marker for monitoring disease activity in patients receiving highly active antiretroviral therapy (HAART), it remains unaffordable in resource-constrained settings. The present study investigated two commercially available kits for the detection of HIV-1 viral load markers as more affordable alternatives to HIV-1 RNA quantitation. The greatly improved heat-denatured, signal-boosted HiSens HIV-1 p24 Ag Ultra kit (Perkin-Elmer) and the ExaVir Load Quantitative HIV-RT kit (Cavidi Tech AB) were compared with the Amplicor HIV-1 Monitor (version 1.5) assay (Roche Molecular Systems Inc.). A total of 117 samples containing HIV-1 subtype C were analyzed by all three methodologies. Eighty-nine of these samples represented serial measurements from 20 patients receiving HAART. The remaining samples analyzed were from a group of treatment-naive patients. The association between the p24 antigen assay and the RNA assay was fairly strong (R(2) = 0.686). The association between the reverse transcriptase (RT) quantitation assay and the RNA assay was strong (R(2) = 0.810). Both alternative assays seemed most useful for the serial monitoring of patients receiving HAART (n = 89 plasma samples from 20 patients), as all assays showed a statistically significant downward trend over time, with the trend being either linear or curvilinear. In addition, all three assays showed negative correlations with the CD4 count (CD4 count versus RNA load, r = -0.336 and P = 0.001; CD4 count versus p24 antigen level, r = -0.541 and P < 0.0001; CD4 count versus RT level, r = -0.358 and P = 0.0006). Still of major concern are both the lack of sensitivity and the wide degrees of variability of both assays. However, both assays provide a less expensive alternative to the Roche viral load assay and demonstrate the same trends during treatment.

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.

Effects of human immunodeficiency virus type 1 infection on CCR5 and CXCR4 coreceptor expression on CD4 T lymphocyte subsets in infants and adolescents

HIV-1 infection alters expression of CCR5 and CXCR4 on CD4 T cells in adults, although an effect by virus on expression of coreceptor genes in pediatric subjects is unknown. We designed an exploratory study to evaluate surface expression of CXCR4 and CCR5 on CD45RA and CD45RO subsets of CD4 T lymphocytes from 17 HIV-1-infected infants and adolescents and 16 healthy age-matched individuals. While age in the absence of HIV-1 infection was unrelated to coreceptor expression, infection affected coreceptor expression differentially in infants and adolescents. Among infected adolescents, CCR5 and CXCR4 expression was significantly increased on CD4 CD45RO T cells, while CXCR4 was diminished in the CD4 CD45RA subset. Although HIV-1 infection in infants was also associated with increased CXCR4 expression on the CD4 CD45RO subset, in contrast to adolescents, infection in infants had no impact on coreceptor expression within the CD45RA CD4 subset. The proportion of CD4 T cells coexpressing CD45RA and CD45RO was increased by infection in both infants and adolescents. The CD45RA CD45RO subset in culture expressed high levels of CD4, CXCR4, and CD69, an early activation marker, and was highly susceptible to HIV-1 infection and replication. Infection of transitional CD4 T cells coexpressing CD45RA and CD45RO could contribute in part to provirus in either CD45RA or CD45RO subsets. Deleterious effects by HIV-1 infection on CD4 T cell homeostasis were greater in infants then adolescents, indicating that adolescence may be an optimal age group for assessing vaccines to prevent or treat HIV-1 infection.

CD8+CD38+ T cells but not HIV type 1 RNA viral load predict CD4+ T cell loss in a predominantly minority female HIV+ adolescent population

The purpose of this study was to evaluate predictors of HIV-1 disease progression in a cohort of predominantly female and minority adolescents who had acquired their HIV-1 infections through sexual risk behaviors. Subjects were identified from the REACH cohort who were not on antiretroviral therapy for at least 1 year and whose baseline CD4(+) T cells were >300 cells/mm(3). Biomedical and demographic characteristics of the subjects at the start of the study period were evaluated as predictors of CD4(+) T cell loss in univariate and multivariate models. Two-thirds of the 99 subjects meeting the selection criteria were female and 87% were black or Hispanic similar to the REACH cohort as a whole. Higher absolute CD8(+) CD38(+) T cell counts at the start of the assessment period were associated with a greater rate of loss of CD4(+) T cells. HIV-1 RNA viral load was among other potential predictors of HIV-1 disease progression that had no association with the rate of CD4(+) T cell loss in this cohort. This study extends the observed association of higher CD8(+) CD38(+) T cells numbers being predictive of HIV-1 disease progression into predominantly female, minority youth.

T cell responses in HIV type 1-infected adolescent minorities share similar epitope specificities with whites despite significant differences in HLA class I alleles

African-Americans (AFAM) and Hispanics (HIS) represent only 13% and 12% of the U.S. population but 54% and 19%, respectively, of annually incident HIV-1 infections in the United States. The 88 patients in the current study were from U.S. racial or ethnic minority groups (72% African-American, 17% Hispanic), female (85%), and adolescent (mean age 20 years). Their HLA allele distributions were distinct from patterns in U.S. whites. Overall, HIV-1-specific T cell responses were observed in 91% of participants: 75% recognized peptides in Gag, 67% Pol, 57% Nef, and 41% Env. The patients recognized 87 (36%) of 244 Gag, Pol, Env, or Nef peptides tested. Similar to what has been seen in white cohorts, epitope-rich peptide clusters were identified within conserved functional domains in Gag matrix, Gag capsid, Pol reverse transcriptase, and Nef. Peptides representing variable regions from within the B subtype or with more changes from the B subtype consensus sequence were less likely to stimulate a positive T cell response. A small percentage (17%) of unique T cell responses was found in this cohort that displayed no previously known T cell epitopes. Dominant responses generally overlapped with epitope-rich regions in HIV-1 described previously for whites, although many of these peptides were likely restricted by HLA class I alleles not previously associated with these epitopes. Hence host genetic variation among different racial groups may have less impact on the utility of candidate HIV-1 vaccines than previously suspected.

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.

Noninvasive detection of new simian immunodeficiency virus lineages in captive sooty mangabeys: ability to amplify virion RNA from fecal samples correlates with viral load in plasma

The sooty mangabey (SM) (Cercocebus atys) is the natural host of a simian immunodeficiency virus, termed SIVsm, which gave rise to human immunodeficiency virus type 2. Data on the geographic distribution, prevalence, and genetic diversity of SIVsm in the wild remains limited. To address this issue, noninvasive strategies based on screening SM fecal and urine specimens for SIVsm-specific antibodies and virion RNA (vRNA) were developed, and the results were correlated with viral loads in plasma. Twenty-three SIVsm-infected and 27 uninfected SMs were evaluated. Time-matched urine, fecal and plasma samples were collected over a 2-month period from 16 captive naturally infected SMs. The remaining 7 infected and 27 uninfected SMs were sampled once. Each specimen was subjected to enhanced chemiluminescence-Western blot analysis and nested reverse transcriptase (RT) PCR. The results showed that urine was highly sensitive (96%) and specific (100%) for detection of SIVsm antibodies, while fecal detection was much less sensitive (16%). Conversely, vRNA detection was more sensitive in feces (50%) than in urine (2%) samples. Fecal-vRNA detection correlated with viral loads in plasma (P < 0.002). SMs with detectable fecal vRNA had a mean viral load in plasma of 458,006 copies/ml, while those with undetectable fecal vRNA had a mean viral load in plasma of 29,428 copies/ml. Moreover, for every log increase in the viral load in plasma, the odds of detecting virus in fecal samples increased 87-fold. Genetic diversity of SIVsm in the SM colony was characterized by sequencing partial gag (846 bp) and gp43 (439 bp) fragments. Surprisingly, four new SIVsm lineages were identified, two of which were initially detected by fecal RT-PCR. This study documents the suitability of noninvasive methods for the detection and molecular characterization of new SIV variants. These assays will be useful for studying the phylogeny and epidemiology of SIVsm infections in the wild, and they hold promise as tools for investigating natural SIV infections in endangered nonhuman primates.

Host genetic profiles predict virological and immunological control of HIV-1 infection in adolescents

OBJECTIVE

To evaluate the correlation between host genetic profiles and virological and immunological outcomes among HIV-1-seropositive participants from the Reaching for Excellence in Adolescent Care and Health (REACH) cohort.

METHODS

HLA class I and chemokine coreceptor (CCR) alleles and haplotypes were resolved in 227 HIV-1-seropositive adolescents (ages 13-18 years; 75% females; 71% African-Americans) and 183 HIV-seronegative individuals, with quarterly follow-up visits between 1996 and 2000. Each HLA and CCR variant with consistent risk and protective effect on HIV-1 pathogenesis was assigned a score of -1 and +1, respectively. All individual markers and genetic scores were analyzed in relation to plasma viral load (VL) and CD4 T lymphocytes during a 6-12-month interval when no antiretroviral therapy was taken.

RESULTS

HLA-B*57 alone was a strong predictor of VL (P < 0.0001), but composite genetic profiles found in over 50% of patients consistently outperformed the individual component markers in multivariable analyses with or without adjustment for gender, race, age, and membership of clinical patient groups. Adolescents (n = 37) with a favorable combination of VL (< 1000 copies/ml) and CD4 T cell counts (> 450 x 10(6) cells/l) consistently had more positive (+1 to +2) than negative (-1 to -4) HLA and CCR scores compared with those (n = 56) with an unfavorable combination (VL > 16,000 copies/ml and CD4 cells < 450 x 10(6) cells/l) or the remainder (n = 134) of the cohort (overall P < 0.0001).

CONCLUSION

A generalizable genetic scoring algorithm based on seven HLA class I and CCR markers is highly predictive of viremia and immunodeficiency in HIV-1-infected adolescents.

CCR2 and CCR5 genotypes in HIV type 1-infected adolescents: limited contributions to variability in plasma HIV type 1 RNA concentration in the absence of antiretroviral therapy

In HIV-1-infected individuals, plasma viral RNA concentration as well as preservation of CD8+ naive T cells can vary by age. Host genetic factors previously shown to mediate HIV-1 pathogenesis in adults and children may operate differently in HIV-1-infected adolescents. Our PCR-based haplotyping of genetic variants at the loci encoding CC (beta) chemokine receptor 2 (CCR2) and CCR5 revealed nine haplotypes (designated A through G*2) in 179 seronegative and 228 seropositive adolescent participants from the Reaching for Excellence in Adolescent Care and Health (REACH) Study of the Adolescent Medicine and HIV/AIDS Research Network. The influence of CCR2-CCR5 haplotypes and genotypes on plasma HIV-1 RNA level was assessed in 207 AIDS-free seropositive individuals (mostly African-American females) who either did not receive therapy or had discontinued therapy for 6-12 months during initial follow-up between 1996 and 1999. The CCR2-64I-coding haplotype F*2 and the infrequent CCR5 Delta32-bearing haplotype G*2 had negligible impact on HIV-1 RNA level (p > 0.83) and CD4+ T cell counts (p > 0.30). In contrast, nine carriers of the E/E genotype had significantly higher (p = 0.007) plasma HIV-1 RNA level and slightly reduced CD4+ cell counts (p = 0.15) compared with those not carrying E/E or F*2 or G*2. The effect of E/E on HIV-1 RNA was stronger (p < 0.001) in a multivariable model adjusted for F*2 or G*2 (p = 0.45), race (p = 0.23), gender (p = 0.002), age (p = 0.26), and history of antiretroviral therapy (p < 0.001). Thus, among the major CCR2-CCR5 haplotypes/genotypes in chronically infected and predominantly African-American adolescents, only the E/E genotype appeared to influence early host-virus equilibration.

Serologic response to hepatitis B vaccine in HIV infected and high-risk HIV uninfected adolescents in the REACH cohort. Reaching for Excellence in Adolescent Care and Health

PURPOSE

To evaluate hepatitis B (HBV) vaccine response rates in HIV infected and high-risk HIV uninfected youth and examine associations with responsiveness in the HIV infected group.

METHODS

Cohorts within the Reaching for Excellence in Adolescent Care and Health (REACH) study population were defined based on receipt of HBV vaccine both retrospectively and prospectively. Sero-responsiveness was determined by HBsAb measurements. Testing was done for HBsAg, HBsAb, and HBcAb. For HBsAb, a value of > 10 International Units per liter was considered a positive response, and the data were collected as either positive or negative from each of the reporting laboratories. Covariates of responsiveness were explored in univariate and multivariate models for each cohort.

RESULTS

Sixty-one subjects had received a three-dose vaccination course at the time of entry into REACH. HIV uninfected subjects had significantly higher rates of response by serology compared with HIV infected subjects (70% vs. 41.1%; chi(2) = .05; RR = .586, 95% CI: .36-.96). By the time of an annual visit 43 subjects had received three vaccinations with at least one occurring in the study period. The rates of response were similar for the HIV infected and uninfected groups (37.1% vs. 37.5%) in this cohort. Univariate and multivariate analysis in the prospective HIV infected group (N = 35) found an association between elevated CD8(+)/CD38(+)/HLA-DR(+) T cells and lack of HBV vaccine responsiveness (6.7% vs. 60%; chi(2) = .03; RR = .12, 95% CI: .02- .55).

CONCLUSIONS

The poor HBV vaccine response rate in the HIV uninfected high-risk adolescents was unexpected and suggests that HBV vaccination doses have not been optimized for older adolescents. This is the first report of decreased responsiveness in HIV infected subjects being associated with elevated CD8(+)/CD38(+)/HLA(-)DR(+) T cells and suggests that ongoing viral replication and concomitant immune system activation decreases the ability of the immune system in HIV infected subjects to respond to vaccination.

Natural killer cell enumeration and function in HIV-infected and high-risk uninfected adolescents

This is the first report of natural killer cell enumeration and function in HIV-infected and high-risk uninfected adolescents. We examined the association of demographic characteristics of this cohort with three outcomes: CD16+ cell absolute count, lytic units per peripheral blood mononuclear cell (PBMC), and lytic units per natural killer (NK) cell. We also examined the association of CD4, CD38, and antiretroviral therapy (ART) use with these outcomes in the subset of HIV-infected adolescents. Adolescents participating in an on-going longitudinal study (the REACH study) were sampled for CD16+ cell count and NK function. This cross-sectional analysis was performed on 412 subjects with NK cell data available. HIV-positive males had higher numbers of CD3-/CD16+/CD56+ NK cells than HIV-positive females. However, for the HIV-negative subjects, we did not observe a gender-related effect for absolute NK cell numbers. Gender, however, was a significant covariate for the analysis, using lytic units per PBMC as the unit of measurement, with males showing higher values than females. Age was not a predictive covariate for any of the three assessments of NK cell number and function examined. Our observations concerning the HIV-positive individuals indicate that reduced CD4+ T cell counts were associated with decreased circulating CD3-/CD16+/CD56+ NK cells. We also observed an association between elevation of CD8+/CD38+/DR+ lymphocytes and lower NK lytic units per PBMC. The results of our multivariate models indicate that there is a reduced number of NK cells and reduced lytic units per PBMC in patients receiving single or multidrug antiretroviral therapy. There are changes in circulating NK cell number and function in HIV-infected adolescents, in comparison with high-risk HIV-negative adolescents. The data suggest that these changes may occur early in the course of HIV disease but that quantitative changes continue to occur with advancing depletion of the CD4+ T cell pool.