Baseline resistance to nucleoside reverse transcriptase inhibitors fails to predict virologic response to combination therapy in children (PACTG 338)

BACKGROUND: The association between baseline drug resistance mutations and subsequent increase in viral failure has not been established for HIV-infected children. We evaluated drug resistance mutations at 39 codon sites (21 protease inhibitor (PI) resistant codons and 18 nucleoside reverse transcriptase inhibitor (NRTI) resistant codons) for 92 clinically stable NRTI-experienced, PI-naive HIV-infected children 2 to 17 years of age who were initiating new therapy with ritonavir plus zidovudine (ZDV) and lamivudine or plus stavudine. The association between baseline drug resistance mutations and subsequent viral failure after 12 and 24 weeks of highly active antiretroviral therapy (HAART) was studied. RESULTS: There were few primary PI associated mutations in this PI-naïve population, but 84% had NRTI mutations – codons 215 (66%), 41 (42%), 67 (37%), 210 (33%) and 70 (32%). None of the specific baseline drug resistance mutations were associated with a higher rate of virologic failure after 12 or 24 weeks of HAART. Median week 12 viral load decreased as the total number of NRTI mutations at baseline increased (P = 0.006). Specifically, a higher level of baseline ZDV resistance mutation was associated with a decrease in viral failure after 12 weeks on a ZDV-containing HAART regimen (P = 0.017). CONCLUSION: No increase was seen in the rate of viral failure after HAART associated with the presence of resistance mutations at baseline. This paradoxical result may be due to adherence, replicative capacity, or ZDV hypersusceptibility to the new regimen

Immunological Response to Highly Active Antiretroviral Therapy in Children with Clinically Stable HIV-1 Infection

We studied changes in 60 immunological parameters after the administration of highly active antiretroviral therapy (HAART) in 192 clinically stable antiretroviral drug–experienced HIV-1–infected children 4 months– 17 years old. The studied immunological parameters included standard lymphocyte subsets and lymphocyte surface markers of maturation and activation. The most significant changes during the 48-week study period were seen for CD8+, CD8+ CD62L+ CD45RA+, CD8+ CD38+ HLA-DR+, and CD4+ T cell percentages (P \u3c .0001 for all parameters). These changes suggest that significant decreases in the expression of activation markers and increases in the expression of naive markers in the CD8+ T cell population may be related to better virologic control in these HIV-1–infected children, who had relatively stable immune function at the initiation of HAART. At week 44 of HAART, the major immunological parameters in these HIV-1–infected children moved from baseline values to about halfway to two-thirds of the way toward the values in healthy, uninfected children

Decay Kinetics of HIV-1 Specific T Cell Responses in Vertically HIV-1 Exposed Seronegative Infants

Objective: The majority of infants born, in developed countries, to HIV-1 positive women are exposed to the HIV-1 virus in utero or peri/post-partum, but are born uninfected. We, and others, have previously shown HIV-1 specific T cell responses in HIV-1 exposed seronegative (HESN) neonates/infants. Our objective in this study was to examine the rate of decay in their HIV-1 specific T cell response over time from birth. Design: Cross-sectional and longitudinal studies of HIV-1 specific T cell responses in HESN infants were performed. Methods: Peripheral blood mononuclear cells (PBMC) were isolated from 18 HIV-1 DNA PCR negative infants born to HIV-1 infected mothers receiving care at the Jacobi Medical Center, Bronx, NY, USA. PBMC were examined for T cell responses to HIV-1 antigens by interferon-gamma (IFN-γ) ELISPOT. Results: PBMC from 15 HESN neonates/infants were analyzed. We observed a decay of HIV-1 specific T cell responses from birth at a rate of −0.599 spot forming unit/106 cells per day, with a median half-life decay rate of 21.38 weeks (13.39–115.8). Conclusion: Our results support the dynamic nature of T cell immunity in the context of a developing immune system. The disparate rate of decay with studies of adults placed on antiretroviral drugs suggests that antigen specific T cell responses are driven by the natural rate of decay of the T cell sub-populations themselves

Pregnancy in women with perinatally acquired HIV-infection: Outcomes and challenges

This is a retrospective comparison of pregnant women with perinatally acquired HIV-infection (PAH) with a cohort of pregnant women with behaviorally acquired HIV-infection (BAH). PAH cases (11 women) included all pregnant adolescents followed at our HIV clinic from January 2000 to January 2009. BAH cases (27 women) were randomly selected from all deliveries within the study period at the same institution. Demographics, mode of delivery, CD4+ counts, and viral loads (VLs) before, during, and six months postpartum, as well as neonatal outcomes, were reviewed

Decline in CD4 T lymphocytes with monotherapy bridging strategy for non-adherent adolescents living with HIV infection: Results of the IMPAACT P1094 randomized trial

Introduction Management of persistently non-adherent youth living with HIV (YLHIV) with virologic failure (VF) on combination antiretroviral therapy (cART) remains challenging. One strategy has been using 3TC/ FTC monotherapy (3TC/FTC), which in the presence of the M184V resistance mutation, does not suppress viral replication nor select for additional drug resistance mutations, and reduces viral fitness with limited side effects. P1094 compared the immunologic outcome of continuing failing cART vs. switching to 3TC/FTC as a “bridging strategy” to subsequent suppressive cART for non-adherent YLHIV with pre-existing M184V resistance. Materials & methods Participants with documented nonadherence, M184V mutation, CD4+ T cell count ≥100 cells/mm3 and VF (HIV-1 plasma RNA ≥400 copies/mL (2.6 log10 HIV-1 RNA) were enrolled and randomized to continue failing cART vs. switch to 3TC/FTC. The primary endpoint (time to ≥30% CD4+ T cell decline or development of CDC class C events) at 28-weeks were assessed by Kaplan-Meier (K-M) curves in an intent-to-treat analysis. Results Thirty-three perinatally acquired YLHIV participants (16 continuing cART and 17 3TC/FTC) enrolled in the study. The median age, entry CD4+ T cell count, and viral load were 15 years (Inter-quartile range (IQR) 14–20), 472 cells/mm3 (IQR 384–651), and 4.0 log10HIV-1 RNA copies/ml (IQR 3.2–4.5), respectively. Five participants, all in the 3TC/FTC arm, reached the primary endpoint for absolute CD4+ T cell decline (p = 0.02, exact log-rank test comparing monotherapy to cART). The Kaplan-Meier estimate of probability of primary endpoint on 3TC/FTC at 28 weeks was 0.41 (standard error 0.14). There were no CDC class C events or deaths and no statistically significant difference in frequencies of adverse events between the arms. Conclusions Non-adherent participants randomized to 3TC/FTC were more likely than those maintained on failing cART to experience a confirmed decline in CD4+ count of ≥30%. Although this study suffers from limitations of small sample size and premature discontinuation, the randomized comparison to continuing failing cART indicates that 3TC/FTC provides inferior protection from immunologic deterioration for non-adherent youth with M184V resistance. Better alternatives to 3TC/FTC such as ART with higher barriers to resistance and novel adherence and treatment strategies for nonadherent youth are urgently needed

Age-Related Expansion of Tim-3 Expressing T Cells in Vertically HIV-1 Infected Children

As perinatally HIV-1-infected children grow into adolescents and young adults, they are increasingly burdened with the long-term consequences of chronic HIV-1 infection, with long-term morbidity due to inadequate immunity. In progressive HIV-1 infection in horizontally infected adults, inflammation, T cell activation, and perturbed T cell differentiation lead to an "immune exhaustion'', with decline in T cell effector functions. T effector cells develop an increased expression of CD57 and loss of CD28, with an increase in co-inhibitory receptors such as PD-1 and Tim-3. Very little is known about HIV-1 induced T cell dysfunction in vertical infection. In two perinatally antiretroviral drug treated HIV-1-infected groups with median ages of 11.2 yr and 18.5 yr, matched for viral load, we found no difference in the proportion of senescent CD28(-)CD57(+)CD8(+) T cells between the groups. However, the frequency of Tim-3(+)CD8(+) and Tim-3(+)CD4(+) exhausted T cells, but not PD-1(+) T cells, was significantly increased in the adolescents with longer duration of infection compared to the children with shorter duration of HIV-1 infection. PD-1(+)CD8(+) T cells were directly associated with T cell immune activation in children. The frequency of Tim-3(+)CD8(+) T cells positively correlated with HIV-1 plasma viral load in the adolescents but not in the children. These data suggest that Tim-3 upregulation was driven by both HIV-1 viral replication and increased age, whereas PD-1 expression is associated with immune activation. These findings also suggest that the Tim-3 immune exhaustion phenotype rather than PD-1 or senescent cells plays an important role in age-related T cell dysfunction in perinatal HIV-1 infection. Targeting Tim-3 may serve as a novel therapeutic approach to improve immune control of virus replication and mitigate age related T cell exhaustion.National Institute of Allergy and Infectious DiseasesNational Institute of Allergy and Infectious Diseases [R56AI083112]National Institutes of Health grant [AI60397]National Institutes of Health gran

Individual and Contextual Factors of Sexual Risk Behavior in Youth Perinatally Infected with HIV

Abstract This study prospectively examines the effects of maternal and child HIV infection on youth penetrative and unprotected penetrative sex, as well as the role of internal contextual, external contextual, social and self-regulatory factors in influencing the sexual behaviors of HIV?infected (PHIV+), HIV?affected (uninfected with an HIV+ caregiver), and HIV unaffected (uninfected with an HIV? caregiver) youth over time. Data (N=420) were drawn from two longitudinal studies focused on the effects of pediatric or maternal HIV on youth (51% female; 39% PHIV+) and their caregivers (92% female; 46% HIV+). PHIV+ youth were significantly less likely to engage in penetrative sex than HIV? youth at follow-up, after adjusting for contextual, social, and self-regulatory factors. Other individual- and contextual-level factors such as youth alcohol and marijuana use, residing with a biological parent, caregiver employment, caregiver marijuana use, and youth self-concept were also associated with penetrative sex. Youth who used alcohol were significantly more likely to engage in unprotected penetrative sex. Data suggest that, despite contextual, social, and self-regulatory risk factors, PHIV+ youth are less likely to engage in sexual behavior compared to HIV? youth from similar environments. Further research is required to understand delays in sexual activity in PHIV+ youth and also to understand potential factors that promote resiliency, particularly as they age into older adolescence and young adulthood.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98470/1/apc%2E2012%2E0005.pd

Baseline resistance to nucleoside reverse transcriptase inhibitors fails to predict virologic response to combination therapy in children (PACTG 338)

Abstract Background The association between baseline drug resistance mutations and subsequent increase in viral failure has not been established for HIV-infected children. We evaluated drug resistance mutations at 39 codon sites (21 protease inhibitor (PI) resistant codons and 18 nucleoside reverse transcriptase inhibitor (NRTI) resistant codons) for 92 clinically stable NRTI-experienced, PI-naive HIV-infected children 2 to 17 years of age who were initiating new therapy with ritonavir plus zidovudine (ZDV) and lamivudine or plus stavudine. The association between baseline drug resistance mutations and subsequent viral failure after 12 and 24 weeks of highly active antiretroviral therapy (HAART) was studied. Results There were few primary PI associated mutations in this PI-naïve population, but 84% had NRTI mutations – codons 215 (66%), 41 (42%), 67 (37%), 210 (33%) and 70 (32%). None of the specific baseline drug resistance mutations were associated with a higher rate of virologic failure after 12 or 24 weeks of HAART. Median week 12 viral load decreased as the total number of NRTI mutations at baseline increased (P = 0.006). Specifically, a higher level of baseline ZDV resistance mutation was associated with a decrease in viral failure after 12 weeks on a ZDV-containing HAART regimen (P = 0.017). Conclusion No increase was seen in the rate of viral failure after HAART associated with the presence of resistance mutations at baseline. This paradoxical result may be due to adherence, replicative capacity, or ZDV hypersusceptibility to the new regimen

CD4+ and viral load outcomes of antiretroviral therapy switch strategies after virologic failure of combination antiretroviral therapy in perinatally HIV-infected youth in the United States

Objective: This study compared 12-month CD4+ and viral load outcomes in HIV-infected children and adolescents with virological failure, managed with four treatment switch strategies. Design: This observational study included perinatally HIV-infected (PHIV) children in the Pediatric HIV/AIDS Cohort Study (PHACS) and Pediatric AIDS Clinical Trials (PACTG) Protocol 219C. Methods: Treatment strategies among children with virologic failure were compared: continue failing combination antiretroviral therapy (cART); switch to new cART; switch to drug-sparing regimen; and discontinue all ART. Mean changes in CD4+% and viral load from baseline (time of virologic failure) to 12 months follow-up in each group were evaluated using weighted linear regression models. Results: Virologic failure occurred in 939 out of 2373 (40%) children. At 12 months, children switching to new cART (16%) had a nonsignificant increase in CD4+% from baseline, 0.59 percentage points [95% confidence interval (95% CI) −1.01 to 2.19], not different than those who continued failing cART (71%) (−0.64 percentage points, P = 0.15) or switched to a drug-sparing regimen (5%) (1.40 percentage points, P = 0.64). Children discontinuing all ART (7%) experienced significant CD4+% decline −3.18 percentage points (95% CI −5.25 to −1.11) compared with those initiating new cART (P = 0.04). All treatment strategies except discontinuing ART yielded significant mean decreases in log10VL by 12 months, the new cART group having the largest drop (−1.15 log10VL). Conclusion: In PHIV children with virologic failure, switching to new cART was associated with the best virological response, while stopping all ART resulted in the worst immunologic and virologic outcomes and should be avoided. Drug-sparing regimens and continuing failing regimens may be considered with careful monitoring

Immunodominance of HIV-1 Specific CD8+ T-Cell Responses Is Related to Disease Progression Rate in Vertically Infected Adolescents

BACKGROUND: HIV-1 vertically infected children in the USA are living into adolescence and beyond with the widespread use of antiretroviral drugs. These patients exhibit striking differences in the rate of HIV-1 disease progression which could provide insights into mechanisms of control. We hypothesized that differences in the pattern of immunodomination including breadth, magnitude and polyfunctionality of HIV-1 specific CD8+ T cell response could partially explain differences in progression rate. METHODOLOGY/PRINCIPAL FINDINGS: In this study, we mapped, quantified, and assessed the functionality of these responses against individual HIV-1 Gag peptides in 58 HIV-1 vertically infected adolescents. Subjects were divided into two groups depending upon the rate of disease progression: adolescents with a sustained CD4%≥25 were categorized as having no immune suppression (NS), and those with CD4%≤15 categorized as having severe immune suppression (SS). We observed differences in the area of HIV-1-Gag to which the two groups made responses. In addition, subjects who expressed the HLA- B*57 or B*42 alleles were highly likely to restrict their immunodominant response through these alleles. There was a significantly higher frequency of naïve CD8+ T cells in the NS subjects (p = 0.0066) compared to the SS subjects. In contrast, there were no statistically significant differences in any other CD8+ T cell subsets. The differentiation profiles and multifunctionality of Gag-specific CD8+ T cells, regardless of immunodominance, also failed to demonstrate meaningful differences between the two groups. CONCLUSIONS/SIGNIFICANCE: Together, these data suggest that, at least in vertically infected adolescents, the region of HIV-1-Gag targeted by CD8+ T cells and the magnitude of that response relative to other responses may have more importance on the rate of disease progression than their qualitative effector functions