Immune correlates of herpes zoster in HIV-infected children and youth.

To identify immunologic factors that modulate the risk of herpes zoster (HZ), we compared varicella-zoster virus (VZV)-specific and nonspecific T-cell subpopulations of 47 HIV-infected children before they developed HZ with those of 141 VZV-positive HZ-negative matched controls. Compared with controls, HZ cases had lower VZV-specific CD8(+) CD107a(+) cell percentages independently of CD4(+) percentages or HIV loads, suggesting that VZV-specific cytotoxic T cells are protective against HZ. In contrast, high nonspecific regulatory and activated T cells were associated with an increased risk of HZ.

Dynamic calibration of pharmacokinetic parameters in dose-finding studies.

We introduce a dose-finding algorithm to be used to identify a level of dose that corresponds to some given targeted response. Our motivation arises from problems where the response is a continuously measured quantity, typically some pharmacokinetic parameter. We consider the case where an agreed level of response has been determined from earlier studies on some population and the purpose of the current trial is to obtain the same, or a comparable, level of response in a new population. This relates to bridging studies. The example driving our interest comes from studies on drugs for HIV that have already been evaluated in adults and where the new studies are to be carried out in children. These drugs have the ability to produce some given mean pharmacokinetic response in the adult population, and the goal is to calibrate the dose in order to obtain a comparable response in the childhood population. In practice, it may turn out that the dose producing some desired mean response is also associated with an unacceptable rate of toxicity. In this case, we may need to reevaluate the target response and this is readily achieved. In simulations, the algorithm can be seen to work very well. In the most challenging situations for the method, those where the targeted response corresponds to a region of the dose-response curve that is relatively flat, the algorithm can still perform satisfactorily.

Long-Term Safety and Efficacy of Dolutegravir in Treatment-Experienced Adolescents With Human Immunodeficiency Virus Infection: Results of the IMPAACT P1093 Study.

BACKGROUND: P1093 is an ongoing phase I/II multicenter open-label study of dolutegravir plus an optimized background regimen in age-defined pediatric cohorts; here we report the long-term safety and virologic efficacy outcomes for the oldest cohort. METHODS: The study enrolled human immunodeficiency virus type 1 (HIV-1)-infected treatment-experienced adolescents aged 12 to <18 years, with an HIV-1 RNA level ≥1000 copies/mL . Cumulative safety and HIV-1 RNA outcomes were assessed once the last enrolled participant reached 144 weeks of follow-up. RESULTS: Among 23 adolescents enrolled, 16 remained in the study at least 144 weeks; the median follow-up was 153 weeks (range, 55-193 weeks). Dolutegravir was well tolerated, with grade 3 clinical adverse events in 5 participants, grade 3 laboratory abnormalities in 3, and grade 4 laboratory abnormalities in 1; none of the adverse events or abnormalities were judged to be treatment related. In an-intent-to-treat analysis, an HIV-1 RNA level <400 copies/mL at week 144 was achieved in 43% (10 of 23 participants; 95% confidence interval, 23.2%-65.5%); in addition, 35% (8 of 23; 16.4%-57.3%) had an HIV-1 RNA level <50 copies/mL. Nine participants (39%) discontinued study treatment before 144 weeks, but none because of adverse events or drug intolerance. All participants with sustained virologic control had excellent adherence; most who experienced virologic failure had adherence levels <90%. HIV-1 genotypic drug resistance testing was available at time of failure from 6 participants; 1 had evolution in integrase resistance with E138T, S147G, and R263K mutations at week 192 and phenotypic dolutegravir resistance of a 5.1-fold change. CONCLUSIONS: Dolutegravir plus an optimized background regimen seemed safe, well tolerated, and efficacious in this cohort of treatment-experienced HIV-1-infected adolescents. Adherence remains problematic in this population. CLINICAL TRIALS REGISTRATION: NCT01302847.

Antenatal Intracellular Concentrations of Tenofovir Diphosphate and Emtricitabine Triphosphate and Associations Between Tenofovir Diphosphate and Severe Adverse Pregnancy Outcomes: IMPAACT-PROMISE (1077BF) Trial.

BACKGROUND: In the Promoting Maternal and Infant Survival Everywhere (PROMISE) trial, tenofovir disoproxil fumarate (TDF) use was associated with moderate or severe adverse pregnancy/neonatal outcomes. This study characterized tenofovir diphosphate (TFV-DP) and emtricitabine triphosphate (FTC-TP) concentrations in dried blood spots (DBS) and assessed association between severe adverse pregnancy/neonatal outcomes and TFV-DP concentration. METHODS: Retrospective case-control study of PROMISE trial arm-C women randomized to receive TDF, FTC, and ritonavir-boosted lopinavir (LPV/r), who took at least 1 dose of TDF + FTC and had week-4 postrandomization DBS drawn before delivery. Cases, defined as severe adverse pregnancy/neonatal outcomes (very preterm delivery before 34 weeks of gestation, stillbirth ≥20 weeks of gestation, or infant death before 14 days-of-age), were matched to controls (1:2 ratio) by site and gestational age at entry. Week 4 and week 8 DBS samples were assayed for TFV-DP and FTC-TP by liquid chromatography and tandem mass spectrometry. Associations were tested using Wilcoxon rank test and conditional logistic regression. RESULTS: Of 447 PROMISE arm-C women, 33 met case definitions, and overall, 22 cases and 44 controls were analyzed. Median (interquartile range) concentrations of TFV-DP at weeks 4 and 8 were 706 (375-1023) fmol/punch and 806 (414-1265) fmol/punch, respectively. Odds ratio (95% confidence interval) for severe adverse pregnancy/neonatal outcome with natural log of TFV-DP concentrations as the predictor were 1.27 (0.74 to 2.18) and 1.74 (0.66 to 4.60) at weeks 4 and 8, respectively. Median (interquartile range) concentrations of FTC-TP at weeks 4 and 8 were 0.27 (0.05-0.36) pmol/punch and 0.29 (0.05-0.40) pmol/punch, respectively. CONCLUSIONS: TFV-DP concentrations in DBS appeared not to be associated with severe adverse pregnancy/neonatal outcomes, although sample size was limited.

An age-dependent association of mannose-binding lectin-2 genetic variants on HIV-1-related disease in children.

BACKGROUND: Mannose-binding lectin (MBL) is part of the lectin pathway of complement activation against various pathogens; however, its role in innate immune responses against HIV-1 infection in children is unknown. OBJECTIVE: This study evaluated the effects of mannose-binding lectin-2 (MBL2) alleles on HIV-1 disease progression and central nervous system (CNS) impairment in children. METHODS: A cohort of 1037 HIV-1-infected children enrolled in Pediatrics AIDS Clinical Trial Group protocols P152 and P300 before the availability of effective antiretroviral therapy was genotyped for MBL2 and evaluated for disease progression. RESULTS: Children with the homozygous variant MBL2-O/O genotype were more likely to experience rapid disease progression and CNS impairment than those with the wild-type AA genotype. The effects were predominantly observed in children younger than 2 years. In unadjusted Cox proportional hazards models, children younger than 2 years with MBL2-O/O experienced more rapid disease progression (O/O vs AA: relative hazard [RH], 1.54; 95% CI, 1.07-2.22; P = .02; O/O vs A/O: RH, 2.28; 95% CI, 1.09-4.79; P = .029). Similarly, children with MBL2-O/O were more likely to experience rapid progression to CNS impairment (O/O vs A/A: RH, 2.78; 95% CI, 1.06-2.69, P = .027; O/O vs A/O: RH, 1.69; 95% CI, 1.07-7.21; P = .035). The effects remained significant after adjustment for CD4(+) lymphocyte count, plasma HIV-1 RNA, and other genotypes. CONCLUSIONS: MBL2-O/O genotypes, which result in lower expression of MBL, are associated with more rapid HIV-1-related disease progression, including CNS impairment, predominantly in children younger than 2 years. These data suggest that MBL2 variants are associated with altered HIV-1 disease progression, particularly in young children.

Association between HIV antiretroviral therapy and preterm birth based on antenatal ultrasound gestational age determination: a comparative analysis.

OBJECTIVE: To evaluate the association between HIV antiretroviral therapy (ART) and preterm birth (PTB), when defined by gold standard antenatal ultrasound versus newborn exam. DESIGN: A secondary analysis of the PROMISE 1077BF/1077FF randomized controlled trial, which compared antiretroviral strategies to reduce perinatal HIV transmission and improve maternal health. The trial used newborn exam (i.e. New Ballard Score, NBS) to assess gestational age. This analysis included liveborn singleton pregnancies with both newborn exam and ultrasound data. The primary exposure was the trial's antiretroviral strategies: zidovudine with intrapartum nevirapine ('ZDV alone'); zidovudine/lamivudine/lopinavir-ritonavir ('ZDV-based ART'); or tenofovir/emtricitabine/lopinavir-ritonavir ('TDF-based ART'). The primary outcome was PTB less than 37 and less than 34 weeks based on the gold standard of ultrasound dating. We evaluated the association between antiretroviral strategy and PTB. We fit multivariable logistic regression models, adjusting for maternal characteristics, obstetric history, and HIV disease severity. RESULTS: Among 720 assessed pregnant women, PTB less than 37 weeks was 15.4% by NBS and 18.3% by ultrasound. The NBS was specific but not sensitive for PTB less than 37 weeks (92.0% and 48.5%). Women receiving ZDV-based and TDF-based ART had significantly higher odds of PTB less than 37 by ultrasound compared with ZDV alone (adjusted odds ratios: 1.68; 95% confidence interval 1.10-2.57, and 2.71; 95% confidence interval 1.39-5.29), as well as for PTB less than 34 weeks. These results held for ultrasounds performed less than 24 weeks, and were generally consistent with prior analyses from the PROMISE trial using the NBS. CONCLUSION: Women starting HIV ART in pregnancy remained at higher risk of PTB when determined by ultrasound, consistent with prior data using newborn exam. However, newborn exam misclassified cases of PTB compared with gold standard ultrasound.

Risk Factors for Adverse Birth Outcomes in the PROMISE 1077BF/1077FF Trial.

BACKGROUND: In the multicountry PROMISE 1077BF/1077FF trial, the risk of low birth weight (LBW; <2500 g) and preterm delivery (PTD; <37 weeks) was significantly higher among women initiating a protease inhibitor-based antiretroviral treatment (ART) regimen than those receiving ZDV alone. Among those assigned to a protease inhibitor regimen, tenofovir/emtricitabine was associated with the more severe outcomes of very LBW (<1500 g) and very PTD (<34 weeks) compared with zidovudine/lamivudine. METHODS: We used multivariate logistic regression to further explore these treatment findings, taking into account demographic baseline clinical and postentry obstetrical factors. We evaluated individual adverse outcomes and composites that included stillbirth and early loss/spontaneous abortion. RESULTS: Among 3333 women delivering at least 1 live infant, median maternal age at enrollment was 26 years; 661 (20%) were primiparous, and 110 (3.3%) reported at least 1 previous PTD. Seventeen percent of newborns were LBW, 1% were very LBW, 17% had PTD, and 3% had very PTD. Treatment allocation remained strongly associated with multiple adverse outcomes after controlling for other risk factors with both ART regimens exhibiting increased risk relative to ZDV alone. Other risk factors remaining significant in at least one of the multivariate models included the following: country, gestational age at entry, maternal age, maternal body mass index, previous PTD, history of alcohol use, baseline HIV viral titer, multiple gestation, and several obstetric risk factors. CONCLUSIONS: ART effects on adverse pregnancy outcomes reported in the randomized PROMISE trial remained strongly significant even after controlling for demographic, baseline clinical, and obstetrical risk factors, which were also associated with these outcomes.

Planned multiple exposures to autologous virus in HIV type 1-infected pediatric populations increases HIV-specific immunity and reduces HIV viremia.

We tested to determine if planned multiple exposures to autologous HIV in pediatric patients with HIV-1 infection will induce cellular immunity that controls viremia. A prospective multicenter study of aviremic pediatric patients on highly active antiretroviral therapy who underwent progressively longer antiretroviral treatment interruptions in cycles starting with 3 days, increasing by 2 days in length each consecutive cycle, was conducted. Eight individuals became viremic and reached Cycle 13 or greater with an "off-therapy" interval of >or=27 days. HIV-specific interferon-gamma (IFN-gamma) production to inactivated HIV and vaccinia vectors expressing gag, env, nef, and pol increased (>10-fold) from baseline in six of eight subjects. The HIV-specific lymphoproliferative response as measured by the median stimulation index (SI) increased in the treatment group from 1 at baseline to 16, 12, 4, and 3 at Cycles 7, 10, 13, and 17, respectively. Median plasma RNA levels peaked at Cycle 7 (4.45 log) and declined to levels <10(4) cp/ml after Cycle 10 (4.1, 3.5, and 3.4 at Cycles 10, 13, and 17). In a subset of five patients who reached Cycle 17, HIV-specific IFN-gamma frequencies were 4- to 30-fold higher and median RNA levels were 0.32-2.10 (median 1.3) log lower than at comparable days off treatment at Cycle 8 (17 days off therapy). A second group of children, not undergoing drug interruption, did not develop significant increases in either HIV-specific IFN-gamma production or SI. Increased HIV-specific immune responses and decreased HIV RNA were seen in those children who have had >10 cycles of antiretroviral discontinuations of increasing durations acting as autologous virus vaccinations. Other studies may have failed due to an insufficient number of exposures to HIV; most of the studies had fewer than six drug interruptions.

Associations of Genetically Determined Continental Ancestry With CD4+ Count and Plasma HIV-1 RNA Beyond Self-Reported Race and Ethnicity.

BACKGROUND: Ancestry informative markers (AIMs) measure genetic admixtures within an individual beyond self-reported racial/ethnic (SRR) groups. Here, we used genetically determined ancestry (GDA) across SRR groups and examine associations between GDA and HIV-1 RNA and CD4 counts in HIV-positive children in the United States. METHODS: Forty-one AIMs, developed to distinguish 7 continental regions, were detected by real-time PCR in 994 HIV-positive, antiretroviral naive children. GDA was estimated comparing each individual's genotypes to allele frequencies found in a large set of reference individuals originating from global populations using STRUCTURE. The means of GDA were calculated for each category of SRR. Linear regression was used to model GDA on CD4 count and log10 RNA, adjusting for SRR and age. RESULTS: Subjects were 61% black, 25% Hispanic, 13% white, and 1.3% Unknown. The mean age was 2.3 years (45% male), mean CD4 count of 981 cells per cubic millimeter, and mean log10 RNA of 5.11. Marked heterogeneity was found for all SRR groups with high admixture for Hispanics. In adjusted linear regression models, subjects with 100% European ancestry were estimated to have 0.33 higher log10 RNA levels (95% CI: 0.03 to 0.62, P = 0.028) and 253 CD4 cells per cubic millimeter lower (95% CI: -517 to 11, P = 0.06) in CD4 count, compared to subjects with 100% African ancestry. CONCLUSION: Marked continental admixture was found among this cohort of HIV-infected children from the United States. GDA contributed to differences in RNA and CD4 counts beyond SRR and should be considered when outcomes associated with HIV infection are likely to have a genetic component.

Long-term safety and efficacy of atazanavir-based therapy in HIV-infected infants, children and adolescents: the Pediatric AIDS Clinical Trials Group Protocol 1020A.

BACKGROUND: Atazanavir (ATV) is an attractive option for the treatment of Pediatric HIV infection, based on once-daily dosing and the availability of a formulation appropriate for younger children. Pediatric AIDS Clinical Trials Group 1020A was a phase I/II open label study of ATV (with/without ritonavir [RTV] boosting)-based treatment of HIV-infected children; here we report the long-term safety and virologic and immunologic responses. METHODS: Antiretroviral-naïve and experienced children, ages 91 days to 21 years, with baseline plasma HIV RNA > 5000 copies/mL (cpm) were enrolled at sites in the United States and South Africa. RESULTS: Of 195 children enrolled, 142 (73%) subjects received ATV-based regimens at the final protocol recommended dose; 58% were treatment naive. Overall, at week 24, 84/139 subjects (60.4%) and at week 48, 83/142 (58.5%) had HIV RNA ≤ 400 cpm. At week 48, 69.5% of naïve and 43.3% of experienced subjects had HIV RNA ≤ 400 cpm; median CD4 increase was 196.5 cells/mm. The primary adverse event (AE) was increased serum bilirubin; 9% of subjects had levels ≥ 5.1 times upper limit of normal (ULN) and 1.4% noted jaundice. Three percent of subjects experienced grade 2 or 3 prolongation in PR or QTc intervals. At week 48, there was a 15% increase in total cholesterol (TC), with TC > 199 mg/dL increasing from 1% at baseline to 5.7%. CONCLUSIONS: Use of once-daily ATV, with/without RTV, was safe and well tolerated in children, with acceptable levels of viral suppression and CD4 count increase. The primary AE, as expected, was an increase in bilirubin levels.

Safety, Pharmacokinetics and Efficacy of Dolutegravir in Treatment-experienced HIV-1 Infected Adolescents: Forty-eight-week Results from IMPAACT P1093.

OBJECTIVE: To assess the pharmacokinetics (PK), safety and efficacy of dolutegravir plus optimized background regimen in HIV-infected treatment-experienced adolescents. METHODS: Children older than 12 to younger than 18 years received dolutegravir weight-based fixed doses at approximately 1.0 mg/kg once daily in a phase I/II multicenter open label 48-week study. Intensive PK evaluation was done at steady state after dolutegravir was added to a failing regimen or started at the end of a treatment interruption. Safety and HIV RNA and CD4 cell count assessments were performed through week 48. RESULTS: Twenty-three adolescents were enrolled and 22 (96%) completed the 48-week study visit. Median age and weight were 15 years and 52 kg, respectively. Median [interquartile range (IQR)] baseline CD4+ cell count was 466 cells/µL (297, 771). Median (IQR) baseline HIV-1 RNA log10 was 4.3 log10 copies/mL (3.9, 4.6). Dolutegravir geometric mean of the area under the plasma concentration-time curve from time of administration to 24 hours after dosing (AUC0-24) and 24 hour postdose concentration (C24) were 46.0 µg hours/mL and 0.90 µg/mL, respectively, which were within the study targets based on adult PK ranges. Virologic success with an HIV RNA <400 copies/mL was achieved in 74% [95% confidence interval (CI): 52-90%] at week 48. Additionally, 61% (95% CI: 39-80%) had an HIV RNA <50 copies/mL at week 48. Median (IQR) gain in CD4 cell count at week 48 was 84 cells/µL (-81, 238). Dolutegravir was well tolerated, with no grade 4 adverse events, serious adverse events or discontinuations because of serious adverse events. CONCLUSIONS: Dolutegravir achieved target PK exposures in adolescents. Dolutegravir was safe and well tolerated, providing good virologic efficacy through week 48.

Increased gut microbial translocation in HIV-infected children persists in virologic responders and virologic failures after antiretroviral therapy.

BACKGROUND: Gut microbial translocation (MT) is considered a major cause of immune activation (IA) and failure of immune reconstitution in HIV infection. This study investigated the relationship of virus replication, IA, CD4 counts and MT in HIV-infected children. METHODS: Lipopolysaccharide, bacterial 16S ribosomal DNA (16SrDNA) and soluble CD14 (sCD14) levels were determined in prospectively collected, stored plasma samples from the Pediatric AIDS Clinical Trials Group Protocol P338, a 48-week study initiated in 1997 to compare efficacy of dual nucleosides with a ritonavir-containing regimen. Results of MT were correlated with study data for T cell IA, plasma viral load and CD4 counts in 85 HIV-infected children (ages 2-17 years) designated as virologic responders or virologic failures (VF) at week 44 based on a cutoff of 400 HIV RNA copies/mL. RESULTS: Levels of plasma lipopolysaccharide, 16SrDNA and sCD14 were increased in comparison with HIV-uninfected controls and did not decrease at week 44 even in virologic responders. T cell IA was correlated with viral load and sCD14 at entry and with 16SrDNA and sCD14 at week 44 in total patients and in the VF group. Changes in 16SrDNA correlated with changes in IA and negatively with changes in CD4 counts. 16SrDNA was correlated with sCD14 but not with lipopolysaccharide. CONCLUSIONS: MT persists after 44 weeks of antiretroviral therapy in VS and VF patients. In VF, 16SrDNA exhibited relationships to monocyte and T cell IA and CD4 counts but not with viral load, suggesting a dominant role for MT in disease pathogenesis in HIV-infected children.

Effect of therapeutic HIV recombinant poxvirus vaccines on the size of the resting CD4+ T-cell latent HIV reservoir.

OBJECTIVES: Therapeutic HIV vaccinations may alter the size of the resting memory CD4 T-cell latent HIV reservoir as HIV establishes latency when memory responses are formed, including those toward HIV. Alternatively, latently infected CD4 T cells maybe killed, while exiting the reservoir upon activation. METHODS: The effect of therapeutic immunization with modified vaccinia Ankara and Fowlpox-based HIV vaccines on the latent reservoir was examined in 19 young adults who were receiving effective antiretroviral therapy. Correlations between size of the reservoir [measured in infectious units per million (IUPM)] resting CD4 T cells and HIV-specific immune responses, including immune activation were examined. Decay of the reservoir was assessed using random-effects model. RESULTS: A modest transient decrease in the size of the reservoir was observed at week 40 [mean -0.31 log(10) IUPM (95% confidence interval: -0.60 to -0.03; P = 0.03] following HIV vaccinations. The estimated half-life (T1/2) of the reservoir during the 40 weeks following vaccination was 9.8 months and statistically different from zero (P = 0.02), but 35.3 months and not different from zero (P = 0.21) over 72 weeks of study. Latent reservoir size at baseline was not correlated with HIV-specific CD4, CD8 responses or immune activation, but became correlated with CD4 IFNγ (r = 0.54, P = 0.02) and IL-2 responses at 6 weeks after immunization (r = 0.48, P = 0.04). CONCLUSION: Therapeutic HIV vaccinations led to a transient increase in decay of latently infected CD4 T cells. Further studies of therapeutic HIV vaccines may provide important insights into facilitating decay of the latent reservoir.

Atazanavir and atazanavir/ritonavir pharmacokinetics in HIV-infected infants, children, and adolescents.

OBJECTIVE: To describe the pharmacokinetics of atazanavir (ATV) and ritonavir-boosted ATV (ATV/r) in children aged 91 days to 21 years. DESIGN: A phase I/II, open-label, multicenter study of once-daily ATV and ATV/r as part of combination antiretroviral treatment in HIV-infected treatment-experienced and treatment-naive children. SETTING: Sites in the United States and South Africa. PARTICIPANTS: One hundred and ninety-five children enrolled; 172 had evaluable ATV pharmacokinetics on day 7. INTERVENTION: Children were entered in age, dose, and formulation (powder or capsule) cohorts. Intensive pharmacokinetic sampling occurred 7 days after starting ATV. ATV doses were increased or decreased if the 24-h area under the concentration time curves (AUC0-24hr) were less than 30 or more than 90 µg × h/ml, respectively. MAIN OUTCOMES: Cohorts satisfied protocol-defined pharmacokinetic criteria if the median ATV AUC0-24hr was 60 µg × h/ml or less, and AUC0-24hr and ATV concentrations 24-h postdose (C24) were more than 30 µg × h/ml and at least 60 ng/ml, respectively, in at least 80% of the children, with no individual AUC0-24hr less than 15 µg × h/ml. RESULTS: Unboosted ATV capsules satisfied pharmacokinetic criteria at a dose of 520 mg/m for those aged more than 2 to 13 years or less and 620 mg/m for those aged more than 13 to 21 years or less. ATV/r capsules satisfied criteria at a dose of 205 mg/m for those aged more than 2 to 21 years or less. ATV/r powder satisfied criteria at a dose of 310 mg/m for those aged more than 2 to 13 years or less, but pharmacokinetics in those aged 2 years or less were highly variable. CONCLUSION: Body surface area-determined doses of ATV capsules and of ATV/r powder and capsules provide ATV exposures in children of more than 2 years that approximate concentrations in adults receiving ATV/r.

Optimization of storage and shipment of cryopreserved peripheral blood mononuclear cells from HIV-infected and uninfected individuals for ELISPOT assays.

Functional immunologic assays using cryopreserved peripheral blood mononuclear cells (PBMC) are influenced by blood processing, storage and shipment. The objective of this study was to compare the viability, recovery and ELISPOT results of PBMC stored and shipped in liquid nitrogen (LN/LN) or stored in LN and shipped on dry ice (LN/DI) or stored at -70°C for 3 to 12 weeks and shipped on DI (70/DI 3 to 12); and to assess the effect of donor HIV infection status on the interaction between storage/shipment and the outcome measures. PBMC from 12 HIV-infected and 12 uninfected donors showed that LN/LN conferred higher viability and recovery than LN/DI or 70/DI 3, 6, 9 or 12. LN/DI PBMC had higher viability than any 70/DI PBMC. The PBMC viability and recovery linearly decreased with the duration of storage at -70°C from 3 to 12 weeks. This effect was more pronounced in samples from HIV-infected than uninfected donors. Results of ELISPOT assays using CMV pp65, CEF and Candida albicans antigens were qualitatively and quantitatively similar across LN/LN, LN/DI and 70/DI 3. However, ELISPOT values significantly decreased with the duration of storage at -70°C both in HIV-infected and uninfected donors. ELISPOT results also decreased with PBMC viability <70%.

Safety and immunogenicity of recombinant poxvirus HIV-1 vaccines in young adults on highly active antiretroviral therapy.

A trial to evaluate the safety and immunogenicity of recombinant modified vaccinia Ankara (MVA) and fowlpox (FP) vectors expressing multiple HIV-1 proteins was conducted in twenty HIV-1 infected youth with suppressed viral replication on HAART. The MVA and FP-based multigene HIV-1 vaccines were safe and well tolerated. Increased frequencies of HIV-1 specific CD4+ proliferative responses and cytokine secreting cells were detected following immunization. Increased frequencies and breadth of HIV-1 specific CD8 T-cell responses were also detected. Plasma HIV-1-specific antibody levels and neutralizing activity were unchanged following vaccination. Poxvirus-based vaccines may merit further study in therapeutic vaccine protocols.

Impaired immunity to recall antigens and neoantigens in severely immunocompromised children and adolescents during the first year of effective highly active antiretroviral therapy.

BACKGROUND: We studied whether severely immunocompromised, human immunodeficiency virus (HIV)-infected children who were beginning highly active antiretroviral therapy (HAART) or changing HAART regimens could spontaneously respond to a recall antigen (tetanus toxoid [TT] vaccine) or respond to a recall antigen and neoantigen (hepatitis A virus [HAV] vaccine) after 3 vaccinations. METHODS: A total of 46 children who had CD4 cell percentages <15% and who demonstrated a >0.75-log reduction in plasma HIV RNA levels within 4 weeks of starting HAART were randomized to receive vaccinations with either TT or HAV vaccines during the first 6 months of HAART. Study subjects then received the alternate vaccine during the next 6 months of HAART. RESULTS: Despite the early decline in viremia and the later increase in the percentage of CD4 T cells, spontaneous recovery of cell-mediated immunity (CMI) was not seen for TT. Serologic responses to TT required 3 vaccinations and were comparable in both groups. Serologic responses to HAV were infrequent and of low titer, although the group that received HAV vaccine after receiving TT vaccine performed somewhat better. CMI to HAV was virtually absent. CONCLUSIONS: Severely immunocompromised children who are receiving HAART develop CMI and antibody to a recall antigen independent of the timing of vaccination, but they require a primary series of vaccinations. Antibodies to a neoantigen, HAV, developed when vaccination was delayed after initiation of HAART. CMI to a neoantigen was difficult to establish. TRIAL REGISTRATION: Clinicaltrials.gov identifier: NCT00004735/PACTG P1006 .

Structured treatment interruptions (STIs) in HIV-1 infected pediatric populations increases interferon gamma production and reduces viremia.

We assessed the effect of progressively longer antiretroviral structured treatment interruptions (STIs) starting with 3 days, increasing by 2 days in length each cycle on HIV-specific immune responses. As well, we correlated these responses with control of HIV viremia. Eight individuals became viremic and reached cycle 13 with an STI of > or =27 days. HIV-specific gamma-interferon production to inactivated HIV and vaccinia vectors expressing gag, env, nef, and pol increased (>10-fold) in six of eight subjects. Median plasma RNA levels peaked @ cycle 7 and declined to levels <10(4)cp/ml after cycle 10. In a subset of five who reached cycle 17, HIV-specific IFN-gamma frequencies increased from cycle 8 to cycle 17 with evidence of improved virologic control over comparable periods off antiretroviral therapy. This allowed us to conclude that exposure to autologous virus increased HIV-specific immune responses and decreased HIV RNA were seen in those who have had >13 interruptions, with STI intervals that exceeded 27 days.