The decay of HIV-1-infected cell populations after treatment with antiretroviral therapy has been measured using simple exponential decay models. These models are unlikely to be realistic over periods longer than a few months, however, because the population dynamics of HIV are complex. We considered an alternate model developed by Perelson and colleagues that extends the standard model for biphasic viral load decline and allows for nonlinear log decay of infected cell populations. Using data from 6 children on highly active antiretroviral therapy (HAART) and a single parameter in the new model, the assumption of log linear decay of infected cell populations is tested. Our analysis indicates that the short-lived and long-lived infected cell populations do not decay according to a simple exponential model. Furthermore, the resulting estimates of time to eradication of infected cell compartments are dramatically longer than those previously reported (eg, decades vs. years for long-lived infected cell populations and years vs. weeks for short-lived infected cell populations). Furthermore, estimates of the second-phase decay rates are significantly different than 0 for most children when obtained using the Perelson biphasic decay model. In contrast, this rate is not significantly different than 0 when the density-dependent decay model is used for parameter estimation and inference. Thus, the density-dependent decay model but not the simple exponential decay model is consistent with recent data showing that even under consistent HAART-mediated suppression of viral replication, decay rates of infected cell reservoirs decay little over several years. This suggests that conclusions about long-term viral dynamics of HIV infection based on simple exponential decay models should be carefully re-evaluated.

Pediatric AIDS Clinical Trials Group protocol 326 is a study of 2 formulations of recombinant canarypox ALVAC vaccine (vCP205) against human immunodeficiency virus type 1 (HIV-1). HIV-1-exposed infants were randomized to receive 1 of 2 formulations of vCP205 or placebo at birth and 4, 8, and 12 weeks. The vaccines were safe. Lymphoproliferative responses were detected at > or =2 time points in 44%-56% of vaccinees and none of the placebo recipients. A cytotoxic T lymphocyte response on at least 1 occasion was detected in 62.5% of infants in cohort 1 (10(6.08) median tissue culture dose [TCID(50)] vaccine formulation) and 44% of infants in cohort 2 (10(6.33) TCID(50) vaccine formulation). Rare mucosal immunoglobulin A responses and no measurable vaccine-elicited serum antibodies were detected. In children, vCP205 appeared to be safe and immunogenic.

Episodes of low-level viremia (LLV), with plasma human immunodeficiency virus type 1 (HIV-1) RNA levels ranging from 50 to 400 copies (c)/ml, occur commonly during highly active antiretroviral therapy (HAART). LLV has been associated with virologic failure of HAART in some studies, while in others LLV did not appear to affect the clinical outcome. To understand the processes leading to LLV, genetic analyses were used to determine whether plasma virions emanated from archived or from newly evolved viral genomes. Episodes of LLV (plasma HIV-1 RNA, 50 to 379 [median, 77] c/ml) were detected in 21/37 (57%) HIV-1-infected children with median plasma HIV-1 RNA levels of < 50 c/ml during 79 patient years of HAART. Viral sequences were derived by direct sequencing of PCR products from 21 plasma specimens diluted to end point. In phylogenetic analysis, LLV viral sequences grouped with virus from early in the course of infection in 8/11 subjects. Six specimens had multiple identical viral sequences, suggesting origin from clonally expanded infected cells. LLV plasma virus evolved over time, indicating viral replication, in 3/11 subjects. Two of these had frequent LLV, including the selection of drug-resistant mutants. In summary, plasma virus from episodes of LLV during effective HAART appeared to originate from two distinct processes, (i) clonal outgrowth from long-lived HIV-1-infected cells, presumably following activation and proliferation of these cells, and (ii) ongoing viral replication that included the selection of new drug-resistant mutants. These observations provide a plausible explanation for the divergent clinical outcomes previously associated with LLV.

We studied the feasibility and acceptability of HIV-1 testing using rapid serological assays in pregnant women presenting in late pregnancy without prior HIV-1 testing. Pregnant women presenting to the emergency room at the Instituto Materno-Perinatal in Lima, Peru, were offered on-site rapid HIV-1 testing. Consenting women were provided HIV counseling and had samples taken for rapid detection of antibodies in the blood and oral secretions. Women testing HIV-1 seropositive by one or both assays were offered standard HIV obstetrical care including antiretrovirals. Between October 2000 and August 2001, 3543 women were tested for HIV-1 antibodies through the rapid testing protocol. Twenty-seven women tested positive by one or both assays. Standard EIA results were negative for two of the 27 women and EIA results were not available for an additional three women. Seventeen of the 19 women (89%) for whom delivery information is available received antiretroviral therapy prior to delivery. Eighty percent of the women treated with nevirapine received the drug at least 1 hr prior to delivery. Study personnel reported problems with performing the rapid assays for less than 1% of the samples and the majority of the women did not express a preference for either the oral fluid or blood sample collection. While HIV-1 testing early in pregnancy is preferable, rapid HIV-1 testing in late pregnancy or at delivery is feasible, acceptable to most women, and allows for timely intervention to reduce maternal-child transmission.

OBJECTIVETo assess the level of immunity to measles, tetanus, and Haemophilus influenzae type b (Hib) in previously immunized children who have human immunodeficiency virus (HIV) infection and were treated with highly active antiretroviral therapy (HAART) and to determine the response to reimmunization.METHODSRetrospective review of clinical data from children who have HIV-1 infection and were treated with HAART. Children were included in the analysis when they had a history of immunizations before treatment with HAART; had specific immunoglobulin G levels to tetanus, measles, or Hib measured after starting HAART but before the receipt of additional immunizations; were reimmunized while on HAART; and had postimmunization immunoglobulin G levels available.RESULTSNineteen children (median age: 7 years; range: 3-14 years) who were treated with 3 to 5 drug HAART regimens for a median of 20 months (range: 8-37) met the criteria for at least 1 antigen and were included in this review. Fifteen (79%) of the 19 had plasma RNA levels <50 copies/mL. The median CD4% before HAART was 26% (range: 1-41) and at the time of immunization, 35% (range: 20-54). Before reimmunization, 1 (5%) of 18 children had detectable antibody levels to measles, 6 (35%) of 17 had detectable antibody levels to tetanus, and 14 (78%) of 18 had detectable antibody levels to Hib. After immunization, 15 (83%) of 18, 10 (90%) of 11, and 3 (75%) of 4 seroconverted to measles, tetanus, and Hib, respectively. Antibody levels remained detectable after 1 year in the majority of children tested.CONCLUSIONSConsideration should be given to readministering childhood immunizations to children who have HIV infection and are treated successfully with combination antiretroviral therapy.

ABSTRACT To evaluate human immunodeficiency virus type 1 (HIV-1) replication and selection of drug-resistant viruses during seemingly effective highly active antiretroviral therapy (HAART), multiple HIV-1 env and pol sequences were analyzed and viral DNA levels were quantified from nucleoside analog-experienced children prior to and during a median of 5.1 (range, 1.8 to 6.4) years of HAART. Viral replication was detected at different rates, with apparently increasing sensitivity: 1 of 10 by phylogenetic analysis; 2 of 10 by viral evolution with increasing genetic distances from the most recent common ancestor (MRCA) of infection; 3 of 10 by selection of drug-resistant mutants; and 6 of 10 by maintenance of genetic distances from the MRCA. When four- or five-drug antiretroviral regimens were given to these children, persistent plasma viral rebound did not occur despite the accumulation of highly drug-resistant genotypes. Among the four children without genetic evidence of viral replication, a statistically significant decrease in the genetic distance to the MRCA was detected in three, indicating the persistence of a greater number of early compared to recent viruses, and their HIV-1 DNA decreased by ≥0.9 log10, resulting in lower absolute DNA levels (P = 0.007). This study demonstrates the variable rates of viral replication when HAART has suppressed plasma HIV-1 RNA for years to a median of <50 copies/ml and that combinations of four or five antiretroviral drugs suppress viral replication even after short-term virologic failure of three-drug HAART and despite ongoing accumulation of drug-resistant mutants. Furthermore, the decrease of cellular HIV-1 DNA to low absolute levels in those without genetic evidence of viral replication suggests that monitoring viral DNA during HAART may gauge low-level replication.

OBJECTIVE:To characterize the long-term tolerance and virologic efficacy of combination antiretroviral therapy consisting of 4 or more agents in a clinical setting.METHODS:An observational review of 36 children infected with human immunodeficiency virus 1 (HIV-1) treated with 4 or 5 antiretroviral agents in 2 university hospital clinics between April 1, 1996, and October 31, 2000. Highly active antiretroviral therapy regimens were chosen with regard to the child's past antiretroviral exposure or results of genotypic resistance data. Plasma HIV-1 RNA levels were monitored weekly to monthly after initiation of highly active antiretroviral therapy, and adherence efforts were actively supported and monitored.MAIN OUTCOME MEASURE:Number of children with undetectable plasma HIV-1 RNA levels at longest follow-up.RESULTS:Four- or 5-drug highly active antiretroviral therapy reduced plasma HIV-1 RNA levels to less than 50 copies/mL in 32 (89%) of 36 children. After a median of 28.7 months of observation, 28 children (78%) remained at this level of suppression. Adverse reactions were limited to mild neutropenia and mild transient or persistent elevations in alanine aminotransferase levels in 11% of children.CONCLUSIONS:Treatment with 4 or 5 antiretroviral agents was well tolerated in HIV-1-infected children and resulted in a high degree of viral suppression, even in children with previous antiretroviral drug experience.

ABSTRACT The detection of virus is used to diagnose human immunodeficiency virus type 1 (HIV-1) infection in infants due to the persistence of maternal antibodies for a year or more. An HIV-1 DNA PCR assay with simple specimen collection and processing was developed and evaluated. Whole blood was collected on filter paper that lysed cells and bound the DNA, eliminating specimen centrifugation and extraction procedures. The DNA remained bound to the filter paper during PCR amplification. Assays of copy number standards showed reproducible detection of 5 to 10 copies of HIV-1 in 5 μl of whole blood. The sensitivity of the assay did not decrease after storage of the standards on filter paper for 3 months at room temperature or after incubation at 37 or 45°C for 20 h. The primers used for nested PCR of the HIV-1 pol gene amplified templates from a reference panel of multiple HIV-1 subtypes but did not amplify a subtype A or a subtype C virus from children living in Seattle. The assay had a sensitivity of 98.4% and a specificity of 98.3% for testing of 122 specimens from 35 HIV-1-infected and 16 uninfected children and 43 seronegative adults living in Washington. The assay had a sensitivity of 99% and a specificity of 100% for testing of 102 HIV-1-positive (as determined by enzyme immunoassay) Peruvian women and 6 seropositive and 34 seronegative infants. This assay, with adsorption of whole blood to filter paper and no specimen processing, provides a practical, economical, sensitive, and specific method for the diagnosis of HIV-1 subtype B infection in infants.

Our objective was to determine whether HIV-infected children treated with protease inhibitors (PIs) have different blood lipid, insulin, and glucose levels and body composition than HIV-infected children not treated with Pts. A cross-sectional cohort study was performed; in which 23 children were treated with combination antiretroviral. therapy including a PI for at least 6 months and 12 children were treated with nucleoside reverse transcriptase inhibitors only (no-PI group). Levels of lipids, apolipoprotein B (apoB), insulin, and glucose were determined in the fasting state. Body composition and fat distribution were determined by anthropometric measurements and dual energy X-ray absorptiometry (DEXA) scan. Total cholesterol levels were higher in the PI-treated children (5.33 +/- 0.87 mM) than in the no-PI children (3.69 +/- 0.59 mM) (p < 0.0001). Similarly, low-density lipoprotein (LDL) levels were also elevated in the PI-treated children (3.27 +/- 0.76 vs. 2.14 +/- 0.51 mM) (p < 0.0001). ApoB and high-density lipoprotein (HDL), and to a lesser degree triglyceride levels, were also increased in the PI-treated children. Apart from percent arm fat as measured by DEXA, there were no differences between the two groups in measures of body composition or in their fasting glucose and insulin levels. The results from this cross-sectional cohort study suggest that the predominant lipid abnormalities associated with treatment with combination antiretroviral therapy including a PI in HIV-1-infected children are elevated total and LDL cholesterol.

A greater understanding of perinatal HIV-1 transmission has resulted in a marked decrease in the incidence of pediatric HIV-1 infection in several affluent nations. Advances in treatment have led to a decrease in HIV-1-related morbidity and mortality in some HIV-1-infected children. Studies are ongoing to determine methods to sustain the salutary effects of treatment. A goal of child advocates is to translate these advances to communities with few resources. Efforts are underway to make infant chemoprophylaxis widely available and to define strategies to reduce exposure to maternal virus. Likewise, there is the need to increase the access of children to treatment.

The pharmacokinetics, safety, tolerance, and antiviral effects of ganciclovir (Gcv) administered orally were evaluated in 36 children infected with cytomegalovirus (CMV) who were severely immunocompromised by infection with human immunodeficiency virus type 1. In this dose-escalation study, 30 mg/kg of Gcv administered every 8 h produced serum levels similar to the dose (1 g/8 h) effective for maintenance treatment of CMV retinitis in adults. In older children, serum Gcv concentrations were similar after the administration of capsules and suspension. All doses (10-50 mg/kg/8 h) studied were safe and, except for the volume of suspension or number of pills, were well tolerated. Oral Gcv was associated with a decrease in the detection of CMV by culture or polymerase chain reaction. CMV disease occurred in 3 children during the study: one developed Gcv resistance, another had harbored resistant virus at study entry, and a third had wild-type CMV

HIV-1-infected children have higher plasma viral loads and progress to disease more quickly than infected adults. To gain insight into the accelerated pathogenesis of HIV-1 in children, viral dynamics were measured following the initiation of highly active antiretroviral therapy (HAART) and compared with those reported for adults. A biphasic decline in plasma HIV-1 RNA was observed, with a rapid decrease during the first 1 to 2 weeks of therapy (phase I) followed by a slower decline (phase II). The phase I and II decay rates were not significantly different among children of different ages, pretherapy plasma HIV-1 RNA levels, or CD4 cell counts. Estimated phase I decay rates were similar to those previously reported in adults with a mean of 0.43 days(-1) and a half-life of 1.6 days. The phase II decay rates were slower in children compared with adults with a mean of 0.016 days(-1) versus 0.066 days(-1), and a half-life of 43.3 versus 14.1 days, respectively (p < .05). The mean time required to reach viral levels below detection thresholds was also longer in these children compared with that in adults. These data suggest that HIV-1 dynamics may be different in children, and that these differences may necessitate different treatment strategies.

Viral suppression may be more difficult to achieve in children compared to adults. However, appropriate regimens at adequate dosages combined with monitoring of adherence and virologic response should allow children with HIV infection to realize a sustained benefit from combination anti-retroviral therapy.

OBJECTIVE:To determine the effects of combination antiretroviral therapy including a protease inhibitor (PI combination therapy) in children with advanced HIV-1 disease.STUDY DESIGN:An observational study of HIV-1 plasma RNA, lymphocyte subsets, delayed type hypersensitivity and physical growth after initiation of PI combination therapy.RESULTS:In nine children the median HIV-1 plasma RNA decreased 1.7 log10 (mean, 1.57; range, 0.7 to 2.2) following PI combination therapy and CD4 cells increased a median of 499 (mean, 528; range, 9 to 1088) cells/microl. A rebound of RNA, associated with the development of resistance to the PI, occurred in three subjects. Three of six children were no longer anergic and all nine achieved normal weight-growth velocities. Ritonavir was well-tolerated, despite its bitter taste; however, four of five children treated with indinavir developed renal complications.CONCLUSIONS:PI combination therapy in children with advanced HIV-1 disease was associated with a decrease in HIV-1 RNA, improved immunologic measures and normal or better weight gain. Of concern was the rebound in plasma HIV-1 associated with resistance to the PI observed in one-third of patients. This emphasizes the need for larger studies to define optimal PI containing regimens with long term efficacy in children.

OBJECTIVE To determine the prevalence of human immunodeficiency virus type 1 (HIV-1) in the saliva of infected children and adolescents. METHODS Saliva and blood samples were collected from 13 patients (age range, 1-15 years) with HIV-1 infection. Eleven were taking antiretroviral agents. The presence of HIV-1 was determined by polymerase chain reaction analysis of RNA and DNA as well as by viral culture of the saliva samples and by culture of peripheral blood mononuclear cells. RESULTS Although HIV-1 was cultured from peripheral blood mononuclear cells of 12 patients, it was not cultured from their saliva. Only 1 of 13 saliva samples yielded positive test results for HIV-1 RNA, and none did so for HIV-1 DNA. The specimen containing HIV-1 RNA was from an untreated 10-year-old asymptomatic boy with a CD4+ lymphocyte count of 0.91 x 10(9)/L (913 cells/microL) and no infectious virus detected in plasma. CONCLUSION The prevalence of HIV-1 in the saliva of HIV-1-infected children and adolescents is low and may not be infectious.

To determine if the 32-bp deletion of the chemokine receptor CCR5 (delta32ccr5) protects against mother-to-infant transmission of HIV-1, specimens from all uninfected and infected children who were perinatally exposed to HIV-1 and observed since 1988 and whose mothers did not take zidovudine were assessed for delta32ccr5. The CCR5 genotype was determined using polymerase chain reaction (PCR) for 122 subjects, of whom 73 were HIV-1 infected and 49 were perinatally exposed but uninfected; 70% and 71%, respectively, were Caucasian. Eleven of 73 (15%) infected children and 4 of 49 (8%) exposed uninfected children were CCR5/delta32ccr5 heterozygotes (p = 0.40). Among subjects who had at least one Caucasian parent or grandparent, 11 of 51 (22%) HIV-1-infected persons and 4 of 35 (11%) uninfected persons were heterozygotes. None were homozygous for the delta32ccr5 allele. The estimated relative risk for mother-to-infant HIV-1 transmission in heterozygotes was 2.0. Furthermore, the 95% confidence interval (0.6, 7.3) suggested that it is unlikely that the true relative risk was <0.6. Thus, the infant CCR5/delta32ccr5 heterozygous genotype was not associated with a diminished risk of perinatally acquired HIV-1 infection.