Hans Spiegel

Human Immunodeficiency Virus Type 1- and Cytomegalovirus-Specific Cytotoxic T Lymphocytes Can Persist at High Frequency for Prolonged Periods in the Absence of Circulating Peripheral CD4+ T Cells

ABSTRACT CD4+ T cells are thought to be critical in the maintenance of virus-specific CD8+ cytotoxic T-cell (CTL) responses. In human immunodeficiency virus type 1 (HIV-1) infection, a selective decline in HIV-1-specific CTL as the CD4+ T-cell count decreases has been reported. Using HLA-peptide tetrameric complexes, we show the presence at high frequency of HIV-1- and cytomegalovirus-specific CD8+ T cells when the peripheral CD4+ T-cell count was low or zero in three HIV-1-infected patients. No direct virus-specific CD8+-mediated effector activity was seen in these subjects, suggesting antigen unresponsiveness, although tetramer-sorted cells could be expanded in vitro in the presence of interleukin-2 into responsive effector cells. Thus, virus-specific CD8+ T cells can be maintained in the peripheral circulation at high frequency in the absence of circulating peripheral CD4+ T cells, but these cells may lack direct effector activity. Strategies designed to overcome this antigen unresponsiveness may be of value in therapies for the treatment of AIDS.

HIV-Specific CD8+ T Cell Function in Children with Vertically Acquired HIV-1 Infection Is Critically Influenced by Age and the State of the CD4+ T Cell Compartment

The immunology of vertical HIV transmission differs from that of adult infection in that the immune system of the infant is not fully matured, and the factors that influence the functionality of CD8+ T cell responses against HIV in children remain largely undefined. We have investigated CD8+ T cell responses in 65 pediatric subjects with vertically acquired HIV-1 infection. Vigorous, broad, and Ag dose-driven CD8+ T cell responses against HIV Ags were frequently observed in children who were older than 3 years of age and maintained CD4+ T cell counts >400 cells/μl. In contrast, younger age or a CD4+ T cell count <400 cells/μl was associated with poor CD8+ T cell responses and high HIV loads. Furthermore, subjects with a severely depleted and phenotypically altered CD4+ T cell compartment had circulating Gag-specific CD8+ T cells with impaired IFN-γ production. When viral load was not suppressed by antiviral treatment, subjects that fell below the putative age and CD4+ T cell count thresholds had significantly reduced CD8+ T cell responses and significantly higher viral loads. Thus, the data suggest that fully effective HIV-specific CD8+ T cell responses take years to develop despite an abundance of Ag in early life, and responses are further severely impaired, independent of age, in children who have a depleted or skewed CD4+ T cell compartment. The results are discussed in relation to differences between the neonatal and adult immune systems in the ability to respond to HIV infection.

Birth defects among children born to human immunodeficiency virus-infected women: pediatric AIDS clinical trials protocols 219 and 219C.

Background: Some studies have detected associations between in utero antiretroviral therapy (ARV) exposure and birth defects but evidence is inconclusive. Methods: A total of 2202 human immunodeficiency virus (HIV)-exposed children enrolled in the Pediatric AIDS Clinical Trials Group 219 and 219 C protocols before 1 year of age were included. Birth defects were classified using the Metropolitan Atlanta Congenital Defects Program coding. Logistic regression models were used to evaluate associations between first trimester in utero ARV exposure and birth defects. Results: A total of 117 live-born children had birth defects for a prevalence of 5.3% (95% confidence interval [CI]: 4.4, 6.3). Prevalence did not differ by HIV infection status or overall ARV exposure; rates were 4.8% (95% CI: 3.7, 6.1) and 5.8% (95% CI: 4.2, 7.8) in children without and with first trimester ARV exposure, respectively. The defect rate was higher among children with first trimester efavirenz exposure (5/32, 15.6%) versus children without first trimester efavirenz exposure (adjusted odds ratio [aOR] = 4.31 [95% CI: 1.56, 11.86]). Protective effects of first trimester zidovudine exposure on musculoskeletal defects were detected (aOR = 0.24 [95% CI: 0.08, 0.69]), while a higher risk of heart defects was found (aOR = 2.04 [95% CI: 1.03, 4.05]). Conclusions: The prevalence of birth defects was higher in this cohort of HIV-exposed children than in other pediatric cohorts. There was no association with overall ARV exposure, but there were some associations with specific agents, including efavirenz. Additional studies are needed to rule out confounding and to evaluate newer ARV agents.

Human parechovirus-3 infection: emerging pathogen in neonatal sepsis.

Human parechovirus-3 (HPeV-3) is an emerging pathogen that has been described as a cause of neonatal sepsis. Human parechoviruses are a family of viruses closely related to enteroviruses; however, enteroviral PCR will not detect HPeVs. We present clinical details of neonatal meningoencephalitis and hepatitis-coagulopathy syndrome caused by HPeV-3 infection.

Changes in Frequency of HIV-1—Specific Cytotoxic T Cell Precursors and Circulating Effectors after Combination Antiretroviral Therapy in Children

Combination antiretroviral therapy has had a major role in reducing human immunodeficiency virus type 1 (HIV-1) plasma viral loads in HIV-1-infected adults but a variable effect in infants, in whom complete viral suppression appears to be less readily achieved. In adults, after the reduction in plasma viremia, there is a decrease in the numbers of circulating cytotoxic T cell (CTL) effectors and precursors in the majority of patients. This longitudinal study assessed the effect of combination drug therapy on the frequency of HIV-1-specific CTL responses in 8 HIV-1-infected children. Following treatment, the frequency of HIV-1-specific CTL responses initially increased, especially in children with incomplete viral suppression but with increasing CD4+ cell counts. In children with complete viral suppression, the frequency of HIV-1-specific CTL responses decreased, suggesting that viral replication is required to maintain CTL responses in the systemic circulation.

Prevalence of Congenital Anomalies in Infants with in Utero Exposure to Antiretrovirals

Background: Although use of efficacious interventions, including antiretrovirals (ARVs), has dramatically reduced the rate of mother-to-child transmission of human immunodeficiency virus, the safety of in utero ARV exposure remains of concern. Methods: Data regarding 1112 infants enrolled in the International Maternal Pediatric Adolescent AIDS Clinical Trials Group protocol P1025 born between 2002 and 2007 were analyzed for this study. Congenital anomalies were classified based on the Metropolitan Atlanta Congenital Defects Program guidelines. Associations between congenital anomalies and timing of first in utero exposure to ARVs were evaluated by logistic regression analysis. Results: Congenital anomalies were identified and confirmed in 61 of the 1112 infants, resulting in a prevalence of 5.49/100 live births (95% confidence interval, 4.22–6.99). Among the 80 anomalies identified, the organ systems involved included cardiovascular (n = 33), musculoskeletal (n = 15), renal (n = 9), genitourinary (n = 6), craniofacial (n = 4), and central nervous system (n = 2). First trimester exposure to efavirenz was associated with a significantly increased risk of congenital anomalies (odds ratio, 2.84; 95% confidence interval, 1.13–7.16). No significant associations were observed between exposure to other individual ARVs or classes of ARVs started at any time during pregnancy and infant congenital anomalies. Conclusions: The observed rate of congenital anomalies in this cohort is higher than previously reported for the general population, but it is consistent with rates observed in other recent studies of children born to human immunodeficiency virus–infected women. Cardiovascular anomalies occurred most frequently. With the exception of a known teratogen (efavirenz), no statistically significant associations between in utero exposure to ARVs and congenital anomalies were identified.

Clinical Case Definitions for Classification of Intrathoracic Tuberculosis in Children: An Update

Consensus case definitions for childhood tuberculosis have been proposed by an international expert panel, aiming to standardize the reporting of cases in research focusing on the diagnosis of intrathoracic tuberculosis in children. These definitions are intended for tuberculosis diagnostic evaluation studies of symptomatic children with clinical suspicion of intrathoracic tuberculosis, and were not intended to predefine inclusion criteria into such studies. Feedback from researchers suggested that further clarification was required and that these case definitions could be further improved. Particular concerns were the perceived complexity and overlap of some case definitions, as well as the potential exclusion of children with acute onset of symptoms or less severe disease. The updated case definitions proposed here incorporate a number of key changes that aim to reduce complexity and improve research performance, while maintaining the original focus on symptomatic children suspected of having intrathoracic tuberculosis. The changes proposed should enhance harmonized classification for intrathoracic tuberculosis disease in children across studies, resulting in greater comparability and the much-needed ability to pool study results.

The impact of early initiation of highly active antiretroviral therapy on the human immunodeficiency virus type 1-specific CD8 T cell response in children

This cross-sectional study investigated the effect of early highly active antiretroviral therapy (HAART) on human immunodeficiency virus (HIV) type 1-specific CD8 T cell responses in children. HIV-1-specific CD8 T cell responses were quantified using an enzyme-linked immunospot assay to measure interferon-gamma-secreting cells. HIV-1-infected children were classified by time of HAART initiation prior to age 1 year or after age 2 years as early (n=24) or late (n=28) treated. The magnitude and breadth of the HIV-1-specific CD8 T cell response was significantly lower in children receiving early compared with late HAART treatment (P=.0007 and.0001, respectively). However, total CD8 T cell responses in the early HAART treatment group did not differ significantly from those of age-matched non-HAART-treated controls (n=30). Thus, the reduced magnitude and breadth of the HIV-1-specific CD8 T cell response in early HAART-treated children is due to their younger age.

A Phase 1 Randomized, Open Label, Rectal Safety, Acceptability, Pharmacokinetic, and Pharmacodynamic Study of Three Formulations of Tenofovir 1% Gel (the CHARM-01 Study)

Objectives The CHARM-01 study characterized the safety, acceptability, pharmacokinetics (PK), and pharmacodynamics (PD) of three tenofovir (TFV) gels for rectal application. The vaginal formulation (VF) gel was previously used in the CAPRISA 004 and VOICE vaginal microbicide Phase 2B trials and the RMP-02/MTN-006 Phase 1 rectal safety study. The reduced glycerin VF (RGVF) gel was used in the MTN-007 Phase 1 rectal microbicide trial and is currently being evaluated in the MTN-017 Phase 2 rectal microbicide trial. A third rectal specific formulation (RF) gel was also evaluated in the CHARM-01 study. Methods Participants received 4 mL of the three TFV gels in a blinded, crossover design: seven daily doses of RGVF, seven daily doses of RF, and six daily doses of placebo followed by one dose of VF, in a randomized sequence. Safety, acceptability, compartmental PK, and explant PD were monitored throughout the trial. Results All three gels were found to be safe and acceptable. RF and RGVF PK were not significantly different. Median mucosal mononuclear cell (MMC) TFV-DP trended toward higher values for RF compared to RGVF (1136 and 320 fmol/106 cells respectively). Use of each gel in vivo was associated with significant inhibition of ex vivo colorectal tissue HIV infection. There was also a significant negative correlation between the tissue levels of TFV, tissue TFV-DP, MMC TFV-DP, rectal fluid TFV, and explant HIV-1 infection. Conclusions All three formulations were found to be safe and acceptable. However, the safety profile of the VF gel was only based on exposure to one dose whereas participants received seven doses of the RGVF and RF gels. There was a trend towards higher tissue MMC levels of TFV-DP associated with use of the RF gel. Use of all gels was associated with significant inhibition of ex vivo tissue HIV infection. Trial Registration ClinicalTrials.gov NCT01575405

Incidence of persistent renal dysfunction in human immunodeficiency virus-infected children: associations with the use of antiretrovirals, and other nephrotoxic medications and risk factors.

Background: Survival of HIV-infected children continues to increase and the use of antiretrovirals (ARVs) is expanding; however there are few data regarding the incidence of renal dysfunction and associated risk factors among HIV-infected children and youth. Methods: A total of 2102 children enrolled in Pediatric AIDS Clinical Trials Group Study 219/219C, were followed and assessed prospectively for >30 months. Occurrence of clinical events and laboratory abnormalities were recorded using standardized criteria and forms. Therapeutic decisions were made by clinicians at each site. Occurrence of persistent renal laboratory abnormalities was the main outcome measure. Results: Four hundred forty-six (22%) enrollees exhibited at least one persistent renal laboratory abnormality. Elevated serum creatinine (Cr) was more common than persistent proteinuria (15% vs. 8%). The incidence of new renal laboratory abnormalities was 3.7 events per 100 person-years with rates increasing between 1993 and 2005. Older age (≥6 years vs. <6 years), Hispanic ethnicity, and Black non-Hispanic race were associated with increased risk of renal dysfunction, but CDC clinical class and plasma HIV RNA levels were not. Subjects exposed to ARV regimens containing tenofovir and/or indinavir had approximately twice the risk of developing renal dysfunction compared with persons exposed to other ARVs. The risk of renal dysfunction was also elevated for other antivirals (hazard ratio = 5.4) and amphotericin B (hazard ratio = 28). Conclusions: Persistent renal function abnormalities occur frequently in HIV-infected children. Improved survival, Black race and Hispanic ethnicity, and exposure to tenofovir, indinavir, and other antimicrobial agents increase the risk for renal dysfunction. All HIV-infected children should be monitored closely for evidence of renal disease.