Continued Production of Drug-Sensitive Human Immunodeficiency Virus Type 1 in Children on Combination Antiretroviral Therapy Who Have Undetectable Viral Loads

Abstract

Highly active antiretroviral therapy (HAART) can suppress plasma human immunodeficiency virus type 1 (HIV-1) levels to below the detection limit of ultrasensitive clinical assays. However, HIV-1 persists in cellular reservoirs, and in adults, persistent low-level viremia is detected with more sensitive assays. The nature of this viremia is poorly understood, and it is unclear whether viremia persists in children on HAART, particularly those who start therapy shortly after birth. We therefore developed a reverse transcriptase PCR (RT-PCR) assay that allows genotyping of HIV-1 protease even when viremia is present at levels as low as 5 copies of HIV-1 RNA/ml. We demonstrated that viremia persists in children with plasma virus levels below the limit of detection of clinical assays. Viremia was detected even in children who began HAART in early infancy and maintained such strong suppression of viremia that HIV-1-specific antibody responses were absent or minimal. The low-level plasma virus lacked protease inhibitor resistance mutations despite the frequent use of nelfinavir, which has a low mutational barrier to resistance. Protease sequences resembled those of viruses in the latent reservoir in resting CD4 ؉ T cells. Thus, in most children on HAART with clinically undetectable viremia, there is continued virus production without evolution of resistance in the protease gene.

An Increasing Proportion of Monotypic HIV-1 DNA Sequences during Antiretroviral Treatment Suggests Proliferation of HIV-Infected Cells

“…In a subset of individuals, increasing genetic distances indicate HIV-1 replication (19)(20)(21)(22)(23)(24)(25). However, the majority of individuals have no evidence of viral evolution (19,26,27), and often, the sequences generated from low-level viremias are monotypic (15,19,(28)(29)(30)(31). The latter observations led us to evaluate the hypothesis that proliferation of HIV-1-infected cells is a mechanism that contributes to HIV-1 persistence during suppressive ART.…”

Autologous Neutralizing Antibody to Human Immunodeficiency Virus-1 and Replication-Competent Virus Recovered from CD4+T-Cell Reservoirs in Pediatric HIV-1–Infected Patients on HAART

“…Other earlier studies in adult LTNP have shown the ability to neutralize primary isolates and heterologous viruses better than those with disease progression. 4,25 However, Montefiori and colleagues 26 found LTNP were unable to neutralize their replicationcompetent HIV with concurrent autologous serum, which differs from our pediatric subjects on HAART who had detectable ANAB to concurrent RCV. Variation in the ability to mount a NAB response to autologous virus may be a reflection of viral diversity and selective pressure on HIV.…”

“…Both adults and children on HAART may have low-level HIV replication detected only by supersensitive real-time PCR techniques with current ART=HAART available drugs. 26 It is unknown whether newer, more potent combination treatments with different mechanisms of actions developed in the future will change this.…”

Characterisation, Evaluation and Clinical Significance of Latent HIV-1 Reservoirs and Therapeutic Strategies for HIV Eradication

“…Since there was no virus evolution, it has been suggested that no residual virus replication was occurring [100]. A novel RT-PCR method for genotyping the HIV-1 protease gene at low viral loads (5 copies/ml) revealed that children who began successful inhibitory HAART soon after birth, also did not exhibit drug-resistance mutations to the protease inhibitor nelfinavir and the virus resembled that found in resting CD4+ T-cells [101]. A longitudinal study has again shown lack of evolution in residual viraemia through analysis of drug resistance mutations in reverse transcriptase and protease sequences from eight patients who maintained undetectable viraemia for 15 months [102].…”