Viral evolution in children with plasma HIV-1 RNA levels <50 copies/mL LM Frenkel, AJ Melvin, GL Sylva, WE Naugler, GM Ellis, BA Keim, I Beck, C Joiner, K
Originally Published on September 1, 1999
Mohan, MJ O'Hara, Y Wang. AG Rodrigo, GH Learn and JI Mullins
ABSTRACT: Objective: The second phase of HIV-1 RNA clearance after beginning HAART was observed to be slower in children compared to that reported for adults. Thus, we hypothesized that ongoing suppression of viral replication would be difficult to achieve in children. HIV-1 proviral sequences in children with plasma HIV-1 RNA levels consistently <50 copies/mL during HAART were evaluated for evidence of ongoing viral replication.
Methods: Fragments of env and pol were PCR-amplified from PBMCs taken from eight children before and at 6 month intervals during 1.5-3.0 years of HAART. PBMCs were serially diluted for PCR. Ten or more amplicons from dilution with a high probability of one copy of HIV-1 were further amplified in independent nested reaction resulting in 1.1 kb of pol and 0.6 kb of env that were sequenced directly.
Results: Proviral nucleotide sequence distances estimated to a hypothetical most-recent common ancestor decreased significantly with increased time of HAART for env sequences in two subjects and for the protease-coding region of pol in one subject. L74V, M184L, T216Y mutations in the RT-encoding region at baseline appeared to revert to wild-type in three children no longer taking the drug; however L74V persisted in a child who continued didanosine. The phylogram suggested that mutations to wild-type genotype characteristic of a non-resistant phenotype were acquired by a continued accumulation of amino acid substitutions in one child.
Conclusions: Among eight children receiving HAART with HIV-1 plasma RNA consistently <50 copies/mL. Sequencing distances, changes in the frequency of specific genotypes, and phylogenetic analyses suggest low level replication in some individuals and selective diminution of genotypes in others.
