The mutational archive in proviral DNA does not change during 24 months of continuous or intermittent highly active antiretroviral therapy.

Objectives: The aim of the study was to determine the modifications of the mutational archive in proviral HIV-1 DNA occurring during 24 months of intermittent or continuous highly active antiretroviral therapy (HAART).
Methods: The study population included subjects enrolled in the Istituto Superiore di Sanità Pulsed Antiretroviral Therapy (ISS PART) clinical trial. All of these patients were on first-line HAART and had plasma HIV-1 RNA below 50 HIV-1 RNA copies/mL. A genotypic resistance test was performed on HIV-1 DNA extracted from peripheral blood mononuclear cells (PBMC) at baseline and after 24 months of follow-up. Resistance-associated mutations (RAMs) were defined according to the International AIDS Society (IAS) USA classification.
Results: Sixty-nine subjects were included in the study [36 enrolled in arm A of the ISS PART (continuous HAART) and 33 enrolled in arm B (intermittent HAART)]. No major modifications of the mutational archive were found in either group after 24 months of follow-up, in terms of both the proportion of subjects with mutations and the total number of mutations.
Conclusions: In this patient population, the mutational archive in HIV-1 DNA extracted from PBMC was stable for 24 months, irrespective of HAART modality, whether continuous or intermittent.