4.5. Definitions

Virological suppression was defined as the first achievement of HIV-1 RNA < 40 copies/mL. Virological failure was considered as either incomplete suppression (a viral load >200 copies/mL after 6 months of ART) or viral rebound (two consecutive HIV-1 RNA > 50 cp/mL or an HIV-1 RNA > 1000 cp/mL after the achievement of virological suppression). In this study, the amount of HIV-1 DNA defining a low-level HIV-1 DNA was set at <200 copies/106 PBMC based on the ANRS 116 SALTO study in which this threshold was associated with a lower probability to reassume therapy after ART interruption [38]. The same threshold of HIV-1 DNA has been already used in the setting of ART started during both chronic and acute HIV infection to define, together with immunological parameters, the status of optimal viroimmunological responders [32]. This value was also reached by the 25th percentile of subjects who started ART during acute HIV infection after 24 months of treatment [39]. Suboptimal adherence was defined as VAS < 100. Finally, the transmitted drug resistance mutations were determined according to the WHO recommended surveillance drug resistance mutation list, updated in 2009, for PIs, nucleoside transcriptase reverse inhibitors (NRTIs), NNRTIs [40], integrated with the Stanford HIV drug resistance database for INSTIs [41].