We will suspend for short periods of time the administration of cART to HIV-1 infected individuals who started the therapy during their primary HIV-1 infection or in their chronic phase in order to dissect-out the dynamics of viral rebound and/or of its immunologic control in the absence of cART. We will investigate the dynamics of HIV-1 RNA and DNA levels, variations in viral quasispecies and changes in HIV-1 co-receptor use and T cell/macrophage tropisms. Detailed phenotypic and functional analysis of CD4 and CD8 T lymphocytes and of monocytes will include metabolic changes, cholesterol metabolism and mitochondrial function; antibody production and its capacity to neutralize or block CCR5-dependent HIV-1 infection will be also evaluated. Perturbations of monocyte subsets (based on CD14/CD16 expression and M1/M2 markers) will be also investigated along with the expression of host antiviral restriction factors and of a panel of soluble biomarkers of chronic inflammation. Central nervous system involvement will be monitored by MRI. A rigorous statistical analysis will define the dynamic hierarchy of immuno-virological determinants associated with the transient control and/or with the failure of controlling viral rebound before reintroduction of cART.