The main goal of this study is to identify and characterise the anatomical component of the replication competent HIV-1 (Human Immunodeficiency Virus-1) reservoir.

The investigators hypothesize that the clinically relevant HIV-1 reservoir is hiding in various but specific anatomic compartments and is able to rebound when therapy is stopped.

This reservoir is probably smaller than the HIV-1 reservoir hiding in the blood but could be more transcriptional active because of its specific environment, possibly influenced by lower concentrations of the antiretroviral therapy.

The current proposal will, for the first time, identify the source of the viral reservoir by phylogenetically backtracking the viral genome of the rebounding virus to the sequences of viral DNA in different anatomical compartments. The subsequent characterization of the viral reservoir markers (size, integration sites, methylation profile, stimulation and inhibition assays) will enable us to understand how this viral rebound occurred.