To investigate the potential impact of HCV coinfection and HCV eradication on HIV reservoir size, we performed both a cross-sectional and a longitudinal analysis of total HIV-DNA content in purified CD4+ T cells from 50 cART-treated patients: 25 HIV-monoinfected patients and 25 HIV/HCV-coinfected patients in whom HCV was eradicated with DAAs-based anti-HCV treatment. The gene discussed is CD4; the disease is coinfection.