Laboratory procedures
HIV-1 quantitative test was performed employing the CobasĀ® HIV-1 kit (Roche Diagnostics, Mannheim, Germany) for RNA extraction from EDTA plasma followed by PCR amplification and detection with CobasĀ® 4800 System (Roche Diagnostics, Mannheim, Germany). Anti-SARS-CoV-2 nucleocapsid antibodies (total Ig) and anti-SARS-CoV-2 spike RBD (total Ig) were measured as previously described. To quantify the neutralizing potential of sera (ND50), we used an in vitro assay based on VSV-pseudoparticles bearing SARS-CoV-2 spike glycoprotein and human ACE-2 over-expressing HEK293TN cell line as previously described.