While SARS-CoV-2 infection seems to be associated with general hypercoagulability, either due to systemic inflammatory response and cytokine storm or ACE-2-mediated endothelial dysfunction, recent reports indicate the presence of circulating antibodies against Platelet Factor 4 (PF4) in some COVID-positive individuals, which drive systemic response resembling the Heparin-Induced Thrombocytopenia and leading to hemorrhagic events. This evidence concerns the gene PF4 and thrombophilia.