Increased levels of PF4 and anti-PF4 antibodies are found in patients with Covid-19 (Liu X. et al., 2020; Cai et al., 2020) and there is a report of a patient who developed immune thrombocytopenia after SARS-CoV-2 infection (Zulfiqar et al., 2020). This evidence concerns the gene PF4 and autoimmune thrombocytopenic purpura.