Context: Until 70% of thrombotic event are reported during Sars-CoV2 infection.Antiphospholipid antibodies (aPL) tests are often positive. We aim to determine if aPLpositivity is involved in thrombose of Sars-CoV2 infection investigating the effect ofaPL on thrombin generation (TG) and leucocyte pathway activation (neutrophilsextracellular traps (NETs) and activation of triggering receptor expressed on myeloidcells 1 (TREM-1)).Method: We will compare plasma from five groups of subjects: patients withantiphospholipid syndrome (APS) and patients hospitalized for Sars-CoV-2 infection withor without aPL, and as control, patients with acute venous thromboembolism event andhealthy volunteers. For each subject, we will analyze aPL, activated protein C (APC)resistance measured by TG and leukocytes markers as circulating neutrophils extracellulartraps (NETs) and soluble triggering receptor expressed on myeloid cells one (sTREM-1). Wewill control aPL test at three month and analyze their persistent positivity andassociation with thrombotic event.Results: we hypothesize that patients with COVID-19 and aPL will have a similar aPL andlevel of APS resistance that patients with APS. Also, we think that circulating NETs andsTREM-1 levels will be more important in patients with COVID-19 with aPL than patientswithout aPL and similar in patients with COVID-19 and aPL and patients with APS.Conclusion: our study will be the first to analyze the potential role of aPL on APCresistance measured by TG and neutrophil activation in COVID-19.