Antiphospholipid antibodies (aPL) in primary or secondary antiphospholipid syndrome (APS) are a major cause for acquired thrombophilia, but specific interventions preventing autoimmune aPL development are an unmet clinical need. While autoimmune aPL cross-react with various coagulation regulatory proteins, lipid-reactive and COVID-19 patient-derived aPL recognize the endo-lysosomal phospholipid lysobisphosphatidic acid (LBPA) presented by the cell surface expressed endothelial protein C …