P09 A case of suspected COVID-19 vaccine-induced antiphospholipid syndrome

Abstract A 50-year-old man presented with an acute onset, painful leg ulcer affecting his right calf. This developed 2 weeks after second COVID-19 vaccine. It started a erythematous plaque, which evolved slowly into deep-seated 5-cm over 6-week period. thorough review was unremarkable. He had no significant medical history and keen athlete nonsmoker. His father unspecified stroke in 80s. Examination revealed signs of chronic venous insufficiency or discoloration to foot, neurovascular examination Investigations for antineutrophil cytoplasm antibodies, antinuclear antibody, complement, paraprotein, HIV hepatitis were all Biopsy demonstrated nonspecific inflammatory changes, wound swabs Initial treatment oral antibiotics, regular dressings, compression, topical emollients, Dermovate® prednisolone (0.5 mg kg−1) only partially effective. subsequently additional superficial erosions ulcers the same limb involving calf shin, surrounding livedoid-like rash shin. Rebiopsy deep dermal subcutaneous thrombosis without vasculitis. Direct immunofluorescence showed presence fibrinogen within vessels. Further investigations lupus anticoagulant. Factor V Leiden, protein C S, anti-B2-GP1 anticardiolipin antithrombin III, homocysteine coagulation profile Histological confirmation serum anticoagulant confirmed diagnosis antiphospholipid syndrome (APS). on warfarin improved. APS is rare autoimmune disorder characterized by recurrent miscarriage, thrombophilia autoantibodies (either anticoagulant, autoantibodies). Positivity antibodies can be found up 5% general population. An individual must have clinical features antibody positivity diagnosed APS. The temporal relationship vaccine raises possibility vaccine-induced limited just few case reports (Moreno-Torres V, Gutiérrez A, Valdenbro M et al. Catastrophic triggered mRNA Clin Exp Rheumatol 2022; 40:1054–5). postulated that vaccines may induce complex immunogenic response type 1 interferon reaction. results prothrombotic cascade individuals pre-existing autoantibody (Talotta R, Robertson E. Antiphospholipid risk post-COVID 19 vaccination thrombophilia: straw breaks camel’s back? Cytokine Growth Rev 2021; 60:52–60).