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

Abstract

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