• hydroxychloroquine
• antibodies
• antiphospholipid
• antibodies
• anticardiolipin
• antiphospholipid syndrome
• lupus erythematosus
• systemic

We thank Amezcua-Guerra et al for their interest in our study reporting on the course of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease 2019 (COVID-19) in a case series of patients with systemic lupus erythematosus under long-term treatment with hydroxychloroquine.1 2 Complementary to our work, Amezcua-Guerra et al address the issue of anti-phospholipid antibodies (anti-PL abs) during the course of COVID-19. Indeed, despite adequate thromboprophylaxis, COVID-19 is associated with a high rates of venous, as well as arterial, thromboembolic events, in particular in patients hospitalised in an intensive care unit.3–5 This state of hypercoagulation has been linked to an important systemic inflammatory response syndrome, with elevated serum levels of fibrinogen, factor VIII and D-dimers.6 7 Several reports, including the study by Amezcua-Guerra et al 2 have emphasised the high frequency of serum anti-PL abs and lupus anti-coagulant (LA) in a case series of patients with severe COVID-19, however with surprisingly heterogeneous results.

Amezcua-Guerra et al report a high frequency (57%) of both conventional (ie, those included in the antiphospholipid syndrome (APS) classification criteria) and non-conventional anti-PL abs in patients with severe and critical COVID-19, which appear to be associated with a hyperinflammatory state. An association with pulmonary thromboembolism has also been suggested although this concerned only 2 …