Correspondence on ‘Anticardiolipin and other antiphospholipid antibodies in critically ill COVID-19 positive and negative patients’

I read with great interest the article by Trahtemberg et al 1 on the clinical relevance of antiphospholipid antibodies (aPLs), in particular anticardiolipin antibodies (aCLs), in critically ill COVID-19 positive and negative patients. Severe COVID-19 is associated with a hypercoagulable state. Early studies identified the presence of aPLs in critically ill COVID-19 patients,2 which has attracted considerable attention as the presence of aPLs is one of the mechanisms leading to coagulopathy. Substantial efforts then tried to associate the thrombotic events seen in COVID-19 to aPLs status. The results seem negative, but a number of different types of autoantibodies were identified.3 Chang et al recently reported that autoantibodies were present in approximately half of the hospitalised patients with COVID-19 but in less than 15% of healthy controls.4 In addition to aCLs and anti-beta 2 glycoprotein 1 antibodies (aβ2-GP1), they also identified autoantibodies targeting autoantigens associated with rare disorders such as myositis, systemic sclerosis and overlap syndromes as well as targeting interferons/interleukins and other cytokines.4 These findings suggest that COVID-19, in particular patients with severe/critical …