High incidence of thrombosis in COVID-19 patients indicates a hypercoagulable state. Hence, exploring the involvement of antiphospholipid antibodies (aPL) in these patients is of interest.
To illustrate the incidence of criteria (lupus anticoagulant (LAC), anticardiolipin (aCL) IgG/IgM, antibeta2-glycoprotein I antibodies (aβ2GPI) IgG/IgM) and non-criteria (anti-prothrombin/phosphatidyl serine (aPS/PT), aCL and aβ2GPI IgA) aPL in a consecutive cohort of critically ill SARS-CoV-2 patients, their association with thrombosis, antibody profile and titers of aPL.
Thirty one consecutive confirmed COVID-19 patients admitted to the Intensive Care Unit were included. aPL were measured at one time point, with part of the aPL positive patients retested after one month.
Sixteen patients were single LAC positive, two triple positive, one double positive, one single aCL and three aCL IgG and LAC positive. Seven out of 9 thrombotic patients had at least one aPL. 16 out of 22 patients without thrombosis were aPL positive, amongst them two triple positives. Nine out of ten retested LAC positive patients were negative on a second occasion, as well as the double positive patient. Seven patients were aPS/PT positive associated to LAC. Three patients were aCL and aβ2GPI IgA positive.
Our observations support the frequent single LAC positivity during (acute phase) observed in COVID-19 infection, however not clearly related to thrombotic complications. Triple aPL positivity and high aCL/aβ2GPI titers are rare. Repeat testing suggests aPL to be mostly transient. Further studies and international registration of aPL should improve understanding the role of aPL in thrombotic COVID-19 patients.