Table 1.

Parallelism between coronavirus disease 2019 (COVID-19) and antiphospholipid syndrome (APS) (summarized after (11).

Antiphospholipid syndrome	COVID-19
Altered APTT, elevated D-dimer	Abnormal coagulation parameters in 69%: prolonged PT and altered APTT, elevated D-dimer, elevated FDP
Vascular thrombosis (≥ 1 clinically documented arterial, venous, or small vessel thrombosis)	Thromboembolic events occurred at a cumulate rate of 21%
Pulmonary complications	Large vessel thrombosis Pulmonary intravascular coagulopathy
Complement activation	Deposition of complement components C5b-9, C4d, and MASP2 in the lung and skin microvasculature
Disturbed cytokine balance and cytokine storm in CAPS	Increased release of inflammatory cytokines characteristic of a cytokine storm
Persistent presence of aPL (LA, aCL, anti-β2GPI) (i.e., determined 2x at 12-week intervals)	Transiently elevated aPL values (LA 64%, aCL 9%, anti-β2-GPI 13%) during the acute phase of the disease

*APTT, activated partial thromboplastin time; PT, prothrombin time; FDP, fibrin degradation products.