Thrombosis and antiphospholipid antibodies in Japanese COVID-19: based on propensity score matching.

Background: Thrombosis is a unique complication of coronavirus disease 2019 (COVID-19). Although antiphospholipid antibodies (aPL) are detected in COVID-19 patients, their clinical significance remains elusive. We evaluated the prevalence of aPL and serum concentrations of beta-2 glycoprotein I (β2GPI), a major self-antigen for aPL, in Japanese COVID-19 patients with and without thrombosis.

Determination of diagnostic threshold in harmonization and comparison of clinical utility for five major antiphospholipid antibody assays used in Japan.

Background: Anticardiolipin antibodies (aCL) and anti-β -glycoprotein I antibodies (aβ GPI) are essential in diagnosing antiphospholipid syndrome (APS) according to the international APS guideline. Five commercial assays for aCL and aβ GPI are available in Japan, but their test results are quite discordant. For harmonization of diagnosing APS, upper reference limit (URL) and diagnostic accuracy of each assay were evaluated and compared by testing common sets of specimens across all assays.

aCL/βGPI and aPS/PT show synergic thrombogenic effects in suppressing anticoagulant activity of APC and stimulating tissue factor expression and TNF-α secretion by mononuclear cells.

Introduction: Patients with systemic lupus erythematosus (SLE) possessing anti-phospholipid antibodies (aPLs) are often complicated by thrombotic vascular events. aPLs commonly associated with the complications are anti-cardiolipin/β-glycoprotein I antibodies (aCL/βGPI) and anti-phosphatidylserine/prothrombin antibodies (aPS/PT). However, the pathological mechanisms leading to thrombosis remain unclear.