Investigation of the risk of thrombosis in anti-phospholipid syndrome using enzyme-linked immunosorbent assay (ELISA)

Abstract

Anti-phospholipid antibodies (aPLs) are heterogeneous autoantibodies that can be identified by enzyme-linked immunosorbent assay (ELISA), particularly anti-cardiolipin antibodies (aCL), anti-cardiolipin/β₂-glycoprotein I antibodies (aCL/β₂GPI), anti-phosphatidylserine antibodies (aPS), and anti-phosphatidylserine/prothrombin antibodies (aPS/PT). These aPLs are frequently found in the plasma of patients with systemic lupus erythematosus (SLE) and have been reported to be associated with clinical events such as arterial and venous thromboses and recurrent fetal loss. Although several aPL-ELISA techniques were established for the diagnosis of anti-phospholipid syndrome (APS), the clinical importance of these ELISA techniques has not yet been determined. In an effort to clarify the clinical significance of aPLs detected by various ELISA techniques, we examined the concentrations of aCL, aCL/β₂GPI, aPS, and aPS/PT in 184 patients with SLE (32 patients with arterial thrombosis, 39 patients with venous thrombosis, and 113 patients without thrombosis). The present study showed that aCL/β₂GPI and aPS/PT detected by specific ELISA techniques could serve as markers of arterial and venous thromboses in patients with SLE, whereas aCL and aPS are less reliable as markers of these complications. Furthermore, we found that the incidences of arterial and venous thromboses were extremely high in patients who had both aCL/β₂GPI and aPS/PT. The occurrence of recurrent thrombotic complications in SLE apparently depends on variable combinations of these types of aPLs. Therefore, it is essential to analyze the spectrum of aPLs types using ELISA in the diagnosis of APS.