Abstract
The high correlation between the IgG isotype of anticardiolipin antibodies (aCLs) and clinical thrombosis was first documented in 1983, and this observation was confirmed in subsequent studies. In addition, the frequency of fetal loss and thrombocytopenia was increased in this group of patients. These findings led in 1986 to recognition of the so-called anticardiolipin syndrome, later termed the antiphospholipid syndrome (APS) . This syndrome was seen mostly in patients with systemic lupus erythematosus (SLE), but it soon became clear other patients not suffering from defined SLE might exhibit features of APS.
aCL found in APS patients are detected in immunoassays using solid phase cardiolipin as a putative antigen. However, antibodies directed against phospholipid-binding plasma or serum proteins, in particular, β2-glycoprotein I (β2 GPI), are also detected. Many recent studies indicated that one of predominant antibodies have been realized as aCL in APS patients are against β2 GPI rather than any of negatively charged phospholipids. We reported that the epitopes recognized by anti-β 2 GPI antibodies raised in APS patients are composed of discontinuous amino acid sequences from the IV domain of human β2 GPI. These epitopes are crvntic when β2 GPI is not interacted with anionic nhosnholmids.
An early event in atherosclerosis is the accumulation of cholesterol-laden foam cells, which originate mainly from monocyte-macrophage cells, by their uptake of chemically modified LDL. We found that β2 GPI directly binds to oxLDL and that the complex of oxLDL and β2 GPI is subsequently recognized by aCL (anti-β2 GPI) to be taken up by macrophages.
Antibodies against phosphatidylserine-prothrombin complex (aPS/PT) are closely associated with APS and lupus anticoagulant. aPS/PT can be one of the strong markers of APS as well as aCL (anti-β2 GPI), considering the correlation between aPS/PT and APS with very high specificity. We proposed that aPS/PT should be performed in conjunction with the other aPL detections to improve the likelihood of recognizing APS, ultimately ameliorating the management for the affected patients.
International consensus statement on classification criteria for APS and the standard therapeutic strategy for this syndrome are also described in this review.
