ANTICARDIOLIPIN AND ANTI-BETA(2)GLYCOPROTEIN-I IMMUNOASSAYS IN THE DIAGNOSIS OF ANTIPHOSPHOLIPID SYNDROME

Autoantibodies directed to phospholipids or to phospholipid binding pr oteins are now studied using a growing number of laboratory tests. How ever, the history of the interest in this area goes back to the identi fication of the so-called false positive reactions in the non-treponem al serological test for syphilis (STS) and to the subsequent descripti on of an in vitro coagulation defect called lupus anticoagulant (LAC). In the 1980s the introduction of the anticardiolipin antibody (aCL) i mmunoassay was a determining factor in the definition of the antiphosp holipid syndrome (APS). In addition, lupus prone mice spontaneously pr oducing aCL antibodies and normal mice passively infused with these an tibodies provided useful models for the study of the pathogenic role o f aPL. When in 1990 a phospholipid binding protein (beta(2)glycoprotei n I, beta(2)GPI) was identified as the cofactor required for aCL antib ody binding, the true antigenic target of the antibodies was first dis cussed. Soon afterwards an anti-beta(2)GPI ELISA was developed that ha s proved to be of great clinical significance. We will discuss here th e similarities and differences between these various assays (LAC, aCL, and anti-beta(2)GPI), focusing on their specificity, sensitivity and practical applications.