ADVANTAGE OF USING BOTH ANIONIC AND ZWITTERIONIC PHOSPHOLIPID ANTIGENS FOR THE DETECTION OF ANTIPHOSPHOLIPID ANTIBODIES

To investigate the benefit of assaying for antiphospholipid antibodies (aPA) with different antigenic specificities, sera from 141 patients suspected of having aPA were tested by ELISA for IgG and IgM antibodie s directed against the following phospholipids (PL) coated individuall y or together: cardiolipin, phosphatidylinositol, phosphatidylserine a nd phosphatidylethanolamine. Nonspecific background optical density (O D) was systematically subtracted from the test OD value. Positive reac tions were defined as having an OD greater than the 97th percentile OD distribution obtained with sera from 100 healthy individuals. Althoug h the majority of the 79 detected aPA (89% Ige and 77% IgM) were polys pecific, 11 reacted with a single PL and, moreover, belonged to only o ne isotype. Seven of these 11 patients presented recurrent fetal losse s or thrombotic events. These results suggest that routine use of a mi xture of both anionic and zwitterionic PL antigens to coat ELISA plate s would better detect aPA involved in suggestive pathologies and enhan ce the ability to identify patients with these mono- or polyspecific a ntibodies directed or not against cardiolipin, the current standard.