Anti-phospholipid antibody profiles of different specificities in syphilis and systemic lupus erythematosus

Controversies exist as to the differences in the specificities of phospholipid antibodies in SLE and syphilis. We report an ELISA assay that could distinguish phospholipid antibodies associated with SLE and syphilis based on their differential reactions with phosphatidyl choline and VDRL antigens. Antibodies to phospholipid from patients with SLE reacted equally well when tested with these two antigens in the ELISA assay whereas phospholipid antibodies present in syphilis patients exhibited little or no binding to phosphatidyl choline. There were no differences in the binding of phospholipid antibodies to other phospholipids such as cardiolipin and phosphatidyl serine. In addition, there was no association of anti-phospholipid antibodies with the presence of either DNA or RPR antibodies suggesting their distinctness from each other.