Biological true and false serological tests for syphilis: their relationship with anticardiolipin antibodies

Anticardiolipin antibodies (ACA) were determined by an ELISA assay in 142 VDRL-positive patients who were classified in two groups: group I consisted of 77 patients with syphilis and group II of 65 patients with biological false-positive reaction in the standard test for syphilis. In group I 10% had ACA versus 52% in group II (p less than 0.0001). Isotype distribution in group II showed a predominance of IgG. These results suggest that antiphospholipid antibodies in VDRL and ACA tests have different specificities.