Chlorpromazine-induced anticardiolipin antibodies and lupus anticoagulant: absence of thrombosis.

Anticardiolipin antibodies were determined in 96 psychiatric patients treated chronically with chlorpromazine by an enzyme-linked immunosorbent assay using anti-IgM and anti-IgG (fab'2 fragment) as the second antibody. Fifty-four of these patients had an IgM-lupus anticoagulant, and the remaining 42 were followed as controls. Elevated IgM-anticardiolipin antibodies (ACA) levels were detected in 31 patients with the lupus anticoagulant and in 5 controls (p less than 0.001). During a median followup of 5 years, single episodes of deep vein thrombosis or pulmonary embolism occurred in three patients; one had the lupus anticoagulant and the other two had low-level ACA. Contrary to the reported experience in systemic lupus erythematosus and related autoimmune disorders, chlorpromazine-induced lupus anticoagulant and anticardiolipin antibodies levels appear not to be associated with an increased incidence of thrombosis.