A decrease in antiphospholipid antibodies before a thrombotic event.

We are reporting a systemic lupus erythematosus patient with antiphospholipid syndrome who developed iliofemoral thrombosis. Before the occurrence of iliofemoral venous thrombosis, antiphospholipid antibodies (aPL) gradually decreased over a period of 18 weeks but were within normal range during its acute phase. In the course of two years following this case of thrombosis, aPL have never returned to the high prethrombotic values. It is therefore most likely that aPL were involved in the process of provoking thrombosis rather than being consumed during its acute phase.