Association of primary antiphospholipid syndrome with inherited activated protein C resistance.

A 65-year-old man had had arterial thromboses of the lower limbs and cerebral region for several years; tests revealed anticardiolipin, antiphosphatidylserine, anti-beta2-glycoprotein I antibodies, and lupus anticoagulant. As well, both phenotypic and genotypic resistance to activated protein C was found. Antiphospholipid antibodies have been reported to interfere in different ways with the functions of protein C; in our patient the simultaneous existence of inherited resistance to activated protein C could account for the thrombophilic status underlying the diffuse and serious arterial thromboses.