Antiphospholipid Antibodies

A 39-year-old man with a history of ischemic stroke presented with right calf swelling and shortness of breath and was diagnosed with pulmonary embolism by CTPA. Testing 2 days later showed elevated titers of anticardiolipin and anti–β2 glycoprotein I antibodies and negative lupus anticoagulant screening assays. How would you interpret these results?