Rituximab Immunotherapy for the Antiphospholipid Syndrome.

The antiphospholipid syndrome (APS) is a heterogeneous disease expressed in a variety of ways, including thromboembolic disease. Therapy for this phase of APS is primarily anticoagulation. When the disease is aggressive and resistant to anticoagulants immunotherpay has been applied with variable success. Steroids, cyclophosphamide, plasma exchange, plasmapheresis, and immunoglobulin infusion have been used. This is a report of a patient with very aggressive APS treated successfully with rituximab immunotherapy. This 60 year old female had four episodes of deep vein thrombosis and two episodes of pulmonary embolus. An inferior vena cava filter had been placed. She came to hematologic attention in 2001, when the APS diagnosis was established based upon positive lupus anticoagulant and antibodies to cardiolipin and phosphatidyl serine. Long term steroid therapy was considered potentially too toxic. Azathioprine therapy was initiated at 100 mg daily and then increased to 150 mg daily without reduction of antibody titers. Thereafter she developed thrombosis in-situ in the pulmonary artery, requiring surgical thrombectomy. Therapy with rituximab was begun at 375 mg/m² weekly times four, with repeat infusions every 6 months. Infusions were well tolerated. Warfarin therapy was continued throughout. Antibody titers have fallen.

There have been no further episodes of TED. Therapy with rituximab has been well tolarted and appears to be effective. Therapy is continuing with additional antibody titers to be obtained.