Abatacept in the Treatment and Prevention of Active Systemic Lupus Erythematosus (SLE) Flares in Combination With Prednisone

The purpose of this clinical research study is to learn whether Abatacept can treat and prevent lupus flares; specifically, in patients with active lupus flares in at least one of three organ systems: skin (discoid lesions); inflammation of the lining of the heart (pericarditis), or inflammation of the lining of the lung (pleuritis/pleurisy); or inflammation of more than 4 joints (arthritis). All participants will receive prednisone or prednisone-equivalent treatment in combination with study medication. The safety of this treatment will also be studied.