--Disease Characteristics-- Mild or moderate generalized myasthenia gravis Grade 2 or 3 myasthenia gravis according to a modified Osserman groups system Ocular myasthenia gravis alone or myasthenia gravis in crisis not eligible Must have elevated acetylcholine receptor antibody titer No evidence of thymoma on chest CT or MRI No immunoglobulin-A deficiency less than 5 mg/dL Group 1: Patients who have not received other immunosuppressive therapy in the past, including intravenous immunoglobulin Group 2: Patients considered steroid-dependent