Performance status: ECOG 0-1 ECOG 2 allowed provided symptoms directly related to autoimmune disease Hepatic: No history of severe, prior or ongoing chronic liver disease Bilirubin less than 2.0 mg/dL AST less than 2 times upper limit of normal (ULN) Alkaline phosphatase less than 2 times ULN Renal: Creatinine less than 2.5 mg/dL OR Creatinine no greater than 2 times normal baseline for age in pediatric patients Cardiovascular: No symptoms of cardiac disease No active ischemic heart disease Ejection fraction greater than 45% by MUGA No uncontrolled hypertension Pulmonary: FEV1/FVC at least 60% OR Resting PO2 at least 80 mm Hg DLCO greater than 50% predicted O2 saturations greater than 94% in children unable to perform PFTs Neurologic: No active or ongoing ischemic or degenerative CNS disease not attributable to underlying disease Other: Not pregnant No poorly controlled diabetes HIV negative