PATIENT CHARACTERISTICS: Age: 16 to 55 Performance status: Not specified Life expectancy: Greater than 60 days Hematopoietic: Not applicable Hepatic: Bilirubin less than 1.5 mg/dl No risk of developing veno-occlusive disease of the liver (i.e., current evidence of hepatitis as manifested by SGOT greater than 1.5 x ULN) Renal: Creatinine less than 2.0 mg/dl Other: No HIV seropositivity No major infection