PATIENT CHARACTERISTICS: Age: 15 to 59 Performance status: Not specified Life expectancy: Not specified Hematopoietic: No prior hematologic malignancy, myeloproliferative disorder, myelodysplastic syndrome, or paroxysmalnocturnal hemoglobinuria No unexplained cytopenias greater than 3 months in duration Hepatic: Not specified Renal: Not specified