DISEASE CHARACTERISTICS: Diagnosis of idiopathic myelofibrosis or other myeloproliferative disorder with myelofibrosis Evidence of advanced disease or hematologic abnormalities due to severe fibrosis such as 1 or more of the following poor prognostic factors: Hemoglobin less than 10 g/dL Platelet count less than 100,000/mm3 WBC less than 4,000/mm3 Symptomatic splenomegaly Constitutional symptoms inadequately controlled with low dose chemotherapy Abnormal karyotype Patients without evidence of advanced disease undergo PBSC harvest and transplantation is delayed until there is evidence of disease progression Leukemia progression (greater than 15% peripheral blood blasts) allowed if the history of a chronic myeloproliferative disorder of at least 6 months duration is well documented Ineligible for or refusal of allogeneic transplantation No other cause of myelofibrosis other than myeloproliferative disorders, such as the following: Metastatic carcinoma Lymphoma Hairy cell leukemia Myelodysplastic syndrome De novo acute leukemia Collagen vascular disorders Granulomatous infections