--Disease Characteristics-- Severe chronic neutropenia (SCN), i.e.: Absolute neutrophil count less than 500/mm3 on 3 occasions within the last 3 months (less than 200/mm3 for cyclic neutropenia) Bone marrow aspirate consistent with SCN History of infection No drug induced neutropenia No myelodysplastic syndrome No aplastic anemia No thrombocytopenia or anemia unless due to Shwachman-Diamond syndrome or glycogen storage disease type IB Prior enrollment on Amgen SCN trials eligible Bone marrow aspiration within 1 year required Cytogenetic evaluation strongly suggested --Prior/Concurrent Therapy-- At least 5 years since prior chemotherapy --Patient Characteristics-- No rheumatoid arthritis No systemic lupus erythematosus No HIV seropositivity