Patients are observed if their transient myeloproliferative disorder (TMD) does not require intervention. Patients who require therapy for TMD undergo leukapheresis or exchange transfusion for up to 3 consecutive days. If the TMD does not resolve or there is significant organ involvement, patients receive low-dose cytarabine IV continuously on days 0-4. Treatment repeats at least every 2 weeks for up to 4 courses. Patients who experience a recurrence of TMD at least 8 weeks after resolution or have refractory disease may proceed to group II for further treatment. patients will continue to be followed for remission induction, EFS, DFS and OS regardless of the type of leukemia that develops.