Fludarabine will be given as a daily IV (intravenous, by vein) infusion for a total of 5 days. CAMPATH-1H will be given as a daily 4-hour IV (intravenous, by vein) infusion for three days. Anti-CD45 will be given as a daily 6-hour IV infusion over the next 4 days. Then patients will have a one-day rest period before receiving the stem cell transplant. To help prevent the body from rejecting the transplant, patients will also receive the drug FK506, starting two days before the transplant and continuing for three months. If there is no GVHD, the amount of FK506 patients are taking will be reduced by 20% every 2 weeks until this medication is stopped.
