Graft-vs-host disease (GVHD) prophylaxis consisting of single-drug low-dose, short- term cyclosporine- A (CSP) 3 mg/kg i.v. daily in two divided doses starting on day -4. Once the patients are mobile CSP will be administered orally. CSP dosage will be tapered during the second or third month post transplant, according to chimeric status and evidence of GVHD and then gradually stopped unless the patient will develop GVHD or graft failure. Immediately upon the appearance of signs and symptoms of GVHD, i.v. methylprednisolone (2 mg/kg) and CSP will be administered.