 IMMUNOSUPPRESSION: Patients with a matched related donor receive cyclosporine IV or orally PO twice daily BID on days -3 to 56 followed by a taper to day 180 in the absence of graft-versus-host disease. Beginning 4-6 hours after PBSC transplant, these patients also receive mycophenolate mofetil PO BID on days 0 to 27. Patients with a matched unrelated donor receive cyclosporine IV or PO BID on days -3 to 100 followed by a taper to day 180. Beginning 4-6 hours after PBSC transplant, these patients also receive mycophenolate mofetil PO thrice daily TID on days 0 to 40 followed by a taper to day 96. 