 RATIONALE: Drugs used in chemotherapy work in different ways to stop the growth of plasma cells, either by killing the cells or by stopping them from dividing. Having a peripheral stem cell transplant to replace the blood-forming cells destroyed by chemotherapy, allows higher dose of chemotherapy to be given so that more plasma cells are killed. Giving a chemoprotective drug such as amifostine may protect kidney cells from the side effects of chemotherapy. 