2nd Autologous Stem Cell Transplant in Patients With Persistent/Recurrent (AL) Amyloidosis

Inclusion criteria: DISEASE CHARACTERISTICS: * Histologically confirmed AL amyloidosis * Persistent or recurrent disease after 1 course of prior high-dose chemotherapy * Previously treated with autologous stem cell transplantation * Significant initial improvement in organ function after prior high-dose melphalan, defined by at least 1 of the following: * Complete hematologic remission (e.g., absence of monoclonal spike by immunofixation in serum and urine AND less then 5% plasma cells in bone marrow with no clonal predominance) OR partial hematologic response (e.g., any decrease in serum or urine monoclonal protein OR decrease in bone marrow plasmacytosis) * Greater than 50% reduction in proteinuria with preservation of creatinine clearance * Greater than 50% reduction in alkaline phosphatase OR at least 2 cm decrease in liver size by physical exam * Subjective neurologic improvement, as confirmed by neurologist * Cardiac stabilization of disease confirmed by echocardiography defined as less than 2 mm increase in mean wall thickness and/or less than 20 g increase in left ventricular mass * Improvement in performance status\* NOTE: \*This criteria alone does not constitute significant improvement in organ function * Prior stem cell yield must have been ≥ 2 x 10\^6 CD34+ cells/kg PRIOR CONCURRENT THERAPY: Biologic therapy * See Disease Characteristics Chemotherapy * See Disease Characteristics * No chemotherapy after first transplantation Endocrine therapy * Not specified Radiotherapy * Not specified Surgery * Not specified PATIENT CHARACTERISTICS: Age * 18 to 65 Performance status * Southwest Oncology Group- 0-2 Life expectancy * More than 6 months Hematopoietic * See Disease Characteristics Hepatic * See Disease Characteristics Renal * See Disease Characteristics Cardiovascular * See Disease Characteristics * Left ventricular ejection fraction ≥ 45% by multiple gated acquisition scan or echocardiogram Pulmonary * diffusing capacity of lung for carbon monoxide ≥ 50% Exclusion Criteria: * No myelodysplastic syndromes * No abnormal bone marrow cytogenetics Other * Not pregnant or nursing * Fertile patients must use effective contraception * Acceptable toxicity from first transplantation, confirmed by the transplant team * HIV negative * No other concurrent malignancy except treated skin cancer