Tandem Autologous Stem Cell Transplantation in Treating Patients With Primary Systemic (AL) Amyloidosis

Inclusion Criteria: DISEASE CHARACTERISTICS: * Histologically confirmed AL amyloidosis, meeting 1 of the following criteria: * Plasma cell dyscrasia, evidenced by 1 of the following: * Monoclonal protein in the serum or urine by immunofixation electrophoresis * Plasmacytosis of the bone marrow with monoclonal staining for kappa or lambda light chain isotype * Macroglossia with at least 1 other site having biopsy proven amyloidosis and absence of a mutant transthyretin is ruled out PATIENT CHARACTERISTICS: Age * 18 to 65 Performance status * SWOG 0-2 Life expectancy * At least 1 year Hematopoietic * Not specified Hepatic * Not specified Renal * Not specified Cardiovascular * LVEF ≥ 45% by MUGA or echocardiogram Pulmonary * DLCO ≥ 50% Other * Not pregnant or nursing * Fertile patients must use effective contraception * Able to tolerate 2 courses of high-dose therapy * HIV negative PRIOR CONCURRENT THERAPY: Biologic therapy * Not specified Chemotherapy * Prior alkylating agent chemotherapy allowed provided there is no morphologic or cytogenetic evidence of myelodysplastic syndromes * Prior total cumulative oral melphalan dose \< 300 mg Endocrine therapy * Not specified Radiotherapy * Not specified Surgery * Not specified Other * At least 4 weeks since prior cytotoxic therapy and recovered Exclusion Criteria: * No senile, secondary, localized, dialysis-related, or familial amyloidosis * No overt multiple myeloma (e.g., greater tha…