This study mainly evaluated the efficacy and safety of autologous stem cell transplantation for the treatment of AL amyloidosis, the role of induction and maintenance therapy in autologous stem cell transplantation, and the long-term efficacy and prognosis risk factors of autologous stem cell transplantation for the treatment of AL amyloidosis.

This study is divided into two parts. In the first part, the investigators retrospectively analyze the data of patients with AL amyloidosis who treated with autologous stem cell transplantation from July 2010 to December 2019. All patients had a biopsy-proven disease by positive Congo red stain with a concomitant demonstration of plasma cell dyscrasia. Organ involvement was established according to the criteria established at the 10th International Symposium on Amyloid and Amyloidosis. The protocol of ASCT included mobilization with colony-stimulating factor alone and conditioning with high-dose melphalan 140 or 200 mg/m2. In addition to analyzing the efficacy and safety of all the patients, the investigators also analyzed the difference in efficacy between patients in different subgroups. For example, subgroups divided according to different induction treatment regimens; subgroups divided according to different plasma cell FISH data and FCM data; subgroups divided according to the degree of organ involvement, and subgroups divided according to different maintenance treatment regimens.

In the second part of the study, the investigators will conduct a prospective study to explore the best autologous stem cell transplantation treatment protocol for AL amyloidosis. The protocol includes the induction therapy with bortezomib and daratumumab before ASCT, the maintenance treatment with lenalidomide after ASCT, and the treatment options for recurrence after transplantation.

Inclusion Criteria:

• Male or female;
• aged 18-75 years;
• Patients with newly diagnosed AL;
• Appropriate for autologous hematopoietic stem cell transplantation;
• Abnormal M protein or free light chain detected in serum and/or urine
• ECOG score 0-2 points;
• Subjects (or their legal representatives) must sign an informed consent document indicating understanding the purpose of and procedures required for the study and willingness to participate in the study.

Exclusion Criteria:

• Pregnant and breastfeeding women;
• Subjects suffering from multiple myeloma;
• hypersensitivity to any treatment drugs;
• Subjects have severe cardiovascular disease;
• Subjects have a serious physical disease and mental illnesses;
• Other conditions that researchers consider are not suitable for transplantation.

All patients had an amyloid disease, which was confirmed by biopsy and documented plasma cell dyscrasia; the AL amyloidosis diagnosis and the assessment of organ involvement were based on previous consensus criteria. All patients had received autologous stem cell transplantation.