Patient characteristics of autoHCT2 and alloHCT2 were not significantly different with respect to gender, stage, high/intermediate risk cytogenetics, immunoglobulin type, beta-2 microglobulin (B2M) at salvage HCT, HCT comorbidity index (CI), lines of chemotherapy before salvage HCT2, chemosensitivity before salvage HCT2, time from diagnosis of MM to autoHCT1, time from autoHCT1 to relapse, time from autoHCT1 to salvage HCT2, salvage HCT2 in first or greater relapse or use of maintenance therapy after HCT2. This evidence concerns the gene B2M and Miyoshi myopathy.