However, long-term maintained remissions are not achieved by most patients and relapse following therapy is frequently observed.179,180 The mechanisms of resistance to CAR-T cell therapy mainly include CAR failure (insufficient expansion or cytotoxicity), antigen modulation (downregulation, DNA mutation, or internalization), inhibitory regulation (elevations of CAR-Treg, anti-CAR-T antibody, or inflammatory cytokines).181–183 A recent study found that MM relapse following CAR-T therapy may relate to the trogocytosis and internalization or biallelic loss of BCMA.130,137,184. This evidence concerns the gene TNFRSF17 and Miyoshi myopathy.