After CAR T cell infusion, the immune interaction between CAR T and MM cells leads to CAR T cell activation and expansion, which subsequently causes massive cytokine production from CAR T cells, e.g., interferon-γ (IFN-γ), tumor necrosis factor α (TNF-α), and granulocyte/macrophage colony stimulating factor (GM-CSF) (77, 78). Here, TNF is linked to Miyoshi myopathy.