CD38 and Miyoshi myopathy: Therefore, the main benefit of being able to control the high affinity CD38-CAR T cells could be the possibility to use them—as they can recognize lower levels of CD38 expression—in situations where CD38 expression on MM cells is strongly downregulated, such as in the case of post CD38-antibody (e.g. Daratumumab) treatments[34], and as a potential risk when using affinity-optimized CD38-CAR T cells.