Isatuximab and its F(ab)'2 fragments also induce (i) apoptosis of MM cells highly expressing CD38, through the activation of caspase 3 and 7, (ii) lysosome-dependent cell death by enlarging lysosomes and increasing permeabilization of lysosomal membrane, and (ii) upregulation of reactive oxygen species. Here, CD38 is linked to Miyoshi myopathy.