CD38 and plasma cell myeloma: To test this hypothesis, we used a method we recently developed termed “antigen escape profiling.”27 We used CRISPRi to transcriptionally repress CD38 in RPMI-8226, AMO-1, and KMS12-PE myeloma cell lines, using this genetic approach to partially mimic the loss of surface antigen seen after mAb therapy (Figure 4A).