To investigate the impact of IKAROS on CD19 surface expression, we targeted IKAROS in B-ALL cell lines using two separate short hairpin RNA (shRNA) sequences (KD1 and KD2, Fig. 2A), or lenalidomide, a cereblon inhibitor that targets IKAROS for degradation26 (Fig. 2B), or a combination of both methods (KD1 with or without 10 μM lenalidomide, Fig. 2C). Here, IKZF1 is linked to acute lymphoblastic leukemia.