CD38 antigen and bound antibody specifically decline following DARA treatment. (A-D) Bound DARA (ie, flow cytometry–based DAT) (A), CD38 antigen (B), Kell antigen (C), and Duffy antigen (D) before and after initial DARA administration (post, same day as administration; week 1, 1 week after initial administration; week 2, 2 weeks after initial administration). (E-H) Western blot analysis of the CD38 antigen (E), β-actin (F), Kell antigen (G), and Duffy antigen (H) before and after DARA administration (1, 1 week following initial administration; 3, 3 weeks following initial administration; 5, 5 weeks following initial administration). Each time point consists of 3 repeat runs of the same sample. Dotted line represents first DARA administration. Significance was determined in panels A-D by 1-way analysis of variance with Tukey post-test (***P ≤ .001).