iC9-T-cell engraftment and in vivo allodepletion by dimerizer drug. Counts of T-cell subsets in 4 patients who received AP1903. CD3⁺CD19⁺ T cells (A, Pt. 6; B, Pt. 8; C, Pt. 9; D, Pt. 12) and CD3⁺CD19⁻ T cells (E, Pt. 6; F, Pt. 8; G, Pt. 9; H, Pt. 12). ●, □, and ▲ represent the CD3⁺, CD4⁺, and CD8⁺ subtypes, respectively. (I) The copy number of the iC9 transgene per microgram of DNA extracted from PBMC, evaluated by Q-PCR. Arrow indicates the time at which the patient was treated with AP1903. Pt., patient.