Fig. 4: UCART123 killed primary AML selectively in co-engrafted model with human normal hematopoiesis and human AML.

a Schematic representation for the competitive BM and AML model. Normal CD34⁺ bone marrow cells (nBM) (6 × 10⁶ cells, HLA-A2-) were co-injected with T-cell depleted human AML cells (2.5 × 10⁵ cells, HLA-A2⁺) into sub-lethally irradiated NSG mice. After 7 weeks, mice were treated with PBS, 1 × 10⁶ UCART123 or 1 × 10⁶ TCRαβ KO T-cells. Normal hematopoietic cells and leukemia cells in PB and BM were monitored with flow cytometry starting on day 2 and later every 1–2 weeks. b Human cells gated with mouse CD45 versus human CD45 (left) were evaluated for CD123 expression level after normal cells (HLA-A2⁻, blue rectangle) and leukemic cells (HLA-A2⁺ , red rectangle) were distinguished (right). Leukemic cells express higher CD123 levels than normal cells and were preferentially eliminated by UCART123 (right bottom). c Normal cells and leukemic cells were tracked in PB by flow cytometry starting on day 2 and at indicated timepoints. Leukemic cells outcompeted normal cells over time in PBS and TCRαβ KO cohorts; cohort size: n = 5 PBS, n = 8 TCRαβ KO, n = 10 UCART123. d Normal cells and leukemic cells were evaluated in BM on day 36 post treatment. PBS (n = 5) and TCRαβ KO (n = 8) cohorts showed progression of leukemia, while UCART123 (n = 10) treated mice did not (top). Evaluation of subsets in BM showed 2-fold decrease in CD33⁺ myeloid cells in UCART123-treated mice, while lymphoid lineages were not impacted. Each symbol represents a mouse and bar represents the mean with the SD. ***p < 0.001, *p < 0.05, one-way ANOVA. Source data are provided as a Source Data file.