Transwell transductions were done under standard conditions: 96-hour coculture of 2 × 10⁶ CD34+ peripheral blood progenitor cells (PBPC) with 1 × 10⁵ MDR virus producer cells in the presence of the indicated cytokines with or without stroma-conditioned medium (SCM). Transductions with cell-free viral supernatant were done in CH-296–coated wells for 48 hours after 48 hours of prestimulation. Mock transductions were performed in all experiments. In experiments with cells from patient samples 1 to 7, CD34+ PBPC aliquots from the same patient separately transduced under otherwise identical conditions were combined for assaying, whereas each transduced CD34+ PBPC aliquot from patient samples 8 to 10 was assayed individually. No colony-forming units granulocyte-monocyte (CFU-GM) from any mock transduction were found to be positive by polymerase chain reaction (PCR) for the transduced MDR1 gene.

Rh denotes rhodamine; NOD/SCID, nonobese diabetic/severe combined immunodeficient; FL, Flt3 ligand; SCF, stem-cell factor; VEGF, vascular endothelial growth factor; T, thrombopoietin; and NA, not available. Values are mean ± SE unless otherwise indicated.

For each sample, ≥18 CFU-GM colonies were analyzed.

Proportion of Rh-123^dull cells in the myelomonocytic progeny of transduced CD34+ PBPC minus background of Rh-123^dull cells in the progeny of mock-transduced CD34+ PBPC (range, 0.1%-1.0%).