Longitudinal assessment of gene-modified WBCs and HSPCs in the PB and BM. (A) Two pigtail macaques were transplanted with gene-modified HSPCs after myeloablative conditioning with total body irradiation. Animals were followed-up for up to 50 months through taking PB and BM draws to measure the gene marking in PB WBCs (top), PB lineages (middle), and BM-derived HSPCs (bottom). (B) Bulk PB WBCs were collected and DNA banked for ISA as indicated with gray symbols, whereas PB blood lineages (T cells: CD3⁺, B cells: CD20⁺, natural killer [NK] cells: CD16⁺, monocytes: CD14⁺, and granulocytes: CD11b⁺CD14^–) were FACS purified as indicated with black symbols. From the BM, CD34⁺ HSPCs were FACS purified and the DNA banked for ISA. (C) Summary of the animal characteristics, ISA sample collection, and analysis.