Longitudinal analysis of T-cell development and persistence of gene marking in different blood cell lineages. (A) Absolute numbers of gene-corrected (GFP⁺) T cells for all 4 dogs treated. The normal absolute number of peripheral T cells in age-matched unaffected dogs is greater than 750/μL. (B) Proportion of gene-corrected (GFP⁺) T cells (•), B cells (▴), monocytes (▪), and granulocytes (○) in dog 1547 (solid lines) and dog 1655 (broken lines).