Live and spleen at day 38 after transplantation.

The liver of untreated, age-matched MPS VII mice (A) showed lysosomal distention in Kupffer cells and a small amount of storage in hepatocytes. At day 38 after transplantation of normal macrophages (B), Kupffer cell storage was markedly reduced. However, reduction of storage in hepatocytes was less marked. The untreated MPS VII mouse spleen showed abundant lysosomal storage in sinus-lining cells in the red pulp (D). At day 38 after transplantation of normal macrophages, there was a similar marked reduction in the amount of lysosomal storage (E). Thirty-eight days after transplantation of genetically modified macrophages, histologic findings in the liver and spleen were similar to those of mice that received normal macrophages (C and F) (A-F, toluidine blue; original magnification × 200).