Histochemical staining for GUSB revealed positive cells in many tissues throughout NOD/SCID/MPSVII mice that received transplants of human CD34⁺ cells.

Tissues from a single NOD/SCID/MPSVII mouse 12 weeks following the transplantation of human CD34⁺ cells from cord blood are shown stained for GUSB activity (red color) and counterstained with methyl green (blue-green color). The bone marrow (A) and spleen (B) contained high levels of positive cells that correlated with a flow cytometric measurement of human CD45 expression (87% human CD45⁺ in the bone marrow and 61% human CD45⁺in the spleen). Groups of GUSB⁺ cells were visible throughout the lymph node (C), whereas scattered GUSB⁺cells were evident in the thymus (D). The liver (E) was uniformly infiltrated with GUSB⁺ cells, and the kidney (F) and lung (G) contained a less dense pattern of positive cells. GUSB staining was also seen in scattered cells in the heart (H), at regular intervals in the meninges (I), and in association with the pigment epithelial layer of the retina (J). Original magnification, × 250.