Human hepatocytes generated in vivo from the human hematopoietic stem cells are functional. (A-B) Low (A) and high (B) magnification of sections of livers from control (no transplantation) sheep stained with an antibody specific for human albumin. (C-D) Low (C) and high (D) magnification of a section from sheep liver given transplanted BM CD34⁺Lin^– cells that had the highest amount of human albumin in serum. Human hepatocytes can be identified by the light brown coloration.