Hepatocytes of donor origin in recipient liver after hematopoietic SCT in β-thalassemia major patients

BM and circulating cells contain stem cells with the potential to differentiate into mature cells of various organs. We determined whether stem cells transformed into hepatocytes. Biopsy specimens from liver were obtained from 11 patients who had undergone transplantation of hematopoietic stem cells from peripheral blood (eight patients) or BM (three patients). Four female patients had received transplants from a male donor and seven male patients had received transplants from a female donor. All patients had β-thalassemia major and fibrosis in biopsy specimens from the liver before hematopoietic SCT. Hematopoietic stem cell engraftment was verified by STR analysis. The biopsies were studied for the presence of donor-derived hepatocytes using FISH of interphase nuclei and immunohistochemical staining for CD45 (leukocyte common Ag), and a hepatocyte-specific Ag. All 11 recipients of sex-mismatched transplants showed evidence of complete hematopoietic donor chimerism. XY-positive hepatocytes accounted for 4–6.7% of cells in histological sections of the biopsy specimens of female patients and XX-positive hepatocytes accounted for 3–7% of cells in histological sections of the biopsy specimens of male patients. These cells were detected in liver tissue as early as 1 year and as late as 8.5 years after hematopoietic SCT. BM and circulating stem cells can differentiate into mature hepatocytes in β-thalassemia major patients who had undergone hematopoietic SCT.