Fusion of circulating blood cells with solid-organ tissue cells in clinical stem cell transplants: a potential therapeutic model?

AIM: In female patients who have undergone sex-mismatched peripheral blood stem cell transplantation, solid-organ tissue cells have been identified that carry the Y-chromosome. How genetic material from circulating cells is acquired by solid-organ tissue cells is debated. The purpose of this study was to provide clinical evidence for cell fusion between circulating cells and solid-organ tissue cells. MATERIAL & METHODS: The clinical model was a male-into-female blood stem cell transplantation setting using the Y-chromosome as a blood-derived cell marker and the patient's BCR/ABL fusion gene. Endometrial cells were chosen as the target cells because of their uniquely female genotype. RESULTS: The Y-chromosome and the BCR/ABL fusion gene were identified by fluorescence in situ hybridization and were colocalized with estrogen receptor-staining endometrial cells. Both donor-derived Y-chromosome and patient-derived fusion gene were identified in the same endometrial cells, thereby indicating cell fusion as the mechanism for genetic material transfer in a clinical setting. CONCLUSION: These findings contribute to our understanding of how blood-derived cells interact with solid-organ tissue cells.