Abstract
A wealth of evidence has surfaced in the last three years to challenge age-old notions of stem cell compartments in mammalian adult tissues. It was only recently realised that large cellular infusions in clinical practice might contain stem cells with flexible fate potential. This review discusses the current status of the occurence of epithelial chimerism after hematopoietic cell transplantation and presents existing data on detection methodology, characteristics, underlying mechanisms, physiological implications and clinical significance.