Abstract
PURPOSE OF REVIEW: Haematopoietic stem cells (HSCs) are characterized by two key features: self-renewal ability and multilineage differentiation potential. Through these cellular activities, HSCs sustain blood and immune system homeostasis throughout life and can also reconstitute the entire haematopoietic system within a bone marrow ablated recipient. This approach of HSC transplantation is used clinically as a curative treatment option for numerous haematological diseases, both malignant and nonmalignant. RECENT FINDINGS: Elucidation of the mechanism of HSC expansion represents a major focus within haematology. Here, we review the recent progress towards understanding HSC expansion in vivo and ex vivo, including a discussion of recent clonal transplantation assays and the development of novel ex vivo culture systems. SUMMARY: Recent findings provide exciting promise for improving the safety and efficacy of current HSC-based therapies as well as for the development of new therapeutic paradigms.