Mobilization and collection of peripheral blood stem cells in healthy donors: risks, adverse events and follow-up.

Allogeneic haematopoietic stem cell transplantation is the choice treatment for many haematological malignancies. Granulocyte-colony-stimulating factor (G-CSF) has been widely used to mobilize stem cells into the peripheral blood from healthy siblings or volunteer unrelated donors. To a large extent, the use of mobilized peripheral blood haematopoietic stem cells has replaced marrow-derived stem cells as the preferred source of donor haematopoietic stem cells. Clinicians have been aware since the first clinical use, that administration of G-CSF, even in a single short course, could possibly be a risk for healthy donors either in short-term or as a delayed effect. The immediate side effects of G-CSF have been established for a long time, most of them are frequent but transient, self-limited and without long-term consequences. Questions have been raised about potential long-term adverse effects such as an elevated risk of haematological malignancies after G-CSF administration. More long-term safety data from registries are needed to adequately evaluate such a relationship. Our objective in this article is to provide an in-depth review of reported adverse events associated with the use of G-CSF in healthy donors and to focus attention on unanswered questions related to their long-term follow-up.