Progenitor cells as a bridging therapy for radiation casualties

Hematopoiesis is the process by which daughter cells of multipotential, self-renewing stem cells progress along differentiation pathways to become progressively more committed to specific lineages while losing their self-renewal capacity. Leucopenia and thrombocytopenia after ionising radiation exposure are due largely to injury to stem cells and progenitors in the hematopoietic tissue of the bone marrow; and in mice, the spleen. Recovery depends on the ability of the remaining stem cells and progenitors to proliferate and differentiate sufficiently to reconstitute the immune system before it is challenged by potential microorganisms and lethal infections occur. This mini review discusses various approaches to the mobilisation of progenitors and their utility as a bridging therapy for radiation casualties.