Addition of plerixafor for CD34+ cell mobilization in six healthy stem cell donors ensured satisfactory grafts for transplantation.

In allogeneic hematopoietic stem cell (HSC) transplantation, collection of a sufficient number of HSCs at a fixed time point is crucial. For HSC mobilization into the peripheral blood, the standard regimen, that is, granulocyte-colony-stimulating factor (G-CSF), may be inadequate. Use of plerixafor as adjuvant to G-CSF is so far off-label in healthy donors. We present six cases in which the "just-in-time" addition of plerixafor ensured proper CD34+ collection from healthy donors with insufficient G-CSF mobilization. In four of these cases a high number of CD34+ cells was needed due to subsequent CD34+ selection or haploidentical transplantation. From all six donors a sufficient number of CD34+ cells was obtained by using plerixafor as an adjuvant to G-CSF. This treatment regimen resulted in only mild side effects for the donor. We have presented six cases with different causes leading to insufficient G-CSF mobilization in allogeneic donors and in which the administration of plerixafor just-in-time ensured a proper graft for transplantation.