Donor evaluation, selection and hematopoietic stem cell mobilization, procurement, and manipulation

Abstract

Donor selection for HSCT is determined by eligibility, suitability, and availability. Donor eligibility is mandated by the regulatory requirements designed to minimize the risk of transmitting infectious diseases from the donor blood product to the HSCT recipient. In contrast, donor suitability is a clinical concept: It involves the incorporation of various factors unique to hematopoietic stem cell transplantation (HSCT), with histocompatibility between the donor and recipient the most important. While many suitable donors may be technically “ineligible,” HSCT may proceed with proper documentation. The most common scenario is for autologous donors, for whom disease transmission into a diseasenaïve donor is not an issue. Selection of a preferred donor must incorporate the availability of potential donors because HSCTs are often time sensitive. Hematopoietic stem cells (HSCs) can be harvested successfully from bone marrow, from umbilical cord blood (which is a rich source of HSCs), and from peripheral blood following cytokine stimulation +/- plerixafor. Each source has its unique set of advantages and drawbacks. Successful engraftment is dependent upon HSC dose which varies by HSC source. A minimum of 2-2.5 × 106 CD34+ cells/kg recipient weight is typically required for successful engraftment following bone marrow or peripheral stem cell transplantation. Minimal cell doses for umbilical cord blood are approximately tenfold lower (~2-2.5 × 107 total nucleated cells/kg recipient weight), which would typically contain ~2 × 10s CD34+ cells/kg recipient weight). Special processing may be required for some donor units; ABO incompatibility between the donor and recipient is one of the most common reasons for special processing. Cryopreservation can allow storage of HSC products for years or even decades. There are many reactions that can occur as a result of HSC infusions, and so careful observation and prompt intervention to treat any reactions are essential.