Page 1707 - Hematology_ Basic Principles and Practice ( PDFDrive )

C H A P T E R 95

PRACTICAL ASPECTS OF HEMATOLOGIC STEM CELL

HARVESTING AND MOBILIZATION

Scott D. Rowley and Michele L. Donato

Hematopoietic stem cell (HSC) products for autologous or allogeneic UCB from public banks has the advantage of being immediately
transplantation are available from bone marrow, peripheral blood, or available, reducing the time to transplantation. Targeting collection
umbilical cord blood (UCB) sources. Bone marrow was the original of UCB products from ethnic populations not well represented in
source of cells for transplantation because of the ease and reliability donor registries will facilitate treatment of ethnic minority patients.
of collecting adequate numbers of cells for transplantation, and it The relative immunologic naïveté of the cord blood donor allows use
remains the standard with which other sources of HSCs are of HLA-mismatched products without an undue increase in GVHD
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compared. risk. The much smaller quantity of HSCs in the cord blood product
Peripheral blood stem cell (PBSC) products have virtually replaced results in slower hematologic recovery and a higher risk for primary
bone marrow as the HSC component for autologous transplantation engraftment failure, which may be partially offset by infusion of
and are frequently used for allogeneic transplantation. Virtually multiple products, and the older adult patient, in particular, may also
all patients undergoing autologous HSC transplantation will have be at greater risk for posttransplant infections because of the relative
PBSCs as the source of HSCs, based on the advantages of ease immature immune system of the donor.
of scheduling of collections, greater quantities of HSCs resulting
in faster hematologic recovery and shorter and less costly hospital
1–6
stays, and potentially lower risks for tumor cell contamination SELECTION AND EVALUATION OF
of the graft. The rapid engraftment kinetics of PBSCs compared THE STEM CELL DONOR
with bone marrow is widely recognized. Median times to achieve
an absolute neutrophil count greater than 500/µL and platelet Selection of the Stem Cell Donor
transfusion independence after PBSC transplantation typically are
approximately 11 to 14 days. The allogeneic donor has a wide range The primary selection criterion for the patient undergoing autologous
of options, including marrow, PBSC, or UCB products from human HSC collection and transplantation is the diagnosis of an illness
leukocyte antigen (HLA)-compatible or partially compatible related amenable to treatment with a dose-intense regimen requiring HSC
or unrelated donors. The availability of HLA-matched related or support. Extensive prior treatments, especially with marrow-toxic
unrelated donors is the primary consideration in the selection of a chemotherapy regimens or with radiotherapy, may prohibit collection
donor, but donor health or donation preferences may restrict what of adequate quantities of autologous HSCs, which would exclude a
products will be available to the recipient. The patient’s physician patient from this treatment option. Proper management of patients
may select a stem cell source based on the expected transplant out- with a disease amenable to dose-intensive therapy should include
comes. PBSC products, for example, have the greatest quantity of provisions for HSC collection before extensive marrow-toxic agents
HSCs and will result in faster hematologic recovery compared with are administered. In general, however, any serious comorbid illnesses
marrow or UCB transplants. Bone marrow transplantation has a that would preclude either marrow or PBSC collection would also
higher risk of graft failure, resulting in a twofold higher probability disqualify the patient from treatment with dose-intensive regimens
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of second harvest request compared with PBSC donation. In some used in preparation for autologous HSC transplantation.
reports, PBSC transplantation also results in a survival advantage. The selection of the allogeneic HSC donor is more complex. The
However, PBSC transplantation is associated with a higher risk for HLA major histocompatibility complex is the primary consideration
difficult-to-control chronic graft-versus-host disease (GVHD) and in selection of a donor for allogeneic HSC transplantation, since its
may not be appropriate for use in patients who would not benefit loci contribute significantly to host-versus-graft (leading to immuno-
from a robust graft-versus-leukemia effect, such as those treated for logic rejection of donor HSCs) and to graft-versus-host (leading to
nonmalignant diseases. The transplant recipient may request a source GVHD and graft-versus-leukemia) reactions. 17,18 Donor age, gender,
of cells, but the donor has the right to decide about the method and parity are secondary considerations in the selection of an alloge-
of donation. Although GVHD prophylaxis with posttransplant neic HSC donor. 18,19 Mismatching for killer-cell immunoglobulin-
methotrexate will slow engraftment, the kinetics of engraftment for like receptor ligands may reduce the risk for posttransplant relapse of
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the allogeneic PBSC recipient is similar to that experienced by the disease. More than 30% of allogeneic HSC transplants from related
autologous PBSC recipient. A number of phase III studies involving or unrelated donors will involve ABO-disparate donors and recipi-
either autologous or allogeneic HSC transplantation confirmed the ents, and donor and recipient pairs may also differ for other red blood
more rapid engraftment kinetics for recipients of PBSCs, 8–11 and cell antigens, with no clear evidence of deleterious effect on engraft-
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this effect is not limited to HSCs collected from the peripheral ment, survival, or GVHD. Cancer, autoimmune disorders, and
blood, because cytokine administration to the patient or donor before genetic diseases such as the hemoglobinopathies can be transmitted
marrow harvesting will also increase the number of HSCs collected to the allograft recipient; thus, donor health is an important consid-
and result in quicker hematologic recovery. 12–14 The disadvantages to eration in donor selection and determination of donor eligibility.
use of PBSC components compared with bone marrow or UCB for
autologous or allogeneic transplantation include the possible need for
multiple days of collection (especially for autologous transplantation), Evaluation of Hematopoietic Stem Cell Donor
the inability to collect adequate components from all patients and Suitability and Eligibility
donors, and a possibly higher risk for chronic GVHD or the occur-
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rence of chronic GVHD that is more difficult to control (see box The immediate precollection evaluation of a patient or donor is
on Choice of Hematologic Stem Cell Product for Transplantation). intended to address the risks of the collection procedure to the donor

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