Autologous Bone Marrow Transplantation - Blog Science Connections

616 Peripheral Stem Cell Transplantation
"normal" stem cells act the same way. In 1980, we in the Oncology Center of
the Johns Hopkins Hospital in Baltimore collected blood stem cells during a
transient chemotherapeutically induced Ph 1 -negative phase. The retransfusion
of those "normal" stem cells into the patient after myeloablative
treatment resulted in complete hematopoietic reconstitution without reappearance
of the Ph 1 -positive cell clone, but the follow-up was too short to
evaluate the reconstitutive potential of those transfused stem cells on a
long-term basis (8).
There are reports of autologous blood stem cell transplantation (ABSCT)
performed as an alternative to bone marrow transplantation in patients with
malignant lymphohematopoietic disorders other than CML or with solid
tumors (9-20; see also Reiffers et al. "Autologous Transplantation of
Circulating Stem Cells in Acute Nonlymphocytic Leukemia," this volume).
These provide clear evidence that hematopoietic engraftment can be
achieved with human stem cells collected from the circulating blood rather
than from the marrow site. In this chapter we describe the reconstitutive
potential of blood-derived hematopoietic stem cells in patients with malignant
lymphohematopoietic disorders and discuss ways of mobilizing stem cells
into the peripheral blood in order to optimize the stem cell-collection
procedure.
METHODS
Stem Cell Harvest
Peripheral blood stem cells were collected by "stem cell apheresis,"
using a continuous-flow blood-cell separator (Fenwal CS-3000, Fenwal
Laboratories, Deerf ield, IL). The total blood volume processed per run was 10
liters at a flow rate of 50-70 ml/minute. Centrifuge speed was 1000-1600
rpm. Anticoagulants added were 5000 0 of heparin as a bolus at the start of
apheresis, anticoagulant-citrate-dextrose-A (ACD-A) by continuous infusion
(500 ml per run), and 5000 CJ of heparin injected into the cell-collection bag at
the completion of apheresis. The interval between stem cell harvests was
between 1 and 3 days (21). To optimize the stem cell yield, stem cell
aphérèses were performed in most cases after transient myelosuppression,
during the subsequent expansion of the circulating blood stem cell pool.
To collect a mononuclear cell product with low RBC contamination we
employed procedure number 1 (platelets) of the Fenwal system, using the 35
Collection Chamber and the Granulo-Separation Chamber. The basic
computer program was modified dependent on the blood flow rate (L-68 was
changed to 0750), not on the patient's hematocrit, and the secondary spin
procedure that removes the platelets from the collected mononuclear cells
was omitted to minimize possible cell loss.