Administrative Office
St. Joseph's Hospital Site, L301-10
50 Charlton Avenue East
HAMILTON, Ontario, CANADA L8N 4A6
PHONE: (905) 521-6141
FAX: (905) 521-6142
http://www.fhs.mcmaster.ca/hrlmp/
Issue No. 55
QUARTERLY NEWSLETTER
February, 2001
BONE MARROW / PERIPHERAL BLOOD PROGENITOR CELL TRANSPLANT
Allogeneic bone marrow transplant, is a collection of blood progenitor cells intended for infusion into a
patient from a donor. The first step towards such a transplant is a search for a family or an unrelated
donor. The HLA Laboratory performs tissue typing and DNA testing. The Transfusion Medicine
Laboratory identifies blood groups of all prospective donors. Once a donor is identified, several laboratory
disciplines including Hematology, Chemistry, Transfusion Medicine and Virology perform tests on blood
samples from the donor to be sure that this is a "safe" donor, and that it is medically safe for the donor to
be harvested. Blood stem cells can be harvested from a donor's bone marrow in the operating room, or
by mobilizing these progenitor cells into the peripheral circulation by administering a drug known as GCSF. Once the product is collected, the Hematology and Special Stains Laboratory provide an accurate
measure of the number of "progenitor cells" in the collection to be sure sufficient are available to enable
grafting of the donor product in the recipient. These cells take a minimum of two weeks to begin to grow
in the patient's bone marrow. Transfusion Medicine provides Red Cells, Platelets and Plasma to the
patient until they begin making blood cells. Hematology, Microbiology and Chemistry laboratories provide
ongoing monitoring of blood counts, sterility, drug levels and functionality of other body organs during this
critical time. Not all patients who require a bone marrow transplant have a matched donor and we are
exploring the potential to use "half-matched" family donors. The Stem Cell Laboratory has research
technology available which can reprocess a bone marrow or peripheral blood progenitor cell harvest to
remove the "T" lymphocytes which would attack the patient, causing severe "graft versus host" disease, if
the donor is only half matched. Using this process, the "T" lymphocytes can be minimized while
maintaining the progenitor cells which can repopulate the patient's bone marrow. A "Haplo Transplant"
requires all the facets of a traditional allogeneic transplant plus the specialized processing provided in the
Stem Cell Laboratory.
Autologous bone marrow transplantation involves collection of blood progenitor cells from a patient
which are intended for infusion into that patient. At our Centre, this type of transplant is used for patients
with Hodgkin's disease, intermediate and high grade Lymphoma and Multiple Myeloma. The Laboratory
is an even larger participant in this type of transplant. The product used is always collected peripherally
by the Apheresis nurses and is called "Autologous Peripheral Blood Progenitor Cells". There is no tissue
typing required because this is a self donation, but Hematology, Special Stains and Virology Laboratories
all provide testing of the donor and the product as described previously to eliminate any possibility of viral
cross contamination from another product during frozen storage. The rationale in this type of transplant is
to store the patient's stem cells to be available to "rescue" the patient's bone marrow after very high dose
chemotherapy given to attack their disease.
The Stem Cell Laboratory processes the patient's harvested Peripheral Blood Stem Cells adding
cryopreservation solution containing dimethyl sulfoxide, plasma and electrolyte solution which helps to
maintain cell viability. Freezing the cells at a controlled rate of -1OC per minute also helps to keep them
viable. Frozen progenitor cells are stored at -150OC in liquid nitrogen. When the patient requires their
transplant, Laboratory staff retrieve the product from the liquid nitrogen freezers, transport it to the
bedside where it is thawed and drawn up into syringes which are passed to the physician for infusion to
the patient. Patient blood counts are monitored in Hematology, and Transfusion Medicine provides Red
Cell and Platelet support during the 10-12 days until the graft is complete.
Advances in Stem Cell Processing
The Stem Cell laboratory has been directly involved in important research projects which aim to advance
the field of stem cell transplantation. We have developed and recently completed a phase II Canadian-
based study evaluating a new growth factor known as stem cell factor (SCF). SCF is a glycoprotein that
acts on primitive progenitor cells and can be used in combination with existing growth factors. We have
found that the addition of stem cell factor was well tolerated and led to a dramatic increase in the number
of stem cells collected following a single collection. The importance of these data directly relates to a
proportion of patients who fail to mobilize sufficient stem cells and can not be transplanted. The utilization
of SCF in these patients has resulted in the ability to safely transplant patients previously considered
ineligible for Bone Marrow Transplantation.
A phase I gene therapy study in patients with metastatic melanoma has been recently completed. This
work highlights a new type of cell known as a Dendritic Cell (DC). DCs are a heterogeneous population of
antigen presenting cells (APCs) identified in various tissues including the skin (Langerhans cells), lymph
nodes (interdigitating and follicular DCs), spleen and thymus. Properties of DCs include the ability to: (1)
capture, process and present foreign antigens, (2) migrate to lymphoid-rich tissue, and (3) stimulate
innate and adaptive antigen-specific immune responses. Until recently the ability to study DCs has been
limited by their relative absence in most culture systems. It is now known that specific cytokines can be
used to expand DCs to numbers sufficient for in vitro evaluation and use in human immunotherapy trials.
Human autologous DCs can be derived from hematopoietic progenitors (CD34+-derived DCs) isolated
from mobilized peripheral blood progenitor cells (PBPC), bone marrow and cord blood, or from adherent
peripheral blood monocytes (monocyte-derived DCs). Cultured DCs are recognized by a veiled
appearance and expression of surface markers, which include MHC class II, CD86/B7.2, CD8O/B7.l,
CD83 and CD1a. DCs are susceptible to a variety of gene transfer protocols that may enhance biological
function in vivo. Transduction of DCs with defined tumour antigens results in sustained protein expression
and presentation of multiple potential tumour peptides to T cells. Alternatively, DCs may be transduced
with genes for chemokines or immunostimulatory cytokines, which can enhance or direct APC function
towards a specific immunological response (i.e. Th1 vs. Th2). Although the combination of ex vivo DC
expansion and gene transfer is new, preliminary studies suggest that injection of genetically modified
autologous DCs may be capable of inducing an anti-tumour immune response in patients with cancer.
Preclinical animal studies, demonstrating the ability of DC-based vaccines to generate potent antigenspecific tumour immunity, support this hypothesis and provide rationale to evaluate this approach in
human patients. These early studies address fundamental issues relating to cell dose, schedule of
vaccination, route of delivery and maturational state of cultured DCs.
Suggested Reading:
1.
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6.
7.
Thomas ED: Bone Marrow Transplantation: A Review. Semin Hematol 36(suppl 7):95-103
Hart DNJ: Dendritic cells: Unique leukocyte populations which control the primary immune response.
Blood 1997, Nov 1; 90(9) 3245-87.
Steinman RM: The dendritic cell system and its role in immunogenicity. Annu Rev Immunol 1991, 9:271.
Siena S, Di Nicola M, Bregni M, Mortarini R, Anichini A, Lombardi L, Ravagnani F, Parmiani G, Gianni
AM: Massive ex vivo generation of functional dendritic cells from mobilized CD34+ blood progenitors for
anticancer therapy. Exp Hematol 1995, 23:1463.
Wan Y, Emtage P, Foley R, Carter R, Gauldie J. Murine dendritic cells transduced with an adenoviral
vector expressing a defined tumor antigen can overcome anti-adenovirus neutralizing immunity and induce
effective tumor regression. Int J of Oncology 1999, 14
Guinan EC, Gribben JG, Boussiotis VA, Freeman GJ, Nadler LM: Pivotal Role of the B7:CD28 Pathway
in Transplantation Tolerance and Tumor Immunity. Blood 1994, Nov 15; 84 (No 10); 3261-3282
Graham FL, Prevec L: Methods for construction of adenovirus vectors. Mol Biotechnol 1995, June; 3(3):
207-20.
S. Ronan Foley, M.D., FRCPC, Assistant Professor
Director, Stem Cell Laboratory
Head, Malignant Hematology Diagnostic Service
Hamilton Regional Laboratory Medicine Program
Hamilton Health Sciences Corporation, Henderson General Hospital Site