Processing of peripheral blood stem cells for transplantation

Area of Science:

• Hematology
• Transplantation Immunology
• Cellular Therapy

Background:

• Hematopoietic stem cell transplantation is crucial for marrow reconstitution following chemotherapy.
• Bone marrow aspiration is the traditional source of these cells, but it is invasive.
• Peripheral blood offers a potential alternative source of hematopoietic stem cells.

Purpose of the Study:

• To evaluate the efficacy of peripheral blood collection by semicontinuous centrifugation for obtaining hematopoietic cells.
• To compare the number and function of hematopoietic progenitor cells (CFU-C) from peripheral blood versus bone marrow.
• To assess the feasibility of using autologous peripheral blood stem cells for marrow reconstitution in canines.

Main Methods:

• Peripheral blood was collected from canines using semicontinuous centrifugation.
• Colony-forming unit-culture (CFU-C) assays were performed on fresh and cryopreserved peripheral blood cells and bone marrow aspirates.
• Peripheral blood mononuclear cells (MNC) were incubated with activated cyclophosphamide to assess selective depletion of immunocompetent cells.
• Mixed lymphocyte culture (MLC) activity was measured to evaluate immune cell function.

Main Results:

• Semicontinuous centrifugation yielded an average of 1.7 x 10^5 CFU-C per run, comparable to bone marrow aspirates (1.9 x 10^5 CFU-C).
• Autologous transplantation with peripheral blood stem cells led to marrow reconstitution within two weeks after lethal chemotherapy.
• Cryopreservation resulted in 82% CFU-C recovery from marrow and 78% from peripheral blood.
• Incubation with cyclophosphamide selectively reduced MLC activity by over 90% while retaining 70% of CFU-Cs.

Conclusions:

• Peripheral blood is a viable source of hematopoietic stem cells for transplantation in canines.
• Semicontinuous centrifugation is an effective method for collecting these cells.
• Peripheral blood stem cell transplantation can restore marrow function after chemotherapy.
• This technique presents a practical alternative to bone marrow harvesting for transplantation studies.