Yesterday I had the opportunity to visit the Clinical Cell Therapy group at the BC Cancer Research Centre. This group prepares donor progenitor cells for transplant into cancer patients. Most of the patients they deal with have multiple myeloid leukemias (cancers of the bone marrow), myelomas (cancers of white blood cells) or lymphomas (cancers of lymphatic tissues).
Admittedly, when I arranged the visit, I expected to see the processing of bone marrow. Instead, they showed me a procedure for prepping the blood to collect hematopoietic progenitor cells, a type of blood stem cell which is able to differentiate into other blood cells. This was news to me!
In this process, the blood came from patients (or donors) who had undergone apheresis, a procedure which removes blood from the donor, separates out the components of interest, and returns the “unused” portion to the donor. In these blood products, the component which was removed was the white blood cell rich layer, containing the progenitor cells.
So why remove progenitor blood cells from a sick patient? Doesn’t the patient need his white blood cells? Well, yes. However, the majority of these patients require chemotherapy during the course of their treatment. Chemotherapy uses cytotoxic chemicals to targets rapidly dividing cells – however, this does not only kill cancer cells but can also kill other rapidly dividing cells, such as bone marrow cells. As a result, one of the common side effects of chemotherapy is a decrease in the production of blood cells, including white blood cells. Low blood cell count is bad! White blood cells in particular are an integral part of defending the body against infectious diseases and foreign agents.
By “saving” white blood cell rich product from pre-treatment patients or healthy donors, patients can receive transfusions of healthy hematopoietic progenitor cells immediately following chemotherapy. These transfusions are essential for facilitating the recovery of normal blood cell counts, which are an important part of patient recovery in general.
After the interview, I did still wonder about bone marrow transplants though – have bone marrow transplants gone the way of the dodo? The short answer is “no”. More on this topic later!
Stay tuned for the full series of articles on this topic! It will be posted on the Stem Cell Network and linked up here.
[Photo by Dale Tidy]