Maisonneuve-Rosemont Hospital Université de Montréal

Transplant expansion

Increasing the supply of stem cells

Researchers have to face the fact that it is sometimes difficult to obtain enough hematopoietic stem cells to go ahead with a transplant. A minimum number of stem cells is required to ensure the recovery of blood and immune systems, as well as their proper functioning for a lifetime.

The number of stem cells infused has an effect on post-transplant recovery. This is based on the assumption that greater numbers of stem cells will mean it will take less time for them to restore the blood and immune systems and begin producing healthy blood cells, which will reduce any period of aplasia, as well as the risk of infections and complications due to a weakened immune response, thus speeding the patient’s recovery.

Certain pre-transplant treatments intended to destroy tumour cells can both affect and reduce the number and quality of stem cells. It can then prove difficult to obtain a satisfactory transplant. However, by using a technique that takes a small number of stem cells from a patient and then multiplies them, autotransplantation remains possible. This technique also enables insufficient allogeneic transplants, often the case when transplants from cord blood are involved, to be expanded.

A team made up of researchers from MRH and the Université de Montréal’s Institute for Research in Immunology and Cancer (IRIC) has recently identified a hematopoietic stem cell growth factor, the HOXB4 protein, that can increase the number of such cells by 1000. Putting this growth factor together with stem cells in the laboratory speeds their increase and allows a suitable number of cells to be obtained in order to have an optimal transplant.