Blood stem cells are often-used tools in immunotherapy, including for transplantation into people with blood cancers. The sources of these cells are often cord blood, but the numbers of cells from cord blood are small, and their use often leads to failure-to-graft complications. This failure to graft is a limitation that is associated with stem cell death soon after transplantation. The root of the graft failure was explored by researchers at the University of Toronto. They found that some of the cord blood stem cells produce tumor necrosis factor-alpha (TNF-alpha) that is used by the immune system against pathogens; however, excessively released TNF-alpha can also attack the immune system’s own cells.
Armed with this information, the research group decided to determine if inhibiting TNF-alpha could support cord blood stem cell survival. However, they did not have to reinvent the wheel because there are already drugs available that can block TNF-alpha. One that was studied is etanercept (Enbrel), a drug that is used to treat autoimmune disorders such as psoriasis, rheumatic disease, and axial spondyloarthritis.
To test the use of etanercept, they conducted a blood stem cell transplant in immune-deficient mice. The results showed that the treatment led increases in surviving blood stem cells and the numbers of different types of cells derived from the stem cells. These observations provide hope for the use of TNF-alpha-blocking drugs for humans to improve post-transplantation blood stem cell survival. This approach may also allow the use of small numbers of blood stem cells obtained from cord blood.
The ability to enhance the use of cord blood stem cells for transplantation by addressing the underlying limitations would increase the effectiveness of the therapy and widen its availability. Making stem cell transplantation achievable and assessable for more people in need is vital. Using a drug that is already available and able to help accomplish this is an exciting prospect for the immunotherapy and blood transplantation arena.