I think I can help you here:
The major advantage of an allogeneic (non-self donor) hematopoietic stem cell transplantation compared to an autologous (self-donor) transplantation in the treatment of blood-based cancers is:
**There is a higher chance of achieving a curative cancer outcome due to the lower risk of relapsing cancer.**
Allogeneic stem cell transplantation allows for the use of donor cells, which can have a graft-versus-tumor effect. This means that the donor's immune cells may recognize and attack remaining cancer cells in the recipient's body, reducing the risk of cancer relapse. However, this advantage comes with the potential downside of graft-versus-host disease (GVHD), where the donor's immune cells may also attack the recipient's healthy tissues, which is a significant concern.
The other options mentioned (Ciclosporin, HLA cross-matching, lower tumor cell contamination, and not needing immunosuppressants after autologous transplants) are considerations in the transplantation process but are not the primary advantage of allogeneic transplantation in terms of curative potential.