Stem Cell Transplant
The treatment Susan needs is called a Autologous haematopoietic stem cell transplant (HSCT). This procedure “reboots” the immune system. This is done by using chemotherapy to stimulate the production of stem cells and promote their release into the blood. These stem cells are collected and stored for later use. The patient undergoes extreme doses of chemotherapy to wipe out the rest of their immune system. Once the old immune system is out of the way, the stem cells are implanted back into the patients blood. The stem cells then rebuild a new immune system.
This article goes into further detail about what stem cells actually are, and the general timeline of a stem cell transplant.