Grafts fail when the body doesn't accept new stem cells (the graft). The stem cells that were administered do not reach the bone marrow or multiply as they should. Graft failure is more common when the patient and the donor do not have a good match and when patients obtain stem cells from which T cells have been removed. It can also occur in patients who receive a low amount of stem cells, such as a single umbilical cord unit.Stem cell or bone marrow transplants are complex treatments that carry a significant risk of serious complications.
The disparity between the recipient and the donor within the major histocompatibility complex (MHC) is of paramount importance for allograft rejection. In leukemia patients undergoing myeloablative conditioning, the rejection rate was 0.1% in patients who received transplants from siblings identical to HLA, compared to 5% in those who received grafts that were not compatible with HLA. Stem cell recipients from unrelated donors also have a higher risk of graft failure, compared to patients who receive grafts from siblings identical to HLA. When using unrelated donors, the disparity of HLA class I between donor and recipient was associated with a higher risk of rejection.
The risk of graft failure usually lasts two to four weeks after the transplant. Sometimes, it can happen later on. If the graft fails, doctors may recommend transplanting more donor stem cells, if available. Graft failure occurs if the transplanted stem cells don't settle in the bone marrow or produce new blood cells.
This means that blood counts don't recover. Graft failure is serious, but it is very rare after an autologous stem cell transplant. The medical team closely monitors blood counts. If the graft doesn't work, you may be treated initially with growth factors or hormones. These stimulate bone marrow stem cells to produce more cells.
You may need a second stem cell transplant. People who receive their own stem cell transplants (autologous transplants) are also less likely to suffer serious side effects. At four weeks, a bone marrow aspirate showed 95% of recipient cells among the CD34+ cells and 80% of recipient T cells. If you're going to have a donor stem cell transplant (allogeneic transplant), you'll need a donor.
Prophylaxis, diagnosis and treatment of infections in patients undergoing high-dose chemotherapy and autologous hematopoietic stem cell transplantation. If you have lymphoma, you may have a stem cell transplant if you need cancer treatment in high doses. This occurs when stem cells transplanted from a donor produce immune system cells that attack the recipient's tissues and organs. Some side effects of a bone marrow or stem cell transplant don't show up until several months or even years after treatment.
Autologous stem cell transplants are used under certain circumstances to cure lymphoma (especially Hodgkin lymphoma or high-grade non-Hodgkin lymphoma) or to make the lymphoma remission last longer than would otherwise be possible. Macmillan Cancer Support has more information about autologous stem cell transplants (also called “high-dose treatment with stem cell support”) for lymphoma not Hodgkin. In all transplants, patients are treated with chemotherapy, followed by an infusion of a blood-forming stem cell graft from a suitable donor. For at least the first 6 weeks after the transplant, until the new stem cells start producing white blood cells (graft), you can easily get serious infections.
If you receive a transplant that uses donor stem cells (allogeneic transplant), you may be at risk of developing graft-versus-host disease (GVHD). Although you may be allowed to go home a couple of weeks after an autologous stem cell transplant, it will take you 3 to 6 months to recover for complete. GVHD can be treated with medications that suppress the immune system and prevent transplanted stem cells from attacking the rest of the body. Graft-versus-host disease (GVHD) can occur if white blood cells that have formed from donor stem cells recognize that the patient's cells and tissues are foreign and attack them.
Anthony Nolan, a charity dedicated to stem cell transplantation, has more information on stem cell transplants for blood cancers, including lymphomas.
