MedifocusHealth

In addition to GVHD, other potential complications of allogeneic SCT include:

• Recurrent infections
• Interstitial pneumonitis - a severe inflammation of the lungs
• Graft failure or rejection
• Veno-occlusive disease -complete blockage of the central veins of the liver leading to liver damage
• Recurrence of the cancer following transplantation.

Autologous Stem Cell Transplantation

Autologous stem cell transplantation (autologous SCT) is a treatment option that is usually reserved for elderly patients who cannot tolerate a standard allogeneic transplant or patients for whom a suitable HLA-matched donor cannot be found. In an autologous transplant, stem cells are obtained from the marrow or peripheral blood of the patient during the chronic phase of chronic myelogenous leukemia. The stem cells are then treated with special chemicals in a technique called "purging" that destroys the leukemic cells but does not harm the small proportion of residual normal stem cells in the marrow or blood sample. The purged stem cell sample is then frozen and stored for later use. The stem cells are returned back into the patient's body by intravenous infusion when the disease has progressed to the accelerated-phase. Essentially, this treatment modality is used to restore patients who have progressed to the accelerated phase of chronic myelogenous leukemia back to the chronic phase of the disease and, therefore, prolong survival. Although autologous SCT does not cure chronic myelogenous leukemia, it can achieve sustained control of the disease in many patients.

Reduced-Intensity Transplants

More recently, a newer type of allogeneic SCT procedure has become available known as a reduced-intensity transplant or non-myeloablative transplant. Sometimes, this is also referred to as a "mini-transplant". The primary difference between a standard allogeneic SCT and a reduced-intensity transplant is that in the latter procedure, much lower doses of chemotherapy (or sometimes radiation therapy) are used to reduce ("debulk") the number of leukemic cells in the patient's marrow and blood (the "leukemic burden") prior to performing the stem cell transplant.

A reduced-intensity transplant is advantageous because it is less toxic to the patient and causes fewer side effects since much lower doses of chemotherapeutic drugs or radiation are used to prepare the patient for the transplant. The "trade-off" with the use of lower intensity doses is that fewer numbers of leukemic cells are destroyed than would otherwise be destroyed by higher-intensity doses that are used in preparation for a standard allogeneic SCT. To destroy the residual leukemic cells remaining in the patient's body, stem cells are harvested from the bone marrow or peripheral blood of a suitable HLA-matched donor and then infused back into the patient (the transplant recipient). The donor's transplanted stem cells serve as a "booster" to the recipient's own immune system to help destroy the residual leukemic cells in the patient's body. This phenomenon is know as the "graft-versus-tumor" effect because the donor's transplanted stem cells (the graft) helps the patient's immune system destroy the residual leukemic cells (the tumor).