Bone marrow transplantation
Despite advances in other treatment modalities, stem cell transplantation remains the only curative treatment for CLL. Since CLL patients tend to be of an older age compared to other types of leukemia, the option of using high-dose chemotherapy in resistant cases may be perilous because of their fragile state. Stem cell transplantation means that after “ablating” the old bone marrow cells, new healthy cells are transplanted and therefore the origin of the disease is removed. Generally, stem cell transplantation is of two types:
- Autologous: Which means that stem cells are harvested from the same person before ablating the bone marrow then re-implanted.
- Allogenic: Which means that the stem cells are harvested from another donor, either from the bone marrow or from the blood (peripheral stem cell transplantation).
In case of CLL, the only recommended option is allogenic since the autologous transplantation always carries the risk or collecting cells with leukemia and recurrence of the disease. The main drawback of allogenic stem cell transplantation is rejection since the body may identify the new bone marrow as foreign leading to graft rejection. To avoid this, high-dose chemotherapy and radiotherapy are administered before the transplantation to “paralyze” the patient’s immune system. Matching of the bone marrow is also necessary between the donor and the recipient, similar to any other organ transplantation. The possibility of autologous stem cell transplantation is still debated, and trials are being carried out.