Leukemia has two major types: acute and chronic. In what concerns acute leukemia, there are two forms: if leukemia involves lymphocytes, we are dealing with acute lymphoblastic leukemia, and if it involves myeloid cells, is called acute myelogenous leukemia. Depending on the particular cell that has become malignant, there can be many different types of acute lymphoblastic leukemia and acute myelogenous leukemia.It was seen that chronic leukemia affects primarily the myeloid cells in the bone marrow.
This is called chronic myelogenous leukemia, and is found mostly in adults, but children and teenagers can develop it too.We must mention that there exists a disorder of the bone marrow known as myelodysplastic syndrome. Often called a pre-leukemia syndrome because patients with it have a significantly increased risk of developing leukemia, this syndrome is often associated with low blood cell counts and increased requirements for transfusions.
Allogeneic bone marrow stem cell transplantation is used to treat a variety of childhood leukemias or cancers and myelodysplastic syndrome that involve the cells within the bone marrow. In this transplant, there are used another person's bone marrow cells to restore bone marrow after high dose chemotherapy and radiation therapy.As an advantage of an allogeneic transplant over an autologous transplant we can mention the "graft-versus-leukemia effect".
The donor’s healthy bone marrow kills residual leukemia cells, and in this way decreases the patient's chance of relapse.As a disadvantage of an allogeneic bone marrow stem cell transplant we can mention the risk of graft-versus-host disease. This happens when the other person's bone marrow attacks the recipient's body. In this way, there appears a disease that affects the skin, liver and many other organs. In this case, therapy with immunosuppressive drugs is needed.
When a matched donor is available, there can be performed transplantation for high-risk leukemia patients in first remission. In very high-risk patients, like those with leukemia who fail to achieve first remission with chemotherapy, there can be done an unrelated donor transplant as soon as remission is achieved. As eligible we can mention infants with leukemia, children with high-risk lymphoblastic leukemia and children with acute myelogenous leukemia. Also, children with myelodysplastic syndrome are eligible for transplant as soon as the diagnosis is established.
Many children with acute leukemias whose leukemia has relapsed can have bone marrow stem cell transplantation. Transplantation can be from related donors like brothers, sisters, parents, and occasionally more distant relatives such as cousins and grandparents.Also, transplantation can be from matched unrelated donors, including umbilical cord blood.In what concerns children with chronic myelogenous leukemia who cannot be put into complete remission with drugs, they should undergo a transplant as early as possible in the course of the disease.