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.
