(Acute Leukemia)- Allogeneic

Patients with acute myeloid leukemia are treated with Allogeneic stem cell transplant. Allogeneic SCT involves collecting a donor’s stem cells and transplanting the same in the patient’s bone marrow, whose natural stem cells got destroyed by high doses of chemotherapy and radiation therapy.

Stem cells in the bone marrow are multicellular organisms that help in the production of three types of blood cells- red blood cells, white blood cells and platelets. When stem cells start developing increased number of abnormal and immature cells, they suppress the production of normal blood, thus leading to anaemia or acute leukemia, etc. There are basically two types of stem cell transplants- allogeneic SCT and autologous SCT.

Although, high doses of chemotherapy or radiation therapy can be used for destroying cancerous cells, they may severely damage the bone marrow in the process. To make sure that chemotherapy is used without disrupting the normal production of blood, stem cell transplant is required.

In case of allogeneic acute leukaemia, a donor’s stem cells are matched with the recipient’s and then the collected donor’s stem cells are transplanted into the patient’s bone marrow.  It should, however, be noted that the recipient’s and donor’s tissues should closely match to carry out the transplant.

The common symptoms of allogeneic acute leukaemia are skin itching, rashes, severe diarrhoea, mouth sores, yellowing of the eyes and skin, liver and lung damage, severe exhaustion, bone and joint pain, etc. Patients should refer to an oncologist immediately once the symptoms start showing.

The procedure of allogeneic acute leukemia stem cell transplant is done in a few steps. First, a donor is searched; stem cells are collected and then transfused into the patient’s bone marrow. Before the treatment of allogeneic stem cell transplant, there are few obligations to be met.

• The first step is to find a matching donor. The possible candidates are human leukocyte antigen (HLA)-matched relative (generally a sibling), HLA-matched unrelated donor, unrelated umbilical cord blood and HLA miss-matched family member.
• Before collecting stem cells from the donor’s bone marrow or blood, the person has to undergo a thorough physical examination and blood test for human immunodeficiency disease (HIV), hepatitis virus and other infectious agents.
• There are three main sources for collecting stem cells that include the bone marrow, blood or stem cells of a baby’s umbilical cord. The donor is asked to visit the outpatient hospital facility or at a blood centre for collection of peripheral blood stem cells (PBSC).
• For five consecutive days, the donor is injected of a kind of drug to help increase the number of blood-forming cells.
• The procedure of collecting PBSC from the donor is non-surgical, which is called apheresis. A needle is inserted into the arm and blood is drawn that is passed through a machine, while remaining blood is returned through a needle into the other arm.
• It takes 1 apheresis session to collect 90% of PBSC donations that takes up to 8 hours, while the rest 10% in completed in 2 sessions that take 4-6 hours.

After the donor stem cells are collected, the leukaemia cancer patient is readied for the transplantation procedure.

• The leukaemia patient undergoes a conditioning regime before an allogeneic stem cell transplant. The regime involves an intensive treatment to kill the cancerous cells. Patients usually receive high doses of radiation therapy or chemotherapy, or a combination of both.
• The transplant is done two days after the intensive treatment. An intravenous channel is created in the arm through which the patient receives blood transfusion. The entire procedure takes an hour to complete.
• After being injected, the stem cells travel to the bone marrow and produces new blood cells, which is called ‘’engraftment’’. Thus, the transplant helps to restore the blood cells that were destroyed by the intensive procedure.

After allogeneic stem cell transplant, doctors closely monitor the patient in the months to follow. A team of hematology oncologists collaborate with the patient to minimize the risk of complications arising after the procedure.

There are chances of having side effects of allogeneic stem cell transplant after the patient undergoes high doses of radiation and chemotherapy. Patients become vulnerable to infections and there is the chance of graft-versus-host-disease (GVHD) where the donor’s cells attack your blood tissues. In that case, specific prescribed drugs help to cease the risk of GVHD.

Recovery of stem cell transplant varies from person to person. The patient’s physical conditions prior to the transplant, the severity of side effects they face are some of the reasons that impact the recovery time. Doctors, however, monitor the patients for blood counts and related side effects, if any. Ask your doctor when you can return to work and resume a normal life.

It takes almost a year for the immune system to return to normalcy and the bone marrow to produce adequate blood cells. This time of recovery may be longer for certain patients who are particularly on immune-suppressing drugs. Generally, after 1-2 years, most people are required to be immunized with vaccines.