Bone Marrow Transplantation for Children

Bone Marrow Transplantation for Children

A bone marrow transplant (BMT) is a procedure to replace a child’s diseased bone marrow with healthy bone marrow by transfusing haematopoietic stem cells. In children, bone marrow transplant is used for the treatment of malignant as well as non-malignant disorders.

What is bone marrow?

Bone marrow is a soft tissue present inside the spaces of large bones. It is similar to a factory that makes stem cells (parent cells or blood-forming cells). These stem cells begin to divide and mature until they are fully developed, forming all the different types of blood cells: white cells, platelets and red blood cells. Stem cells are usually found inside the bone marrow spaces of large bones. The easiest way to obtain stem cells are from hip bones.

Besides bone marrow, stem cells are found in umbilical cord blood and in the peripheral blood.

What are the types of bone marrow transplant?

The stem cells can be collected from patient’s own body or can be harvested from another person. This other person is known as donor.

Autologous Transplant

Stem cells are taken from the patient blood through apheresis using special machines (peripheral) and then given back to the patient after conditioning treatment.

Allogeneic Transplant

The donor is either a relative or unrelated but has a similar Human Leukocyte Antigen (HLA) typing. Matching the HLA of donor & patient is done by blood tests or saliva.

Stem cells donation is a safe procedure. It is usual to start by testing the brothers and sisters, as they are likely to provide the best match.

The donor should be in good health. He or she will be given a thorough medical checkup to make sure that there will be no risk to his or her own health from the procedure.

What If the Siblings Do Not Fully Match As Donors?

• Haploidentical Donors: 50% matched siblings or either parent can be considered as alternative donor once Donor specific antibody testing is negative in patient.
• Unrelated Donors: Donors are selected from stem cell registers (Independent after thorough work up & consent)

When is a bone marrow transplant necessary?

The blood cells begin as immature cells. They leave the bone marrow and enter the blood after maturing. When the bone marrow is damaged, it produces fewer blood cells and fewer immune cells. That is why, to replace damaged or diseased bone marrow, a bone marrow transplant is required.

Indications for bone marrow transplant:

• High risk Leukemia (cancer of the white blood cells) or relapsed leukemias
• Solid tumors such as High risk neuroblastomas, lymphomas, and brain tumors
• Aplastic anemia (a condition where the body stops producing new blood cells)
• Sickle cell disease (a condition that affects shape of red blood cells affecting haemoglobin)
• Thalassemia (a condition affects the body’s ability to produce normal haemoglobin)
• Inherited metabolic disorders (genetic conditions that affect metabolism)
• Immune disorders – Primary immunodeficiency disease, Multiple sclerosis.

What is the procedure of bone marrow transplant?

Pre-transplant evaluation

There will be a variety of tests and procedures to assess your child’s overall health and condition, as well as to make sure the child is fully prepared for the transplant. The tests may take a few days or more and include laboratory blood tests, imaging tests, tests to examine hearing, vision, lung function, intellectual and developmental screening, and heart function.

Collecting stem cells for transplant

If an autologous transplant is expected, you will perform a procedure called apheresis to collect stem cells. You will need a donor if you are performing an allogeneic transplant using stem cells from the donor. Once a donor has been identified, stem cells are removed from that person in preparation for transplantation. Sources of stem cells include:

• Peripheral blood hematopoietic stem cells:

They are obtained by apheresis, using a special machine. In general, a special type of IV (catheter) is used to facilitate blood flow through the machine to collect the stem cells. However, if your child’s veins are not large enough to obtain an adequate blood flow, he/she may need to have a special temporary catheter placed for the collection process. Now-a-days this one is the preferred way to collect stem cells.

• Bone marrow

Stem cells are collected from iliac crest which is a part of hip bone of the donor under anaesthesia.

• Umbilical Cord Blood

Stem cells are taken from an umbilical cord immediately after delivery of an infant. The stem cells are tested, typed, counted and frozen until they are ready to be transplanted.

Bone marrow transplant process:

There is no surgery involved in Transplant for the patient. Stem cell donation is a safe procedure for donors under controlled settings. Nothing is lost permanently in the body e.g. as in kidney Transplant. Stem cells regenerate in few days. Stem cells are infused into the patient body like a simple Blood Transfusion.

There are three main steps in the bone marrow transplantation process.

Step 1: Collecting of the bone marrow or stem cells (the harvest) from the donor.

Step 2: Completely destroying the existing bone marrow and thereby help the patient receive the new stem cells.

Step 3: Infusing the bone marrow or the stem cells through the intravenous route, like a blood transfusion. There may be no signs of a new bone marrow growing for two to three weeks, and occasionally it may take much longer before the new bone marrow produces all the components of the blood adequately.

Which type of transplant is best?

Your child’s treating doctor will advise on the best type of stem cell transplant, whether autologous or allogeneic, as well as the perfect source of cells. This selection is influenced by various factors, including:

• the type of disorder your child have
• your child’s overall health

Are there any side effects of Bone marrow transplant?

Side effects of bone marrow can occur. These are unique to everyone. They vary according on the kind of transplant, your child’s overall health, and other variables.

Immediate side effects may include infection, graft-versus-host disease (GVHD) – a condition in which donor’s transplanted bone marrow reacts against the recipient’s tissues (in case of Allogenic transplant), nausea, vomiting, mouth sores, fatigue, low levels of platelets, low levels of red blood cells (causing anaemia), and diarrhoea.

When to call the doctor?

Consult the treating doctor immediately if you notice the following signs in the child:

• Fever
• Pain that interferes with eating, playing, walking, or moving
• Persistent cough
• Vision problems
• Urinary problems
• Rashes
• Unusual fatigue
• Changes in stool pattern
• Major changes in the activity or behaviour

How will a transplant affect my child’s life? Can my child go to school and do regular activities?

Your child’s time to return to school depends on the type of bone marrow transplant he/she underwent. Usually, the child can return to school in 6 months to 1 year after the transplant. It is necessary to avoid crowds and practice social isolation at least for 6 months to prevent the infection. Your doctor will inform you when it is okay for the child to resume regular activities.

Inputs by Dr. Vipin Khandelwal, Consultant, Haemto-oncology and Bone Marrow Transplant Physician, Apollo Cancer Centres Navi Mumbai