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