Pediatric Bone Marrow Transplant

Overview

Blood cells are normally formed in bone marrow, a soft, spongy substance located in the core of some bones. That marrow is responsible for the production of healthy new blood cells. A bone marrow transplant involves the use of stem cells to regenerate healthy bone marrow. A transplant may significantly improve or cure illnesses such as cancer, blood diseases, and immune system disorders.

 

What is Pediatric Bone Marrow Transplant?

It is typical to experience a range of emotions when you discover that your kid requires a bone marrow transplant, also known as a hematopoietic cell transplant. On the one hand, this operation can help your child get back to living a regular, healthy life. On the other hand, the transplant procedure can raise hundreds of new concerns.

Bone marrow is situated in the middle of bones and is the site of blood cell production. It can be found in the spongy parts of the bones, particularly the hips, ribs, breastbone, and spine. Hematopoietic stem cells are the youngest form of blood cells found in bone marrow. A hematopoietic stem cell matures into a white cell, red cell, or platelet. Bone marrow, peripheral blood (bloodstream), and umbilical cord blood all contain hematopoietic stem cells.

 

Types of bone marrow transplant

There are two types of BMT, and the type your child will receive is determined by the diagnosis.

• Allogeneic: When bone marrow or blood cells are obtained from a donor other than the patient, an allogeneic transplant is done. These can originate from a related, unrelated, or cord blood donor. Patients with leukemias and certain lymphomas may benefit from this sort of transplant.
  
• Autologous: An autologous transplant is one that uses the patient's own bone marrow or blood cells. The marrow or cells are harvested and stored before being thawed for reinfusion. Patients with solid tumors such as neuroblastoma, Hodgkin's disease, and brain tumors are candidates for this sort of transplant.
  
• Umbilical Cord Blood Transplant
  Stem cells are extracted from a baby's umbilical cord shortly after birth. These stem cells turn into mature blood cells faster and more efficiently than stem cells from another child's or adult's bone marrow. The stem cells are examined, typed, numbered, and frozen until used in a transplant.

 

Types of cancers treated through bone marrow transplant

We may use a bone marrow transplant to treat several types of cancer. It’s also sometimes an option for noncancerous conditions.

• Hematologic cancers
  Hematologic cancers form in the bone marrow or the immune system. They include:
  • Acute lymphoblastic leukemia
  • Acute myeloid leukemia
  • Chronic myeloid leukemia
  • Hodgkin's lymphoma
  • Non-Hodgkin's lymphoma
    
    
• Solid tumors
  Solid tumors are abnormal growths in the body that don't contain cysts or liquid. Types include:
  • Brain tumor
  • Ewing sarcoma
  • Neuroblastoma
  • Rhabdomyosarcoma
    
    
• Bone marrow failure syndromes
  Bone marrow failure syndromes are a rare group of conditions. They prevent the body from making enough blood. Types include:
  • Aplastic anemia
  • Fanconi anemia
    
    
• Hemoglobinopathies
  Hemoglobinopathies are disorders that impair hemoglobin synthesis. Hemoglobin is an oxygen-transporting protein found in red blood cells. Hemoglobinopathies include the following:
  • Hemophagocytic lymphohistiocytosis
  • Sickle cell anemia
  • Thalassemia
    
    
• Primary immune deficiencies
  Primary immune deficiencies are inherited disorders. They have an impact on the body's ability to fight infections. Some examples are:
  • Chronic granulomatous disease
  • Hemophagocytic lymphohistiocytosis
  • Langerhans cell histiocytosis
  • Severe combined immunodeficiency syndrome
  • Wiskott-Aldrich syndrome
    
    
• Resistant cancers
  Cancer does not always react to therapies in the way we expect. We provide clinical studies for potential novel stem cell transplant therapy for specific malignancies. We are the country's sole transplant clinic that provides some of these therapies. Our research efforts are aimed at improving cancer therapies for all children.

 

Obtaining Bone Marrow Cells

• Allogeneic BMT

The first stage is to find a donor whose blood cells are almost identical to those of the patient. This is accomplished by tissue typing potential donors. Tissue typing is performed with a blood sample and is known as HLA typing (Human Lymphocyte Antigens). These antigens can be detected on white blood cells' surfaces. Each of a patient's full siblings has a 25% probability of being a tissue type match. A parent may occasionally match the patient. A less-than-perfectly matched related donor is occasionally utilized.

If a related donor is not available, the National Marrow Donor Program searches for a compatible, unrelated donor. Unrelated donor cells might originate from either a living or frozen cord blood donor. Your doctor will choose the best source of donated cells for your kid. This is determined by the transplant's urgency, your child's weight, and the greatest tissue type match. A search for an unrelated donor can take months; cord blood can be acquired in a matter of weeks.

 

• Autologous BMT

Peripheral stem cells are often harvested for autologous transplant; however bone marrow stem cells can also be employed. These are collected either before or after a round of chemotherapy is administered to the patient. To harvest peripheral stem cells, the patient is given drugs that increase the quantity of accessible peripheral blood stem cells.

Apheresis is a technique used to harvest cells. The circuit of an apheresis machine collects blood, separates and removes white blood cells carrying stem cells, and then returns red blood cells to the patient. This procedure takes around 4 hours and may need to be performed twice or three times in a succession. To prevent tumor cells from being reintroduced into the patient's body in the case of certain disorders, the peripheral blood stem cells may be treated with anticancer drugs.

 

Performing a Bone Marrow Transplant

• Before the transplant admission:

When your child's healthcare team determines that BMT is the best treatment choice, they will schedule a lengthy session with you to describe the procedure. They will discuss the numerous hazards of BMT, as well as what to expect before, during, and after the transplant.

Your child will be tested to ensure that he or she is healthy enough to tolerate the rigors of transplant. Testing will include an electrocardiogram (ECG) and echocardiography examination of heart function, lung function (if your child is old enough), kidney and liver function, and infection status. A bone marrow aspirate and spinal tap may be done depending on the condition.

When your kid is declared healthy enough for BMT, a central line catheter is generally inserted to give simple access to a big vein in the chest. During therapy, the catheter will be used to administer the new stem cells, as well as blood, antibiotics, and other drugs.

 

• Preparation Before Transplant:

Prior to the transplant, your kid will get "conditioning" treatment. Conditioning entails massive doses of chemotherapy and, in certain cases, total body radiation. Conditioning may entail the following depending on your child's underlying diagnosis:

1. Elimination of the cancer
2. Making space in the bone marrow for new cells to grow
3. Suppression of the immune system so that new cells may be accepted

 

• Commonly used drugs include:
  

1. Cyclophosphamide
2. Melphalan
3. Busulfan
4. Etoposide
5. Thiotepa
6. Carboplatin

 

• The Transplant

After conditioning, stem cells are administered via catheter. This is analogous to receiving a blood transfusion. The transplanted stem cells will begin to produce red and white blood cells, as well as platelets, after traveling via the circulation to the bone marrow.

It can take 14 to 30 days for the body to produce enough blood cells, particularly white blood cells, to combat infection. Engraftment is the detection of new blood cells and an increase in white blood cells following BMT. Your child will be at great risk of infection, anemia, and bleeding until then. Your child will be hospitalized until he or she is well enough to be discharged.

 

What happens after a bone marrow transplant for a child?

After infusion, your child may:

• Be at risk for infection
• Have some bleeding
• Have nausea, vomiting, diarrhea, mouth sores and extreme weakness
• Have some emotional distress

Your child will get supportive care to prevent and treat infections, side effects and complications.

During this time, your child may:

• Spend several weeks in the hospital
• Be confined to a very clean environment to reduce the chance of infection
• Take multiple antibiotics and other medicines
• Need blood transfusions
• Be given medicine to prevent graft-versus-host disease
• Have daily blood tests

Engraftment of stem cells occurs when donor cells enter the bone marrow and begin producing new blood cells. Engraftment often occurs between days +15 and +30. This varies according to the type of transplant and the ailment being treated. Following the transplant, blood tests will be performed on a regular basis to count blood cells. Platelets are often the final blood cells to heal.

Engraftment might be delayed in rare circumstances. This might be related to an infection, medications, a limited number of donated stem cells, or transplant failure. The new bone marrow may begin producing cells within 30 days after the transplant. However, your child's immune system may take months or years to fully heal.

When your kid is ready to return home, the transplant team will notify you. This is determined by a variety of factors, including:

• Extent of engraftment
• Complications
• Your child's overall health
• How far you live from the facility

Before you go home, you'll be instructed on ways to reduce your child’s risk of infection. These include:

• Special air filtered rooms
• Diet restrictions
• Limiting visitors
• Strict hygiene
• Frequent bed linen changes

Your child will then need to see the transplant team often to:

• See how well the treatment is working
• Look for signs of problems such as infection
• Treat side effects, infection and other problems

The long-term success of each child differs. Emotional support for your kid and family is essential throughout the transplant process. Your transplant team will help you cope with the stress of the procedure and will be there for you when your kid comes home. They will tell you about medications, child care, and when and how to contact them with questions.

Your child's transplant team will also discuss his or her prognosis, follow-up care, and future therapies with you.

 

Why are There Side Effects of Bone Marrow Transplant?

The BMT process puts a significant load on the body throughout training, the actual transplant, and the days following the transplant. Conditioning will essentially destroy your child's immune system. As a result, your kid will be at significant risk for infection and blood-related complications right after the transplant. Careful monitoring, the use of antibiotics to cure or prevent infections, and other types of supportive care can make your kid feel as at ease as possible.

 

Common, Immediate Side Effects

• Infection is very common before, during, and after transplant.
• Thrombocytopenia (low red blood cell count) with anemia (low platelets): Transfusions of red blood cells and platelets will be required until the new cells multiply adequately.
• Mucositis (sore mouth, sore throat): These symptoms are treated with IV fluids, nourishment, and pain medications. This condition normally improves as the patient's new cells develop.
• Nausea and loss of appetite: Weight loss is avoided by using IV feeding and/or nutrition delivered through a tube into the stomach. To prevent or lessen nausea, medications can be administered.
  
  

Long-term Risks

Infection - After a transplant, the patient's immune system is decimated, and it takes months, if not years, to recover. Bacterial, fungal, and viral infections are all possibilities. Some patients are given preventive antibiotics. To prevent your kid from infection, special precautions are required, such as restricting visits and avoiding busy locations (such as supermarkets) following discharge.

Graft vs. host disease (GVHD) - This only happens with allogeneic blood or marrow transplants. T cells (or T lymphocytes) are donor cells that respond to the patient's body and perceive it as "foreign." Although medications are provided post-transplant to avoid this problem, it may occur anyway.

• Acute graft vs. host disease is most frequent within three months of transplantation. It is possible that the skin, liver, and intestines will be impacted. Skin involvement manifests as a red rash that may be itchy or blister. Jaundice or an increase in other liver tests may result from liver involvement. Intestinal involvement might result in extremely acute, watery diarrhea. Steroids, for example, are commonly used to treat GVHD and are typically effective in managing it.
• Chronic graft vs. host disease can develop months or even years following a transplant. The most prevalent cause is a recurrence of acute GVHD. Various sections of the body may be impacted. Skin is the most commonly afflicted organ; sufferers may have red, scaly skin or thicker, rough skin. Changes in the oral lining may also occur, as well as dry eyes, dry mouth, joint stiffness, lung limitation, and difficulties absorbing nutrients from diets. Furthermore, due of the drugs required to treat the GVHD, as well as the influence of GVHD on the immune system, patients are at risk for infection.

Organ toxicity - Conditioning and past cancer treatment have the potential to harm the lungs, liver, kidneys, and heart. These consequences are unpredictable, and not every kid recovers from organ poisoning.

Late Effects - There is a considerable risk that there will be long-term complications from BMT that will not be discovered until years after therapy. These are some examples:

• Growth and other endocrine (gland) problems may develop depending upon the type of conditioning used.
• Sterility is common for most patients.
• Organ Damage can occur to the liver, kidneys, lungs, or heart.
• Cataracts may develop clouding the lens of the eye and reducing vision.

 

Conclusion 

Blood and Marrow Transplantation (BMT) is a procedure used to replenish stem cells and bone marrow that have been damaged by high-dose chemotherapy or radiation treatment. BMT involves filtering stem cells and reinserting them into the same infant. Or they are transferred to another ill youngster. These stem cells will develop into fresh, healthy bone marrow. The graft refers to stem cells that have been transplanted.