What is a Bone Marrow Transplant, and what are its Types?

Bone Marrow Transplant is a curative /medical treatment in which defective bone marrow is replaced by healthy marrow. The marrow is either transplanted from a healthy matched donor or the patient’s own disease-free marrow. Bone marrow transplant is indicated in diseases such as blood cancers. Diseases that do not respond to other medication/treatments like Chemotherapy or Immunotherapy.

Moreover, it is also indicated in diseases in which the Bone Marrow of the patient, or some blood components, becomes unable to perform its function. For example, some disorders like aplastic anemia, Thalassemia, or some platelet dysfunction diseases like Bernard- Soulier syndrome, and red cell dysfunction like red cell aplasia.

Types of Bone Marrow Transplant

There are three types of transplants

• Allogenic Bone Marrow Transplant.
• Autologous Transplant
• Haplocentric Transplant
• Syngenic Transplant.

Allogenic Bone Marrow Transplant:

 In this type of transplant, a healthy, fully matched donor is selected to donate Bone Marrow or stem cells. The fully matched donor is then thoroughly screened for any kind of infectious disease, like hepatitis B, hepatitis C, syphilis, etc. After declaring physical fitness, if a peripheral stem cell transplant is recommended by the consultant, the donor is prepared by injecting a drug called G-CSF (granulocyte-stimulating factor) to increase the stem cells in the marrow. The total recommended dose is based on the donor’s weight, and the injection is normally administered subcutaneously in the abdomen for good results. Furthermore, growth factors are given for 4 days, then the donor is admitted on the day of the transplant.

What types of cancers are treated with Allogenic transplants?

Allogenic transplant is offered in the following diseases.

Leukemia(Acute myeloid leukemia, Acute lymphoblastic leukemia,Chronic lymphocytic leukemia, etc)

Severe Aplastic Anaemia

Thalassemia Major

Sickle cell anemia

Red cell aplasia

Bernard-Soulier syndrome and Glanzman thrombasthenia, etc.Moreover,

Allogeneic transplant is also offered in some diseases that relapse after an autologous transplant

What is the process of stem cell collection?

Stem cells are collected peripherally by inserting a large catheter in the neck called a Dialysis Catheter, OR if Peripheral veins are patent, then a large-bore needle is inserted to draw blood containing stem cells.

The Apheresis machine is attached, and the donor blood is moved through the machine. Stem Cells are collected in a bag called the stem cells collected bag. The rest of the blood is returned to donor circulation through another large -bore cannula.

The donor remains stable throughout the procedure; sometimes needs calcium supplements for hypocalcemia correction. The total time duration for this procedure is around 3-4 hours. After the cell dose is collected, the donor is discharged home.

Stem Cell Infusion:         

 Stem cells are infused into the patient on the same day via a central line. Before the infusion, it is necessary to administer anti-allergy medications to prevent stem cell-related reactions. This is also known as TRALI (transfusion-related acute lung injury).

What are the symptoms of TRALI?

if the reaction occurs during the infusion, the patient will show the following symptoms.

shortness of breath

shivering and chills

Decreased oxygen saturation

What is the management of TRALI?

If the reaction occurs immediately, follow the steps below

Stop the infusion or the stem cells

Inform the primary physician

take the blood bank onboard to store the remaining stem cells under aseptic conditions

Maintain air and oxygen levels by administering oxygen

Administer steroids to decrease the swelling and suppress the reaction

If the patient becomes febrile (develops fever), give antipyretics to decrease the temperature.

In case the patient’s condition does not improve, transfer or shift the patient to the intensive care unit to prevent further complications.

Bone Marrow Collection in Operation Theater:

 When the Bone Marrow is collected in the OR, the donor is given full anesthesia, and marrow is collected from the iliac crest or the hip bone by inserting needles to aspirate the marrow. The collected marrow is then infused into the patient through the central line on the same day. The donor is then discharged home on the same day.

Autologous Bone Marrow Transplant:

In this type of transplant, the patient is his /her own donor, meaning the patient’s own stem cells are collected first and reinfused into him/her. After the patient is free from disease again, he is given a G-CSF injection to make healthy marrow. This process is known as stem cell mobilization.

After 4 days of GCSF injection, as prescribed by the transplant consultant, the patient is admitted to collect healthy stem cells via a dialysis catheter, and then the cells are preserved in the blood bank.

The patient has been given high-dose chemotherapy. These high doses of chemotherapy are given to finish the defective marrow and to create space for the new cells. Furthermore, the days of chemotherapy depend on the type of disease. After the course of chemotherapy, the stem cells are re-infused into the patient.

Haploclonal Transplant/ half -matched transplant:

Half-matched bone marrow /stem cell Transplant is the same as Allogenic transplants, but in this transplant, the donor is half-matched with the patient. The process of transplant, e.g., the collection of marrow and infusion, is the same as in a fully matched Bone Marrow transplant.

Syngenic Transplant: This type of transplant is the same as an allogenic transplant. However, the only difference is that the donor is an identical twin of the patient. Usually, this type of transplant is discouraged due to the same genetic makeup of the sibling twins.

Bone Marrow transplant consists of special chemotherapy protocols and has different procedures for stem cell collection and infusion.

Your transplant consultant will suggest to you the type of transplant you need. Diseases that need Bone Marrow Transplants are oncological, like Leukemia and Lymphomas (AML, ALL, CML, HODGKINS, NON-HODGKINS), multiple Myeloma, etc. Non-malignant diseases include Thalassemia, major Aplastic Anemia, etc. Care of patients after transplant is crucial for better results.

Which stem cell transplant is more complicated?

Usually, the complexity and complications of transplant depend upon the comorbidities and physical health of the patient. However, the complications of allogenic specially the half-matched transplant, are more than a full-matched or autologous transplant.