Background

Bone marrow transplantation also referred to as BMT is a therapeutic process used to address number of diseases, however its use mostly in treating blood diseases and hereditary disorders. 

Historical Development 

• Early Research: The history of bone marrow transplantation was initiated in the mid of the twentieth century. Early studies were done using animal subjects. 
• First Human Transplant: The first successful human bone marrow transplant being done in 1968 by E. Donnall Thomas, who is considered the father of the field. He was responsible for some of the contemporary BMT concepts and practices. 

Different Kinds of Bone Marrow Transplantation are 

• Autologous Transplantation: Peripheral blood stem cells or bone marrow harvested from the patient’s own body are taken out, preserved, and replaced into the body after a high level of chemotherapy or radiation has been applied to the patient.  
• Allogeneic Transplantation: Stem cells are harvested from the donor and the donor may be a close relative of the patient such as a sibling or from any unrelated donor.  
• Syngeneic Transplantation: The donor is an identical twin, which might indicate a genetic predisposition to neurological conditions. This reduces the chances of development of graft versus host disease (GVHD). 

Indications

• Hematologic Malignancies: Leukemias such as AML and ALL, lymphomas like NHL and Hodgkin lymphoma, and multiple myeloma. 
• Non-Malignant Hematologic Disorders: Non-spherocytic hemolytic anemias (e. g., aplastic anemia, myelodysplastic syndromes, hemoglobinopathies such as sickle cell disease, thalassemia). 
• Genetic Disorders: They include inherited metabolic diseases such as Hurlers syndrome, severe combined immunodeficiency (SCID). 
• Autoimmune Diseases: Critical cases of autoimmune diseases which are challenging to treat (for example, SLE, multiple sclerosis). 
• Solid Tumors: Only neuroblastoma and Ewing sarcoma (in some cases) 

Contraindications

• Severe Comorbidities: Severe uncontrollable medical illnesses (i. e., cardiovascular, respiratory or renal diseases) which put the patient at risk for transplantation. 
• Advanced Age: Patient specific characteristics that can be related to an increased risk associated with the procedure include the very elderly though this depends on the individual’s general health. 
• Active Infections: Infections that can occur before and after BMT are especially dangerous if left untreated or if they cannot be controlled. 
• Uncontrolled Malignancies: A current diagnosis of cancer or a previous diagnosis of cancer that has shown moderate or severe activity or has the potential to progress or relapse. 
• Poor Performance Status: The consolation for patients with severely impaired activities is that such patients may not be able to tolerate the procedure. 
• Significant Mental Health Issues: The major psychiatric disorders that may impact the patient’s adherence to recommended treatments and care after the transplant. 

Outcomes

Equipment

• Apheresis machine 
• Centrifuge 
• Infusion pumps 
• Radiotherapy equipment 
• Cryopreservation units 
• Bone marrow biopsy needles 
• Ventilators 
• Central venous catheters 
• HEPA filters 
• Positive pressure rooms 
• Flow cytometer 

Patient preparation

• Pre-Transplant Evaluation: Medical screening of potential candidates involving blood test results, imaging studies, and review of their clinical status to qualify for BMT. 
• Conditioning Regimen: Intensive dose chemotherapy /radiation to eradicate the cancerous cells and immunosuppressive which are effective in reducing immune response to the transplant. 
• Stem Cell Collection: In autologous transplants, the patient’s stem cells are harvested and preserved. For allogeneic transplants, the HSCs are harvested from a donor, an individual who is either a matched related donor, an unrelated matched donor or a matched unrelated donor. 
• Psychological Support: Psychosocial intervention in case the patient needs to be comforted after understanding the surgical procedures that the surgeons are going to carry out on him/her. 
• Infection Prevention: Specific precautions to minimize the spread of active infection and ways of preventing or curing them – vaccinations (if any), cleanliness. 
• Nutritional and Hydration Support: Monitoring patient status before and during the transplant to guarantee adequate fluid and nutrient intake. 

Patient position

• Infusion of Stem Cells: The patient is typically positioned supine (lying on their back) for the stem cells to be delivered by IV line or central venous catheter. 
• Monitoring: The patient may have to be placed in a comfortable posture during the process and may require continuous monitoring of the blood pressure, heart rate and the blood cell count. 
• Comfort and Safety: The position of the patient shall be appropriate to guarantee that they are well comfortable and well secured to avoid situations such as pressure sore or any form of discomfort. 

Technique

Step 1- Pre-Transplant Preparation: Medical evaluation with particular attention to the patient’s medical history and physical examination, labs, imaging studies, and occasionally bone marrow aspirate/biopsy. The patient receives chemotherapy and/or radiation to concentrate on elimination of the abnormal cells, the patient’s immunity is weakened and the bone marrow is prepared for the new stem cells. 

Step 2- Stem Cell Collection 

Autologous Transplant: Patients own stem cells are then harvested, typically by a procedure known as apheresis, during which the patient’s blood is drawn, the stem cells removed, and the rest of the blood returned to the patient. The received stem cells are also prepared and stored for future use by freezing them. 

Allogeneic Transplant: Haematopoietic stem cells are harvested from a related donor by a procedure known as apheresis where blood is taken from the donor, the stem cells are isolated, and the rest of the blood returned to the donor’s body or through bone marrow collection. 

Bone marrow is harvested from the donor’s pelvic bone (as the marrow is collected directly from the donor’s pelvic bones). 

Step 3- Conditioning Regimen: Chemotherapy and/or Radiation is given to the patient to kill cancer cells and to inhibit the immunity of the body to reduce the chances of rejection of transplanted cells. 

Step 4-Stem Cell Infusion: The usual position of a patient is the supine position. The collected or donor stem cells are thawed if they were preserved in the state called cryopreservation. 

Step 5- Infusion: The stem cells are given to the patient through the process of intravenous infusion that provides direct access to the patient’s bloodstream through a central venous catheter. This process is like a blood transfusion and normally takes a couple of hours. 

Bone marrow transplant 

Step 6-Post-Transplant Care: Prolonged assessment of the cardiac rate and oxygenation, hemoglobin, appropriateness of the transfusion, and clinical symptoms of syndromes like infections or GVHD. This is especially important during early stage since the patient is more likely to suffer adverse effects. Also encompasses treatment of conditioning regimen toxicities (e. g., nausea, mucositis) and infection prevention (antibiotics, antifungals), as well as supportive care (e. g., blood product transfusions, nutritional support). Various tests to confirm that the donated stem cells are incorporating into the patient’s body and manufacturing additional blood cells. 

Step-7-Long-Term Follow-Up: Includes regular visits for assessing for GVHD, relapse of the original disease, and other long-term effects. Ongoing support for physical, emotional, and psychological well-being. 

Laboratory tests

• Complete Blood Count (CBC) 
• Blood Chemistry Panel 
• Bone Marrow Biopsy 
• HLA Typing 
• Infectious Disease Screening 
• Coagulation Tests 

Complications

• Graft-Versus-Host Disease (GVHD) 
• Infections 
• Graft Failure 
• Relapse of Original Disease 
• Organ Toxicity 
• Mucositis 
• Infertility 
• Secondary Cancers 

References

Bone Marrow Transplantation 1957-2019 – PMC (nih.gov) 

[Indications, technique and risks in bone marrow transplantation in adulthood] – PubMed (nih.gov) 

References

Bone Marrow Transplantation 1957-2019 – PMC (nih.gov) 

[Indications, technique and risks in bone marrow transplantation in adulthood] – PubMed (nih.gov)