A bone marrow infusion is a medical procedure used to replace damaged or diseased bone marrow with healthy stem cells. This therapy offers life-saving potential by restoring the body’s ability to produce healthy blood cells, which are essential for overall health and functioning. It serves as a transformative treatment for conditions that compromise the bone marrow’s vital role in blood cell formation.
Understanding Bone Marrow Infusion
Bone marrow infusion is more accurately known as a hematopoietic stem cell transplant (HSCT). This procedure involves the transfer of specialized cells, called hematopoietic stem cells, which have the remarkable ability to develop into all types of blood cells, including red blood cells, white blood cells, and platelets. These stem cells primarily reside within the spongy tissue inside bones, known as bone marrow, where the continuous production of blood cells occurs.
There are two primary types of hematopoietic stem cell transplants. An autologous transplant uses the patient’s own stem cells, collected and stored before high-dose treatments, then returned to the patient. Conversely, an allogeneic transplant involves stem cells from a donor, who may be a related family member or an unrelated individual with a compatible tissue type. Autologous transplants avoid immune rejection risks since the cells are from the patient’s own body.
When Bone Marrow Infusion is Needed
Bone marrow infusion is a necessary treatment for medical conditions that impair the body’s ability to produce healthy blood cells. Common diseases that benefit from this procedure include various types of leukemia, lymphoma, multiple myeloma, aplastic anemia, a condition where the bone marrow fails to produce enough blood cells, and certain inherited blood disorders.
The infusion restores blood-forming capabilities after intensive treatments like high-dose chemotherapy or radiation therapy, which can destroy both cancerous and healthy bone marrow cells. For malignant conditions, the goal is to replace diseased cells with healthy ones and, in some allogeneic cases, to introduce a new immune system that can help eliminate remaining cancer cells.
The Bone Marrow Infusion Process
The process of a bone marrow infusion involves several distinct stages from a patient’s perspective. For allogeneic transplants, identifying and selecting a suitable donor is the initial step, requiring a close match of human leukocyte antigens (HLA) to minimize rejection. Siblings have a 1 in 4 chance of being a perfect match, but unrelated donors can also be found through registries.
Stem cells can be collected from donors through two methods. Bone marrow harvest is a surgical procedure under general anesthesia, where a needle extracts marrow from the pelvic bone. Peripheral blood stem cell apheresis involves giving the donor growth factors to mobilize stem cells into the bloodstream, which are then collected via a machine similar to blood donation. Peripheral blood collection is now more common.
Before the infusion, the patient undergoes a “conditioning regimen,” typically involving high-dose chemotherapy, with or without radiation therapy. This intense treatment destroys existing cancer cells, suppresses the patient’s immune system to prevent rejection, and creates space in the bone marrow for the transplanted stem cells to engraft. The conditioning phase usually lasts 5 to 10 days before the transplant day.
The infusion itself is a straightforward procedure that resembles a blood transfusion. The collected stem cells are delivered intravenously through a central venous catheter directly into the patient’s bloodstream. Once infused, these healthy stem cells migrate to the bone marrow, where they begin producing new, healthy blood cells. The day of the infusion is referred to as Day Zero in the transplant timeline.
Life After Infusion: Recovery and Outlook
Following the bone marrow infusion, patients typically remain hospitalized for three to four weeks while the body recovers. During this time, engraftment occurs, where the newly infused stem cells settle in the bone marrow and start producing new blood cells. Signs of successful engraftment, such as an increase in white blood cell counts, usually appear within two to three weeks.
Patients may experience short-term side effects from the intensive conditioning regimen and transplant. Common issues include nausea, vomiting, fatigue, mouth sores (mucositis), and diarrhea. Hair loss, a temporary drop in blood cell counts leading to anemia and bleeding risks, and increased susceptibility to infections are also common as the immune system rebuilds. Close monitoring and supportive care, including transfusions and medications, are provided during this period.
Longer-term complications can arise, particularly with allogeneic transplants. Graft-versus-host disease (GVHD) is a significant concern where the donor’s immune cells recognize the recipient’s tissues as foreign and attack them, affecting various organs and potentially becoming chronic. Other long-term risks include increased susceptibility to infections, organ damage (affecting the liver, lungs, or heart), fertility issues, and a small risk of developing secondary cancers. Ongoing medical monitoring, including frequent clinic visits for at least the first 100 days, is necessary to manage these potential issues and support the patient’s long-term health. A successful bone marrow infusion can lead to a significant improvement in health and quality of life for many patients.