Welcome to the final part of our four-part series on blood cancer, written for Blood Cancer Awareness Month. This article will take a closer look at how cord blood stem cells are used to treat blood cancers.
What are stem cells?
Stem cells are the building blocks of the human body. They have the remarkable ability of being able to create copies of themselves and turn into different types of cells.
Some stem cells are highly specialised and can only differentiate into one type of cell, while others can produce many types of cells. Hematopoietic stem cells (HSCs), for example, can only turn into blood cells. Mesenchymal stem cells (MSCs), on the other hand, can turn into many types of cells including bone cells (osteoblasts), fat cells (adipocytes), cartilage cells (chondrocytes).
Researchers have discovered that they can transplant stem cells into patients to treat them for a wide range of illnesses — including blood cancer.
Why use cord blood stem cells?
Stem cells can be obtained from bone marrow, peripheral blood and umbilical cord blood. Cord blood is a particularly rich source of hematopoietic stem cells (HSCs) which can be used to treat blood cancers.
Cord blood stem cells are very useful because they are young cells with an increased tolerance for Human Leukocyte Antigen (HLA) mismatches. In simple terms, this means that cord stem cells are less likely to be rejected by the recipient’s immune system after being transplant. This also means that cord blood stem cells can be used even when there is only a partial HLA match between donor and recipient.
Another advantage of using cord blood stem cells is that they are easy to obtain. It takes about 15 minutes to extract the blood found in the umbilical cord and placenta after the birth of a child. It is a completely pain-free and risk-free process for both mother and child.
It is even possible for a parent to store the umbilical cord blood of their children, so their child will have stem cells available should they contract blood cancer at a later date. When a person receives a transplant of their own stem cells, it is called an autologous transplant.
How does a stem cell treatment work?
The most common treatment for blood cancer is chemotherapy. It involves the use of chemotherapy drugs to destroy or damage cancer cells.
Very high doses of chemotherapy are sometimes required to completely eliminate all of the cancer cells in a person’s body. Unfortunately, this can damage the bone marrow and make it impossible for the body to continue producing healthy blood cells. This makes the patient highly vulnerable to infections and diseases.
This is where stem cell treatments are valuable. The hematopoietic stem cells found in cord blood can be transplanted to re-establish the body’s ability to produce healthy blood cells. This restores the patient’s immune system and helps them recover after chemotherapy.
Certain types of blood cancers can also use mini allografts or reduced-intensity allografts. They are newer forms of transplantation that involve lower doses of chemotherapy. The stem cells are used to encourage the body to fight the cancer cells.
In most cases, stem cell treatments will not be used until conventional treatments like low dose chemotherapy have been tried and failed.
The stem cell transplantation process works as follows:
- Stage 1: Evaluation and preparation - Doctors will evaluate the health of the patient to determine if they can safely receive a transplant. Stem cell transplants can be hard on the body and there are certain risks involved. It is also a very emotionally draining experience as patients will have to be placed in isolation while their immune system is re-established. A variety of tests will be performed to check the patient’s eligibility for a stem cell transplant, including HLA tissue typing, physical exams, bone marrow biopsies, psychological evaluations, heart tests, lung studies, blood tests, and so on.
- Stage 2: Conditioning treatment - During this stage, the patient will receive multiple doses of chemotherapy and/or radiation therapy to kill the cancer cells in their body. This process will also suppress the patient’s immune system so it will accept the transplanted stem cells and make room in the bone marrow for additional stem cells. Typically, this process takes one or two weeks. The treatment will vary based upon the type of cancer that the patient is suffering from.
- Stage 3: Infusion of stem cells - The patient will then receive an infusion of stem cells via a central venous catheter. If the stem cells that the patient is receiving were in storage, some drugs may be needed to reduce the risk of an adverse reaction to the preservatives used when storing the sample. While there is a small amount of pain involved with inserting the catheter, receiving a stem cell transfusion is painless. There may be some mild side effects after the transfusion has been delivered including shortness of breath, coughing, chest pain, chest tightness, weakness, and hives.
- Stage 4: Recovery - Once the stem cells have been transplanted, it will take some time for the cells to engraft (merge into the recipient’s bone marrow), multiply, and produce healthy blood cells. In most cases, it will take between 2 to 6 weeks before the stem cells have brought the patient’s blood count back to normal. During the recovery phase, the patient’s immune system will be weak, so they will be kept in isolation and given antibiotics.
- Stage 5: Rehabilitation - Some patients will experience some side effects after having a stem cell transplant. This might include tiredness, inflammation, emotional distress, nausea and weakness. There is also an increased risk of infections, graft-versus-host disease, low thyroid function, reproductive or sexual problems, and slowed growth. During this time, the patient will require ongoing support and will need to regularly see their physician.
Thanks for reading How Cord Blood Stem Cells are Used to Treat Blood Cancers. We hope you enjoyed this series and gained some insight into blood cancer.