FAQs About Bone Marrow Transplant for Porphyria
Porphyria is a group of rare diseases related to the production of a molecule called heme. Each type of porphyria is associated with a different mutation, affecting an enzyme in the metabolic pathway of heme production. As a result, high levels of heme precursors called porphyrins, accumulate in different parts of the body to cause disease symptoms.
In some types of porphyria, the faulty enzyme is made in the liver. In others, it is made in the bone marrow —and a bone marrow transplant might be a treatment option for these people.
Here are some frequently asked questions about bone marrow transplants and porphyria.
What is a bone marrow transplant?
A bone marrow transplant for porphyria involves transfusing to a patient hematopoietic (blood) stem cells from the bone marrow of a matched donor (an allogeneic transplant). The bone marrow is the spongy tissue inside bones that contains hematopoietic stem cells. These are cells that can give rise to a number of different blood cells, including red blood cells, platelets, and cells of the immune system.
Bone marrow transplants can treat, and possibly cure blood disorders.
What does a bone marrow transplant involve?
For a bone marrow transplant, stem cells are taken from the bone marrow of a matching donor, typically from their hip bone. They are then directly infused into your (or the patient’s) bloodstream while you are awake.
Prior to the infusion, you must undergo treatment to condition your body to accept the new cells. This conditioning usually involves the use of chemotherapy and, possibly, radiation therapy to make room to kill your cells for the donor’s healthy stem cells.
After the procedure, you will need an extended hospital stay — ranging from several weeks to, possibly, several months — until you are considered well enough to continue recovering at home.
Does it benefit all porphyria patients?
A bone marrow transplant is a possible treatment for hematopoietic porphyrias, or those where the excess porphyrins are produced in the bone marrow. Because of the potential and serious risks involved, however, they are typically considered only in severe cases of this disease, including those with secondary liver injury.
Researchers have tested bone marrow transplant in patients with congenital erythropoietic porphyria (CEP) and erythropoietic protoporphyria (EPP), including X-linked protoporphyria (XLP).
Where can I find a donor?
Donors can be a family or friend who is a match for you. In cases where donor matches do not exist, the U.S., like many countries, has a National Bone Marrow Donor Program that might help you find a suitable donor.
What are the risks of a bone marrow transplant?
A number of risks are associated with a bone marrow transplant. This procedure should only be considered if the benefits outweigh the risks for a given patient.
Initial treatments with chemotherapy and radiation therapy can cause damage to the mucous membranes in the body. They can also damage the liver and lead to a condition called veno-occlusive disease, in which small veins in this organ obstruct. Their use can also cause small blood clots to form in organs that include the kidneys and brain, a disorder called thrombotic microangiopathy. Your risk of infections also greatly increases following the chemotherapy and radiation therapy given before this transplant, as they are meant to wipe out your immune system so it won’t target the donor cells to come.
Donor stem cells can also cause potential damage to organs, possibly leading to a disorder known as graft-versus-host disease. In GVHD, which can be acute or chronic, the donor cells attack your cells and tissues, seeing them as foreign.
How long might recovery take?
The length of recovery varies from patient to patient. However, you likely will need to stay in the hospital for several weeks after the transplant. During the first 30 days following the infusion, the new stem cells will begin to grow inside your bones and make new blood cells. This is the engraftment period.
Patients usually leave the hospital within the first 100 days after their transplant. You then will need to continue to attend frequent outpatient care appointments, where crucial exams are given. It may take several more months, and possibly even years, for a full recovery from the procedure.
What can I expect?
For some patients, a bone marrow transplant can significantly ease and potentially end porphyria symptoms. But the procedure involves serious risks, and generally is only used to treat severe cases.
Last updated: Jan. 26, 2021
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