The soft, fatty tissue in the cavity of the bones is bone marrow. It is composed of a number of things, perhaps most importantly stem cells, which produce blood cells—both white and red. Somtimes bone marrow or stem cells get damaged, whether from an acquired disease (such as cancers or bone marrow failure syndromes), severe immunodeficiencies, medical treatments (such as chemotherapy), or genetic disorders (such as sickle cell anemia). Bone marrow transplants can be used to help the stem cells begin functioning properly again by introducing new cells into the marrow.
A transplant may be autologous, which means your own stem cells are removed before undergoing chemotherapy or radiation, cryofrozen quickly and at extreme temperatures, and then replaced after treatment so that blood cell production can be regenerated.
If someone else donates marrow or stem cells to you, cells may be collected via bone marrow harvesting, a minor operation in which marrow is removed from the hips or clavicle with a large needle. Leukapheresis is another option. With it, blood is drawn with a needle from one arm, sent into a machine that extracts peripheral blood stem cells, and then sent back into the donor’s body through a needle in the other arm. This is known as an allogeneic transplant.
While it can be a life saving procedure (although painful, especially for the donor), there are some serious risks associated with both sides of a bone marrow transplant.
Risks for Recipients
For those receiving a transplant, how severe and what kind of complications you will face depends on what disease the transplant is intended to help, how healthy you are otherwise, and your current age. During the procedure, you may experience a fever, chills, pain (especially in the chest), and even hives. Afterwards, when waiting for engraftment (which occurs when stem cells enter the marrow and begin producing new blood cells) the risks are much more serious.
You may be looking at a hospital stay of several weeks, as your chances of contracting an infection are greatly increased. Additionally, you may bleed more than normal and need transfusions.
Your doctor will probably write you a lot of prescriptions—specifically, antibiotics to stave off infection and, in allogeneic transplants, medication to keep your cells from attacking the new cells that have been introduced to your system. These medications can come with their own risks and complications. Symptoms such as diarrhea, nausea, feelings of weakness, confusion, and sores in the mouth are all potential risks of these drugs.
Cataracts, infertility, and new cancers are also potential complications, according to the Mayo Clinic, as is, unfortunately, death.
Risks for Donors
The worst part of donating marrow is the pain that follows, which can be managed with pain relievers. It may take a couple of days before you feel completely normal again, during which you may experience some weakness, be more tired than normal, and find walking difficult. The spots from which the marrow or blood are drawn may be tender and painful as well. Bone marrow harvesting is more likely to cause these issues than leukapheresis, especially since harvesting comes with all the risks associated with an operation that requires anesthesia.
The risks of leukapheresis are pretty minimal, which is part of the reason it has become the more common method. There are still some side effects though. The medication you must take in the days leading up to the procedure in order to move stem cells into the blood can cause nausea and vomiting, tiredness, and aches in the head, bones, and muscles.
Although the following symptoms should disappear once everything is over, during the procedure, your hands may cramp and your mouth may feel numb or tingle. Some people have veins that are simply too small to draw blood of this magnitude from, and so the catheter will have to be placed in the larger veins of the neck, groin, or chest.
It is possible, although rare, for bleeding or infection to occur, as well as for air to become trapped between the lungs and chest. However, overall, the risks are extremely low, especially when you consider the benefit: saving a life.