Every 16 minutes, a person in Germany receives the diagnosis of leukemia. If chemotherapy or radiation is not successful, stem cell or bone marrow transplantation is often the last chance for patients. In about one third of the patients a donation from the family comes into question, but often a donor is needed, which can be found by a donor file. Read here how you can be typified and learn more about the process and risks of a stem cell donation.
Looking for a "genetic twin"
For a leukemia patient to receive a stem cell donation, a "genetic twin" must be found: a donor that matches certain tissue features and surface markers on the white blood cells with those of the patient. If these features are very rare, only one in millions of people may be considered donors. That's why the search often takes several months.
To facilitate the search, it is important that as many people as possible are registered in a donor file. The largest and most well-known organization in Germany is the DKMS - the German bone marrow donor file. Since 1991, 3.7 million people have typed there.
By typing donors will be
Anyone between the ages of 18 and 55, physically healthy and weighing more than 50 kg can register in a donor file. In the past, it was necessary to take a blood sample for typing; today, a smear of the cheek mucosa is sufficient with a cotton swab. At DKMS you can register online and then receive a set sent home. After the swab has been removed, simply return the cotton swab - free of charge, of course. However, typing costs the DKMS 50 euros, which cover the laboratory costs for determining the characteristics. Therefore, the donor files are constantly dependent on donations and financing actions.
Frequently, typing actions are organized by the DKMS or other organizations, where everyone can obtain information and register directly without registering. There helpers remove the smear and are available for questions.
Find the right dispenser
After typing, the anonymous donor data is forwarded to the Central Bone Marrow Registry of Germany (ZKRD) where it is collected and distributed to patients worldwide. If a similarity has been identified between a leukemia patient and a potential donor, a blood sample will check additional donor tissue characteristics. If there is sufficient agreement, the potential donor is thoroughly examined physically.
Only when all prerequisites have been met and a doctor has clarified the procedures and all possible side effects, will the potential donor finally decide whether to donate. If it comes to a donation, stem cells can be removed by two different methods.
Donate stem cells or bone marrow?
Today, in 80 percent of cases, the so-called peripheral stem cell donation (apheresis) is performed. The donor is given a hormone-like substance (growth factor C-GSF) injected under the skin for five days. This causes the stem cells, which are usually predominantly located in the bone marrow, to increase and be swept into the blood. In this phase of stimulation, flu-like symptoms may occur.
After completing this phase, the so-called apheresis follows, which works in a similar way to a blood donation: via a venous access the blood is discharged and the stem cells are filtered out, at the same time the rest of the blood is returned to the donor. This method takes about four hours and is more convenient for the donor than a bone marrow donation, since it is done on an outpatient basis and no anesthesia is needed. If not enough cells could be collected, the procedure must be repeated the next day.
Operation with bone marrow donation
In the conventional method - bone marrow donation - bone marrow and life-saving stem cells are removed from the iliac crest under general anesthesia. Bone marrow is not to be confused with the spinal cord, which belongs to the central nervous system and has nothing to do with stem cell donation. The bone marrow is replicated quickly by the body, so it comes with the donor is not a defect. As with any surgery, there is a minimal risk of anesthesia and infection, and wound pain may occur. Mostly, the donor stays in hospital for one to two nights.
Since 1996, this method has increasingly been superseded by peripheral stem cell donation and is now only used in special cases. For example, a bone marrow donation is used when the recipient is a child or has some form of leukemia in which bone marrow is more effective.
Overall, the risks are low in both methods, usually the donor is fit again after a few days. The donation is usually made in a collection center in the vicinity of the donor in order to keep the effort for this as low as possible. All costs incurred will be covered by the health insurance of the recipient. After removal, the cells are taken by a courier to the patient's clinic where they are transplanted the same day.
What do the stem cells do?
In a preparatory phase (conditioning), the patient is completely destroyed by chemotherapy and other medications. This is important for two reasons:
- First, the cancer cells that are derived from the bone marrow must be destroyed as much as possible.
- On the other hand, the immune system of the patient must be suppressed so that the foreign stem cells are not rejected.
After this phase, the donor's healthy stem cells are transplanted, which the recipient receives as a blood transfusion into the veins. From the bloodstream, the cells find their way into the patient's own bone marrow by themselves. There, the stem cells settle and form new, healthy blood cells that kill the remaining cancer cells. Ideally, the donated stem cells thus defeat the leukemia and the patient is cured.
Risks and complications
The success rate of a stem cell transplantation is around 40 to 70 percent and depends on many factors such as the age and condition of the patient and the type of disease. In addition, as with any treatment complications may occur: Since the patient lives a few weeks completely without immune system, infections are very common despite extensive hygiene measures.
In addition, it can come to the so-called "graft-versus-host disease": The "foreign" immune system resulting from the donated stem cells attacks the body of the recipient. This manifests itself for example by skin and mucous membrane inflammation or by problems in the gastrointestinal tract. Last but not least, there is always the possibility that the cancer will come back.
Contacting the patient
You don't get any money for the stem cell donation - the reward is the good feeling of possibly saving a person's life. The donation is made anonymously, however, it is possible to contact the patient by letter. At the request of both sides, the anonymity is lifted after two years and there can be a meeting between the donor and the patient.