Definition
A stem cell transplantation is the transfer of stem cells from a donor to a recipient. Stem cells are body cells that are the origin for the development of other cells. They have the ability to differentiate into, for example, muscle, nerve and blood cells.
Mature stem cells are found in more than 20 organs of our body. They fulfil the special task of forming replacement cells and develop into a certain type of tissue. In everyday clinical practice, mature stem cells are usually obtained from the pelvic bone by means of bone marrow puncture. Nowadays, the transplantation of blood stem cells is of utmost importance.
Allogeneic stem cell transplantation
Allogeneic stem cell transplantation is defined as the transfer of stem cells between two different individuals. The receiving person receives the stem cells from a matching donor. The transplantation is preceded by a so-called conditioning phase. It serves on the one hand to suppress an immune reaction of the recipient against the transplanted cells and on the other hand to destroy the malignant, functionless cells. For this purpose, high-dose chemotherapy is used alone or in combination with radiotherapy.
Autologous stem cell transplantation
In an autologous stem cell transplantation, the recipient and donor are the same person. The stem cells are taken from the patient and stored. The transplantation is performed later and also after a so-called conditioning phase. As a result of chemo- and/or radiotherapeutic treatment, bone marrow and its cells are destroyed and replaced within the transplantation. The therapy efficiency is significantly increased compared to chemotherapy or radiation therapy alone.
Stem Cell Donation
If a suitable donor with similar characteristics to the recipient is found in the German donor file, a detailed examination of the donor is carried out with a lead time of about one month. There are two possibilities for stem cell collection. The stem cells are taken either from the bone marrow or from the blood.
Taking stem cells from the blood by means of stem cell apheresis through a vein is the most common method of obtaining the stem cells. It is performed on an outpatient basis and takes between four and five hours. A few days before the stem cell separation, the donor receives a drug that causes the stem cells to enter the blood.
The stem cell apheresis is performed in specialized centers. The venous blood enters a separator that filters out the stem cells and returns the blood to the body. A much less frequently performed method is the bone marrow puncture of the iliac crest.
The bone marrow donation is performed under general anesthesia. Between 0.5 and 1.5 liters of bone marrow are taken from the donor using a needle. The duration of the puncture is about one hour. Since this procedure may involve a greater loss of blood, the donor is given an autologous blood donation at the same time as the collection.
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