Stem Cell Transplant: What Is It?

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Stem Cell Transplant: What Is It?
Stem Cell Transplant: What Is It?

Video: Stem Cell Transplant: What Is It?

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Video: Types of stem cell transplants: autologous vs. allogeneic 2023, January
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Stem cell transplant: what is it?

Stem cell transplantation is a tried and tested treatment for severe diseases of the blood-forming system (e.g. leukemia, myelodysplastic syndrome, congenital anemia), lymphomas, congenital immune defects or certain metabolic diseases. These diseases often have life-threatening consequences.

Stem cells are obtained from the peripheral blood, from the bone marrow or from umbilical cord blood and prepared for therapy. The stem cells can come from the patient himself (autologous stem cell transplantation) or from a tissue-compatible, related or unrelated person (allogeneic stem cell transplantation).

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  • more on the subject
  • What are stem cells?
  • What happens during a stem cell transplant?
  • What is an autologous stem cell transplant?
  • What is an allogeneic stem cell transplant?
  • What is a haploidentical stem cell donation?
  • What pre- and post-treatment are necessary?
  • What complications and side effects can occur?
  • What happens during aftercare?
  • Where can I find an adult stem cell transplant center?
  • How are the costs going to be covered?

An optimal match of the HLA (human leukocyte antigen) tissue characteristics of the recipient and the donor is important for the success of an allogeneic stem cell transplant. Matching stem cell donors can be found in the nuclear family (with siblings) and rarely in other close relatives.

For the majority of patients, however, an unrelated donor - an unrelated donor - has to be found. The chance of the search being successful depends on the tissue characteristics of the patient. Certain tissue features are relatively common, while others are very rare. On average, the probability of finding a suitable donor is around 1: 500,000.

What are stem cells?

Stem cells are responsible for blood formation. They are located in the bone marrow and constantly renew themselves through cell division. Blood stem cells produce mature blood cells, namely leukocytes, erythrocytes or platelets.

In diseases of the blood-forming system, stem cells can be affected. This can lead to increased production (leukemia) or decreased production (aplasia) of blood cells.

What happens during a stem cell transplant?

In stem cell transplantation, donated stem cells are transferred to the patient after therapy (e.g. chemotherapy, radiation). This rebuilds the blood-forming system. As a result, the immune system is also restored.

The patient is first prepared to accept the foreign stem cell donation using conditioning therapy. So that the stem cell donation is not rejected later, the patient's immune system is suppressed with medication or with whole-body radiation (immunosuppression).

When the stem cells are transplanted, the stem cell preparation is administered in the form of an intravenous infusion.

What is an autologous stem cell transplant?

With autologous stem cell transplantation, the patient's own stem cells are transplanted.

This treatment is primarily used for multiple myeloma, certain malignant lymphomas, and testicular cancer. First, the patient is treated with chemotherapy. This is to remove tumor cells. The patient then receives a special medication, a so-called growth factor. This stimulates an increased transport of stem cells from the bone marrow into the bloodstream. After a few days or weeks, the stem cells can be collected from the blood using a special procedure (stem cell apheresis). The stem cell preparation obtained is stored frozen until the transplant. Often, additional chemotherapy is carried out before the stem cell transplant.

What is an allogeneic stem cell transplant?

In allogeneic stem cell transplantation, patients are treated with stem cells that have been donated by another person.

This method is mainly used for severe diseases of the blood-forming system (e.g. leukemia, myelodysplastic syndrome, congenital anemia), for lymphomas, congenital immunodeficiencies or certain metabolic diseases.

The stem cells for the transplant mostly come from a tissue-compatible person. It can be an HLA (human leukocyte antigen) identical sibling or an unrelated person who shares as many HLA characteristics as possible with the patient (third party donor). HLA traits are hereditary blood group properties that can be detected on the cell membrane of leukocytes. The variety of HLA characteristics is very large. Over 10,000 HLA "types" are currently known.

What is a haploidentical stem cell donation?

In addition, there is the possibility of an HLA-haploidentical stem cell donation. In these donors, only half of the HLA characteristics match the patients. With this method, parents or biological children are usually used as donors. In these cases HLA characteristics do not match between recipient and donor; This fact can now be taken into account through special treatment protocols.

What pre- and post-treatment are necessary?

Before and for some time after the stem cell transplant, the immune system is weakened due to the treatments. Therefore, the patient is given preventive medication to reduce the risk of infections. In addition, red blood cell and platelet concentrates can support the therapy.

In most cases, the patient's blood formation regenerates two to four weeks after the stem cell transplant. This improves the blood values. Around three months after the transplant, the recipient's hematopoietic system is completely replaced, and the recipient has thus also accepted the donor's blood group.

A moderate immunological rejection reaction of the transplanted stem cells (graft-versus-host reaction) on the organism or on the cells of the recipient is desired: It is also directed against remaining tumor cells / leukemia cells that are destroyed as a result (graft-versus Tumor / leukemia effect). This fact contributes to the long-term success of the therapy.

However, in order to avoid severe, life-threatening rejection reactions, the patient is given special medication to suppress the immune system (immunosuppressants) for around six months. A lifelong intake of immunosuppressants is not necessary with stem cell transplants - in contrast to organ transplants. For more information, see Transplant: Immunosuppression.

What complications and side effects can occur?

Before and after a stem cell transplant, various complications can occur as a result of chemotherapy, radiation, and immunosuppression. These include:

  • Nausea, vomiting, hair loss, inflammation of the oral mucosa and skin,
  • Infections caused by bacteria, fungi and viruses,
  • delayed regeneration of the bone marrow - neutropenia, aplasia.
  • Disorders of the endocrine system (infertility), growth retardation in children.

Another frequent complication after an allogeneic stem cell transplant is graft versus host disease (GvHD): The transplanted immune cells (T lymphocytes) are directed against the patient's tissue and can damage organs.

The GvHD can be different:

  • Acute GvHD shows symptoms such as rashes, diarrhea, or liver inflammation shortly after the transplant.
  • Chronic GvHD can occur several months after the transplant. It is characterized by recurring infections. Numerous organs can be affected. Symptoms are, for example, skin rashes, inflammation of the mucous membranes and the gums, nausea, diarrhea, weight loss etc.

What happens during aftercare?

Regular medical checks are necessary after the stem cell transplant and discharge from the hospital. Follow-up care takes place on an outpatient basis in the transplant center. Often the referring specialist in hematology and oncology is also involved in the follow-up care.

During follow-up care, the doctor checks the patient's state of health. Complications and long-term effects should be recognized in good time and treated if necessary through various examinations (e.g. blood tests). The doctor checks the medication and, in the case of an allogeneic stem cell transplant, the immune status. In some cases, further psychological support can be helpful due to the stressful life situation.

Where can I find an adult stem cell transplant center?

Stem cell transplants are carried out in hospitals with transplant centers. The referring doctor will carry out the referral.

You can find a list of stem cell transplant centers here.

How are the costs going to be covered?

All necessary and appropriate diagnostic and therapeutic measures are taken over for the insured by the respective social insurance. In principle, your doctor will settle accounts directly with your health insurance provider. With certain health insurance providers, however, you may have to pay a deductible (e.g. BVAEB, SVS, SVS, BVAEB). However, you can also use a doctor of your choice (ie doctor without a health insurance contract). For more information, see Costs and Deductibles.

For certain examinations (e.g. MRI), approval from the chief physician may be required. For certain non-drug treatments (e.g. physical therapy) - in some cases only when a certain level has been reached - approval from the health insurance provider may be required. For certain services (e.g. inpatient stays, aids and medical aids) - depending on the health insurance provider - patient co-payments are provided. Further information can be found under What does the hospital stay cost. Medical aids must first be prescribed by the doctor. Most health insurance providers provide for a permit, sometimes depending on the type of medical aid. The prescription fee has to be paid for medication on a “cash prescription”.For information on the respective provisions, please contact your health insurance provider, which you can find on the social security website.

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