Bone marrow donation

• Contact between donor and recipient

definition

People from one Bone marrow donation can benefit are patients with a leukemia, which is generally referred to as blood cancer, such as one acute myeloid leukemia or one acute lymphoblastic leukemia. Be in the course of the bone marrow donation Blood stem cells (hematopoietic stem cells). Your whereabouts are primarily in Bone marrowwhere cells in the blood, such as red blood cells (Erythrocytes) getting produced. This formation is known as Hematopoiesis. It is responsible for the continuous supply of blood cells.

In the case of bone marrow or stem cell transplants, it is possible that the donor and recipient are one and the same person, i.e. the person concerned receives hematopoietic cells from himself. In this case, one speaks of an autologous transplant. In an allogeneic transplant, the donor and recipient are two different people (see: stem cell donation)

Autologous and allogeneic transplant

• As part of a autologous transplant the person affected receives their own haematopoietic stem cells. These are in front of a chemotherapy from the blood or that Bone marrow isolated. If you intend to take a sample from the peripheral blood, the hematopoietic stem cells be lured from their location, the bone marrow, by the administration of haematopoietic growth factors. The hematopoietic growth factors are among the skin injected. The searched cells can then be sorted with the help of cell separators (Leukapheresis) are separated from the blood. Tumor cells can then be differentiated from haematopoietic stem cells using special methods, so that later transplantation no tumor cells in the affected person be introduced.
• For one allogeneic transplant becomes a willing and tissue-compatible bone marrow donor needed. This type of transplant is usually used when the hematopoietic stem cells of the person affected have been completely destroyed by treatment measures. This happens as part of a myeloablative therapy, a therapy that leads to the destruction of the bone marrow and the hematopoietic stem cells enclosed in it. Usually requires high-dose chemotherapy or a Irradiation such a downfall. Recently, however, allogeneic transplantation has also been used in patients whose haematopoietic stem cells have not been destroyed.

Bone marrow donation

For the one just described allogeneic transplant people are needed who one Consent to bone marrow donation. When looking for a suitable bone marrow donor, one can look to three different ways get to the goal.

1. The greatest likelihood of finding a suitable donor is there among siblings, it is included about 25%. This type of search is known as Core Family Donor Search (CFDS).
2. Also at other members of the family can be kept on the lookout for a suitable donor (Extended Family Donor Search EFDS for short). The probability of a successful search decreases to approx. 5%.
3. Finally there is still the possibility of External donation, i.e. a donor search among unrelated people registered in a register. This search is as Unrelated Marrow Donor Search (UMDS) known. Due to the worldwide number of more than 14 million donors, a search success is possible with a probability of about 90% considerable. Even if a suitable donor can be identified in this way, the chances of success are higher for tissue-compatible related donorsthan for tissue-compatible unrelated donors.

Bone marrow donation file

All over the world there are more than 14 million peoplewho, if necessary, have a Bone marrow donation would undergo. In Germany are about 4 million donors registered. The German bone marrow donor file (DKMS) in Tübingen is the world's largest register of potential donors. The dates of people who would undergo bone marrow donation are from central bone marrow donor registry in Germany (ZKRD) based in Ulm. This is where data from patients and donors come together and are compared to each other in order to find a suitable donor for the bone marrow donation.

Requirements for inclusion in the German bone marrow donation file:

• between the 18th and 55th (maximum 60) years of age
• physical health
• Body weight of at least 50 kg and Body mass index (BMI) of maximum 40
• Place of residence in Germany or a maximum of 50 km from the German border away

There are also exclusion criteria for the safety of the potential donor and also of the person concerned, i.e. the recipient:

• Belonging to one of the German Medical Association designated risk group and several diseases: diseases of the central nervous system and the psyche, Diseases of the respiratory tract, Cardiovascular disease, Disorders of the Blood clotting and other diseases of the Blood and the Blood vessels, Diseases of the endocrine glands (e.g. pancreas), Autoimmune diseases, Cancers and also serious infectious diseases (e.g. Hepatitis B., Hepatitis C. or HIV)
• Alcohol, drug, or medication addiction
• one or more from another person donated organs or tissues
• also widespread diseases: an inadequately adjusted one high blood pressure, one coronary heart disease, Diabetes mellitus and severe chronic asthma

That's enough Existence of an exclusion criterionto make inclusion in the file impractical.

Without one of the exclusion criteria and the endeavor possibly one time Bone marrow donation to complete, nothing stands in the way of inclusion in the German bone marrow donation file. This can be done through a Online registration, during a Registration action or in one permanent establishment respectively.
The necessary information about the donor can be obtained with the help of a Blood collection or one Smear of the cheek mucosa be won. These are then saved in the German bone marrow donor file (DKMS) and im National Marrow Donor Program (NMDP) recorded in the USA and made available anonymously for a potential recipient around the world. The determination of the tissue characteristics is associated with costs that are borne by the Central Bone Marrow Donor Register for the Federal Republic of Germany (ZKRD) through monetary donations. A short time after successful registration, the potential donor will receive an Donor card with a donor numberwith which he can identify himself for all things relating to bone marrow donation.

Information needed to be able to say whether the donor and recipient are compatible, are information about the HLA antigens ("Human leukocyte antigens"). These are with the Blood group antigens comparable that determine whether someone has blood group A, B, AB or 0. The blood group itself does not play a role in a bone marrow donation, which means that the blood type from donor and recipient do not necessarily match have to.
The HLA antigens are Surface structures on human cellswhich represent a possibility for the organism to distinguish between the body's own and non-body tissue. To a Rejection reaction on the part of the recipient is a high degree of prevention Similarity between the tissue features absolutely necessary. The five essential HLA characteristics are A., B., C., DRB1, DQB1which are all located on one chromosome of the 46 chromosomes of a human being. This brings the inheritance together as a so-called haploid genotype (haplotype for short) instead. We ever get a haplotype from the mother and a haplotype from the father inherited. As a result, an ideal donor must have exactly the 10 HLA characteristics of the recipient.
However, there are HLA traits of each very many designs (so-called Alleles), which leads to an immeasurably large number of possible combinations. This requires a vanishingly small probability of a perfect match the HLA characteristics. Due to the conditions to be met, it occurs at maximum five out of a hundred donated bone marrow donors within a period of 10 years. Young donors who have agreed to donate bone marrow are slightly more likely.

What if a potential donor is tissue compatible?

Do they fit Tissue characteristics of the registered human to those of an affected person, the German bone marrow donor center (DKMS) in contact with the donor.
The rest of the procedure involves a health check and a new HLA typing, the so-called Confirmation typing, on English Confirmatory Typing (CT). The one sent Health questionnaire serves to record possible current health exclusion criteria. With the help of another Blood collection it can be verified whether the HLA characteristics of the donor and recipient actually match. The confirmation typing can via the family doctor happen or through a doctor who is registered with the German bone marrow donor database (DKMS).

For donors who were registered a certain time ago, to be precise, took place before 2010 can have a determination of other HLA characteristics in the blood be necessary, as these in particular have not yet been evaluated at the time of registration. In addition to a renewed determination of the HLA characteristics is also in the blood Infectious agents, like for example Hepatitis viruses looked. With the help of the results, a decision is made as to whether the donor and recipient are compatible. If this is the case, nothing stands in the way of a bone marrow donation.

It will then be determined by different aspectssuch as the current health condition of the person concerned. Once all the hurdles have been overcome, the donor becomes one final decision expected after a enlightenment on the part of the donor file about the upcoming intervention is done. The donor then becomes a written declaration of consent required. A physical examination is also part of the procedure, which is carried out in advance. Begins with the person affected about a week before the planned donation preparing for the bone marrow transplant. This includes one targeted destruction his damaged bone marrow using high-dose chemotherapy or radiotherapy. Once this has been initiated, the person concerned is dependent on a bone marrow donation, because without this his survival is at risk.

Process of bone marrow donation

The hematopoietic stem cells required are primarily located in the iliac crest. There are currently two ways to obtain the desired haematopoietic stem cells. A peripheral removal of hematopoietic stem cells and classic bone marrow donation must be distinguished from one another.

As a rule, a donor must be willing for both procedures. If you prefer a certain method of bone marrow donation, you will of course try to take it into account. However, from a medical point of view, there is a possibility that only one specific procedure is possible for the person concerned.

1. Peripheral collection: The donor must be given hematopoietic growth factors (G-CSF) over a period of five days so that the hematopoietic stem cells are produced in greater numbers and are lured out of their location, the bone marrow. The abbreviation G-CSF is derived from the English term Granulocyte Colony Stimulating Factor, which means granulocyte colony stimulating factor in German.
   Once this has happened, the cells can be removed. This is done on an outpatient basis without anesthesia and takes about 3 - 4 hours. Here, the blood is drawn from a vein in the arm through a cell separator, where components of the blood are filtered out. The blood then returns to the organism via an arm vein in the other arm. Occasionally, if the yield is poor, it may be necessary to take it again the next day. The procedure is known as stem cell apheresis and is now used in around 80% of cases. This means that in most cases a bone marrow donation does not require any surgical intervention at all.
2. The classic bone marrow donation: about 1 - 1.5 liters of bone marrow-blood mixture are removed from the iliac crest with a special needle under general anesthesia. Within a few weeks, the donated bone marrow has formed again. All in all, the procedure with induction and discharge of the anesthesia takes up to 1 ½ hours. For this, the donor is admitted to the hospital the evening before and can usually leave the hospital on the day of the removal, but no later than one day after the removal. The removed bone marrow can then be transfused to a suitable recipient.

Read more on the topic: Bone marrow puncture

Possible complications

The risk for the donor in the course of a bone marrow donation is low and, in the case of classic bone marrow donation, is largely the same as the risk of anesthesia that is associated with every anesthetic performed.

Inadequate differentiation between bone marrow and spinal cord is widespread. Since the spinal cord plays no role whatsoever for a bone marrow donation, bone marrow donation does not involve an intervention on the spine, as is often assumed by the public. Therefore, paraplegia as a complication of bone marrow donation is not to be feared.

Complications that can occur are subsequent local pain and bruising in the area of ​​the removal site. Pain that extends over a longer period of time is rare. If the bone marrow donation takes place via a peripheral removal, the ingestion of the haematopoietic growth factor (G-CSF) can lead to symptoms that are familiar from the flu. Diffuse muscle and bone pain and headaches can also occur. However, the symptoms usually subside within a few days and can also be treated with painkillers if necessary.

You might also be interested in: Pain in the iliac crest

Financial and organizational aspects

All the costs brought about by the Bone marrow donation arise, such as for preliminary examinations or hospitalization covered by the health insurance. Also Traveling expenses or costs incurred by one occurring loss of earnings are covered by the health insurance.

Depending on the type of bone marrow donation, a Sick leave for the days of the donation (peripheral extraction) or for issued approximately one week (classic bone marrow donation). The German bone marrow donor file (DKMS) will contact the employer in the event of an upcoming bone marrow donation. The Sick pay is carried out either by the employer or the German bone marrow donor database (DKMS).

About the statutory accident insurancewhich also protects donors of autologous tissue, and two other accident insurance policies that are taken out by the German bone marrow donor database (DKMS) are the donors during the procedure and also on the way to and from the removal site, assured.

Contact between donor and recipient

Generally a contact is when Both donors and recipients agree, possible. On a personal basis or through direct letter contact, however, this is in view of the German guidelines only after two yearsafter the bone marrow donation has taken place. In the meantime is a anonymous exchange of letters or gifts Can be implemented via the German bone marrow donor database (DKMS). In the case of bone marrow donations for those affected abroad, the regulations may differ from the German regulations.