Haploidentic Bone Marrow Transplantation

Haploidentical transplantation:

In this type of transplantation, donor is a relative of patient who is not fully compatible.

It is a good alternative for patients who has no fully HLA-compatible donor. Fully compatible donor should be preferred, but if there is no such donor, partially compatible related donor should be considered. The consequence of this method in patients, who have not a chance to spend time searching for a non-related donor, is as successful as other transplantation methods. The most important disadvantage of haploidentical transplantation is higher risk of infection (since there is a significant antigen incompatibility). Therefore, it is necessary to monitor infections very carefully and take protective measures timely.

If a donor is searched for allogeneic stem cell transplantation, tissue groups of siblings, if available, are first analyzed. If no fully compatible donor can be found among siblings, close relatives of patient can be screened and final option will be “bone marrow banks”, if screening result is negative. It may take 2 to 10 months to search for a compatible donor from bone marrow banks.

Patient is first given high-dose chemotherapy in allogeneic stem cell transplantation, similar to autologous stem cell transplantation. Next, stem cells collected from a healthy donor (sibling, related or non-related) are transplanted to the patient. These stem cells enable production of healthy blood cells in bone marrow of the patient.

In allogeneic stem cell transplantation, “Graft versus host disease”(GvHD) is a possible risk that is secondary to tissue incompatibility between donor and patient. GvHD is a serious disease that can cause severe damage in organs of recipient. Therefore, it is critically important that patient and donor are fully compatible to the maximum extent possible.

Bone marrow is responsible for synthesis of cells that are needed for life and for coping with harmful factors and results. Uncontrolled or false synthesis or inability to synthesize these cells may result with diseases.

After these diseases occur, hematopoetic stem cell transplantation can be sometimes required due to recurrence of disease, even if recoveries can be achieved with various medical therapies, and/or inability to achieve recovery or need to high-dose chemotherapy in order to achieve recovery.

One should always remember that in bone marrow transplantations, patients are vulnerable to infection and sometimes bleeding. Generally, almost all patients who undergo allogeneic transplantation use immunosuppressive drugs and thus, one should be very careful for both risks of infection and drug interactions in other therapies.

While these risks are highly possible in allogeneic transplantations, there are short-term risks in autologous transplantations as no immunosuppressive drug is used. The compliance between stem cell of donor and tissue of patient is ensured with various immunosuppressive therapies.

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