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Transplantation of organs and tissues

Transplantation of organs and tissues (synonym organ and tissue transplantation). Transplantation of organs and tissues within one organism is called autotransplantation, from one organism to another within one species - by homotransplantation, from the organism of one species to the organism of another species - by heterotransplantation.

Transplantation of organs and tissues with subsequent engraftment is possible only with biological compatibility - the similarity of antigens (see) that make up the tissue proteins of the donor and recipient. In its absence, the tissue antigens of the donor cause the production of antibodies in the recipient organism (see). There is a special protective process - the reaction of rejection, followed by the death of the transplanted organ. Biological compatibility can only be with autotransplantation. It is not with homo-and heterotransplantation. Therefore, the main task in the implementation of transplantation of organs and tissues is to overcome the barrier of tissue incompatibility . If, during the embryonic period, the body is exposed to some antigen, then after birth, this organism no longer produces antibodies in response to the repeated introduction of the same antigen. There is an active tolerance (tolerance) to the foreign tissue protein.

It is possible to reduce the rejection reaction by various actions that suppress the functions of systems that produce immunity against a foreign organ. For this purpose, the so-called immunosuppressive substances are used - imuran, cortisone, anti-lymphocyte serum, as well as total X-ray irradiation. However, this results in the suppression of the body's defenses and the function of the hematopoietic system, which can lead to serious complications.

Currently, autotransplantation of the skin is widely used to close post-burn defects, and bones, cartilage, tendons , etc. are successfully transplanted. Homotransplantation is used in cornea and cartilage transplants. Renal transplantation from one person to another is becoming more common. The greatest chances of engraftment occur in cases where the donor and recipient tissues are close in their antigenic composition. The most ideal conditions exist in identical twins. However, the kidneys are transplanted not only from living persons, but also from corpses. The selection of a donor, which is carried out by determining the compatibility of blood erythrocyte and leukocyte antigens, is important. There are a number of other samples to establish the degree of similarity between organs and tissues of the donor and recipient.

Indications for kidney transplantation occur when a sharp violation of their function due to severe illness ( chronic nephritis , polycystic, etc.). Many kidney transplants have already been performed, some patients have been living for more than three years after the operation and are quite able-bodied.

In 1967, Barnard (S. N. Barnard) and his collaborators produced the world's first successful homotransplantation of a person’s heart. Further success in organ transplantation is associated with finding ways to overcome the barrier of tissue incompatibility.