Transplantation

Transplants may be:

the patient's own tissue (autografts: bone, bone marrow and skin grafts);
genetically identical tissue (isografts: donor tissue from a monozygotic twin);
genetically dissimilar donor tissue (allografts or homografts)
less commonly: grafts from another species (xenografts or heterografts)

The transplanted tissue may be:

cells;
parts or segments of an organ;
whole organs;
tissues.

Transplantation is performed to replace an organ with end-stage disease, restoring organ function and improving patient survival. Many procedures (for example, transplantation of the hand, larynx, tongue and face) improve quality of life but do not improve survival, and they carry considerable risks associated with the surgery and with immunosuppression. These types of transplantation are still at an early, experimental stage.

With rare exceptions, clinical practice uses allografts from living relatives, unrelated donors or deceased donors. From living donors, the kidney and haematopoietic stem cells (HSC) are retrieved most often, liver segments less often, and pancreas and lung grafts more rarely still.

Graft rejection and GvHD (graft-versus-host disease)

All allograft recipients are at risk of rejection; the recipient's immune system recognises the graft as foreign and attempts to destroy it. Recipients of tissue grafts that contain immune cells (notably bone marrow, intestine and liver) are at risk of developing graft-versus-host disease. The risk of these complications is minimised by pre-transplant screening and by immunosuppressive therapy during and after transplantation.

Pre-transplant screening

Before a transplant procedure, doctors carry out a comprehensive work-up of the potential recipient to identify medical and non-medical factors that may affect the success of the operation.

Tissue compatibility

Pre-transplant screening of recipients and donors determines:

human leukocyte antigens (HLA);
ABO antigens.

Recipients are also tested for pre-existing sensitisation to donor antigens.

HLA tissue typing is most important for:

kidney transplantation;
HSC transplantation.

Some organs are usually transplanted without delay, often before HLA typing results are available, so the significance of tissue compatibility for these organs is less well studied.

heart;
liver;
pancreas;
lungs.

Infection

Before transplantation, the risk of infection is reduced by ruling out any possible exposure of the donor and the recipient to infectious pathogens, any active or latent infectious process, and the risk that an existing infection in the recipient will worsen or reactivate (as a result of the immunosuppressants used).

Contraindications to transplantation

Absolute contraindications to transplantation include the following:

active infections;
cancer (except hepatocellular carcinoma and certain neuroendocrine tumours in the recipient);
a positive cross-match between donor and recipient blood, determined by lymphocytotoxic testing.

Relative contraindications include the following:

age > 65
poor functional status or poor nutritional status of the patient (for example, severe obesity);
HIV infection;
multiple organ failure.

Post-transplant immunosuppression

Immunosuppressants suppress graft rejection and the primary response to the transplant itself. At the same time they suppress all types of immune response and play a negative role in the development of numerous post-transplant complications, such as cancer, accelerated progression of cardiovascular disease and even death from severe infections.

Post-transplant complications:

rejection;
infection;
renal failure;
cancer;
atherosclerosis.

Transplantation in Germany

Although transplantation in Germany has become a routine procedure in recent years, this field of medicine is particularly closely regulated by law. Organ and tissue transplant procedures in Germany are performed exclusively in clinics and centres certified to the highest quality standards.
Modern transplant medicine gives preference to the transplantation of human organs and tissues.
Even though organ transplantation in Germany is far more expensive than in other countries, patients from many countries are drawn to it by the qualifications of German transplant specialists, the high standard of preliminary diagnostics, and the quality of post-operative treatment and monitoring.

International patients most often turn to German clinics for transplantation of the following:

liver;
kidneys;
pancreas;
small intestine;
stem cells;
heart;
cornea, etc.

Performing the organ transplant is only half the job. It is vital to achieve stable function of the organ and to prevent rejection. That is why German centres devote enormous attention to: