At the National Institute of Surgery and Transplantology named after O. O. Shalimov, the success of organ transplantations is ensured by precise selection of donors and recipients based on HLA antigens and constant monitoring of patients' immune systems. Thanks to this, patients with terminal organ failure get a chance not only to survive but also to live long and full lives, reports UNN.
Details
It is noted that there is a paradox in transplantology: the only chance to save a person in the terminal stage of kidney, liver, heart, lung, or pancreatic failure is organ transplantation. But along with the chance comes the biggest challenge: the patient's own immune system, which learns to recognize "self" throughout life and performs this job so well that it perceives any genetically foreign organ as a danger.
Specific proteins — HLA (human leukocyte antigens) — are located on the surface of each nucleated cell. They act as identifiers: "I am self."
When the immune system sees HLA that do not match the genetic "signatures" of the body, a chain of reactions is triggered: lymphocytes are activated, multiply, become cytotoxic, and synthesize antibodies against foreign antigens.
Therefore, complete or near-complete HLA compatibility between donor and recipient and the absence of HLA antibodies is the gold standard that significantly reduces the risk of rejection.
As soon as a patient is included in the "Waiting List" for transplantation, HLA typing is performed — a molecular genetic study that determines the individual set of antigens. This allows the system to automatically select potential donors with a related HLA profile
The next stage is HLA antibody screening, the so-called PRA test (Panel Reactive Antibody).
This is an indicator of how "alert" the recipient's immune system is.
PRA < 20% — minimal risks.
PRA > 20% — extended testing is required to determine against which specific HLA antigens antibodies have been formed. This avoids transplanting an organ that has "forbidden" antigens.
Immediately before solid organ transplantation, a study is conducted to determine donor-specific antibodies – Cross-match (CDC-test). This is one of the most important studies, the necessity of which prevents acute solid organ rejection on the operating table.
The selection of a "donor-recipient" pair is carried out only in specialized laboratories equipped with special equipment and staffed by qualified specialists who work around the clock (24/7). In Ukraine, there are only a few such fully functioning laboratories, mainly due to the lack of appropriate specialists and immunologists who would have specializations in transplant immunology.
However, such a laboratory has been established in our Center and successfully operates around the clock, meeting the urgent needs of the Center.
Even ideal compatibility does not guarantee that antibodies will not appear over time, therefore:
- kidney transplant recipients are tested for donor-specific antibodies every 3–6 months;
- recipients of other organs — once a year.
If signs of organ dysfunction appear, the immunogram changes, or HLA antibodies are detected, additional, sometimes urgent, testing is performed. And the "gold standard" for confirming rejection remains a puncture biopsy of the transplant. It is thanks to the thoroughness of these studies that transplantology today can not just prolong life — but give a chance to live long and full lives,