The success of the transplantation depends on many factors. These include, inter alia, the appropriate selection of donor age, compliance within HLA, degree of sensitization – anti-leucocyte antibodies level, primary disease causing the need of kidney replacement therapy, state of the other organs and coexisting diseases. No less important are the other donor-dependent factors, time of the cold ischemia, ischemia-reperfusion injury and a number of immunological and genetic factors.

All these conditions affect the function of the transplanted kidney, including the possibility of acute and chronic rejection occurrence. Since the early 1970s of the last century, kidney biopsy has become the gold standard for diagnosis of its function abnormalities. This examination allows to an assessment of the appropriate kidney morphology, processes underway in the various structures, mainly glomeruli and interstitium, as well as the severity of the disease. Transplanted kidney biopsy is carried out in patients with acute rejection suspicion, as well as in assessing the extent of chronic rejection. In addition, protocol biopsy is performed in order to monitor the function of transplanted organ.

All components of the immune system are implicated in inflammatory response after transplantation. The grade of immunological response is dependent on the compatibility of the antigens between donor and recipient. This immune system reaction to the transplanted organ is called rejection. In regard to severity and duration of this process we can distinguish: hyperacute, acute and chronic rejection. Hyperacute rejection appears immediately and is correlated mostly with the presence of antibodies against MHC antigens, ABO group antigens, and other present on the surface of endothelial cells. Acute rejection may appear after a few days or months or even a year after transplantation. It is initiated by activation of cellular response to donors’ tissue.

The process of transplanted organ rejection includes interstitial tissue and endothelial cells damage, due to the complex activity of T lymphocytes, granulocytes, macrophages and circulating antibodies. Cell-mediated immune response is associated with a number of processes, leading to the activation and proliferation of specific lymphocytes, involved in the process of transplanted kidney rejection. In the course of this reaction synthesis and release of inflammatory reaction of many mediators can be observed, leading to changes within the renal vessels walls with reduction of their light, and even complete occlusion. The consequence of this process is necrosis of the organ. In cellular immunological response mediators for activated T and B lymphocytes are implemented and initiate a cascade of inflammatory process. In the early stage of inflammation, leukocytes interact with walls of the vessels, thanks to the presence of the adhesion molecules on the surface of endothelial cells and inflammatory cells. This allows the adhesion of inflammatory cells to endothelial cells, and then transmigration through the wall to the place of inflammation. This is a key process for the development of the immune response.

Written by: Karolina Kłoda MD, PhD

Source:
1. Analysis of the ICAM1 gene and VCAM1 gene promoter polymorphisms association with function of the transplanted kidney. Doctoral thesis. Karolina Kłoda, Pomeranian Medical University, Stettin 2009
2. http://medtube.pl/patomorfologia/filmy-medyczne/656-nerki-ostre-odrzucanie-przeszczepu


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“Acute rejection of the transplanted kidney”