Figure 3.

(A) Interaction of NKG2D receptor with its ligand MICA, expressed on endothelial cells, results in activation of NK cells leading to their damage. (B) Over expression of MICA on endothelial cells membrane and its proteolytic shedding from the surface leading to the formation of sMICA. The latter interacts with the NKG2D receptor, resulting in its internalization and subsequent suppression or impairment of NKG2D-mediated immune response; (C) preformed or de novo-developed MICA antibodies recognize MICA antigens present on the allograft leading to acute or chronic rejection; (D) potential impact of MICA-129 met/val dimorphism on renal graft outcome. Patients expressing met/met in homozygous state are prone to rejection episodes than those with val/val genotype.