Figure 3.

Proposed combined donor HLA genotype and recipient KIR haplotype effect on controlling BKV infection in kidney transplant recipients and further effect on BKV-associated nephropathy development. (A) Lack of an HLA-Cw7 molecule in donor causes non-efficient binding and presentation of viral peptides to NK cells in combination with low affinity of KIR-HLA binding; conversely, recipient carrying KIR haplotype AA lacks activating KIR receptors, which could recognize other non-HLA ligands to activate the NK cell. Without NK cell activation, a virus-infected cell remains unrecognized. (B) HLA-Cw7 molecule in donor strongly binds the viral peptide and presents it to recipient’s NK cells carrying KIR receptors of haplotype Bx, which have strong affinity for HLA ligands; recipients carrying KIR haplotype Bx have higher number of activating KIRs leading to NK cell activation and the killing of the infected cell.