Impact of killer immunoglobulin-like receptor-human leukocyte antigens ligand incompatibility among renal transplantation

Fatal accelerated rejection with a prominent natural killer cell infiltrate in a heart transplant recipient with peripartum cardiomyopathy

Accelerated rejection is uncommon after cardiac transplantation. The mechanism is hypothesized to be mediated by cytotoxic T cells and anti-HLA antibodies resulting from a memory response to the donor allograft in sensitized patients. A role for Natural Killer (NK) cell in cellular rejection has also been suggested. We report a case of fulminant accelerated rejection in a heart transplant recipient, with a history of peripartum cardiomyopathy (PPMC). The patient had no pre-transplant donor specific antibody and flow cytometric T and B cell crossmatches were negative. Autopsy revealed left ventricular subendocardial and intramyocardial hemorrhage with diffuse lymphocytic infiltrates and myocyte damage (Grade 3R rejection). Immunohistochemistry revealed a large proportion (50-70%) of mature CD16+ NK cells with cytotoxic potential in the interstitium and the intra capillary compartments. This case highlights the need for evaluating the potential role of NK cells in accelerated rejection in heart transplant recipients.

Putative role of KIR3DL1/3DS1 alleles and HLA-Bw4 ligands with end stage renal disease and long term renal allograft survival

BACKGROUND

Killer immunoglobulin receptors (KIR) are highly polymorphic in nature. KIR3DL1/3DS1 genes are known to affect HLA-B antigen binding affinity causing natural killer (NK) cell inhibition, which results into successful renal transplantation. In this study we have examined whether alleles of KIR3DL1/3DS1 play any role in changing the binding affinity with HLA-Bw4 antigen and if so then how are they associated with long term renal allograft survival. We have also evaluated plausible association of KIR3DL1 with HLA-A23/A24/A32 with renal pathophysiology.

MATERIALS AND METHODS

KIR3DL1/3DS1 allelic diversity was examined in 501 renal transplant cases and 507 controls. PCR-SSP was used to determine the incidence of KIR3DL1/3DS1 genes and HLA class-I antigens. KIR3DL1/3DS1 alleles were determined by sequencing. Expression at transcription level for KIR3DL1/3DS1 genes was evaluated in the presence of HLA-Bw4. Different statistical analyses were performed using SPSS v 22.0. p≤0.05 was considered significant. Sequence based variant effect was predicted using Variant Effect Predictor. To evaluate whether variation in KIR3DL1 and HLA interaction changes the binding affinity structure based effect prediction was carried out using MutaBind and BindProf software.

RESULTS

For KIR3DL1*0010101, no-risk and low mRNA expression was seen among antibody mediated acute rejection (ABMR) and chronic rejection (CR) cases. Whereas, 3DS1*01301, 3DL1*00401, and 3DL1*00402 showed susceptibility and elevated mRNA expression with ABMR and CR. Two mutations c.320C>T (rs143159382) and c.911G>T (rs35974949), present in alleles 3DL1*00402 and 3DL1*00401 were predicted to be deleterious. Reduced renal allograft survival was observed for individuals possessing KIR3DL1*00401-HLA-Bw4+. In relation to HLA-A locus no significance was observed with ESRD, ABMR, and CR.

DISCUSSION

The experimental and computational data corroborated with each other suggesting susceptibility for renal allograft in presence of 3DL1*00402 and 3DL1*00401 alleles.