54-P: NO ASSOCIATION BETWEEN THE NUMBER OF ACTIVATING KIR GENES AND THE INCIDENCE OF CMV DISEASE IN LIVER TRANSPLANT RECIPIENTS

Abstract

Aim Late onset CMV disease is an important complication in CMV seronegative transplant recipients (R-) receiving livers from CMV positive donors (D+) after discontinuation of antiviral prophylaxis. Predicting the risk of developing CMV disease will allow for better targeted therapy. Natural Killer (NK) cells may play a role in modulating CMV disease. Increased number of NK activating killer cell immunoglobulin-like receptors (KIR) genes has previously been associated with a lower rate of CMV disease in kidney transplant recipients. Methods We assessed the relationship between recipient, or donor, KIR genotype and the incidence of CMV disease in a cohort of consecutive CMV D+R- liver transplant recipients (n = 170). All recipients received 3 months of standard anti-viral prophylaxis and were followed for 1 year post transplant or until death. Fifty six patients (33%) developed CMV disease post transplant. HLA and KIR genotyping of recipients and donors was performed by SSP and SSO methods respectively. Results We observed no association between the number or type of recipient, or donor, activating KIR genes and the incidence of CMV disease. There was a trend towards a lower incidence of CMV disease in patients who had 1) 3 recipient inhibitory KIR genes (2DL1, 2DL2, 2DL3) compared to patients with only 1 or 2 genes (27.8% vs. 35.7%), 2) licensed donor NK cells with cognate recipient HLA-C ligands (28.8% vs. 39.3%), p > 0.05 for all comparisons. Conclusions Our results do not support a role for activating KIR in the control of CMV disease in the current setting. Inhibitory KIR may play a role in controlling CMV disease in liver transplant recipients and should be further explored in a larger study.