Multivariate analysis showed that donor-recipient KIR ligand graft-versus-host or host-versus-graft direction mismatch was associated with increased refractory CMV infection (Hazard ratio = 2·556, 95% confidence interval, 1·377-4·744, P = 0·003) post-transplantation.
There was no significant difference between the two genotype groups with regard to occurrence of CMV disease, although there was a trend toward a lower incidence of CMV disease in recipients carrying the KIR-AA genotype.
Since the respective activities of the different KIR proteins expressed by NK cells during CMV infection have not been extensively studied, we analyzed the expression of KIRs in a cohort of 22 CMV-IgG(+) renal transplant patients at the time of CMV reactivation, after antiviral therapy and 6 months later.
Analysis of a cohort of previously human cytomegalovirus (HCMV)-negative patients, who developed primary HCMV infection following HCMV-positive renal transplant (n=76), revealed an increase in the frequency of KIR genes located on the telomeric region of B haplotypes (Tel B).
Collaborative studies suggested that both activating and inhibitory KIR and functionally relevant MBL2 haplotypes are important factors for control of CMV infection in the elderly and therefore for chronic low-grade inflammation.
We have shown that the absence of the HLA-C ligand for inhibitory KIR and the presence of activating KIR genes in the recipients were both associated with a lower rate of CMV infection after transplantation.