Investigation of CMV-specific T cell and latent CMV load to predict the reactivation of CMV after kidney transplantation

Abstract

Cytomegalovirus is the major opportunistic virus in kidney transplant. In South Korea, most of adult have CMV infection, thus there is possible risk of CMV reactivation. It is important to predict significant CMV reactivation that may require antiviral treatment. In this study, CMV-specific T cell immunity and latent CMV viral load were measured to predict significant CMV reactivation that may require antiviral treatment. A total 194 kidney transplant recipients were enrolled at a tertiary hospital during an 18-month period. CMV-specific T cell responses and latent CMV viral load were measured in peripheral blood mononuclear cells obtained at pre- and 1-month post-transplantation. Patients with significant CMV reactivation had lower frequencies of CMV IE-1- specific single cytokine producing CD4+ T cells and CMV pp65-specific polyfunctional CD8+ T cells than others. In addition, the frequency of PD-1+ T cells and latent CMV load were higher in patients with significant CMV reactivation. Taken together, it suggests that kidney transplant recipients who had impaired functions of CMV-specific T cells due to repeated exposure to CMV by subclinical reactivation might be prone to high level CMV replication after transplantation. Therefore, pre-transplant screening of latent CMV viral load and CMVspecific T cell responses might be useful to predict significant CMV reactivation after transplantation.