SO014
THE PRESENCE OF CMV-SPECIFIC T-CELLS IN CMV-SERONEGATIVE KIDNEY TRANSPLANT RECIPIENTS PREDICTS OUTCOME AFTER KIDNEY TRANSPLANTATION

Introduction and Aims: CMV-seronegative kidney transplant recipients (KTRs) from CMV-seropositive donors are at highly increased risk of primary CMV-infection with associated inferior outcomes after kidney transplantation. Presence of CMV-specific T-cells despite seronegativity, however, may result from absence of detectable circulating antibodies despite CMV specific memory B-cells or cross-reactivity due to allogeneic presensitization.

Methods: Here, we studied all CMV-seronegative KTRs between 2008 and 2013 for the presence of CMV-specific T-cells pre transplantation. Among 87 CMV-seronegative KTRs, 49 KTRs (56%) received an allograft from a CMV-seropositive and 38 KTRs (44%) from a CMV-seronegative donor. Samples were collected pretransplantation, at +1, +2, +3 months post transplantation. CMV-specific T-cells to CMV-pp65, -IE1, and alloreactive T-cells were measured using an interferon-γ Elispot assay.

Results: Among 49 KTRs from CMV-seropositive donors, 11 KTRs (22%) showed detectable CMV-specific T-cells pretransplantation. Although no differences were observed for the incidence of CMV-replication, KTRs with CMV-specific T-cells presented with shorter duration of CMV replication, lower initial and peak CMV-loads, less CMV disease, and less need for intravenous antiviral therapy (p<0.05). KTRs with CMV replication despite CMV-specific T-cells showed a loss of CMV-specific T-cells from pre- to post transplantation (p<0.05). KTRs with no CMV-specific T-cells pre transplantation showed inferior patient survival, allograft survival, and allograft function (p<0.05). KTRs with CMV replication showed a higher incidence of alloreactive T-cells and acute cellular rejection episodes (p<0.05).

Conclusions: A relevant proportion of CMV-seronegative KTRs shows CMV-specific T-cells pretransplantation with less severe primary CMV-infection and superior allograft outcomes compared to KTRs without CMV-specific T-cells. Higher frequencies of alloreactive T-cells may contribute to the higher incidence of acute cellular rejection in KTRs with CMV-replication.