Donor anti-cytomegalovirus IgG titer and risk of cytomegalovirus infection after D+R- kidney transplantation, results from the TransplantLines Biobank and Cohort Study

Cytomegalovirus (CMV) infection after kidney transplantation is associated with poorer patient and graft outcomes. Nearly half of CMV seronegative kidney transplant recipients (KTR) with a CMV seropositive donor (D+R-) experience CMV infection. We hypothesized that the anti-CMV immunoglobulin G (IgG) titer of CMV seropositive donors is a risk factor for CMV infection in D+R- kidney transplantations, since higher titers may reflect more intense prior CMV viremia or impaired cell-mediated CMV control in donors. Anti-CMV IgG titers were measured using an enzymatic immunoassay. CMV DNAemia was defined as a positive CMV polymerase chain reaction (PCR), seroconversion as a positive anti-CMV IgG in a previously seronegative recipient. Cox regression analysis was performed to evaluate the risk of CMV infection. A total of 111 D+R- KTR with a living donor from the TransplantLines Study were included at 6 months post-transplantation. The mean age was 49.6 ± 15.0 years and 32 (29%) were female. Overall, 31 (28%) developed CMV DNAemia and 35 (32%) seroconverted. Recipients with donors with an anti-CMV IgG titer above 250 AU/mL (n = 19; 17%) had a significantly higher risk of CMV DNAemia (HR=2.49, 95% CI (1.15-5.42), p = 0.02) and CMV seroconversion (HR=3.07 (1.49-6.32), p = 0.002). High donor anti-CMV IgG titer is associated with an increased risk of CMV infection in CMV seronegative KTR. These findings support the hypothesis that a high anti-CMV IgG titer reflects a higher CMV tissue load, a poorer cell-mediated CMV response, or both. Donor anti-CMV IgG titer might be a useful parameter to guide individualized CMV prophylaxis and surveillance strategies.