Despite a large body of literature, the impact of chronic cytomegalovirus (CMV) infection in donor on long-term graft survival remains unclear, and factors modulating the effect of CMV infection on graft survival are presently unknown. In this retrospective study of 1279 kidney transplant patients, we analyzed long-term graft survival and evolution of CD8+ cell population in donors and recipients by CMV serology and antigenemia status. A positive CMV serology in the donor was an independent risk factor for graft loss, especially among CMV-positive recipients (R+). Antigenemia was not a risk factor for graft loss and kidneys from CMV-positive donors remained associated with poor graft survival among antigenemia-free recipients. Detrimental impact of donor's CMV seropositivity on graft survival was restricted to patients with full HLA-I mismatch, suggesting a role of CD8+ cells. In R+ patients with positive CMV antigenemia during the first year, CD8+ cell count did not increase at 2 years posttransplantation, in contrast to R− recipients. In addition, marked CD8+-cell decrease was a risk factor of graft failure in these patients. This study identifies HLA-I full mismatch and a decrease of CD8+ cell count at 2 years as important determinants of CMV-associated graft loss.
This large retrospective study shows that positive CMV serostatus of recipient and full HLA class I mismatching are the main determinants of poor graft outcome associated with CMV seropositivity of donor.