Cytomegalovirus (CMV) infection detrimentally influences graft survival in kidney transplant recipients, with the risk primarily determined by recipient and donor serostatus. However, recipient CD8 + T cells play a crucial role in CMV control. The optimal preventive strategy (prophylaxis vs. pre-emptive treatment), particularly for seropositive (intermediate risk) recipients, remains uncertain. We investigated CD8 + T cell subpopulation dynamics and CMV occurrence (DNAemia ≥ 100 IU/mL) in 65 kidney transplant recipients, collecting peripheral blood mononuclear cells before (T1) and 1 year after transplantation (T2). Comparing the two timepoints, we found an increase in granulocyte, monocyte and CD3 + CD8 + T cells numbers, while FoxP3 + CD25 + , LAG-3 + and PD-1 + frequencies were reduced at T2. CMV DNAemia occurred in 33 recipients (55.8%) during the first year. Intermediate risk patients were disproportionally affected by posttransplant CMV ( N = 29/45, 64.4%). Intermediate risk recipients developing CMV after transplantation exhibited lower leukocyte, monocyte, and granulocyte counts and higher FoxP3 + CD25 + frequencies in CD3 + CD8 + T cells pre-transplantation compared to patients staying CMV negative. Pre-transplant FoxP3 + CD25 + in CD3 + CD8 + T cells had the best discriminatory potential for CMV infection prediction within the first year after transplantation (AUC: 0.746). The FoxP3 + CD25 + CD3 + CD8 + T cell subset may aid in selecting intermediate risk kidney transplant recipients for CMV prophylaxis.

Pre-Transplant Frequencies of FoxP3+CD25+ in CD3+CD8+ T Cells as Potential Predictors for CMV in CMV-Intermediate Risk Kidney Transplant Recipients