*Purpose: Impairment of cellular immune function in kidney transplant candidates is not concomitantly restored with the recovery of renal function, as alloimmune response and implementation of immunosuppressive regimens induce further changes in the recipient’s T cells. In the present study, the potential association between T lymphocyte subset changes and posttransplant graft function was determined.

*Methods: Flow cytometry analysis was performed on 65 kidney transplant recipients before transplantation and at different time points post-transplantation (3, 6, and 12 months) to estimate CD3+, CD4+, CD8+, CD4CD28null, CD8CD28null, CD4CD25FoxP3+ (Tregs), and natural killer (NK) subsets. All recipients received basiliximab as induction therapy. Patients were classified into two groups according to renal function at 3 months, with an eGFR cut-off value of 50 ml/min/1.73 m².

*Results: In all 65 patients, there was an increase in the absolute numbers of lymphocytes (p<0.001), CD4+ (p<0.001), and CD8+ (p=0.001) cell populations and a reduction in NK cell subsets (p<0.001) a trimester post-transplant that persisted thereafter. The percentage of the CD4CD28null population significantly decreased (3.3 [0.7-8.8] vs. 5.3 [2.4-9.8] %, p=0.009) until the 6th month post-transplant, while the absolute number of Tregs showed a significant increase (37 [23-50] vs. 20 [15-31] cells/μL, p<0.001) at 6 months. Twelve patients (19%) were included in the low-eGFR group. Patients with a lower eGFR did not show any significant change in total lymphocyte, CD4+, Treg, and NK cell counts or CD4CD28null percentage.

*Conclusions: After kidney transplantation, many alterations in T cell subpopulations observed in chronic kidney disease were restored, which might be mediated by the recovery of adequate renal function. This is especially important for Tregs, as immunosuppression therapy affects CD4CD25+ T cells early in renal transplantation.

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