Dynamic Changes in Functional CTL and NK Lymphocyte Subsets in the Early Stage After Renal Transplantation.

Background: Functional lymphocytes play a pivotal role in renal injury and rejection following transplantation. Understanding their dynamic changes is essential for evaluating renal allograft function and predicting rejection. However, the early postoperative dynamics of these subsets and their relationship with renal function remain unclear. This study investigated the early postoperative changes in functional CD3+CD8+T (CTL) and CD3-CD16+56+T (NK) lymphocyte subsets in the peripheral blood of renal transplant recipients and their correlation with renal function.

Methods: Peripheral blood samples were collected from patients undergoing their first renal transplantation at 1, 2, and 3 weeks postoperatively. Flow cytometry was used to quantify CTL and NK lymphocyte subsets, with granzyme B (Gzm B+) and interferon-gamma (IFNγ+) expression serving as markers of cytotoxic function. Changes in these lymphocyte subsets and their correlation with renal function markers, including serum creatinine levels, were analyzed.

Results: Serum creatinine levels significantly decreased at 2 weeks compared to 1 week (p = 0.009) and stabilized by 3 weeks (p > 0.05), indicating substantial renal recovery. The proportion of CD3+T and CTL cells increased significantly at 2 weeks (p < 0.001 and p = 0.012, respectively) but showed no further changes by 3 weeks (p > 0.05). Conversely, NK cell proportions decreased significantly at 2 weeks (p = 0.011) and remained unchanged thereafter. Both Gzm B+CTL and IFNγ+CTL cell proportions decreased significantly from 1 to 2 weeks (p < 0.001 and p = 0.006, respectively) and stabilized at 3 weeks. While IFNγ+NK cell proportions remained unchanged across all time points (p > 0.05), Gzm B+NK cells increased from 2 to 3 weeks. Serum creatinine levels were negatively correlated with CD3+ T (r = -0.371, p = 0.003) and CTL cell proportions (r = -0.366, p = 0.003) and positively correlated with Gzm B+CTL (r = 0.418, p < 0.001) and IFNγ+CTL cell proportions (r = 0.377, p = 0.003).

Conclusions: Functional CTL cells exhibit significant dynamic changes during the early postoperative period, stabilizing by 3 weeks. These changes are strongly correlated with serum creatinine levels, suggesting their potential as biomarkers for renal allograft function.