Objective: To investigate the correlation between peripheral blood CD4 T lymphocyte subsets and delayed graft function (DGF) and short-term prognosis in kidney transplant recipients, so as to help optimize preoperative assessment for kidney transplantation and provide insights into the immune mechanisms of DGF. Methods: A retrospective analysis was conducted on the clinical data of 103 kidney transplant recipients at the First Affiliated Hospital of Soochow University during Jun.2022 and Oct.2023. A total of 61 recipients were finally included in this study, and were categorized into two groups based on postoperative renal function recovery：the DGF group (n=20) and the immediate graft function (IGF) group (n=41).Flow cytometry was used to detect the proportions and absolute counts of various CD4 T lymphocyte subsets in the peripheral blood on postoperative day 7.The clinical data and peripheral blood lymphocyte subsets between the two groups were compared.For the subsets that exhibited significant differences, the correlation between their proportions and absolute counts and serum creatinine (Scr) levels on postoperative day 7 was further analyzed in the DGF group.Receiver operating characteristic (ROC) curves were plotted, and the area under the curve (AUC) was calculated to evaluate the predictive performance of the most strongly correlated CD4 T lymphocyte subset in terms of proportion and absolute count for short-term renal function. Results: There were no statistically significant differences in the proportions and absolute counts of Th1, Th2, Th17, and regulatory T cells (Treg) between the DGF and IGF groups (P>0.05).The proportions and absolute counts of follicular helper T cells (Tfh) and PD-1 Tfh cells were significantly higher in the DGF group than in the IGF group (P＜0.000 1). The Scr levels at 1 month and 1 year postoperatively were significantly higher in the DGF group than in the IGF group (P＜0.01), while the estimated glomerular filtration rate (eGFR) was significantly lower in the DGF group compared with the IGF group (P＜0.01, P=0.02).Spearman correlation analysis showed that the proportions and absolute counts of Tfh and PD-1 Tfh cell subsets were positively correlated with the Scr level on post-operative day 7 in the DGF group (P＜0.05).The ROC curve demonstrated that the AUC for the proportion of PD-1 Tfh cells in predicting Scr and eGFR at 1 month after surgery was 0.73(95%CI:0.61-0.86) and 0.75 (95%CI:0.62-0.88), respectively.Additionally, the AUC for predicting Scr and eGFR at 1 year was 0.72(95%CI:0.59-0.86) and 0.70(95%CI:0.58-0.83), respectively. Conclusion: The increase in the proportions and absolute counts of Tfh and PD-1 Tfh cells is associated with postoperative DGF of renal transplant recipients, and the proportion of PD-1 Tfh cells may help predict the short-term renal function of recipients.