Objective To explore the diagnostic value of soluble C5b-9 (sC5b-9) for delayed graft function (DGF) following kidney transplantation. Methods Clinical data of 49 kidney transplant recipients who underwent sC5b-9 detection at the Second People’s Hospital of Shanxi Province between January 2024 and December 2025 were retrospectively analyzed. Recipients were divided into the DGF group (n=25) and the non-DGF group (n=24) according to the occurrence of DGF. Baseline characteristics and serum sC5b-9 levels were compared between the two groups. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic efficacy of sC5b-9 for DGF. A restricted cubic spline model was adopted to investigate the association between sC5b-9 and DGF. Results Among the 49 recipients, DGF occurred in 25 patients. Compared with the non-DGF group, the DGF group presented a higher proportion of male patients, a higher incidence of adverse transplant outcomes, and elevated final serum creatinine levels (all P<0.05). Within 30 days after transplantation, sC5b-9 concentrations were significantly higher in the DGF group than those in the non-DGF group (P<0.001). ROC analysis revealed that the area under the curve (AUC) of sC5b-9 for diagnosing DGF was 0.81, with a 95% confidence interval (CI) of 0.68-0.92, and the optimal cutoff value was 265.7 ng/mL. Recipients with elevated sC5b-9 (≥265.7 ng/mL) had a significantly higher incidence of DGF than those with low sC5b-9 levels (<265.7 ng/mL) (P<0.001). Recipients with adverse outcomes exhibited significantly higher sC5b-9 levels than those without adverse outcomes (P<0.001), and the AUC of sC5b-9 for identifying adverse outcomes was 0.82 (95%CI 0.63-0.95). A significant nonlinear correlation was observed between sC5b-9 and final serum creatinine (P<0.001). Conclusions Elevated sC5b-9 is correlated with the development of DGF after kidney transplantation and exhibits favorable diagnostic performance. It may serve as a potential biomarker for predicting early allograft dysfunction and adverse outcomes in kidney transplant recipients.

Objective To investigate the predictive value of serum 25-hydroxyvitamin D[25(OH)D]level in early renal transplantation for acute rejection(AR).Methods A total of 324 renal transplant recipients from January 2019 to August 2022 in the Second People's Hospital of Shanxi Province were selected.The clinical data of the recipients were collected.The levels of serum 25(OH)D,parathyroid hormone(PTH),and calcium,phosphorus in early(within 1 month)transplantation were detected by chemiluminescence immunoassay and colorimetry,respectively.The detection season was recorded,and the occurrence of AR within 1 year after renal transplantation was observed.The 25(OH)D level ≥ 20ng/ml was defined as normal,≥ 12 ng/ml～＜20 ng/ml as insufficient and＜12ng/ml as deficient,they were divided into of 25(OH)D normal group(n=106),insufficient group(n=112)and deficient group(n=106).According to the occurrence of AR,they were divided into AR group(n=51)and non-AR group(n=273).The basic situation of serum 25(OH)D level was analyzed.The differences in serum PTH,calcium,phosphorus levels and seasons as well as AR incidence among the three groups of 25(OH)D were compared.Multivariate logistic regression was used to analyze the influencing factors of AR,and receiver operating characteristic(ROC)curve was used to analyze the predictive value of serum 25(OH)D level for AR.Results The incidence of serum 25(OH)D deficiency or insufficiency was 67.28％(218/324).In the 25(OH)D normal group,insufficient group and deficiency group,the serum PTH levels were 75.44(46.42,113.23)pg/ml,78.29(58.27,152.10)pg/ml and 86.84(54.64,127.3)pg/ml,and the incidences of AR were 2.47％(8/324),6.17％(20/324)and 7.10％(23/324),respectively.All of them were the highest in the deficiency group and the lowest in the normal group,and the differences were significant(H=6.784,x2=8.580,all P＜0.05).Additionally,25(OH)D deficiency(OR=3.340,95％CI:1.409～7.916),25(OH)D insufficiency(OR=2.442,95％CI:1.006～5.925)and human leucocyte antigen(HLA)mismatch(4～6)(OR=2.117,95％CI:1.027～4.363)were independent risk factors for AR(all P＜0.05).The area under the curve(AUC)of serum 25(OH)D level in predicting AR was 0.702(95％CI:0.625～0.779),the optimal cut-off value was 13.59 ng/ml,the specificity and the sensitivity were 66.7％and 65.6％,respectively.Conclusion In this study,25(OH)D deficiency(＜12ng/ml)or insufficiency(≥ 12～＜20ng/ml)was an independent risk factor for AR,and serum 25(OH)D level may have a certain predictive value for AR.