分析肾移植术后早期血清胱抑素C(Cys-C)和β2微球蛋白(β2-MG)的水平变化，评估其对移植肾功能恢复的诊断价值。

回顾性分析山西省第二人民医院2018年6月至2020年12月首次行同种异体肾移植的70例受者资料(移植组)，以同期30例健康体检者作为对照。移植组分别于术前和术后1、7、14和30 d采集血液标本，对照组于体检当日空腹采集血液标本，检测血清肌酐(SCr)、血尿素氮(BUN)、Cys-C、β2-MG和估算肾小球滤过率(eGFR)。计量资料组内比较采用重复测量方差分析，组间比较采用t检验。线性相关采用Pearson相关分析。采用logistic回归联合受试者操作特征(ROC)曲线分析Cys-C和β2-MG对移植肾功能的联合诊断价值。P<0.01为差异有统计学意义。

移植组术前和术后各阶段SCr、BUN、Cys-C、β2-MG、eGFR与对照组比较，差异均有统计学意义(P均<0.01)。移植组术后30 d内SCr、BUN、Cys-C和β2-MG持续下降，eGFR持续升高，与术前相比差异均有统计学意义(P均<0.01)。Pearson相关分析结果显示，BUN、Cys-C、β2-MG与eGFR均呈线性相关(r＝－0.719、－0.780、－0.711)。ROC曲线分析显示，SCr、BUN、Cys-C及β2-MG评估移植肾功能的曲线下面积(AUC)分别为0.955(95%CI：0.936~0.975)、0.940(95%CI：0.917~0.963)、0.992(95%CI：0.984~0.999)及0.918(95%CI：0.891~0.945)，均有统计学意义(P均<0.01)。Cys-C截断值为1.305 mg/L，灵敏度和特异度分别为0.996和0.966；β2-MG截断值为3.055 mg/L，灵敏度和特异度分别为0.826和0.922。Cys-C与β2-MG联合诊断移植肾功能的AUC为0.991(95%CI：0.983~0.999，P<0.01)。

Cys-C是评估早期移植肾功能恢复的较优指标，血清β2-MG也有一定的参考价值，但二者联合检测相比单独检测Cys-C并无显著优势。

Analysis of the dynamic changes in serum cystatin C(Cys-C) and β2-microglobulin(β2-MG) levels in the early period after renal transplantation, and evaluation of their diagnostic value for the recovery of graft renal function.

A total of 70 patients who underwent allogeneic kidney transplantation in the Second People′s Hospital of Shanxi Province from June 2018 to December 2020 were retrospectively collected as the transplant group. 30 healthy physical examination subjects in the same period were randomly selected as the control group. Blood samples were collected from the transplantation group before operation, and at 1, 7, 14 and 30 days after operation, while fasting blood samples were collected from the control group on the day of physical examination. The levels of serum creatinine (SCr), blood urea nitrogen (BUN), Cys-C, β2-MG, and estimated glomerular filtration rate (eGFR) were measured, respectively. Differences in quantitative variables within groups were analyzed using repeated-measures ANOVA, and intergroup comparisons were conducted with the independent samples t-test. Pearson correlation analysis was used to examine the linear association. A combination of logistic regression and receiver operating characteristic (ROC) curve analysis was performed to assess the integrated diagnostic value of Cys-C and β2-MG for renal allograft function.

All parameters (SCr, BUN, Cys-C, β2-MG, eGFR) in the transplant group at pre- and post-transplant stages differed significantly from controls (all P< 0.01). Within 30 days post-transplant, SCr, BUN, Cys-C and β2-MG in recipients continuously decreased while eGFR steadily increased, with all changes statistically significant vs. baseline (all P< 0.01). Pearson correlation analysis showed that BUN, Cys-C, and β2-MG were significantly negatively correlated with eGFR (r=-0.719, -0.780, and -0.711). ROC curve analysis demonstrated that the areas under the curve (AUC) of Cr, BUN, Cys-C, and β2-MG for evaluating renal allograft function were 0.955 (95%CI: 0.936-0.975), 0.940 (95%CI: 0.917-0.963), 0.992 (95%CI: 0.984-0.999), and 0.918 (95%CI: 0.891-0.945), respectively (all P<0.01). The optimal cutoff value of Cys-C was 1.305 mg/L, with a sensitivity of 0.996 and specificity of 0.966. For β2-MG, the sensitivity and specificity at the cutoff value were 0.826 and 0.922, respectively. The AUC of combined detection of Cys-C and β2-MG for diagnosing renal allograft function was 0.991 (95%CI: 0.983-0.999, P<0.01).

Cys-C is a superior indicator for evaluating the early recovery of renal allograft function. Compared with Cys-C alone, the combined detection of Cys-C and β2-MG shows no significant advantage in evaluating the early recovery of renal allograft function after renal transplantation.