目的 研究预后营养指数（PNI）与外周血细胞毒性Ｔ淋巴细胞相关抗原４(CTLA⁃4)表达水平在食管鳞状细胞癌（ESCC）术 后复发转移中的预测价值。 方法 选取2014年4月至2018年6月盐城市亭湖区人民医院和东部战区总医院收治并行根治性手术治 疗的133例ESCC患者为研究对象，回顾性收集其临床病理资料及随访数据。通过受试者操作特征曲线（ROC曲线）确定术前PNI与 外周血CTLA⁃4表达预测ESCC术后复发转移的最佳临界值及诊断效能。采用Kaplan⁃Meier 曲线评估二者对ESCC患者无复发生存 的影响，Cox多因素回归分析评估影响ESCC复发转移的独立预测因素。结果 PNI与外周血CTLA⁃4表达水平预测ESCC术后复发 转移的截止点分别为48.2和0.410 ng/ml，曲线下面积（AUC）值分别为0.666 (95%CI= 0.572～0.759)与0.606 (95%CI= 0.507～0.704)。 基于截止点，发现CTLA⁃4高表达明显与组织学分级(χ２= 10.231, P=0.001)及T分期(χ２= 5.198，P=0.023)相关。与CTLA ⁃4低表达者 相比，高表达者5年无复发生存率明显更低(41.7% 比 61.2%)，差异有统计学意义(χ２= 3.919，P=0.047)。同样，与PNI≥48.2者相比，术 前PNI<48.2提示ESCC患者预后不佳(5年无复发生存率：39.6% 比 61.3%，χ２= 6.362，P=0.016)。多因素Cox回归分析进一步证实了 PNI (HR=3.043，95%CI=1.290～7.179，P=0.011)与外周血CTLA4表达 (HR=2.250，95%CI=1.286～3.938，P=0.004)在ESCC患者中的 独立预后价值。ROC曲线显示，PNI联合外周血CTLA⁃4表达预测ESCC复发转移的AUC值为0.694 (95%CI= 0.604～0.7849), 优于 二者的单独预测。结论 PNI联合外周血CTLA⁃4表达进一步提高了对ESCC术后复发转移的预测效能，二者的联合分析或许是ESCC 患者预后评估的敏感指标。

Objective To investigate the predictive value of prognostic nutritional index (PNI) and cytotoxic T lymphocyte associated antigen 4 (CTLA⁃4) expression level in peripheral blood for postoperative recurrence of esophageal squamous cell carcinoma (ESCC) patients. Methods A total of 133 ESCC patients who underwent curative resection in People's Hospital of Tinghu District, Yancheng City and General Hospital of Eastern Theater Command from April 2014 to June 2018 were included, and the clinic pathological and follow⁃up data of all patients were retrospectively collected. Receiver operating characteristics (ROC) curve was used to determine the optimal cut⁃off point and predictive value of preoperative PNI and CTLA⁃4 expression level in peripheral blood for postoperative recurrence in ESCC patients. Kaplan⁃Meier curve was plotted to evaluate the impact of PNI and CTLA⁃4 expression level in peripheral blood on the recurrence⁃free survival (RFS) of ESCC patients. In addition, Cox multivariate regression analysis was performed to determine the independent predictors of postoperative recurrence and metastasis in ESCC patients. Results ROC curve indicated that the cut⁃off values of PNI and CTLA⁃4 expression in peripheral blood for predicting recurrence of ESCC patients were 48.2 and 0.410 ng/ml, respectively. The AUC values for PNI and CTLA⁃4 expression in peripheral blood were 0.666 (95%CI= 0.572-0.759) and 0.606 (95%CI=0.507-0.704), respectively. Based on the optimal cut⁃off point, high CTLA⁃4 expression in peripheral blood was significantly associated with histological grade (χ２ = 10.231, P=0.001) and T stage (χ２ = 5.198, P=0.023). Kaplan⁃Meier curve showed that ESCC patients with high CTLA⁃4 expression had a poorer RFS than those with low CTLA⁃4 expression (5⁃year RFS rate, 41.7% vs 61.2%), with a statistically significant difference (χ２= 3.919, P=0.047). On the other hand, the 5⁃year RFS of ESCC patients with preoperative PNI <48.2 was significantly worse than that of those with PNI ≥48.2 (39.6% vs 61.3%, χ２ = 6.362, P=0.016). Multivariate Cox regression analysis further confirmed the independent prognostic significance of PNI (HR=3.043, 95%CI=1.290-7.179, P=0.011) and CTLA⁃4 expression in peripheral blood (HR=2.250, 95%CI=1.286-3.938, P=0.004) in ESCC patients. In addition, ROC curve showed that the AUC value of PNI combined with CTLA⁃4 expression in peripheral blood for predicting recurrence in ESCC patients was 0.694 (95%CI= 0.604-0.7849), which was better than that of either PNI or CTLA⁃4 expression alone. Conclusion Combination of PNI and the expression level of CTLA⁃4 in peripheral blood further improved predictive performance of recurrence in ESCC patients, and it might be a sensitive indicator for prognostic assessment of ESCC patients.