目的 探讨复发后再次治疗前髓母细胞瘤（MB）患儿外周血血小板淋巴细胞比值、预后营养指数与预后的关系。方法 对2015年9月—2022年9月收治的82例MB患儿进行回顾性研究，比较高/低NLR组、高/低PLR组、高/低SII组、高/低PNI组之间的复发后OS率，分析预后相关因素。结果 中性粒细胞-淋巴细胞比值（NLR）、血小板-淋巴细胞比值（PLR）、系统性炎症指数（SII）、预后营养指数（PNI）的临界值分别为3.10、311.70、763.70、49.00，单因素分析提示高NLR、高PLR、高SII、低PNI均与更短的OS率有关，组间差异有统计学意义；COX回归模型分析提示PLR为复发后OS相关的独立危险因素，PNI为复发后OS相关的保护因素，高PLR组死亡风险为低PLR组的3.889倍，高PNI组的死亡风险为低PNI组的0.484倍。结论 复发是影响儿童MB预后的重要因素，高PLR为复发MB患儿预后不良的危险因素，高PNI为复发MB患儿的保护因素。

Objective To investigate the relationship between peripheral blood platelet-lymphocyte ratio, prognostic nutritional index and prognosis in patients with medulloblastoma (MB) after recurrence and before re-treatment. Methods A retrospective study was conducted on 82 patients with MB admitted from September 2015 to September 2022. The post-recurrence OS rates were compared between high/low neutrophil-lymphocyte ratio (NLR) group, high/low platele-lymphocyte ratio (PLR) group, high/low systemic inflammation index (SII) group, and high/low prognostic nutritional index (PNI) group, and the prognostic factors were analyzed. Results The critical values of NLR, PLR, SII and PNI were 3.1, 311.7, 763.7 and 49.0, respectively. Univariate analysis suggested that high NLR, high PLR, high SII and low PNI were associated with shorter OS rate, and the differences between groups were statistically significant (P<0.05). COX regression analysis suggested that PLR was an independent risk factor and PNI was a protective factor for OS after recurrence (P<0.05). The risk of death in the high PLR group was 3.889 times that of the low PLR group, and the risk of death in the high PNI group was 0.484 times that of the low PNI group. Conclusions Relapse has a significant impact on the prognosis of children with MB. For children with recurrent MB, high PNI was a protective factor, but high PLR is a risk factor for a poor prognosis.