目的 探索肾小球C3沉积对儿童原发性膜性肾病（PMN）患者临床、病理特征及预后的影响。方法 回顾性分析2008年1月至2020年12月经肾穿刺诊断为PMN患儿的临床资料。根据肾脏病理免疫荧光染色肾小球C3染色强度患儿分为低强度组（LI组，C3+）和高强度组（HI组，C3++或+++），比较两组基线时临床病理特征及治疗转归，分析PMN患儿进展至终末期肾病（ESRD）的影响因素。结果 共纳入213例患儿。LI组92例，HI组121例。与LI组相比，HI组年龄较大，24 h尿蛋白定量较高，血清白蛋白和eGFR水平较低，大量蛋白尿、IgG免疫荧光染色强度+++、IFTA分级为中度的比例较高，差异均有统计学意义（P<0.05）。LI组环磷酰胺的使用率高于HI组，差异有统计学意义（P<0.05）。经43.0（13.0~85.0）个月的随访，LI组92例患儿完成随访，1例进展至ESRD；68例转归为完全缓解（CR）和部分缓解（PR），24例为未缓解（NR）。经57.0（20.0~86.0）个月的随访，HI组121例患儿完成随访，5例进展至ESRD；86例转归为CR和PR，35例为NR。Log-rank检验发现，基线时eGFR≤90 mL·min^-1·1.73 m^-2，达ESRD时间较短，差异有统计学意义（P<0.05）。多因素Cox回归分析发现，基线时eGFR增加是延长患儿病情进展至ESRD的独立保护因素（HR=0.96，95%CI：0.929~0.987），而肾小球C3沉积与ESRD的发生无关。结论 广泛的肾小球C3沉积不是儿童PMN患者肾衰竭的预测因子。

Objective To investigate the effect of glomerular C3 deposition on clinical and pathological features and prognosis of primary membranous nephropathy (PMN) in children. Methods The clinical data of children diagnosed with PMN by renal puncture from January 2008 to December 2020 were retrospectively analyzed. According to the intensity of glomerular C3 staining by immunofluorescence of renal pathology, the children were divided into low-intensity group (LI group, C3+) and high-intensity group (HI group, C3++ or +++). The clinicopathological features at baseline and treatment outcomes were compared between the two groups. The influencing factors of PMN progressing to end-stage renal disease (ESRD) were analyzed. Results A total of 213 children were included. There were 92 children in LI group and 121 children in HI group. Compared with the LI group, the HI group was older, the 24h urine protein quantity was higher, the serum albumin and eGFR levels were lower, the proportion of massive proteinuria, IgG immunofluorescence staining intensity +++, and IFTA moderate grade were higher, and the differences were statistically significant (P<0.05). The utilization rate of cyclophosphamide in LI group was higher than that in HI group, and the difference was statistically significant (P<0.05). After 43.0 (13.0-85.0) months of follow-up, 92 patients in the LI group completed the follow-up, and one patient progressed to ESRD. Sixty-eight children had complete response (CR) and partial response (PR), and 24 had no response (NR). After 57.0 (20.0-86.0) months of follow-up, 121 patients in HI group completed the follow-up, and five patients progressed to ESRD. Eighty-six children had CR and PR, and 35 had NR. The log-rank test showed that when baseline eGFR≤90 mL·min^-1·1.73 m^-2, the time of progression to ESRD was shorter, and the difference was statistically significant (P<0.05). Multivariate Cox regression analysis showed that increased eGFR at baseline was an independent protective factor for delaying the progression to ESRD (HR=0.96, 95% CI: 0.929-0.987), while glomerular C3 deposition was not associated with the occurrence of ESRD. Conclusions Extensive glomerular C3 deposition is not a predictor of renal failure in children with PMN.