Background: The classic disorder of placental malperfusion is preeclampsia (PE), in which the kidney is also a target organ, leading to renal dysfunction. Although the precise pathogenesis of PE is unknown, increasing evidence suggests that PE is associated with complement dysregulation. The maternal immune response to an allogenic fetus and excessive activation of the complement system may both be involved in the pathogenesis of PE. C4d deposition is considered to be evidence of antibody-mediated rejection in an allograft. This study investigated a correlation between C4d expression in the placenta and clinicopathologic features of PE patients. Materials and Methods: Immunohistochemical staining for C4d was performed on placental tissue of PE patients (n=70) and normal pregnancy patients (n=30). Clinicopathologic features, such as maternal age and parity, placental weight, proteinuria, and histologic features of the placenta were evaluated. One PE patient who suffered from proteinuria after delivery received a renal biopsy. Results: C4d expression was demonstrated in syncytiotrophoblast of chorionic villi. The expression of C4d was significantly more frequent in the placenta with PE (50%) than in the placenta lacking complications (14.3%) (P=0.001). C4d expression was significantly accompanied by increased syncytial knots in PE (P=0.045). Among PE patients, C4d expression was significantly correlated with low placental weight (P=0.001) and high proteinuria (P=0.018, Mann-Whitney U test). Renal biopsy of a PE patient after delivery also showed deposition of C4d along the glomerular capillary walls. Conclusions: C4d may play an important role in placental tissue injury and in renal complications in PE.

中文翻译：

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1 次产后肾活检中先兆子痫患者胎盘和肾小球的补体成分 C4d 沉积

背景：胎盘灌注不良的经典疾病是先兆子痫（PE），其中肾脏也是靶器官，导致肾功能障碍。尽管 PE 的确切发病机制尚不清楚，但越来越多的证据表明 PE 与补体失调有关。母体对同种异体胎儿的免疫反应和补体系统的过度激活都可能参与 PE 的发病机制。C4d 沉积被认为是同种异体移植物中抗体介导的排斥的证据。本研究调查了胎盘中 C4d 表达与 PE 患者临床病理特征之间的相关性。材料与方法：对PE患者（n=70）和正常妊娠患者（n=30）的胎盘组织进行C4d免疫组化染色。临床病理特征，如母亲的年龄和产次、胎盘重量、蛋白尿和胎盘的组织学特征。一名分娩后出现蛋白尿的 PE 患者接受了肾活检。结果：C4d在绒毛膜合体滋养细胞中表达。与没有并发症的胎盘（14.3%）相比，PE 胎盘中 C4d 的表达（50%）明显更频繁（P=0.001）。C4d 表达显着伴随 PE 中合胞结的增加（ P = 0.045）。在 PE 患者中，C4d 表达与胎盘重量低（P=0.001）和高蛋白尿（P=0.018，Mann-Whitney U 检验）显着相关。分娩后 PE 患者的肾活检也显示 C4d 沿肾小球毛细血管壁沉积。结论：