Abstract：
Background: Increasing studies in the last decade have led to the widespread understanding that C4d, a split product of complement component 4 (C4), is a potential biomarker for systemic lupus erythematosus (SLE) and lupus nephritis (LN).Purpose: The aim of this review is to summarize the highlights of studies investigating the use of C4d as a biomarker for diagnosing and monitoring SLE and LN patients.Data collection: we searched PubMed/Medline and Wanfang databases using the terms \"C4d and systemic lupus erythematosus\", \"C4d and lupus nephritis\", and \"Complement C4d\".Results: The deposition of C4d on circulating blood cells has been shown in several clinical studies to be a potential diagnostic marker that can be used to monitor patients with SLE. In addition, C4d deposits on circulating blood cells may be a helpful diagnostic marker for LN, one of the most severe complications of SLE. Meanwhile, studies utilizing renal biopsy specimens have indicated that C4d deposition in the renal peritubular capillaries of LN patients may predict more severe LN or a worse patient prognosis. Generally, a high plasma C4d level and a high plasma C4d/C4 ratio may also be promising indicators that can be used to monitor patients with SLE and LN.Conclusions: C4d detection may be a novel strategy for further clinical prediction and therapy.
摘要：
背景：在过去的十年中，越来越多的研究导致了人们对C4d的广泛理解，补体成分4(C4)的分裂产物，是系统性红斑狼疮（SLE）和狼疮性肾炎（LN）的潜在生物标志物。目的：这篇综述的目的是总结研究使用C4d作为诊断和监测SLE和LN患者的生物标志物的研究重点。数据收集：我们使用术语“C4d和系统性红斑狼疮”搜索PubMed/Medline和Wanfang数据库，“C4d和狼疮肾炎”，和“补充C4d”。结果：多项临床研究表明，C4d在循环血细胞上的沉积是一种潜在的诊断标志物，可用于监测SLE患者。此外,循环血细胞上的C4d沉积物可能是LN的有用诊断标记，SLE最严重的并发症之一。同时,使用肾活检标本的研究表明，LN患者肾小管周围毛细血管中的C4d沉积可能预测更严重的LN或更差的患者预后。一般来说,高血浆C4d水平和高血浆C4d/C4比值也可能是有前景的指标,可用于监测SLE和LN患者.结论：C4d检测可能是进一步临床预测和治疗的新策略。
