Xie Weiji, Zhang Yixin, He Shiting, Lin Xuewan, Zhao Shuping, Xiao Zeen, Zhang Yimin
Department of Nephrology, The Second Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China.
Hemodialysis Center, The First Affiliated Hospital of Shantou University Medical College, Shantou, Guangdong, China.
Clin Rheumatol. 2025 Apr 7. doi: 10.1007/s10067-025-07429-5.
Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disease that predominantly affects women of childbearing age. Lupus nephritis (LN) is a relatively common and serious complication in clinical patients. The aim of this study was to evaluate the correlation of complement levels and SLEDAI- 2000 (SLEDAI- 2 K) with renal activity in different pathological types of LN.
A total of 220 patients with SLE and LN were included. Renal active inflammation was calculated using the National Institutes of Health (NIH) Activity Index (AI) . Patients were classified into two groups based on the AI at the time of kidney biopsy: low-to-moderate-activity group with an AI < 10 and high-active group with an AI ≥ 10. Laboratory indicators, including complement levels and the SLEDAI- 2 K, were collected to assess their correlation with renal activity in LN.
The average complement levels in class V LN were higher than that in class III/IV and III/IV + V LN. Serum creatinine and 24-h urine protein were lower than those in class III/IV and III/IV + V LN. Laboratory indicators, including complement levels and SLEDAI- 2 K, shown no correlation with AI in class V LN. Appropriate clinical indicators of AI in patients with class III/IV and III/IV + V LN were further assessed by ROC curves, SLEDAI- 2 K exhibiting the highest performance (AUC 0.757, 95% CI 0.687-0.817), 24-h urine protein (AUC 0.736, 95% CI 0.665-0.798), hemoglobin (AUC 0.726, 95% CI 0.655-0.789), C3 (AUC 0.676, 95% CI 0.603-0.744), serum creatinine (AUC 0.664, 95% CI 0.591-0.733), and C4 (AUC 0.660, 95% CI 0.586-0.729).
Decreased levels of complement C3 and C4 have limited predictive value as a clinical tool for assessing disease activity in patients with LN, especially in class V LN. SLEDAI- 2 K, a widely used clinical scale, correlates with disease activity in patients with class III/IV, III/IV + V LN. Serum creatinine is a clinical indicator of chronic kidney damage in patients with class III/IV, III/IV + V, and V LN. Key Points Complement levels: can they accurately assess disease activity in lupus nephritis? • Studies investigating the correlation between complement levels and disease activity in patients with SLE and LN yield inconsistent results, and the ambiguity of these findings may stem from factors such as the pathological staging of LN and individual variations in complement levels. Fewer studies in the current research on disease activity in patients with LN will be based on different pathological types of LN, which leads to limitations in the final findings. • This study aimed to analyze the feasibility of complement levels and SLEDAI- 2 K in assessing renal activity in patients with different pathological types of LN. • We assessed disease activity by obtaining AI from renal biopsies in 220 patients with LN and examined their correlation with disease activity through the collection of laboratory indicators from these patients. • Decreased levels of complement C3 and C4 have limited predictive value as a clinical tool for assessing disease activity in patients with LN, especially in patients with class V LN.
系统性红斑狼疮（SLE）是一种慢性多系统自身免疫性疾病，主要影响育龄女性。狼疮性肾炎（LN）是临床患者中较为常见且严重的并发症。本研究旨在评估补体水平和SLEDAI - 2000（SLEDAI - 2K）与不同病理类型LN肾脏活动度的相关性。
共纳入220例SLE合并LN患者。采用美国国立卫生研究院（NIH）活动指数（AI）计算肾脏活动性炎症。根据肾活检时的AI将患者分为两组：AI < 10的低至中度活动组和AI≥10的高活动组。收集包括补体水平和SLEDAI - 2K在内的实验室指标，以评估它们与LN肾脏活动度的相关性。
Ⅴ型LN的平均补体水平高于Ⅲ/Ⅳ型和Ⅲ/Ⅳ + Ⅴ型LN。血清肌酐和24小时尿蛋白低于Ⅲ/Ⅳ型和Ⅲ/Ⅳ + Ⅴ型LN。包括补体水平和SLEDAI - 2K在内的实验室指标在Ⅴ型LN中与AI无相关性。通过ROC曲线进一步评估Ⅲ/Ⅳ型和Ⅲ/Ⅳ + Ⅴ型LN患者AI的合适临床指标，SLEDAI - 2K表现最佳（AUC 0.757，95%CI 0.687 - 0.817），其次是24小时尿蛋白（AUC 0.736，95%CI 0.665 - 0.798）、血红蛋白（AUC 0.726，95%CI 0.655 - 0.789）、C3（AUC 0.676，95%CI 0.603 - 0.744）、血清肌酐（AUC 0.664，95%CI 0.591 - 0.733）和C4（AUC 0.660，95%CI 0.586 - 0.729）。
补体C3和C4水平降低作为评估LN患者疾病活动度的临床工具，预测价值有限，尤其是在Ⅴ型LN患者中。广泛使用的临床量表SLEDAI - 2K与Ⅲ/Ⅳ型、Ⅲ/Ⅳ + Ⅴ型LN患者的疾病活动度相关。血清肌酐是Ⅲ/Ⅳ型、Ⅲ/Ⅳ + Ⅴ型和Ⅴ型LN患者慢性肾损伤的临床指标。要点补体水平：它们能否准确评估狼疮性肾炎的疾病活动度？• 研究SLE和LN患者补体水平与疾病活动度之间相关性的结果并不一致，这些结果的不确定性可能源于LN的病理分期和补体水平的个体差异等因素。目前关于LN患者疾病活动度的研究中，基于不同病理类型LN的研究较少，这导致最终结果存在局限性。• 本研究旨在分析补体水平和SLEDAI - 2K在评估不同病理类型LN患者肾脏活动度方面的可行性。• 我们通过获取220例LN患者肾活检的AI来评估疾病活动度，并通过收集这些患者的实验室指标来检查它们与疾病活动度的相关性。• 补体C3和C4水平降低作为评估LN患者疾病活动度的临床工具预测价值有限，尤其是在Ⅴ型LN患者中。
