低补体和高滴度抗 Sm 抗体可预测系统性红斑狼疮患者无异常尿液分析的组织病理学证实的无症状狼疮肾炎。

Low complements and high titre of anti-Sm antibody as predictors of histopathologically proven silent lupus nephritis without abnormal urinalysis in patients with systemic lupus erythematosus.

机构信息

First Department of Internal Medicine, Second Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health and Department of Hematology, Clinical Immunology and Infectious Diseases, Ehime University Graduate School of Medicine, Matsuyama, Japan. First Department of Internal Medicine, Second Department of Internal Medicine, School of Medicine, University of Occupational and Environmental Health and Department of Hematology, Clinical Immunology and Infectious Diseases, Ehime University Graduate School of Medicine, Matsuyama, Japan.

出版信息

Rheumatology (Oxford). 2015 Mar;54(3):405-12. doi: 10.1093/rheumatology/keu343. Epub 2014 Sep 2.

DOI:10.1093/rheumatology/keu343

PMID:25183834

Abstract

OBJECTIVE

The aim of this study was to clarify the clinical characteristics and predictors of silent LN (SLN), a type of LN in SLE without abnormal urinalysis or renal impairment.

METHODS

Of 182 patients who underwent renal biopsy, 48 did not present with abnormal urinalysis or renal impairment at the time of biopsy. The patients with LN (SLN group, n = 36) and those without LN (non-LN group, n = 12) were compared with respect to their baseline characteristics. Bivariate analysis comprised Fisher's exact test and the Mann-Whitney test, whereas multivariate analysis employed binomial logistic regression analysis.

RESULTS

LN was histopathologically identified in 36 of 48 patients. According to the International Society of Nephrology/Renal Pathology Society classification, 72% of the SLN patients were classified as having class I/II, with a further 17% having class III/IV. Bivariate analyses indicated that platelet count, serum albumin, complement components (C3 and C4), complement haemolytic activity (CH50), anti-Sm antibody titre and anti-ribonucleoprotein antibody titre were significantly different between groups. Multivariate analysis indicated that CH50 and C3 titres were significantly lower in the SLN group, whereas anti-Sm antibody titre was significantly higher. The cut-off titre, calculated based on the receiver operating characteristic curve for CH50, was 33 U/ml, with a sensitivity and specificity of 89% and 83%, respectively. The cut-off titre for anti-Sm antibodies was 9 U/ml, with a sensitivity and specificity of 74% and 83%, respectively.

CONCLUSION

Low titres of CH50 and C3 and a high titre of anti-Sm antibody were identified as predictors of SLN.

摘要

目的

本研究旨在阐明隐匿性狼疮肾炎（SLN）的临床特征和预测因素，SLN 是一种在狼疮患者中无异常尿液检查或肾功能损害的狼疮肾炎类型。

方法

在 182 例行肾活检的患者中，有 48 例在活检时无异常尿液检查或肾功能损害。比较了有 LN（SLN 组，n = 36）和无 LN（非 LN 组，n = 12）的患者的基线特征。采用 Fisher 确切检验和 Mann-Whitney 检验进行双变量分析，采用二项逻辑回归分析进行多变量分析。

结果

48 例患者中有 36 例病理组织学证实有 LN。根据国际肾脏病学会/肾脏病理学会分类，72%的 SLN 患者被分类为 I/II 级，另有 17%的患者被分类为 III/IV 级。双变量分析表明，血小板计数、血清白蛋白、补体成分（C3 和 C4）、补体溶血活性（CH50）、抗 Sm 抗体滴度和抗核糖核蛋白抗体滴度在两组间差异有统计学意义。多变量分析表明，SLN 组 CH50 和 C3 滴度明显较低，而抗 Sm 抗体滴度明显较高。根据 CH50 的受试者工作特征曲线计算出的 SLN 切点滴度为 33 U/ml，其敏感性和特异性分别为 89%和 83%。抗 Sm 抗体的切点滴度为 9 U/ml，其敏感性和特异性分别为 74%和 83%。