目的 探讨狼疮性肾炎（LN）患儿血浆miR-145及miR-183表达水平及其诊断价值。方法 选取2016年1月至2019年5月收治的LN患儿92例为LN组，其中Ⅱ型17例、Ⅲ型15例、Ⅳ型36例、Ⅴ型18例、Ⅵ型6例，另选取健康体检正常儿童40例作为健康对照组。采用系统性红斑狼疮病情活动指数（SLEDAI）评分将92例LN患儿分为LN稳定组（n=34，SLEDAI评分<10分）和LN活动组（n=58，SLEDAI评分≥10分）。实时荧光定量PCR法检测各组血浆miR-145及miR-183表达水平；ROC曲线分析血浆miR-145、miR-183及抗双链DNA（dsDNA）抗体水平对LN的诊断价值；Pearson相关分析LN患儿血浆miR-145及miR-183表达水平与各实验室指标的相关性。结果 LN组、LN活动组和LN稳定组抗dsDNA抗体、C反应蛋白（CRP）、血肌酐（Scr）及血尿素氮（BUN）水平均明显高于健康对照组（P < 0.05），且LN活动组SLEDAI评分、抗dsDNA抗体、Scr及BUN水平均明显高于LN稳定组（P < 0.05）。LN组、LN活动组和LN稳定组补体C3、补体C4及血清白蛋白（ALB）水平均明显低于健康对照组（P < 0.05），且LN活动组ALB水平明显低于LN稳定组（P < 0.05）。LN组、LN活动组和LN稳定组血浆miR-145及miR-183表达水平均明显低于健康对照组（P < 0.01），且LN活动组血浆miR-145及miR-183表达水平均明显低于LN稳定组（P < 0.01）。不同分型LN患儿血浆miR-145及miR-183表达水平均明显低于健康对照组（P < 0.01），且Ⅴ~Ⅵ型组和Ⅳ型组血浆miR-145及miR-183表达水平均明显低于Ⅱ~Ⅲ型组（P < 0.01）。血浆miR-145、miR-183及抗dsDNA抗体水平诊断LN的最佳截断值分别为1.05、0.62、186.30 IU/mL，三项联合诊断LN的曲线下面积（0.896，95% CI：0.835~0.955）最大，其灵敏度（90.5%）和特异度（84.2%）较好，优于各单项诊断价值（P < 0.05）。LN患儿血浆miR-145及miR-183表达水平与SLEDAI评分、抗dsDNA抗体、Scr及BUN水平均呈负相关（P < 0.05），与补体C3、补体C4及ALB水平均呈正相关（P < 0.05）。结论 LN患儿血浆miR-145及miR-183表达水平明显降低，且与LN活动度及病理分型相关，联合抗dsDNA抗体检测对LN诊断具有较高的价值。

Objective To study the expression and diagnostic value of plasma miR-145 and miR-183 in children with lupus nephritis (LN). Methods A total of 92 children with LN who were admitted from January 2016 to May 2019 were enrolled as the LN group, among whom 17 had type II LN, 15 had type III LN, 36 had type IV LN, 18 had type V LN, and 6 had type VI LN. Forty healthy children who underwent physical examination were enrolled as the healthy control group. According to Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), the 92 children with LN were further divided into a stable LN group with 34 children (SLEDAI score <10) and an active LN group with 58 children (SLEDAI score ≥ 10). RT-PCR was used to measure the expression of miR-145 and miR-183 in plasma. The receiver operating characteristic (ROC) curve was used to analyze the value of plasma miR-145, miR-183, and anti-dsDNA antibody in the diagnosis of LN. Pearson correlation analysis was used to investigate the correlation of the expression levels of miR-145 and miR-183 in plasma with laboratory markers. Results The LN, active LN, and stable LN groups had significantly higher levels of anti-dsDNA antibody, C-reactive protein, serum creatinine (Scr), and blood urea nitrogen (BUN) than the control group (P < 0.05). The active LN group had significantly higher SLEDAI score, anti-dsDNA antibody, Scr, and BUN than the stable LN group (P < 0.05). The LN, active LN, and stable LN groups had significantly lower levels of complement C3, complement C4, and serum albumin (Alb) than the control group (P < 0.05). The active LN group had a significantly lower level of Alb than the stable LN group (P < 0.05). The LN, active LN, and stable LN groups had significantly lower plasma levels of miR-145 and miR-183 than the control group (P < 0.01). The active LN group had significantly lower plasma levels of miR-145 and miR-183 than the stable LN group (P < 0.01). The children with difference types of LN had significantly lower plasma levels of miR-145 and miR-183 than the control group (P < 0.01), and the type V-VI group and the type IV group had significantly lower plasma levels of miR-145 and miR-183 than the type II-III group (P < 0.01). The ROC curve analysis showed that the optimal cut-off values of plasma miR-145, miR-183, and anti-dsDNA antibody were 1.05, 0.62, and 186.30 IU/mL respectively, in the diagnosis of LN, and the combination of these three indices had the largest area under the ROC curve of 0.896 (95%CI:0.835-0.955), with a sensitivity of 90.5% and a specificity of 84.2%. In the children with LN, the plasma levels of miR-145 and miR-183 were negatively correlated with SLEDAI score, anti-dsDNA antibody, Scr, and BUN (P < 0.05) and were positively correlated with complement C3, complement C4, and Alb (P < 0.05). Conclusions There are significant reductions in the expression levels of miR-145 and miR-183 in plasma in children with LN, which are correlated with the activity level and pathological typing of LN. Combined measurement of miR-145, miR-183, and anti-dsDNA antibody has a high value in the diagnosis of LN.