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中国循证儿科杂志

中国循证儿科杂志 ›› 2021, Vol. 16 ›› Issue (5): 374-378.

• 论著 • 上一篇    下一篇

血清IgA、IgA/C3比值对儿童原发性IgA肾病的诊断价值和肾脏病理的相关性分析

王嘉1, 丁娟娟1, 栾江威1, 戚畅1, 祝高红1, 江倩倩1, 刘黎黎2, 王筱雯1    

  1. 华中科技大学同济医学院附属武汉儿童医院 武汉，430015 ；1 肾脏内科，2 病理科
  • 收稿日期:2021-07-12 修回日期:2021-10-25 出版日期:2021-10-25 发布日期:2021-10-25
  • 通讯作者: 王筱雯

A study on the correlation and diagnostic value of serum IgA, IgA/C3 ratio and renal pathology in children with IgA nephropathy

WANG Jia1, DING Juanjuan1, LUAN Jiangwei1, QI Chang1, ZHU Gaohong1, JIANG Qianqian1, LIU Lili2, WANG Xiaowen1 #br# #br# #br# #br#   

  1. Wuhan Children's Hospital, Wuhan 430015, China;1 Department of Nephrology,  2 Department of Pathology
  • Received:2021-07-12 Revised:2021-10-25 Online:2021-10-25 Published:2021-10-25
  • Contact: WANG Xiaowen

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摘要： 背景：IgA肾病是亚洲人群最常见的原发性肾小球肾炎，目前肾活检是诊断金标准，寻找可用于辅助诊断原发性IgA肾病的血清标志物有重要意义。 目的：探讨血清IgA及IgA/C3比值对儿童原发IgA肾病的诊断价值及其与病理分级的关系。 设计：诊断准确性研究。 方法：以肾活检病理为金标准分为原发性IgA肾病（真阳性）和非IgA肾病的原发性肾小球肾炎病（真阴性），以血清IgA和IgA/C3比值为待测标准，建立预测儿童原发性IgA肾病的诊断模型。截取人口学特征、血清免疫球蛋白和补体检测结果、肾活检病理检查报告和其他实验室检查结果。按年龄分为1~4岁、~7岁、~11岁和~18岁亚组；根据入院时24 h尿蛋白定量水平（mg·kg-1·d-1）分为＜50和≥50亚组。 主要结局指标：血清IgA和IgA/C3比值对原发性IgA肾病的诊断效能。 结果：原发性IgA肾病150例、非IgA肾病474例进入分析。①原发性IgA肾病患儿血清IgA和IgA/C3 比值高于非IgA肾病患儿，且在各年龄亚组血清IgA升高的比例均高于非IgA肾病患儿。②血清IgA和IgA/C3比值的AUC 分别为0.824和0.851，敏感度分别为80.0%和74.3%，特异度分别为73.1%和82.7%；IgA和IgA/C3均以1~4岁的AUC最大；IgA和IgA/C3的诊断截断值均随年龄增加而升高。③血清IgA和IgA/C3比值在24 h 尿蛋白水平＜50 mg·kg-1·d-1亚组的敏感度分别为90.3%和93.5%，在不同年龄亚组24 h 尿蛋白水平＜50 mg·kg-1·d-1的患儿中的敏感度为86.8%~100%。在不同尿蛋白水平亚组，IgA和IgA/C3 比值的诊断截断值亦随年龄增加而升高。④病理分级：无论是2016版牛津分级积分＜4分和≥4分患儿比较，还是LEE氏分级Ⅰ~Ⅱ级和Ⅲ~Ⅴ级患儿比较，性别、年龄、血清IgA、补体C3和IgA/C3比值差异均无统计学意义。 结论：血清IgA/C3比值和IgA升高对于筛查原发性IgA肾病有重要价值，尤其是24 h尿蛋白＜50 mg·kg-1·d-1患儿。

关键词: 儿童, IgA肾病, IgA/C3比值, 病理分级, 诊断价值

Abstract: Background: IgA nephropathy is the most common primary glomerulonephritis in Asian population. Kidney biopsy is the gold standard for diagnosing the disease. The exploration and discovery of non-invasive markers with diagnostic value of the disease is still a hot research topic. Objective: To investigate the diagnostic value of serum IgA and IgA/C3 ratio in children with primary IgA nephropathy and its relationship with pathological grade. Design: Diagnostic test accuracy. Methods: Taking renal biopsy pathology as the gold standard, children undergone kidney biopsy were divided into primary IgA nephropathy (true positive) and non-IgA primary glomerulonephritis (true negative). Taking IgA and IgA/C3 ratio as the test standard, a diagnostic model for predicting primary IgA nephropathy in children was established. Demographic characteristics, serum immunoglobulin and complement test results, renal biopsy pathological examination reports and other laboratory test results were intercepted. According to age, children were divided into 1-4 years old, -7 years old, -11 years old and -18 years old subgroups and according to the 24 h urinary protein level at the time of admission, children were divided into two subgroups of <50 and ≥50 mg·kg-1·d-1. Main outcome measures: The diagnostic power of serum IgA and IgA/C3 ratio for primary IgA nephropathy. Results: A total of 150 cases in the primary IgA nephropathy group and 474 cases in the non-IGA nephropathy group were included into analysis. The serum IgA and IgA/C3 ratio in primary IgA nephropathy group was higher than that in non-IgA nephropathy group, and the proportion of serum IgA elevation in all ages was higher than that in non-IgA nephropathy group. The AUC of serum IgA and IgA/C3 ratio was 0.824 and 0.851, the sensitivity was 80.0% and 74.3%, and the specificity was 73.1% and 82.7%, respectively. The AUC of IgA and IgA/C3 was the largest in 1-4 years old subgroup. The diagnostic cutoff values of IgA and IgA/C3 increased with age. The sensitivity of serum IgA and IgA/C3 ratio in the subgroup with 24 h urinary protein level <50 mg·kg-1·d-1 was 90.3% and 93.5% respectively. The sensitivity ranged from 86.8% to 100% in different age subgroups of children with 24 h urinary protein level <50 mg·kg-1·d-1 , indicating that serum IgA and IgA/C3 ratio had a high recognition degree in the subgroup with 24 h urinary protein level <50 mg·kg-1·d-1, and the diagnostic cutoff values were also increased with age. There were no significant differences in gender, age, serum IgA, C3 and IgA/C3 ratio between children with MESTC score < 4 and ≥4, or between children with LEE grade Ⅰ-Ⅱ and Ⅲ-Ⅴ. Conclusion: Serum IgA/C3 ratio and IgA elevation are important for differential diagnosis of primary IgA nephropathy, especially in patients with 24 h urinary protein level < 50 mg·kg-1·d-1.

Key words: Children, IgA nephropathy, IgA/C3 ratio, Pathological grade, Diagnostic value