He Pei-Hua, Liu Li-Chang, Zhou Xing-Fu, Xu Jun-Jie, Hong Wei-Hong, Wang Li-Chun, Liu Su-Jun, Zeng Jia-Hao
The Second Clinical Medical College, Guangzhou University of Chinese Medicine, Guangzhou 510006, Guangdong Province, China.
Department of Nephrology, Zhuhai Hospital of Guangdong Provincial Hospital of Chinese Medicine, Zhuhai 519015, Guangdong Province, China.
World J Clin Cases. 2023 Mar 6;11(7):1656-1665. doi: 10.12998/wjcc.v11.i7.1656.
IgG4-related disease (IgG4-RD) is a chronic fibrotic disease mediated by immunity recognized by clinicians in recent years. When the kidney is involved, it is called IgG4-related kidney disease (IgG4-RKD). IgG4-related tubulointerstitial nephritis (IgG4-TIN) is a representative manifestation of IgG4-RKD. IgG4-TIN can cause obstructive nephropathy complicated by retroperitoneal fibrosis (RPF). Cases of IgG4-TIN complicated with RPF are rare. Glucocorticoids are the first-line therapeutic medication for IgG4-RD and can significantly improve renal function.
Herein, we report the case of a 56-year-old man with IgG4-RKD complicated with RPF. The patient presented to the hospital with complaints of elevated serum creatinine (Cr), nausea, and vomiting. During hospitalization, Cr was 1448.6 µmol/L, and serum IgG4 was increased. A total abdominal computed tomography (CT) scan and enhanced CT scan obviously indicated RPF. Although this patient had a long course and renal insufficiency, we performed a kidney biopsy. Renal biopsy showed that the renal tubulointerstitium had focal plasma cell infiltration and increased lymphocyte infiltration accompanied by fibrosis. After combining the biopsy results with immunohistochemistry, it was found that the absolute number of positive IgG4+ cells per high power field exceeded 10, and the ratio of IgG4/IgG was over 40%. Finally, the patient was diagnosed with IgG4-TIN complicated with RPF and given glucocorticoids as long-term maintenance therapy, helping him keep out of dialysis. After a follow-up of 19 mo, the patient had recovered well. Previous literature on IgG4-RKD and RPF was retrieved from PubMed to characterize the clinical and pathological features and to identify the diagnosis and treatment of IgG4-RKD.
Our case report demonstrates the clinical characteristics of IgG4-RKD complicated with RPF. Serum IgG4 is a favorable indicator for screening. Performing renal biopsy actively plays a vital role in diagnosis and treatment, even if the patient has a long course and manifests with renal insufficiency. It is remarkable to treat IgG4-RKD with glucocorticoids. Hence, early diagnosis and targeted therapy are essential for reversing renal function and improving extrarenal manifestations in patients with IgG4-RKD.
IgG4相关疾病（IgG4-RD）是近年来临床医生认识到的一种由免疫介导的慢性纤维化疾病。当肾脏受累时，称为IgG4相关肾病（IgG4-RKD）。IgG4相关肾小管间质性肾炎（IgG4-TIN）是IgG4-RKD的一种典型表现。IgG4-TIN可导致梗阻性肾病并伴有腹膜后纤维化（RPF）。IgG4-TIN合并RPF的病例较为罕见。糖皮质激素是IgG4-RD的一线治疗药物，可显著改善肾功能。
在此，我们报告一例56岁男性IgG4-RKD合并RPF的病例。患者因血清肌酐（Cr）升高、恶心和呕吐入院。住院期间，Cr为1448.6µmol/L，血清IgG4升高。全腹部计算机断层扫描（CT）及增强CT扫描明显显示有RPF。尽管该患者病程长且存在肾功能不全，但我们仍进行了肾活检。肾活检显示肾小管间质有局灶性浆细胞浸润，淋巴细胞浸润增加并伴有纤维化。结合活检结果及免疫组化发现，每高倍视野IgG4+阳性细胞绝对数超过10个，IgG4/IgG比例超过40%。最终，该患者被诊断为IgG4-TIN合并RPF，并给予糖皮质激素长期维持治疗，使其避免了透析。随访19个月后，患者恢复良好。从PubMed检索了以往关于IgG4-RKD和RPF的文献，以描述其临床和病理特征，并确定IgG4-RKD的诊断和治疗方法。
我们的病例报告展示了IgG4-RKD合并RPF的临床特征。血清IgG4是一个良好的筛查指标。积极进行肾活检在诊断和治疗中起着至关重要的作用，即使患者病程长且表现为肾功能不全。用糖皮质激素治疗IgG4-RKD效果显著。因此，早期诊断和靶向治疗对于逆转IgG4-RKD患者的肾功能及改善肾外表现至关重要。
