ANCA相关性肾小球肾炎合并IgG4相关性肾小管间质性肾炎一例

抗中性粒细胞胞质抗体（ANCA）相关性血管炎常累及肺肾等器官,该文报道1例ANCA相关性肾小球肾炎（ANCA-GN）合并IgG4相关性肾小管间质性肾炎（IgG4-TIN）病例,患者为51岁男性,以发热伴咳嗽起病,伴尿量减少,蛋白尿、血尿不明显,其血清学髓过氧化物酶滴度明显升高、核周型ANCA阳性,IgG4轻度升高（肾上腺皮质激素使用后）,肾脏病理学检查示有毛细血管袢断裂、皱缩伴新月体形成,肾间质可见较多淋巴细胞、浆细胞浸润伴轻度纤维化,免疫组织化学染色浆细胞显示以IgG⁺及IgG4⁺浆细胞为主,存在ANCA-GN合并IgG4-TIN可能,予抗感染、抗血管炎及血浆置换后患者病情好转出院。该例的诊治提示,对于不典型ANCA-GN患者如无明显血尿、蛋白尿、尿量减少等表现,需检测血清IgG4,病理上需注意观察有无IgG4-TIN特征性改变;对于临床上高度可疑的IgG4-TIN患者,还需同时排查IgG4所致的其他脏器改变,基线血清IgG4水平是IgG4相关性疾病活动、预测复发的标志物。

ANCA-associated glomerulonephritis complicated with IgG4-related tubulointerstitial nephritis： one case report

Anti-neutrophil cytoplasmic antibody （ANCA）-associated vasculitis constantly affects the lung, kidney and other organs. In this article, one case of ANCA-associated glomerulonephritis （ANCA-GN） complicated with IgG4-related tubulointerstitial nephritis （TIN） was reported. The 51-year-old male patient initially developed fever complicated with cough, decreased urine volume and insignificant proteinuria and hematuria. He presented with evident increase in the titer of serological myeloperoxidase, positive perinuclear ANCA and slight increase in IgG4 （after the administration of adrenocortical hormone）. Renal pathological examination showed the signs of capillary loop breakage, shrinking accompanied by crescent formation. A large quantity of lymphocytes and plasma cell infiltration complicated with mild fibrosis were found in the renal interstitium. Immunohistochemical staining revealed that IgG⁺ and IgG4⁺ plasma cells were the dominant plasma cells. The possibility of ANCA-GN complicated with IgG4-TIN was considered. After anti-infection, anti-vasculitis and plasma exchange, the patient was discharged from hospital. The diagnosis and treatment of this case suggested that for atypical ANCA-GN patients without obvious hematuria, proteinuria or decreased urine volume, serum IgG4 level should be detected. Pathologically, the characteristic changes of IgG4-TIN should be intimately observed. For clinically highly suspicious IgG4-TIN patients, the changes in other organs caused by IgG4 should be monitored simultaneously. The baseline serum level of IgG4 is a marker of IgG4-related disease activity and predicting recurrence.