Cho Won-Hee, Park Seon-Hwa, Choi Seul-Ki, Jung Su Woong, Jeong Kyung Hwan, Kim Yang-Gyun, Moon Ju-Young, Lim Sung-Jig, Sung Ji-Youn, Jhee Jong Hyun, Chin Ho Jun, Choi Bum Soon, Lee Sang-Ho
Department of Medicine, Graduate School, Kyung Hee University, Seoul 02447, Korea.
Division of Nephrology, Department of Internal Medicine, Kyung Hee University Hospital at Gangdong, Seoul 05278, Korea.
J Clin Med. 2020 Aug 12;9(8):2619. doi: 10.3390/jcm9082619.
Approximately 5% of patients with IgA nephropathy (IgAN) exhibit mild mesangial lesions with acute onset nephrotic syndrome and diffuse foot process effacement representative of minimal change disease (MCD). It is not clear whether these unusual cases of IgAN with MCD (IgAN-MCD) are variant types of IgAN or coincidental deposition of IgA in patients with MCD. In a retrospective multicenter cohort study of 18 hospitals in Korea, we analyzed 46 patients with IgAN-MCD. Patients with endocapillary proliferation, segmental sclerosis, and crescent were excluded, and the clinical features and prognosis of IgAN-MCD were compared with those of pure MCD. In addition, we performed galactose-deficient IgA1 (KM55) staining to characterize IgAN-MCD. Among the 21,697 patients with glomerulonephritis enrolled in the database, 46 patients (0.21%) were diagnosed with IgAN-MCD, and 1610 patients (7.4%) with pure MCD. The 46 patients with IgAN-MCD accounted for 0.6% of primary IgAN patients ( = 7584). There was no difference in prognosis between patients with IgAN-MCD and those with only MCD. IgA and KM55 showed double positivity in all patients with IgAN-MCD ( = 4) or primary IgAN ( = 5) under double immunofluorescent staining. However, in four patients with lupus nephritis, mesangial IgA was deposited, but galactose-deficient-IgA1 (Gd-IgA1) was not. These findings suggest that IgAN-MCD is a dual glomerulopathy in which MCD was superimposed on possibly indolent IgAN. We confirmed by KM55 staining that IgAN-MCD is true IgAN, enabling better characterizations of the disease. Furthermore, IgAN-MCD shows a good prognosis when treated according to the usual MCD treatment modality.
约5%的IgA肾病（IgAN）患者表现为轻度系膜病变，伴有急性起病的肾病综合征及弥漫性足突融合，具有微小病变性肾病（MCD）的特征。目前尚不清楚这些不寻常的IgAN合并MCD（IgAN-MCD）病例是IgAN的变异类型，还是MCD患者中IgA的偶然沉积。在韩国18家医院进行的一项回顾性多中心队列研究中，我们分析了46例IgAN-MCD患者。排除了伴有毛细血管内增生、节段性硬化和新月体形成的患者，并将IgAN-MCD的临床特征和预后与单纯MCD患者进行比较。此外，我们进行了半乳糖缺陷型IgA1（KM55）染色以对IgAN-MCD进行特征性描述。在数据库中登记的21697例肾小球肾炎患者中，46例（0.21%）被诊断为IgAN-MCD，1610例（7.4%）为单纯MCD。46例IgAN-MCD患者占原发性IgAN患者的0.6%（n = 7584）。IgAN-MCD患者与仅患有MCD的患者在预后方面无差异。在双重免疫荧光染色下，所有IgAN-MCD患者（n = 4）或原发性IgAN患者（n = 5）的IgA和KM55均呈双阳性。然而，在4例狼疮性肾炎患者中，系膜IgA沉积，但半乳糖缺陷型IgA1（Gd-IgA1）未沉积。这些发现表明，IgAN-MCD是一种双重肾小球病，其中MCD叠加在可能隐匿的IgAN之上。我们通过KM55染色证实IgAN-MCD是真正的IgAN，从而能够更好地对该疾病进行特征描述。此外，IgAN-MCD按照常规MCD治疗方式治疗时预后良好。
