肾小球IgG4沉积与原发性膜性肾病临床及病理的关系

目的分析原发性膜性肾病肾小球免疫荧光IgG4亚型分布特点,探讨IgG4阳性强度与肾脏病理、临床表现及预后的关系。方法回顾分析2015年9月至2017年4月本院行原位肾活检、免疫荧光显示毛细血管袢上有IgG沉积且至少一个IgG亚型阳性强度1+及以上的原发性膜性肾病病例,分析肾小球IgG4亚型分布特点,探讨IgG4阳性强度与临床表现、病理指标及临床缓解的关系。结果共纳入250例患者,其中男性157例(62.8%),女性93例(37.2%),年龄(54.4±14.6)岁;IgG4阴性组40例,IgG4阳性组210例;IgG4阳性组根据IgG4阳性程度又分为弱阳性组(1+,114例)、中度阳性组(2+,62例)、强阳性组(3+、4+,34例)。IgG4阳性组24 h尿蛋白量、肾组织磷脂酶A2受体染色强阳性比例均高于IgG4阴性组(均P<0.05);IgG4强阳性组血白蛋白水平低于IgG4弱阳性组(P<0.05),且随着IgG4的阳性程度增高,IgG1的阳性强度也增高,IgG4强阳性组IgG1强阳性比例明显高于IgG4弱阳性组(P<0.05);各组肾小球硬化比例、肾小管萎缩程度、IgG2、IgG3及其余免疫荧光指标组间比较差异均无统计学意义。中位随访180(122,209)d,32例患者失访,余218例患者中,45例(20.6%)完全缓解,104例(47.7%)部分缓解,69例(31.7%)未缓解。以未缓解定义为结局事件,多因素Cox回归分析显示,肾组织IgG4高阳性强度(HR=1.371,95%CI 1.068~1.759,P=0.013)、男性(HR=1.818,95%CI 1.028~3.214,P=0.040)、初始24 h尿蛋白量大(HR=1.108,95%CI 1.003~1.225,P=0.043)是疾病缓解的独立危险因素。结论肾小球IgG4阳性与否及阳性程度与原发性膜性肾病的疾病严重程度相关,肾小球IgG4阳性程度可能成为原发性膜性肾病治疗反应的指标之一。

Clinical significance of glomerular IgG4 deposition in primary membranous nephropathy

Objective To analyze the distribution of glomerular immunofluorescence IgG4 subtypes in primary membranous nephropathy, and to explore the relationship between IgG4 deposit intensity and renal pathology, clinical manifestations and prognosis. Methods All the patients of biopsy-proven primary membranous nephropathy with IgG staining and at least one IgG subtype staining 1+ or higher on capillary loops from September 2015 to April 2017 were retrospectively enrolled. The distribution of IgG4 deposits were analyzed, and the relationship between IgG4 positive intensity and clinical manifestations, pathological indexes and clinical remission was investigated. Results A total of 250 cases were enrolled, including 157 males (62.8%) and 93 females (37.2%), and age was (54.4 ± 14.6) years. There were 40 patients in IgG4-negative group, and 210 patients in IgG4-positive group. The IgG4-positive group was divided into subgroups as 114 cases of the mild positive subgroup (1+) and 62 cases of the moderate positive subgroup (2+), and 34 cases of the strong positive subgroup (3+, 4+). The IgG4-positive group had higher 24-hour urine protein and higher positive rate of phospholipase A2 receptor staining than those in the negative group (both P＜0.05), while the strong positive subgroup had lower serum albumin and higher IgG1 staining than those in the mild positive subgroup (both P＜0.05). There was no difference in the ratio of glomerular sclerosis, tubular atrophy, IgG2, IgG3 or other immunofluorescence between the groups. After a median follow-up of 180(122, 209) days, 32 individuals were lost to follow-up. Among the rest 218 patients, 45 patients (20.6%) got complete remission, 104 patients (47.7%) got partial remission, and 69 patients (31.7%) showed no response. For no response as the outcome event, multivariate Cox regression analysis showed that higher IgG4 staining intensity (HR=1.371, 95%CI 1.068-1.759, P=0.013), male (HR=1.818, 95%CI 1.028-3.214, P=0.040), higher 24-hour urine protein level (HR=1.108, 95%CI 1.003-1.225, P=0.043) were independent risk factors for disease remission. Conclusions The glomerular IgG4 positivity and intensity are related to the severity of primary membranous nephropathy. The glomerular IgG4 deposit degree may be an effective prognostic marker for the treatment response of primary membranous nephropathy.