伴有H因子下降的儿童C3肾小球病的临床与病理三例

Characteristics of pediatric C3 glomerulopathy with decreased factor H in 3 cases

目的分析3例诊断为c3肾小球病患儿的临床病理特点，提高对该病的认识。方法对患儿临床病理资料进行分析，并对预后转归进行随访。结果（1）3例患儿中2例男性，1例女性；起病年龄分别为9岁、12岁及5岁4个月；至活检时的病程分别为3个月、7个月及20d，随访时间分别为2年7个月、8个月及1年6个月。（2）临床特征：全部病例都有镜下血尿，伴或不伴肉眼血尿、蛋白尿；2例血补体c3持续下降，l例位于正常低限；3例均出现H因子浓度下降，1例H因子抗体阳性。临床曾分别诊断为链球菌感染后肾小球肾炎、肾病综合征肾炎型和系膜增生性肾小球肾炎。（3）肾脏病理特征：3例患儿均出现免疫荧光下C3为主的基底膜及系膜区的沉积。电镜可见系膜区、内皮下和基底膜内的电子致密物沉积。（4）治疗及随访：诊断为肾病综合征者激素治疗无效，肾穿刺后激素减停，应用血管紧张素Ⅱ转换酶抑制剂（ACEI）＋血管紧张素受体拮抗剂（ARB）类药物对症治疗。余两例均为ACEI＋保护肾脏治疗。1例出现肌酐清除率下降、血肌酐升高，另两例血肌酐及肌酐清除率正常，但出现肾脏早期损伤指标轻度升高。结论C3肾小球病的临床及病理表现具有多样性，其诊断依赖于肾活检免疫荧光可见孤立的C3沉积。患儿出现血补体C3和H因子水平降低，提示补体代谢调节异常参与其发病。

Objective To study the characteristics of clinicopathology and prognosis of 3 pediatric cases diagnosed as C3 glomerulopathy, and to improve the understanding of C3 glomerulopathy in children. Method The medical record, plasma complement C3, Factor H （FH） and its autoantibody, and therapeutic response of the 3 cases were analyzed, and their prognosis were followed up. Result Of the 3 cases, 2 were male and 1 was female, the age of onset was 9 years, 12 years, 5 years 4 months, the duration from onset to renal biopsy was 3 months, 7 months and 20 days, and the follow-up period were 2.6 years, 8 months and 1.5 years respectively. Clinical manifestations ： All the 3 cases showed microscopic hematuria, with or without gross hematuria and proteinuria. Two showed persistently decreased plasma complement C3, in the other one C3 was in normal lower limit, all presented with decreased FH concertration, in 1 case anti- FH antibody was positive. Their clinical diagnosis was post-streptococcal glomerulonephritis, nephrotic syndrome （NS） nephritis type, and mesangial proliferative glomerulonephritis respectively. Pathological findings： All showed evident deposition of C3 on glomerular basement membrance （GBM） and mesangial region by immunofluorescence （IF） and electron dense deposit in GBM, mesangial region or para-mesangial region by Electron microscopic （EM） examination Treatment and prognosis： The case with NS showed no response to steroid, so steroid was gradually stopped after renal biopsy and replaced by angiotensin converting enzyme inhibitors （ACEI） and angiotensin receptor antagonist （ARB）. The other two cases were treated with ACEI and renal protective treatment. Of the 3 cases, one gradually showed elevated serum ereatinine （Ser） and decreased creatinine clearance rate （Cer）, the other two were normal, but slightly increased indications for early kidney injury. Conclusion C3 glomerulopathy is characterized by evident C3 deposition under IF. Its clinical and pathological manifestations vary a lot. The decreased plasma C3 and FHsuggest that the abnormal regulation of complement system play an importment role in its pathogenesis.