乙肝相关性膜性肾病中IgG亚型的表达及意义

目的 检测和比较乙肝病毒相关性膜性肾病( HBV-MN )和原发性膜性肾病( IMN )中IgG亚型(IgG1、IgG2、IgG3、IgG4)组间及组内的表达差异，探讨IgG亚型在二者诊断和鉴别诊断中的应用价值。方法 32例肾活检确诊为乙肝病毒相关性膜性肾病病例为实验组，20例原发性膜性肾病为对照组，分别进行IgG各亚型的免疫荧光染色。结果 实验组中30例肾组织以IgG1沉积为主, 6例出现IgG4阳性表达，其中5例同时伴有IgG1沉积，21例IgG2阳性，13例IgG3阳性。对照组中19例以IgG4沉积为主，15例可见IgG1沉积，但以弱阳性为主，伴有IgG2阳性7例，IgG3阳性4例。结论 乙肝病毒相关性膜性肾病以IgG1沉积为主，原发性膜性肾病以IgG4沉积为主，可伴有IgG1。两组间IgG1阳性率无明显差异，但实验组的表达强度明显高于对照组。结果提示二者发病机制不同可能引起不同类型的免疫复合物的沉积，IgG4与IgG1有望成为二者鉴别诊断的有应用价值的生物学指标。

Expression of IgG subclasses and its significance in hepatitis B virus associated membranous nephropathy

Objective To detect and compare the expression levels of four IgG subclasses(IgG1、 IgG2、 IgG3 and IgG4)in glomeruli between hepatitis B viral clearance membranous nephropathy (HBV-MN) and idiopathic membranous nephropathy (IMN), and to explore the role of IgG subclasses in the diagnosis and differential diagnosis in nephropathy. Methods Immunofluorescence was utilized to determine the expressions of IgG1、 IgG2、 IgG3、 IgG4 in kidney biopsy tissues from 32 patients with HBV-MN and 20 patients with IMN. Results Among the 32 cases of patients with HBV-MN, deposition of IgG1 was identified in 30 cases; IgG4 was positively expressed in 6 cases, and 5 out of these 6 cases were with simultaneous IgG1 deposition; IgG 2 was expressed in 21 cases, and IgG3 was positive in 13 cases. By contrast, deposition of IgG4 was identified in 19 cases with IMN; IgG1 deposition was present in 15 cases, but with weak expression only; Expressions of IgG2 and IgG3 were present in 7 and 4 cases, respectively. Conclusion IgG1 deposition is mainly present in HBV-MN , but IgG4 deposition is mainly present in IMN, sometimes with IgG1 together.The positive rate between the two groups has no significant difference,but the expression intensity of the HBV-MN group is significantly higher than that of the IMN group. The different patterns of immune complex deposition suggest that the pathogenesis of HBV-MN differs from that of IMN．IgG4 and IgG1 may be the valuable biological indicator in diagnosis and differential diagnosis for IMN and HBV-MN.