肾小球半乳糖缺乏型IgA1在IgA异常沉积肾小球疾病中的表达及意义

Expression and significance of glomerular galactose-deficient IgA1 in glomerular disease characterized by abnormal deposition of IgA

目的探讨肾小球半乳糖缺乏型IgA1(Gd-IgA1)在IgA异常沉积肾小球疾病中的表达及意义。方法纳入2020年1月至2024年6月天津医科大学总医院收治的IgA异常沉积肾小球疾病患者35例(IgA异常沉积组),包括IgA沉积型感染相关性肾小球肾炎(IgA-IRGN)5例,伴IgA沉积的糖尿病肾病(IgA-DN)8例,伴IgA沉积的ANCA相关性血管炎肾损害(IgA-ANCA-GN)9例,伴IgA沉积的微小病变肾病(IgA-MCD)13例。另选择同期住院的35例性别、年龄匹配的原发性IgA肾病(IgAN)患者作为对照(IgAN组)。分析两组患者临床和病理特征,评估肾活检中肾小球Gd-IgA1染色的强度和分布特点。结果两组患者主要临床表现均为蛋白尿和(或)血尿、血肌酐水平升高。肾病理检查显示,IgAN组患者毛细血管内增生更常见,而IgA异常沉积组患者纤维素样坏死、新月体形成及基底膜增厚较多见。Gd-IgA1抗体KM55免疫组化染色显示,IgAN组患者肾小球KM55主要表达于系膜区,染色强度范围为轻度阳性(+)至强阳性(+++),染色强度显著高于IgA异常沉积组(P<0.05)。电镜检查显示,IgAN组肾小球电子致密物沉积(EDD)位置与IgA免疫荧光及KM55染色一致;IgA异常沉积组肾小球EDD位置与IgA免疫荧光染色一致,但与KM55染色一致性较差。结论在IgA异常沉积肾小球疾病中,肾小球Gd-IgA1沉积明显少于IgA沉积,提示Gd-IgA1在其发病机制中可能不占重要地位。

Objective To explore the expression and significance of glomerular galactose-deficient IgA1(Gd-IgA1)in glomerular disease characterized by abnormal deposition of IgA.Methods Thirty-five patients with glomerular disease characterized by abnormal deposition of IgA who were admitted to Tianjin Medical University General Hospital from January 2020 to June 2024 were included as the IgA abnormal deposition group,including 5 cases of IgA-dominant infection-related glomerulonephritis(IgA-IRGN),8 cases of diabetic nephropathy with IgA deposition(IgA-DN),9 cases of anti-neutrophil cytoplasmic antibodies(ANCA)-associated glomerulonephritis with IgA deposition(IgA-ANCA-GN),and 13 cases of minimal change disease with IgA deposition(IgA-MCD).Other 35 sex-and age-matched primary IgA nephropathy(IgAN)patients hospitalized during the same period were selected as the controls(IgAN group).The clinical and pathological features of the patients in the two groups were analyzed,and the intensity and distribution characteristics of Gd-IgA1 staining in glomeruli in renal biopsy were evaluated.Results The main clinical manifestations of the patients in the two groups were proteinuria and(or)hematuria,and elevated levels of blood creatinine.The results of renal pathological examination showed that endocapillary proliferation was more common in the patients in the IgAN group,while fibrinoid necrosis,crescent formation and basement membrane thickening were more common in the patients in the IgA abnormal deposition group.The results of immunohistochemical staining of Gd-IgA1 antibody KM55 showed that KM55 was mainly expressed in the mesangial region in the IgAN group,and the staining intensity ranged from mildly positive(+)to strongly positive(+++),and the staining intensity in the patients of the IgAN group was significantly higher than that in the patients of the IgA abnormal deposition group(P<0.05).The results of electron microscopy examination showed that the location of electron-dense deposits(EDD)in the glomeruli of the IgAN group was consistent with the IgA immunofluo-rescence and the KM55 staining.The location of glomerular EDD in the IgA abnormal deposition group was consistent with the IgA immunofluorescence staining,but was poorly consistent with the KM55 staining.Conclusion In the glomerular disease characterized by abnormal deposition of IgA,glomerular Gd-IgA1 deposition is significantly less than glomerular IgA deposition,which suggests that Gd-IgA1 may not play an important role in its pathogenesis.