局灶节段性肾小球硬化症C4d表达的特点及意义

Characteristics and significance of C4d deposition in primary focal segmental glomerulosclerosis

目的研究不同类型的原发性局灶节段性肾小球硬化症(FSGS)中C4d表达的特点及意义。方法采用免疫组化染色方法,并结合PASM-C4d套染和免疫组化双标染色方法,观察了97例FSGS中C4d在肾小球上沉积部位和强度,及其与病理类型之间的关系。结果88例(90.7%)FSGS的肾小球C4d阳性表达,C4d主要沉积在FSGS肾小球硬化病变处。细胞型、顶端型、塌陷型及非特殊型FSGS中均表现为硬化病变处血管袢C4d不均匀粗线状沉积,系膜区散在多少不等的颗粒状沉积;顶端型和非特殊型为节段沉积,细胞型和塌陷型为球性沉积。门部型FSGS主要在门部有C4d颗粒状沉积,未见血管袢沉积。结论补体经典途径激活参与了FSGS的发病机制;硬化病变处血管袢C4d不均匀粗线状沉积是细胞型、塌陷型、非特殊型和顶端型FSGS重要的免疫病理形态特点之一。

Purpose To study the characteristics and significance of the C4d deposition in different types of primary focal segmental glomerulosclerosis（FSGS）. Methods With the immunohistochemistieal methods, including PASM-C4d counterstaining and double staining, the distribution and intensity of the C4d deposition and the relationship between the C4d and pathological type were observed in the glomeruli of ninety-seven kidney-puncture tissues. Results In 88 cases （90. 7% ） of FSGS, there was C4d deposited in the glomeruli. Of the five FSGS variants characterized, CAd deposition was predominantly found in the sclerotic glomerular lesion of FSGS, not otherwise specified, cellular and collapsing variants of FSGS. Within these variants, linear deposits of C4d were frequently observed along thickened, collapsed or wrinkled glomerular basement membranes with coarse granular shape, and lumpy or coarse granular deposits of C4d were found in mesangial regions. However, in the perihilar variant of FSGS, C4d was characterized by lumpy or coarse granular deposits in the perihilar lesions, but the basement membranes were negative for C4d reactivity. Conclusions The activation of classical complement pathway may be the key factor to segmental glomerulosclerosis of FSGS. The deposition C4d along the glomerular basement membrane of sclerosed region with coarse granular shape is an important immunopathological feature to tip variant, cellular variant, collapsing variant and classic type of FSGS.