Division of Pathology, Hospital das Clinicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
Nephrol Dial Transplant. 2013 Jan;28(1):91-8. doi: 10.1093/ndt/gfs325. Epub 2012 Aug 1.
Focal segmental glomerulosclerosis (FSGS) is the most prevalent primary glomerulopathy in Brazil and its incidence is increasing worldwide. Pathogenesis is related to podocyte injury, which may be due to several factors including viruses, drugs, immunology. In 2004, the Columbia classification of FSGS identified five histologic variants of the disease: collapsing (COL), usual (not otherwise specified, NOS), tip lesion (TIP), perihilar (PHI) and cellular variant (CEL). Several studies have demonstrated molecular changes in podocytes of FSGS patients. This study sought to classify a large series of FSGS biopsies according to the Columbia classification and analyze the occurrence of immunohistochemical differences among the five variants.
Approximately 131 cases of renal biopsies with a diagnosis of primary FSGS during the period from 1996-2006 were classified according to the criteria of Columbia and were then submitted to immunohistochemical staining to the following antibodies: CD10, WT-1, Vimentin, Synaptopodin, α-actinin-4, GLEPP-1, cytokeratin (CK) 8-18, CK19 and Ki-67.
The FSGS classification resulted in 38.2% of NOS variant, in 36.6% COL, in 14.5% TIP, in 6.9% PHI and in 3.8% CEL. COL variant distinguished themselves among the others for having loss of expression of CD10, WT1 and α-actinin-4 (P < 0.05). Furthermore, COL gained expression of the CK8-18 and CK19 diverging from the other variants (P < 0.05).
COL variant of FSGS presented immunohistochemical characteristics that distinguished it from others pointing to additional studies in this area. The distinct immunohistochemical properties of COL might be of help in the comprehension of this aggressive form of FSGS.
局灶节段性肾小球硬化症（FSGS）是巴西最常见的原发性肾小球疾病，其发病率在全球范围内呈上升趋势。发病机制与足细胞损伤有关，可能与多种因素有关，包括病毒、药物、免疫学。2004 年，哥伦比亚 FSGS 分类将该疾病分为五种组织学变异型：塌陷型（COL）、常见型（非特指，NOS）、尖端病变型（TIP）、近旁型（PHI）和细胞型（CEL）。几项研究表明 FSGS 患者足细胞存在分子变化。本研究旨在根据哥伦比亚分类对大量 FSGS 活检进行分类，并分析五种变异型之间免疫组织化学差异的发生。
根据哥伦比亚标准对 1996-2006 年期间诊断为原发性 FSGS 的约 131 例肾活检进行分类，然后对以下抗体进行免疫组织化学染色：CD10、WT-1、波形蛋白、突触蛋白、α-辅肌动蛋白-4、GLEPP-1、细胞角蛋白（CK）8-18、CK19 和 Ki-67。
FSGS 分类结果为 NOS 变异型占 38.2%，COL 变异型占 36.6%，TIP 变异型占 14.5%，PHI 变异型占 6.9%，CEL 变异型占 3.8%。与其他类型相比，COL 变异型表达缺失 CD10、WT1 和 α-辅肌动蛋白-4（P<0.05）。此外，COL 获得 CK8-18 和 CK19 的表达，与其他变异型不同（P<0.05）。
FSGS 的 COL 变异型具有免疫组织化学特征，可将其与其他类型区分开来，提示在该领域进行更多研究。COL 独特的免疫组织化学特性可能有助于理解这种侵袭性 FSGS 形式。
