Yoshioka K, Hino S, Takemura T, Maki S, Wieslander J, Takekoshi Y, Makino H, Kagawa M, Sado Y, Kashtan C E
Department of Pediatrics, Kinki University School of Medicine, Osaka-sayama, Japan.
Am J Pathol. 1994 May;144(5):986-96.
Although the evidence indicates that mutation of the gene for the alpha 5 chain of type IV collagen, alpha 5-(IV), is the primary defect in X-linked Alport syndrome, protein data for the alpha 5(IV) chain with regard to its normal distribution and its distribution in patients with Alport syndrome is lacking. We produced a rat monoclonal antibody (H51) by immunizing rats with a synthetic peptide corresponding to the nonconsensus amino acid sequence of alpha 5(IV) NC1 domain. H51 reacted by Western blotting with 26-kd cationic monomers and associated dimers of human type IV collagen NC1 domain. Immunohistochemical studies demonstrated that in normal human kidney alpha 5(IV) was present in the glomerular basement membrane and basement membranes of the Bowman's capsule and in some tubules (collecting ducts). The alpha 5(IV) chain was also detected in the basement membranes of normal skin, eye, and lung. Male patients with X-linked Alport syndrome revealed no reactivity of renal and epidermal basement membranes with H51, whereas alpha 5(IV) staining was normal in the glomerular basement membrane of patients with other types of glomerular diseases, including benign familial hematuria. The staining was also normal in the skin of nonaffected males in X-linked Alport families. Female heterozygous for Alport syndrome exhibited a discontinuous or mosaic pattern in the immunofluorescent staining of the epidermal basement membrane. These findings confirm that in patients with X-linked Alport syndrome there are abnormalities in alpha 5(IV) in renal and epidermal basement membranes at the protein level. Immunofluorescent staining of skin biopsies with this antibody may be of value in making a diagnosis of Alport syndrome, and, furthermore, may aid in detecting carrier females in whom urinary abnormalities are often mild or silent.
尽管有证据表明，IV型胶原α5链（α5-(IV)）基因的突变是X连锁遗传性Alport综合征的主要缺陷，但关于α5(IV)链的正常分布及其在Alport综合征患者中的分布情况，目前尚无蛋白质数据。我们用对应于α5(IV) NC1结构域非共有氨基酸序列的合成肽免疫大鼠，制备了一种大鼠单克隆抗体（H51）。H51通过蛋白质印迹法与人类IV型胶原NC1结构域的26-kD阳离子单体及相关二聚体发生反应。免疫组织化学研究表明，在正常人类肾脏中，α5(IV)存在于肾小球基底膜、鲍曼囊基底膜以及一些肾小管（集合管）中。在正常皮肤、眼睛和肺的基底膜中也检测到了α5(IV)链。患有X连锁遗传性Alport综合征的男性患者，其肾脏和表皮基底膜与H51无反应，而在包括良性家族性血尿在内的其他类型肾小球疾病患者的肾小球基底膜中，α5(IV)染色正常。在X连锁遗传性Alport家族中未受影响的男性皮肤中，染色也正常。Alport综合征的女性杂合子在表皮基底膜的免疫荧光染色中呈现出不连续或镶嵌模式。这些发现证实，在患有X连锁遗传性Alport综合征的患者中，肾脏和表皮基底膜中的α5(IV)在蛋白质水平上存在异常。用该抗体对皮肤活检组织进行免疫荧光染色，可能有助于诊断Alport综合征，此外，还可能有助于检测尿液异常通常较轻或无症状的携带者女性。
