ETIOLOGIC FACTOR IN FOCAL GLOMERULOSCLEROSIS

描述（改编自研究者摘要）：证据表明 循环因子是FSGS中蛋白尿的原因，包括早期 移植肾蛋白尿复发，临床反应良好 血浆置换和免疫吸附治疗，我们观察到， FSGS患者血浆增加肾小球白蛋白渗透性（Palb） 在体外孵育分离的肾小球到血清或血浆， 某些FSGS患者 我们在该测定中通过Palb 在标准条件下孵育后分离的肾小球的体积为“FS 活动”。 我们已经表明，FS活动之前获得的标本， 移植预示着蛋白尿的复发和随后的同种异体移植物丢失。 FS活性通过血浆置换和血浆置换中的蛋白质部分降低。 血浆除去液携带这种活性。 静脉注射 来源于FSGS患者血浆并携带FS活性的组分 大鼠一过性蛋白尿。 血浆或其组分的FS活性是 浓度依赖性。 在纯化过程中，相对活性为 与血浆置换液相比增加超过33，000倍， 收率在80%以上。 活性组分或“FSGS因子”是 蛋白质，如其在有机溶剂中的不溶性所证明的， 热不稳定性和蛋白酶敏感性。 它在生理pH下是阴离子， 在最高富集级分中，表观分子大小为 30-50 kD。 我们利用该因子对某些 碳水化合物来设计其富集的简化方案。 在 本研究拟从FSGS患者血浆中纯化FSGS因子， 患者的同质性，并将确定其氨基酸序列， 碳水化合物组成 将采用的技术来进一步纯化 材料包括亲和层析、层析聚焦、尺寸排阻 色谱法、离子交换色谱法、等电聚焦和 使用单克隆抗体的亲和层析。 我们将比较 FSGS因子与已知的蛋白质和糖蛋白结合，以确定它是否是一种 如前所述的新型介体。 我们将使用单克隆 抗体，以开发免疫测定法，用于进一步研究人类FSGS。 这些信息的应用将有助于早期识别患者 最具侵略性的疾病，并最终，设计 用于自体肾和肾移植物中FSGS的特异性治疗。

DESCRIPTION (Adapted from Investigator's Abstract): Evidence that a circulating factor is responsible for proteinuria in FSGS includes early recurrence of proteinuria in renal allografts, favorable clinical responses to plasmapheresis and immunoadsorption therapy, and our observation that plasma from FSGS patients increases glomerular albumin permeability (Palb) following in vitro incubation of isolated glomeruli to serum or plasma of certain FSGS patients. We have defined activity in this assay by the Palb of isolated glomeruli after incubation under standard conditions as "FS activity". We have shown that FS activity of specimens obtained prior to transplantation predicts recurrence of proteinuria and later allograft loss. FS activity is diminished by plasmapheresis and a protein fraction of plasmapheresis fluid carries this activity. Intravenous injection of fractions derived from FSGS patients' plasma and carrying FS activity causes transient proteinuria in rats. FS activity of plasma or its fractions is concentration dependent. During purification, relative activity is increased by more than 33,000 fold compared to plasmapheresis fluid and the yield is more than 80 percent. The active component or "FSGS factor" is a protein, as evidenced by its properties of insolubility in organic solvents, heat-lability, and protease sensitivity. It is anionic at physiologic pH, and in the most highly enriched fractions, has an apparent molecular size of 30-50 kD. We have used the high affinity of the factor to certain carbohydrates to design a simplified protocol for its enrichment. In the proposed studies, we will purify the FSGS factor from plasma of FSGS patients to homogeneity and will determine its amino acid sequence and carbohydrate composition. Techniques to be employed to further purify the material include affinity chromatography, chromatofocusing, size exclusion chromatography, ion exchange chromatography, isoelectric focusing and affinity chromatography using monoclonal antibodies. We will compare the FSGS factor to known proteins and glycoproteins to determine whether it is a previously described for a novel mediator. We will use monoclonal antibodies to develop an immunoassay for further studies of human FSGS. Application of this information will permit early identification of patients with the most aggressive forms of the disease, and, eventually, to design specific treatment for FSGS in native kidneys and renal allografts.