ETIOLOGIC FACTOR IN FOCAL GLOMERULOSCLEROSIS

描述(改编自调查人员摘要)：证据 循环因子对FSGS患者蛋白尿的影响包括早期 肾移植术后蛋白尿复发，临床反应良好 对于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通透性(PALB) 将分离的肾小球与血清或血浆孵育后， 某些FSGS患者。我们已经通过PALB定义了该化验中的活性 在标准条件下孵育后的分离肾小球 我们已经证明，在此之前获得的样本的FS活性 移植可预测蛋白尿复发和以后的同种异体移植物丢失。 FS活性通过血浆置换和部分蛋白质组分降低 血浆置换液携带这种活性。静脉注射 源于FSGS患者血浆和携带FS活动原因的部分 大鼠一过性蛋白尿。血浆或其组份的FS活性为 依赖于浓度。在纯化过程中，相对活性是 与血浆置换液相比增加了33,000倍以上， 收益率超过80%。有源成分或“FSGS因数”是 蛋白质，如其在有机溶剂中不溶的特性所证明的， 耐热性和对蛋白酶的敏感性。它在生理pH值下是阴离子的， 在浓缩程度最高的馏分中，其分子大小明显为 30-50kD。我们利用了因子的高亲和力来确定 碳水化合物以设计一种简化的浓缩方案。在 建议研究，我们将从FSGS的血浆中提纯FSGS因子 患者的同源性，并将确定其氨基酸序列和 碳水化合物组成。将采用的技术进一步净化 材料包括亲和层析、层析聚焦、尺寸排除 层析、离子交换层析、等电聚焦和 使用单抗的亲和层析。我们将比较 将FSGS因子与已知蛋白质和糖蛋白结合，确定其是否为 先前描述的是一种新的调解器。我们将使用单克隆 为进一步研究人的FSGS建立一种免疫分析方法。 这一信息的应用将有助于及早识别患者 最具侵袭性的疾病形式，并最终设计 对自体肾脏和同种异体肾移植中的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.