Erythrocytes as Time Capsules of Disease Activity in SLE

红细胞作为系统性红斑狼疮疾病活动的时间胶囊

• 批准号: 6677400
• 负责人: Joseph M Ahearn
• 金额: $ 29.8万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-07 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6677400
• 关键词: SDS polyacrylamide gel electrophoresis; autoimmunity; clinical research; complement; erythrocytes; flow cytometry; genetic polymorphism; human subject; immunoprecipitation; inflammation; longitudinal human study; polymerase chain reaction; systemic lupus erythematosus

DESCRIPTION (provided by applicant): Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease affecting multiple organs. Using a recently developed flow cytometric assay, we discovered the deposition of significant amounts of complement C4-derived activation product on the surface of erythrocytes of SLE patients. Additional interesting findings emerging from the preliminary studies include: 1) elevated and fluctuating levels of erythrocyte-bound C4-derived activation products (E-C4) were detected among SLE patients, and 2) distinct subpopulations of erythrocytes with different E-C4 levels were concurrently present in the same patient. These findings have led to the central hypothesis of this proposal that erythrocytes and reticulocytes may serve as, respectively, "time capsules" and "instant messenger" of the inflammatory condition in vivo (and thus disease activity) in SLE patients. On one hand, erythrocytes circulating during a disease flare may acquire an increased amount of C4-derived activation products on their surface, whereas erythrocytes emerging from the bone marrow during remission may bear decreased levels of C4-derived products. On the other hand, reticulocytes (the youngest form of erythrocytes), when emerging from the bone marrow during an active disease state, may immediately be exposed to and acquire high levels of C4-derived products. Therefore, determination of the levels of C4-derived activation products on the surface of erythrocytes and reticulocytes circulating at any given time should reveal disease activity during the preceding 120 days (the life span of erythrocytes) and may provide clues to ongoing/forthcoming disease activation. The research proposed in this application is aimed to verify this hypothesis (Specifics Aim 1 and 2), to investigate the relationship between C4 polymorphism and the deposition of C4-derived products on erythrocytes/reticulocytes (Specific Aim 3), and to elucidate the biochemical basis of the deposition of C4-derived products on erythrocytes/reticulocytes (Specific Aim 4). The proposed studies will be accomplished by i) flow cytometric analysis of age-fractionated erythrocytes and reticulocytes, ii) statistical analysis of the correlation between E-C4 levels, reticulocyte-bound C4 levels, and SLE disease activity, iii) genotyping and phenotyping of C4 in SLE patients and healthy controls, and iv) biochemical studies of the interaction between erythrocytes and C4. These proposed studies will constitute the first endeavor aimed to investigate the biochemical and clinical relevance of the interaction between complement and erythrocytes/reticulocytes, in the context of SLE disease activity. Ultimately, information derived from the proposed studies may aid in the development of new laboratory tests for earlier and more accurate detection of SLE flares, and thereby facilitating the formulation and assessment of new therapeutic approaches for SLE.

描述（由申请人提供）：系统性红斑狼疮（SLE）是一种影响多个器官的原型自身免疫性疾病。使用最近开发的流式细胞仪检测，我们发现了大量的补体C4衍生的活化产物的SLE患者的红细胞表面上的沉积。初步研究中出现的其他有趣的发现包括：1）在SLE患者中检测到红细胞结合C4衍生活化产物（E-C4）水平升高和波动，2）同一患者中同时存在具有不同E-C4水平的不同红细胞亚群。这些发现导致了这一提议的中心假设，即红细胞和网织红细胞可能分别作为SLE患者体内炎症状态（从而疾病活动）的“时间胶囊”和“即时信使”。一方面，在疾病爆发期间循环的红细胞可以在其表面上获得增加量的C4衍生的活化产物，而从疾病爆发期间出现的红细胞可以在其表面上获得增加量的C4衍生的活化产物。 缓解期间的骨髓可能具有降低水平的C4衍生产物。另一方面，网织红细胞（红细胞的最年轻形式）在活动性疾病状态期间从骨髓中出现时，可立即暴露于并获得高水平的C4衍生产物。因此，在任何给定时间循环的红细胞和网织红细胞表面上的C4衍生活化产物的水平的测定应揭示在前120天（红细胞的寿命）期间的疾病活动，并且可以提供正在进行/即将发生的疾病活化的线索。本申请中提出的研究旨在验证这一假设（具体目标1和2），探讨C4多态性与C4衍生产物在红细胞/网织红细胞上沉积之间的关系（具体目标3），并阐明C4衍生产物沉积的生化基础红细胞/网织红细胞（具体目标4）。拟定的研究将通过以下方式完成：i）年龄分级红细胞和网织红细胞的流式细胞术分析，ii）E-C4水平、网织红细胞结合C4水平和SLE疾病活动性之间相关性的统计分析，iii）SLE患者和健康对照中C4的基因分型和表型，以及iv）红细胞和C4之间相互作用的生化研究。这些拟定研究将构成旨在研究SLE疾病活动背景下补体与红细胞/网织红细胞之间相互作用的生化和临床相关性的首次奋进。最终，从拟议的研究中获得的信息可能有助于开发新的实验室检查，以更早，更准确地检测SLE发作，从而促进制定和评估新的SLE治疗方法。