Discovery of Novel Autoantigens in Patients with Inclusion Body Myositis

描述(申请人提供)：包涵体肌炎(IBM)是一组被称为炎症性肌病的肌肉疾病之一，其特征是慢性肌肉炎症伴随肌肉无力。IBM没有治愈的方法，也没有标准的疗程。我们已经确定，在这种疾病中，以前未被认识到的免疫系统组件，即分泌抗体的浆细胞，渗透到肌肉组织中。这些细胞的作用和它们产生的抗体的目标(S)都是未知的，但它们的鉴定是理解IBM免疫病理学机制的关键第一步。我们着手在IBM患者的组织和外周组织中确定自身免疫反应的靶点。为了确定抗原靶标的身份，从通过活检获得的IBM肌肉组织中显微解剖了单个组织相关浆细胞。然后用单细胞聚合酶链式反应从一系列单细胞中扩增出免疫球蛋白重链和轻链。制备重组免疫球蛋白，用于肌肉抗原的分离。我们发现IBM组织源性免疫球蛋白能够识别一种肌肉中间丝蛋白。我们建议的研究旨在检查这种新发现的自身免疫靶点在疾病中的流行率和相关性。首先，使用激光辅助显微解剖，从一大组IBM肌肉活检组织中分离出单个浆细胞。然后，从这些单个细胞中提取的重组免疫球蛋白将被测试与肌肉中间丝蛋白和其他候选自身抗原的反应性。在该项目的第二部分，将确定IBM自身抗体的血清流行率。在这里，我们将使用高通量抗原阵列识别IBM血清自身抗体的靶标。血清自身抗体的存在将与疾病特征相关，作为识别这些分子作为有用的临床诊断或预后生物标记物的先决条件。

DESCRIPTION (provided by applicant): Inclusion body myositis (IBM) is one of a group of muscle diseases known as the inflammatory myopathies, which are characterized by chronic muscle inflammation accompanied by muscle weakness. There is no cure for IBM, nor is there a standard course of treatment. We have determined that previously unappreciated components of the immune system, namely antibody-secreting plasma cells, infiltrate the muscle tissue in this disease. Both the role of these cells and the target(s) of the antibody they produce are not known, yet their identification is a critical first step to understanding the mechanisms of IBM immunopathology. We set out to identify the targets of the autoimmune response in both the tissue and periphery of patients with IBM. To determine the identity of the antigen target, single tissue-associated plasma cells were micro-dissected from IBM muscle tissue acquired through biopsy. Single cell PCR was then used to amplify the immunoglobulin heavy and light chain from a series of single cells. Recombinant immunoglobulin was then prepared and used to isolated muscle antigens. We discovered that a muscle intermediate filament protein was recognized by IBM tissue-derived immunoglobulin. Our proposed research is designed to examine both the prevalence and relevance of this newly identified autoimmune target in the disease. First, single plasma cells, will be isolated, using laser-assisted microdissection, from a large set of IBM muscle biopsy tissues. Then, recombinant immunoglobulin derived from these single cells will be tested for reactivity to muscle intermediate filament proteins and other candidate autoantigens. In the second part of the project, the sero-prevalence of IBM autoantibodies will be determined. Here we will identify targets of IBM serum autoantibodies using high throughput antigen arrays. The presence of serum autoantibodies will be correlated with disease features as a prerequisite for identifying these molecules as useful clinical diagnostic or prognostic biomarkers.