M3 RECEPTOR: DIAGNOSTIC MARKER FOR SJOGREN'S SYNDROME

干燥综合征是一种人类唾液腺和泪腺的自身免疫性疾病，导致口干症(口腔干燥)和干眼症(眼睛干燥)。这种疾病可能是一种原发自身免疫性疾病，也可能是一种继发性自身免疫性疾病，伴有其他结缔组织疾病或糖尿病。虽然被列为孤儿疾病，但它被严重低估；因此，据估计，多达200万至400万人(其中90%是妇女)实际上患有某种形式的疾病。目前，干燥综合征的诊断包括在唇腺活检组织中检测到淋巴细胞渗入，类风湿因子和细胞成分(如SS-A/Ro，SS-B/La，α-fodrin和核物质)的自身抗体的存在，高丙种球蛋白血症，以及刺激后外分泌腺流量的丧失。这些标记物本身都不是疾病特异性的。最近，我们和其他人发现，所有确诊的干燥综合征患者的血清中都含有针对外分泌腺细胞上表达的M胆碱能-3受体(M3)的自身抗体。这一发现表明，这一单一标记物可能能够定义自身免疫性外分泌病。因此，我们建议研究开发一种能够识别干燥综合征患者的简单、非侵入性诊断测试的可行性。这一阶段STTR赠款的具体目的是：i)确定使用全长M3蛋白重组形式的ELISA测试是否可以特定和普遍地识别Sjogren综合征患者，以及2)将ELISA测试结果与使用M3表达的转基因COS-7细胞株获得的结果进行比较。如果这项研究的结果证实并扩展了我们的初步数据，那么对临床诊断实验室和患者来说，最终开发出一种简单、非侵入性的干燥综合征特异性诊断测试将是一个受欢迎的补充。建议的商业应用：鉴定外分泌腺细胞上的抗乙酰胆碱-3受体(M3)的自身抗体现在似乎是干燥综合征(自身免疫性外分泌病)中最好的自身免疫单一标志物。虽然干燥综合征被归类为孤儿疾病，但它也被认为被低估了；因此，美国可能有200-400万患者，其中90%是女性。发展一种基于M3自身抗体检测的非侵入性诊断试验将是临床实验室的一大进步。

Sjogren's syndrome is a human autoimmune disease of the salivary and lacrimal glands resultIng in debilitating xerostomia (dry mouth) and xerophthalmia (dry eyes). This disease may present as either a primary autoimmune disease or as a secondary autoimmune disease concomitant with other connective tissue diseases or diabetes. Although classified as an orphan disease, it is grossly under-diagnosed; thus, it is estimated that as many as 2-4 million individuals (90% of which are women) actually have a form of the disease. At present, diagnosis of Sjogren's syndrome involves detection of lymphocytic infiltrates in biopsies of the labial glands, the presence of autoantibodies to rheumatoid factor and cellular components (e.g., SS-A/Ro, SS-B/La, alpha-fodrin and nuclear material), hypergammaglobulinemia, and loss of exocrine gland flow rates following stimulation. None of these markers is, by itself, disease specific. Recently, we and others have shown that all sera from patients with confirmed Sjogren's syndrome contain an autoantibody to the muscarinic cholinergic-3 receptors (M3) expressed on exocrine gland cells. This finding presents the possibility that this single marker may be able to define autoimmune exocrinopathy. Thus, we propose to investigate the feasibility of developing a simple, non-invasive diagnostic test capable of identifying patients with Sjogren's syndrome. Specific aims of this phase STTR grant are i) to determine if Sjogren's syndrome patients can be identified specifically and universally with an ELISA test using a full-length recombinant form of the M3 protein, and 2) compare the results from ELISA testing with those obtained utilizing a M3-expressing, transfected COS-7 cell line. If results of this study confirm and expand our preliminary data, then final development of a simple, non-invasive, Sjogren's syndrome-specific diagnostic test would be a welcome addition to the clinical diagnostic laboratory and the patient. PROPOSED COMMERCIAL APPLICATIONS: Identification of autoantibodies against the muscarinic acetylcholine-3 receptor (M3) on exocrine gland cells now appears to be the best single marker of autoimmunity in Sjogren's syndrome (autoimmune exocrinopathy). While Sjogren's syndrome is classified an orphan disease, it is also recognized as being under-diagnosed; thus, there may be perhaps 2-4 million patients in the US, 90% of which are women. Development of a non-invasive diagnostic test based on detection of M3 autoantibody would be a major advancement for the clinical laboratory.