Untreated DQA1*0501+JDM:Clinical and Genetic Profiles

描述(由申请人提供)：青少年皮肌炎(JDM)是一种经常影响幼儿的破坏性疾病，通常在上呼吸道感染之前出现。在JDM中，85%的人是DQA1*0501+，而TNFpha-308a等位基因与TNFpha的产生增加和病程延长相关。对未经治疗的JDM DQA1*0501+儿童的肌肉活检(MBX)研究表明，与正常儿童或儿童坏死性肌病的MBX相比，干扰素(干扰素)诱导基因显著增加，与抗微生物反应一致。这项研究的目的是确定1)JDM特有的基因表达谱，无论种族或性别，以及2)区分JDM儿童的迁延性与非迁延性疾病。特定目标1A将比较5个DQA1*0501+未治疗的白人女孩和JDM+TNFA的基因表达谱；在特定目标1B，将研究5DQA1*0501-白人女孩+TNFa-308A等位基因；在特定目标1C，将检测患有3 DM的西班牙裔、非裔美国人和美洲原住民儿童，在特定目标1D，将比较男孩和女孩的基因表达。JDM MBX的细胞将通过激光捕获显微切割进行分离，以确定基因表达的来源，并将测试富含特定淋巴细胞表型(如CD4、CD8)的外周血淋巴细胞(PBL)。在表达谱中表达的选定基因将通过qRT-PCR进行确认，其蛋白将通过免疫组织化学、Western印迹和ELISA法进行鉴定。特异性目标2将比较诊断时和外周血淋巴细胞中选定基因的MBX基因表达谱，以及JDM对免疫抑制治疗的反应大于或等于6个月的随访(针状MBX和PBL)。具体目标3将描述JDM以及患有肌炎相关抗体的儿童的基因表达谱，这些儿童患有非迁延性疾病。为此，诊断时MBX和PBL中的表达谱将与获得大于或等于36个月的针刺MBX和PBL中的表达谱进行比较。在特定的目的3D中，将抗肿瘤坏死因子α的生物制剂，如依那西普，用于治疗非复发性疾病的儿童，并比较治疗前后的基因表达情况。我们推测，1)DQA1*0501+JDM和DQA1*0501-JDM的基因表达谱将不同，证实了疾病发病机制的不同，男孩和女孩也可能不同，暗示了性别效应；以及2)TNFpha的产生(和TNFpha-308A等位基因)的增加将与在患有反复疾病的肌炎儿童中持续显示INF诱导基因的基因表达谱有关。了解这些表达基因的功能应该会导致针对JDM的新疗法。

DESCRIPTION (provided by applicant): Juvenile dermatomyositis (JDM), a frequently devastating disease affecting young children, is often preceded by an upper respiratory infection. In JDM, 85% are DQA1*0501+ and the TNFalpha-308A allele is associated with increased TNFalpha production and a prolonged disease course. Study of muscle biopsy (MBx) from untreated DQA1*0501+ children with JDM, compared with MBx from normal children or from a pediatric necrotizing myopathy showed a striking increase in interferon (IFN)-inducible genes, compatible with an anti-microbial response. The purpose of this study is to determine the gene expression profiles that are 1) specific to JDM regardless of race or gender, and 2) distinguish the JDM child with remittent as opposed to nonremittent disease. Specific Aim 1A will compare the gene expression profiles of 5 DQA1*0501+ untreated white girls with JDM + TNFA; in Specific Aim 1B, 5DQA1*0501 - white girls + the TNFa-308 A allele will be studied; in Specific Aim 1C, Hispanic, African-American and Native American children with 3DM will be tested, and in Specific Aim 1D the genes expressed in boys will compared with girls. Cells from the JDM MBx will be isolated by laser capture microdissection to determine the origin of the gene expression and peripheral blood lymphocytes (PBL) enriched for a specific lymphocyte phenotype (e.g. CD4, CD8) will be tested as well. Selected genes expressed in the expression profiles will be confirmed by qRT-PCR, and their proteins identified by immunohistochemistry, western blot, and ELISA. Specific Aim 2 will characterize the gene expression profiles in MBx at diagnosis compared with selected genes in PBL, and at greater than or equal to 6 months of follow-up (needle MBx and PBL) of JDM responsive to immunosuppressive therapy. Specific Aim 3 will characterize the gene expression profiles in JDM as well as children with myositis related antibodies, who have nonremittent disease. In this aim, the expression profiles in MBx and PBL at diagnosis will be compared with needle MBx and PBL at obtained greater than or equal to 36 months. In Specific Aim 3d, an anti-TNFalpha biologic agent, such as Etanercept, will be administered to children with nonremittent disease, and the expressed genes compared before and after therapy. We speculate that 1) the gene expression profile in DQA1*0501+ JDM will differ from DQA1*0501- JDM, confirming a difference in disease pathogenesis, and that boys and girls may also differ, suggesting a gender effect; and 2) increased production of TNFalpha (and the TNFalpha-308 A allele) will be associated with persisting gene expression profiles displaying INF-inducible genes in children with myositis who have nonremittent disease. Understanding the function of these expressed genes should lead to novel therapies specific for JDM.