Characterization of B Lymphocyte Deficiency in Pediatric Sickle Cell Disease

儿童镰状细胞病 B 淋巴细胞缺乏的特征

• 批准号: 10199779
• 负责人: Venee N Tubman
• 金额: $ 16.32万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-20 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10199779
• 关键词: 5 year old; ANXA5 gene; Abnormal Cell; Acute; Africa; Africa South of the Sahara; Age; Apoptosis; B cell differentiation; B-Cell Development; B-Lymphocyte Subsets; B-Lymphocytes; BCL2 gene; Bacteremia; CASP3 gene; Cessation of life; Chest; Child; Childhood; Clinical; Coculture Techniques; Custom; Cytokine Signaling; Development; Disease; Enrollment; Environment; Enzyme-Linked Immunosorbent Assay; Exposure to; Fibrinogen; Funding; Goals; Histopathology; Human Herpesvirus 4; Immune; Immune response; Immune system; Impairment; In Vitro; Infection; Inflammatory; Innate Immune Response; Intrinsic factor; Investigation; Kinetics; Lead; Life; Lymphocyte Count; Malaria; Marginal Zone B-Lymphocyte; Measures; Memory B-Lymphocyte; Mentorship; Modeling; Monitor; Morbidity - disease rate; Natural Immunity; Osteomyelitis; Patients; Plasma Cells; Plasmodium; Population; Research; Research Personnel; Risk Assessment; Risk Reduction; Role; Sampling; Serum; Sickle Cell Anemia; Spleen; System; T-Lymphocyte; Tanzania; Texas; Therapeutic; Tissue Banks; Tissues; Training; Viral; Virus; Work; biomarker development; clinical phenotype; cohort; cytokine; driver mutation; experience; humoral immunity deficiency; immune function; infancy; infection risk; inflammatory milieu; insight; mortality; new therapeutic target; pathogen; patient stratification; peripheral blood; programs; risk stratification; sample collection; therapeutic biomarker; therapeutic target; tool

PROJECT SUMMARY Infections are frequent complications in sickle cell disease (SCD), occurring in up to 45% of patients. In Africa, where up to 90% of children with SCD die by age 5 years, many of these deaths are attributed to infection. In SCD, the spleen is damaged in infancy and results in marginal zone B cell deficiency. The clinical implications of B cell deficiency in SCD are not fully understood and requires investigating both disease-intrinsic and - extrinsic modifiers of B cell subsets. In this investigation, I will quantify B cell subsets in children with and without SCD in Texas and in Tanzania, investigate mechanisms of B cell deficiency, and compare them to important clinical endpoints. Aim 1: Characterize mechanisms of MZB deficiency in SCD. Hypotheses: There is a difference in the development, survival, and function of B cells from SCD and non-SCD subjects due to B-cell intrinsic factors. Differences in B cell populations may be due to differences in kinetics of differentiation and proliferation and/or survival. To examine differentiation and proliferation, I will measure the efficiency of differentiation of transitional B cells from SCD and non-SCD donors into MZBs, and MZBs into plasma cells using an in vitro B cell co-culture system. To examine survival, I will measure the rate of apoptosis and expression of markers of apoptosis (e.g. annexin V, caspase 3/9, BCL2) in native and culture-derived MZBs in culture. Aim 2: Determine the effect of the microenvironment of the spleen in SCD on B cells. Hypothesis: Extrinsic factors such as the inflammatory environment in SCD impair B cell development, survival, and function. To examine the effect of the microenvironment on B cells in culture, I will culture non-SCD B cells in media supplemented with SCD serum or spleen extract. To investigate which components of the extract impact B cells, I will develop a cytokine profile for the extract and serum using multiplex ELISA. Aim 3: Determine whether low MZB is associated with infectious and inflammatory complications of SCD. Hypothesis: Life-threatening infections in SCD are more common among children with severe MZB deficiency. To determine whether B-cell tropic viruses have a confounding effect on MZB number, I will measure immune response to EBV and malaria using a custom multiplex ELISA panel. To determine whether infectious complications are associated with more severe MZB deficiency in SCD, I will compare MZB among children with and without complications such as acute chest, osteomyelitis, or bacteremia. Despite a shared driver mutation, the clinical phenotype in SCD is highly variable. Together, the studies in this proposal will overcome critical barriers to risk-stratifying patients for infectious and inflammatory complications of SCD. Increased insights into how SCD catalyzes B cell deficiency may help identify novel therapeutic targets or biomarkers to mitigate the impact of infections on SCD. My central hypothesis is that B cell abnormalities contribute to morbidity and mortality in children with SCD.

项目摘要 感染是镰状细胞疾病（SCD）的常见并发症，最多45％的患者发生。在非洲， 在5岁时，有多达90％的SCD儿童死亡的儿童死亡，其中许多死亡归因于感染。在 SCD，脾脏在婴儿期受损，并导致边缘区域B细胞缺乏症。临床意义 SCD中B细胞缺乏症的缺乏尚未完全了解，需要研究疾病中的疾病和 - B细胞子集的外部修饰符。在这项调查中，我将量化患有和 在德克萨斯州和坦桑尼亚没有SCD，研究B细胞缺乏的机制，并将其比较 重要的临床终点。 AIM 1：表征SCD中MZB缺乏的机制。假设： 由于B细胞固有因素，SCD和非SCD受试者的B细胞的开发，生存和功能。 B细胞种群的差异可能是由于分化和增殖动力学的差异以及/或 生存。为了检查分化和增殖，我将衡量 从SCD和非SCD供体的过渡B细胞进入MZB，并使用体外B进入血浆细胞 细胞共培养系统。为了检查生存，我将衡量凋亡率和标记的表达速率 在培养物中，天然和文化衍生的MZB中的凋亡（例如Annexin V，caspase 3/9，Bcl2）。 AIM 2：确定SCD中脾微环境对B细胞的影响。假设： 外部因素，例如SCD中的炎症环境损害B细胞的发展，生存和 功能。为了检查微环境对培养物中B细胞的影响，我将培养非SCD B细胞 补充SCD血清或脾脏提取物的培养基。调查提取物的哪些组成部分 B细胞，我将使用多重ELISA开发用于提取物和血清的细胞因子谱。 AIM 3：确定低MZB是否与感染和炎症并发症有关 scd。假设：严重MZB儿童中SCD中威胁生命的感染更为常见 不足。为了确定B细胞热带病毒是否对MZB数字产生混杂影响，我将 使用自定义的多重ELISA面板测量对EBV和疟疾的免疫反应。确定是否 传染性并发​​症与SCD中更严重的MZB缺乏有关，我将比较MZB 患有和没有并发症的儿童，例如急性胸部，骨髓炎或菌血症。 尽管有共同的驱动突变，但SCD中的临床表型却高度可变。在一起的研究 提案将克服风险分层的患者的关键障碍，以感染和炎症并发症 SCD。对SCD如何催化B细胞缺乏症的洞察力增加可能有助于鉴定新的治疗性 靶标或生物标志物减轻感染对SCD的影响。我的中心假设是B细胞 SCD儿童的发病率和死亡率有助于异常。