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

基本信息

批准号：
10465088
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
项目类别：
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/10465088
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

项目摘要

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.

项目概要感染是镰状细胞病 (SCD) 的常见并发症，高达 45% 的患者会发生感染。在非洲，高达 90% 的 SCD 儿童在 5 岁时死亡，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 B 细胞缺乏。临床意义 SCD 中 B 细胞缺陷的影响尚不完全清楚，需要研究疾病内在和 - B 细胞亚群的外在修饰物。在这项研究中，我将量化患有以下疾病的儿童的 B 细胞亚群：德克萨斯州和坦桑尼亚没有 SCD，研究 B 细胞缺陷的机制，并将其与重要的临床终点。目标 1：表征 SCD 中 MZB 缺乏的机制。假设：存在差异由于 B 细胞内在因素，SCD 和非 SCD 受试者的 B 细胞的发育、存活和功能。 B 细胞群的差异可能是由于分化和增殖动力学的差异和/或生存。为了检查分化和增殖，我将测量分化的效率使用体外 B 细胞将 SCD 和非 SCD 供体的 B 细胞转化为 MZB，以及将 MZB 转化为浆细胞细胞共培养系统。为了检查存活率，我将测量细胞凋亡率和标记物的表达培养物中天然和培养物衍生的 MZB 的细胞凋亡（例如膜联蛋白 V、半胱天冬酶 3/9、BCL2）。目标 2：确定 SCD 中脾脏微环境对 B 细胞的影响。假设： SCD 中的炎症环境等外在因素会损害 B 细胞的发育、存活和功能。为了检查微环境对培养中的 B 细胞的影响，我将在补充有 SCD 血清或脾提取物的培养基。研究提取物的哪些成分会产生影响 B 细胞，我将使用多重 ELISA 开发提取物和血清的细胞因子谱。目标 3：确定低 MZB 是否与感染和炎症并发症相关 SCD。假设：危及生命的 SCD 感染在患有严重 MZB 的儿童中更为常见不足。为了确定 B 细胞嗜性病毒是否对 MZB 数量有混杂影响，我将使用定制多重 ELISA 面板测量对 EBV 和疟疾的免疫反应。判断是否感染并发症与 SCD 中更严重的 MZB 缺乏有关，我将比较 MZB 患有或不患有急性胸部、骨髓炎或菌血症等并发症的儿童。尽管存在共同的驱动突变，但 SCD 的临床表型差异很大。总之，这方面的研究该提案将克服对感染性和炎症并发症患者进行风险分层的关键障碍 SCD 的。深入了解 SCD 如何催化 B 细胞缺陷可能有助于确定新的治疗方法减轻感染对 SCD 影响的目标或生物标志物。我的中心假设是 B 细胞异常会导致 SCD 儿童的发病率和死亡率。