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: 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
• 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

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 感染是镰状细胞病（SCD）的常见并发症，发生在高达45%的患者中。在非洲， 其中高达90%的患有SCD的儿童在5岁之前死亡，这些死亡中的许多人归因于感染。在 SCD，脾脏在婴儿期受损，导致边缘区B细胞缺乏。及其临床意义 B细胞缺乏症的发病机制尚不完全清楚，需要研究疾病内在因素和 B细胞亚群的外源性修饰剂。在这项研究中，我将量化儿童的B细胞亚群， 在德克萨斯州和坦桑尼亚，研究B细胞缺乏的机制，并将其与 重要的临床终点。 目的1：研究SCD患者MZB缺乏的机制。假设：存在差异， 来自SCD和非SCD受试者的B细胞由于B细胞内在因子的发育、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，我将测量细胞的分化效率。 使用体外B转化系统，将SCD和非SCD供体的过渡B细胞转化为MZB，并将MZB转化为浆细胞 细胞共培养系统。为了检测存活率，我将测量细胞凋亡率和 在培养物中的天然和培养物衍生的MZB中的细胞凋亡（例如膜联蛋白V、半胱天冬酶3/9、BCL 2）。 目的2：探讨SCD时脾脏微环境对B细胞的影响。假设： 外源性因素如SCD中的炎性环境损害B细胞发育、存活， 功能为了检测微环境对培养物中B细胞的影响，我将在培养液中培养非SCD B细胞。 补充SCD血清或脾提取物的培养基。研究浸提液的哪些成分会影响 B细胞，我将使用多重ELISA开发提取物和血清的细胞因子谱。 目的3：确定低MZB是否与感染和炎症并发症有关。 SCD。假设：SCD中危及生命的感染在重度MZB儿童中更常见 缺陷为了确定嗜B细胞病毒是否对MZB数量具有混杂效应，我将 使用定制的多重ELISA板测量对EBV和疟疾的免疫应答。以确定是否 感染性并发症与SCD中更严重的MZB缺乏相关，我将比较MZB与 有或无并发症的儿童，如急性胸部、骨髓炎或菌血症。 尽管存在共同的驱动突变，但SCD的临床表型高度可变。总之，这方面的研究 一项提案将克服对感染和炎症并发症患者进行风险分层的关键障碍 的SCD。对SCD如何催化B细胞缺陷的深入了解可能有助于确定新的治疗方法 靶点或生物标志物，以减轻感染对SCD的影响。我的主要假设是B细胞 异常导致SCD儿童的发病率和死亡率。