Quantitative Biomarkers for Loiasis

罗阿西病的定量生物标志物

• 批准号: 10303430
• 负责人: Philip Budge
• 金额: $ 23.63万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10303430
• 关键词: Adverse event; African; Antigens; Area; Biological Assay; Biological Markers; Blood; Cameroon; Case Management; Cessation of life; Clinical; Collaborations; Coma; Detection; Development; Diagnosis; Diagnostic tests; Elephantiasis; Ensure; Filarial Elephantiases; Filariasis; Goals; Individual; Infection; Interruption; Ivermectin; Loa; Loa loa; Loiasis; Mass Spectrum Analysis; Measures; Metabolic Pathway; Metabolism; Microscopy; Monitor; Ocular Onchocerciasis; Onchocerciasis; Patients; Pharmaceutical Preparations; Plasma; Positioning Attribute; Proteins; Proteomics; Rapid diagnostics; Research; Resources; Sampling; Serious Adverse Event; Serum; Specificity; Test Result; Testing; Therapeutic; Tropical Disease; Universities; Washington; Work; antigen detection; base; biomarker discovery; candidate marker; candidate selection; clinical assay development; cross reactivity; detection assay; drug distribution; experience; experimental study; field study; improved; innovation; metabolic profile; metabolomics; predictive marker; prevent; programs; prospective; protein biomarkers; protein metabolite; success; tandem mass spectrometry; transmission process; treatment program; treatment response; treatment risk

PROJECT SUMMARY / ABSTRACT Significance. A quantitative antigen assay for loiasis is needed to diagnose active infection in non-endemic areas, to follow response to treatment, and to prevent severe adverse events by identifying and excluding from mass drug administrations individuals with heavy Loa loa infections (>20,000 microfilariae [Mf] per mL of blood). The goal of the work proposed here is to determine which circulating L. loa proteins adequately differentiate infected from uninfected individuals, and to define serum metabolic profiles that are associated with heavy L. loa microfilarial loads. Innovation. Prior attempts to develop quantitative antigen assays for loiasis have relied on targeted selection of candidate protein biomarkers based on their predicted specificity for L. loa and other factors felt to increase the chances of finding these candidates in infected plasma/serum. To date, these attempts have produced assays with inadequate sensitivity and poor to moderate correlation between the candidate biomarker and Mf loads. We propose an alternative approach that prioritizes detection of biomarkers with discriminatory capacity over predicted specificity. Using immunoaffinity purification and tandem mass spectrometry, we have previously detected over 200 L. loa proteins in plasma from one individual and one pooled plasma sample from patients with loiasis and falsely-positive rapid diagnostic tests for lymphatic filariasis (LF). We hypothesize that a subset these L. loa proteins found in cross-reactive sera are excreted/secreted by Mf and will therefore be present in sera from all loiasis patients in proportion to microfilarial loads. We further hypothesize that alteration in serum metabolite levels will correlate with the presence excreted/secreted filarial antigens, and will be more reliable than circulating filarial antigen levels at predicting total Mf load. We will test these hypotheses by defining the filarial antigen and metabolite profiles of banked plasma samples from 146 patients with L. loa Mf loads ranging from 8,000 – 114,000 Mf/mL and a matching number of amicrofilaremic endemic controls. Key to the success of this project is our access to 354 de-identified patient samples collected in collaboration with colleagues in Cameroon over the past 4 years. This will be the first application of metabolomic profiling to loiasis, and will be the most extensive proteomics analysis of loiasis samples to date. Impact. These studies will identify protein and metabolite biomarkers that correlate with L. loa infection intensity, and will identify metabolic processes that correlated with the presence of circulating Mf and filarial antigen in individuals with loiasis. This will provide promising candidates for the development of quantitative diagnostic tests for loiasis that can improve clinical case management and simplify test and not treat strategies for preventing loiasis-related adverse events during mass drug distributions for LF and onchocerciasis.

项目摘要 /摘要 意义。需要用于散型的定量抗原测定法来诊断非末端感染的主动感染 领域，跟随对治疗的反应，并通过识别和排除在 大规模药物管理人员感染重LOA LOA感染（每毫升血液> 20,000个微毛皮菌[MF]）。 这里提出的工作的目的是确定哪种循环LOA蛋白充分区分 从未感染的个体中感染，并定义与重L. Loa相关的血清代谢谱 微载载荷。 创新。事先尝试开发拟态定量抗原分析的尝试已依赖于目标选择 候选蛋白生物标志物基于其对L. Loa的预测特异性和其他因素，以增加 在感染的血浆/血清中找到这些候选者的机会。迄今为止，这些尝试已经产生了测定 候选生物标志物和MF载荷之间的灵敏度不足，较差至中等相关性。我们 提案一种替代方法，优先考虑对具有歧视能力的生物标志物的检测 预测的特异性。使用免疫亲和力纯化和串联质谱法，我们以前有 从一个个体中检测到等离子体中的200 L. loa蛋白，并从患者中检测到一个合并的血浆样品 进行卵巢丝虫病（LF）的遗嘱和错误阳性的快速诊断测试。我们假设一个子集 在交叉反应血清中发现的这些L. loa蛋白是由MF额外的/分泌的，因此将存在于 来自所有Loiasis患者的血清与微移动负荷成比例。我们进一步假设串行的变化 代谢物水平将与超过/分泌的丝状抗原相关，并且将更可靠 比循环丝抗原水平在预测总MF负载方面。我们将通过定义 来自146例L. loa MF负载范围内的146例库存血浆样品的丝状抗原和代谢物概况 从8,000至114,000 MF/mL和匹配的疗养院疗法内粒对照组。成功的关键 该项目是我们访问与同事合作收集的354个取消识别的患者样本 喀麦隆过去四年。这将是代谢组分析到loiasis的首次应用，将是 迄今为止，冰虫样品最广泛的蛋白质组学分析。 影响。这些研究将确定与L. loa感染强度相关的蛋白质和代谢物生物标志物， 并将确定与循环MF和丝状抗原存在相关的代谢过程 具有loiasis的人。这将为候选人提供定量诊断的发展 可以改善临床病例管理并简化测试并且不处理策略的贷款测试 在LF和OnChocerciasis的大规模药物分布期间，可以防止与路降相关的不良事件。