Quantitative Biomarkers for Loiasis

罗阿西病的定量生物标志物

• 批准号: 10415212
• 负责人: Philip Budge
• 金额: $ 19.69万
• 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 2024-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10415212
• 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; Persons; 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 意义重大。非地方性血吸虫病活动性感染的诊断需要血吸虫病的定量抗原检测。 地区，跟踪治疗反应，并通过确定和排除以下各项来预防严重不良事件 大规模给药给有重度LOA感染的个人(&gt；每毫升血液20,000微丝虫病[MF])。 这项工作的目标是确定哪些循环中的L.LoA蛋白能够充分区分 从未感染的个体感染，并确定与重度Lloa相关的血清代谢谱 微丝虫病负荷。 创新。先前开发血吸虫病定量抗原分析的尝试依赖于对 候选蛋白质生物标记物基于对L.LoA和其他因素的预测特异性，认为可以增加 在受感染的血浆/血清中发现这些候选者的机会。到目前为止，这些尝试已经产生了分析 敏感性不足，候选生物标记物与MF负荷之间的相关性较差至中等。我们 提出一种替代方法，优先检测具有区分能力的生物标记物 预测的特异性。利用免疫亲和纯化和串联质谱学，我们之前已经 从一名个体和一名患者的混合血浆样本中检测到200多种L.LoA蛋白 血吸虫病和淋巴丝虫病(LF)快速诊断试验假阳性。我们假设有一个子集 这些在交叉反应血清中发现的L.LOA蛋白是由MF排泄/分泌的，因此将存在于 所有血吸虫病患者的血清与微丝虫病载量成比例。我们进一步假设血清中的变化 代谢物水平将与排泄/分泌丝虫抗原的存在相关，并且将更加可靠。 比循环丝虫抗原水平在预测总MF负荷时更重要。我们将通过定义 146例钩端螺旋体微囊虫载量变化患者的血样丝虫抗原和代谢物分析 从8,000-114,000毫微克/毫升，以及与之相匹配的无微丝虫病地方病对照。成功的关键 这个项目是我们与同事们合作收集的354个未确认身份的患者样本的访问 喀麦隆在过去的4年里。这将是代谢组学首次应用于血吸虫病，并将是 迄今为止对血吸虫病样本进行的最广泛的蛋白质组学分析。 冲击力。这些研究将确定与LOA感染强度相关的蛋白质和代谢物生物标记物， 并将确定与循环中的MF和丝虫抗原的存在相关的代谢过程 患有肺吸虫病的个体。这将为定量诊断的发展提供有前途的候选者 可以改善临床病例管理并简化检测而不是治疗策略的钩端螺旋体病检测 在LF和盘尾丝虫病的大规模药物分配期间预防与血吸虫病相关的不良事件。