Rapid Diagnosis of Early TB in HIV+ Patients

HIV 患者早期结核病的快速诊断

• 批准号: 8121268
• 负责人: Suman Laal
• 金额: $ 20.95万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-28 至 2013-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8121268
• 关键词: Affect; Antibodies; Antigens; Blood; CD4 Positive T Lymphocytes; Cessation of life; Clinical; Cloning; Country; Detection; Diagnosis; Diagnostic; Diagnostic Procedure; Diagnostic tests; Early Diagnosis; Early treatment; Epitopes; Evaluation; Frequencies; Goals; HIV; HIV Infections; Human Resources; Immune System Diseases; Immune response; Immunodominant Epitopes; Immunosuppression; India; Individual; Infection; Laboratories; Lung; Maps; Microscopic; Microscopy; Morbidity - disease rate; Mycobacterium tuberculosis; Nucleic Acid Amplification Tests; Opportunistic Infections; Patients; Peptides; Performance; Pharmaceutical Preparations; Population; Preventive; Prospective Studies; Proteins; Recombinants; Recruitment Activity; Research Infrastructure; Resources; Risk; Serum; Signal Transduction; Site; Solid; Specimen; Sputum; Symptoms; Testing; Thoracic Radiography; Time; Training; Urine; Work; base; cohort; enzyme linked immunospot assay; immunogenic; mortality; rapid diagnosis; response; tool; tuberculosis treatment

DESCRIPTION (provided by applicant): TB diagnosis in India relies on clinical symptoms, microscopic examination of smears made directly from sputum and/or chest X-rays (CXR). The immune dysfunction caused by HIV-infection alters clinical and radiological presentation of TB, and microbiological confirmation of TB is problematic since HIV+TB+ patients have increased frequency of smear-negative (SN) TB and extrapulmonary TB (EPTB). Despite being totally treatable with the existing drugs, the poorer performance of insensitive diagnostic tests in HIV+ patients leads to significant under-diagnosis of TB in the very population where TB progression is rapid and often fatal. A simple, rapid test to identify smear-positive (SP) and SN symptomatic or asymptomatic TB in HIV+ patients would have significant impact on TB-related morbidity and mortality. Five immunogenic proteins of M. tuberculosis that are potential candidates for devising a simple diagnostic test for TB in HIV+ patients have been identified. These are MS, MPT51, PPE55, ESAT6 and CFP10. Antibodies (Abs) to these antigens have been demonstrated at all levels of immune-suppression, regardless of pulmonary manifestations and site of TB in HIV+TB+ patients, and are also detectable in sera of asymptomatic HIV+ patients who progressed to symptomatic TB in the subsequent 2-6 months. Absence of Abs to these antigens in retrospective sera from CD4 T cell-matched HIV+ patients who did not eventually develop TB suggests that in HIV+ patients, these Ab responses signal active TB whether or not clinical symptoms of TB are present and before the bacterial burden reaches the threshold of detection by direct microscopy. In the current studies we propose to evaluate the potential of these Abs to identify SN and SP symptomatic/asymptomatic HIV+TB+ patients in prospective studies and to map their dominant epitopes that are recognized by Abs in Indian patients. For this, we will recruit a cohort of ~200 ART-na¿ve HIV+ patients and investigate them for TB using direct microscopy as well as with decontaminated/concentrated sputum smears, cultures on solid media and NAAT evaluation of sputum, blood and urine (Aim 1); evaluate the presence of Abs to recombinant purified MS, MPT51, ESAT6, CFP10 and PPE55 in serum specimens from the recruited individuals and correlate the presence of Abs with bacteriological confirmation of TB (Aim 2) and identify the immunodominant epitopes on the 5 antigens recognized by serum Abs from Indian patients on peptide microarrays to define peptides that can be used to devise a peptide-based rapid test for TB in Indian HIV+ patients. PUBLIC HEALTH RELEVANCE: The immune dysfunction caused by HIV-infection alters clinical and radiological presentation of TB, and microbiological confirmation of TB is problematic since HIV+TB+ patients have increased frequency of smear- negative (SN) TB and extrapulmonary TB (EPTB). Despite being totally treatable with the existing drugs, the lack of appropriate diagnostic tools results in identification of less than half of the HIV+TB+ patients being diagnosed before death in TB-endemic countries. More sensitive diagnostic tests like microscopy with decontaminated and concentrated smears, culture of M. tb and PCR-based nucleic acid-amplification tests (NAAT) significantly enhance the identification of SN patients. However, routine implementation of these advanced diagnostic techniques is not economically feasible in high-burden countries. Studies over the last 15 years have led to the identification, cloning, and evaluation of a panel of well-defined highly immunogenic proteins of M. tb that are potential candidates for devising a simple diagnostic test for TB in HIV+ patients whether or not clinical symptoms of TB are present and before the bacterial burden reaches the threshold of detection by direct microscopy. The goal of the current studies is to evaluate the ability of Abs to these antigens to detect SN and SP symptomatic/asymptomatic HIV+TB+ patients in prospective studies. We will also map the dominant epitopes of these proteins that are recognized by Abs in Indian patients that may be used to devise a peptide-based rapid diagnostic test for HIV+TB+ patients.

描述(申请人提供)：在印度，结核病的诊断依赖于临床症状、直接从痰和/或胸部X光(CXR)获得的涂片的显微镜检查。艾滋病毒感染引起的免疫功能障碍改变了结核病的临床和放射学表现，由于HIV+TB+患者涂片阴性(SN)和肺外结核病(EPTB)的频率增加，结核病的微生物确认存在问题。尽管现有药物完全可以治疗，但在艾滋病毒阳性患者中，不敏感的诊断测试表现较差，导致在结核病进展迅速且往往致命的人群中严重低估结核病。一种简单、快速的测试来识别HIV+患者中的涂阳(SP)和SN症状或无症状的结核病，将对结核病相关的发病率和死亡率产生重大影响。已经确定了五种结核分枝杆菌免疫原蛋白，它们可能是设计一种简单的HIV+患者结核病诊断试验的候选者。它们是MS、MPT51、PPE55、ESAT6和CFP10。这些抗原的抗体已经在所有水平的免疫抑制中被证明，无论HIV+TB+患者的肺部表现和结核的部位，也可以在随后2-6个月发展为有症状的TB的无症状HIV+患者的血清中检测到。在CD4T细胞相合的HIV+患者中，这些抗原的追溯血清中没有针对这些抗原的抗体，这表明在HIV+患者中，这些抗体反应向活动性结核病发出信号，无论是否有结核病的临床症状，并且在细菌负荷达到直接显微镜检测的阈值之前。在目前的研究中，我们建议评估这些抗体在前瞻性研究中识别SN和SP症状/无症状HIV+TB+患者的潜力，并绘制其在印度患者中被Abs识别的优势表位。为此，我们将招募约200名艾滋病病毒阳性患者，并使用直接显微镜以及去污染/浓缩痰涂片、固体培养和痰、血、尿NAAT评估来调查结核病(目标1)；评估重组纯化的MS、MPT51、ESAT6、CFP10和PPE55抗体在招募个体的血清样本中的存在，并将抗体的存在与结核病的细菌学确认(AIM 2)相关联，并在多肽芯片上鉴定印度患者血清抗体识别的5种抗原的免疫优势表位，以确定可用于印度HIV+患者结核病的多肽快速检测。 公共卫生相关性：艾滋病毒感染引起的免疫功能障碍改变了结核病的临床和放射表现，由于艾滋病毒+结核病患者涂片阴性(SN)结核病和肺外结核病(EPTB)的频率增加，结核病的微生物确认存在问题。尽管现有药物完全可以治愈，但由于缺乏适当的诊断工具，在结核病流行国家，只有不到一半的艾滋病毒+结核病+患者在死前被确诊。更敏感的诊断试验，如净化和浓缩涂片的显微镜检查、结核分枝杆菌培养和基于聚合酶链式反应的核酸扩增试验(NAAT)显著提高了对SN患者的识别能力。然而，在高负担国家，常规实施这些先进的诊断技术在经济上是不可行的。过去15年的研究导致了一组定义明确的高度免疫原性的结核分枝杆菌蛋白的鉴定、克隆和评估，这些蛋白可能是设计一种简单的结核病诊断试验的候选对象，无论是否存在结核病的临床症状，并且在细菌负荷达到直接显微镜检测的阈值之前。目前研究的目的是评估针对这些抗原的抗体在前瞻性研究中检测SN和SP有症状/无症状的HIV+TB+患者的能力。我们还将绘制这些蛋白的主要表位图，这些表位可被印度患者的抗体识别，可用于设计一种针对HIV+TB+患者的基于多肽的快速诊断测试。