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Quantification of circulating Mycobacterium tuberculosis antigen peptides allows rapid diagnosis of active disease and treatment monitoring.

ABSTRACT: Tuberculosis (TB) is a major global health threat, resulting in an urgent unmet need for a rapid, non-sputum-based quantitative test to detect active Mycobacterium tuberculosis (Mtb) infections in clinically diverse populations and quickly assess Mtb treatment responses for emerging drug-resistant strains. We have identified Mtb-specific peptide fragments and developed a method to rapidly quantify their serum concentrations, using antibody-labeled and energy-focusing porous discoidal silicon nanoparticles (nanodisks) and high-throughput mass spectrometry (MS) to enhance sensitivity and specificity. NanoDisk-MS diagnosed active Mtb cases with high sensitivity and specificity in a case-control study with cohorts reflecting the complexity of clinical practice. Similar robust sensitivities were obtained for cases of culture-positive pulmonary TB (PTB; 91.3%) and extrapulmonary TB (EPTB; 92.3%), and the sensitivities obtained for culture-negative PTB (82.4%) and EPTB (75.0%) in HIV-positive patients significantly outperformed those reported for other available assays. NanoDisk-MS also exhibited high specificity (87.1-100%) in both healthy and high-risk groups. Absolute quantification of serum Mtb antigen concentration was informative in assessing responses to antimycobacterial treatment. Thus, a NanoDisk-MS assay approach could significantly improve the diagnosis and management of active TB cases, and perhaps other infectious diseases as well.

SUBMITTER: Liu C

PROVIDER: S-EPMC5393254 | biostudies-literature | 2017 Apr

REPOSITORIES: biostudies-literature

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Quantification of circulating Mycobacterium tuberculosis antigen peptides allows rapid diagnosis of active disease and treatment monitoring.

Liu Chang C Zhao Zhen Z Fan Jia J Lyon Christopher J CJ Wu Hung-Jen HJ Nedelkov Dobrin D Zelazny Adrian M AM Olivier Kenneth N KN Cazares Lisa H LH Holland Steven M SM Graviss Edward A EA Hu Ye Y

Proceedings of the National Academy of Sciences of the United States of America 20170327 15

Tuberculosis (TB) is a major global health threat, resulting in an urgent unmet need for a rapid, non-sputum-based quantitative test to detect active Mycobacterium tuberculosis (Mtb) infections in clinically diverse populations and quickly assess Mtb treatment responses for emerging drug-resistant strains. We have identified Mtb-specific peptide fragments and developed a method to rapidly quantify their serum concentrations, using antibody-labeled and energy-focusing ...[more]

PMID: 28348223

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Project description:BackgroundNew diagnosis tests are urgently needed to address the global tuberculosis (TB) burden and to improve control programs especially in resource-limited settings. An effective in vitro diagnostic of TB based on serological methods would be regarded as an attractive progress because immunoassays are simple, rapid, inexpensive, and may offer the possibility to detect cases missed by standard sputum smear microscopy. However, currently available serology tests for TB are highly variable in sensitivity and specificity. Lipolytic enzymes have recently emerged as key factors in lipid metabolization during dormancy and/or exit of the non-replicating growth phase, a prerequisite step of TB reactivation. The focus of this study was to analyze and compare the potential of four Mycobacterium tuberculosis lipolytic enzymes (LipY, Rv0183, Rv1984c and Rv3452) as new markers in the serodiagnosis of active TB.MethodsRecombinant proteins were produced and used in optimized ELISA aimed to detect IgG and IgM serum antibodies against the four lipolytic enzymes. The capacity of the assays to identify infection was evaluated in patients with either active TB or latent TB and compared with two distinct control groups consisting of BCG-vaccinated blood donors and hospitalized non-TB individuals.ResultsA robust humoral response was detected in patients with active TB whereas antibodies against lipolytic enzymes were infrequently detected in either uninfected groups or in subjects with latent infection. High specifity levels, ranging from 93.9% to 97.5%, were obtained for all four antigens with sensitivity values ranging from 73.4% to 90.5%, with Rv3452 displaying the highest performances. Patients with active TB usually exhibited strong IgG responses but poor IgM responses.ConclusionThese results clearly indicate that the lipolytic enzymes tested are strongly immunogenic allowing to distinguish active from latent TB infections. They appear as potent biomarkers providing high sensitivity and specificity levels for the immunodiagnosis of active TB.

Project description:Clinical and laboratory diagnosis of Active Tuberculosis (ATB) and latent Mycobacterium Tuberculosis (M. tuberculosis) infections (LTBI) among people living with HIV/AIDS (PLWHA) presents formidable challenges. In the past, WHO issued an advisory against the use of existing TB sero-diagnostics. Emerging evidence, however, points to a precision of TB sero-diagnostics based on secretory rather than structural M. tuberculosis antigens. We hypothesized that secretory levels of M. tuberculosis thymidylate kinase (TMKmt) can Designate ATBI from LTBI and no TB (NTB). Here, we report in-house validation studies of levels of TMKmt antigen (Ag) and host specific TMKmt antibody (Ab) amongst HIV +ve and HIV -ve participants. Direct TMKmt Ag and host specific IgG Ab detection EIAs were conducted on broadly consented, stored serum (N=281[Ag] vs. 214 [Ab] respective) samples stratified as either HIV +ve or HIV-ve ATB relative to LTBI and No TB. On one hand, UG-peptide 1 and its PAb-based EIAs accurately diagnosed ATB relative to LTBI and NTB among HIV +ve subjects {irrespectively: (a) Ag detection ATB=OD>0.490; 95% CI: 0.7446 to 0.8715 vs. LTBI=OD<0.490; 95% CI 0.4325 to 0.4829 vs. NTB=OD<0.26; 95% CI 0.1675 to 0.2567 and (b) TMKmt specific IgG detection ATB=OD>1.00; 95% CI 1.170 to 1.528 [HIV +ve] and 2.044 to 2.978 [HIV -ve] respectively vs. LTBI=OD<1.00; 95% CI 0.2690 to 0.6396 vs. NTB=OD<; 95% CI 0.1527 to 0.8751}. HIV -ve ATB presented with Ag levels greater than NTB and less than LTBI (i.e. ATB -ve=<0.490 ODs>0.26), but displayed better ant-TMKmt IgG responses (OD>2.00; 95% CI 2.044 to 2.978) relative to HIV +ve ATB (OD<1.600; 95% CI 1.170 to 1.528); suggesting a better control of M. tuberculosis-septicemia. On the other hand, UG-peptide 2 and its PAb-based EIAs did not demonstrate ATB diagnostic potential regardless of HIV sero-status, except towards designating NTB. TMKmt Ab and Ag detecting EIAs based on UG-peptide 1 and its derivative PAb can accurately demarcate ATB from LTBI and NTB among HIV +ve subjects.

Project description:Background: Safe and sensitive methods for glioblastoma diagnosis and disease monitoring are urgently needed. Exosomes are nano-sized extracellular vesicles that contain molecules characteristic of their cell-of-origin, including microRNA. Exosomes released by glioblastoma tumors cross the blood-brain-barrier ino the peripheral circulation. Methods: Serum exosomal-microRNA isolated from IDH-wildtype glioblastoma (n=12) and IDH-mutant glioma grades II-III (n=10) were analyzed using small-RNA next generation sequencing and compared to age- and gender-matched healthy controls. Differentially expressed miRNAs (|fold change|³2 and p-value ≤ 0.05 in three statistical tests, Fischer-exact, t-test, and Wilcoxon) were identified and the predictive power of individual and subsets of miRNAs were tested using univariate (logistic regression) and multivariate (Random Forest) analyses. Additional glioblastoma sera (n=4) and independent sets of healthy (n=9) and non-glioma (n=10) controls were used to further test the predictive power of our glioblastoma miRNA signature. Results: Twenty-six miRNAs were differentially expressed in glioblastoma relative to healthy controls. Seven miRNAs (miR-182-5p, miR-328-3p, miR-339-5p, miR-340-5p, miR-485-3p, miR-486-5p and miR-543) were the most stable for classifying glioblastoma, achieving a predictive power of 91.7%. Strikingly, the combined expressions of miR-182-5p, miR-328-3p miR-485-3p miR-486-5p distinguished glioblastoma patients from controls with perfect accuracy. This miRNA panel was able to correctly classify all specimens in validation cohorts (n=23). An analogous approach was used to identify 23 dysregulated miRNAs in IDH-mutant gliomas, including a distinct subset of stable miRNAs for classifying patients with lower-grade IDH-mutant gliomas. Conclusions: Our serum exosomal-miRNA signature can accurately diagnose glioblastoma preoperatively. These findings have significant scope to revolutionize glioblastoma tumor diagnosis and disease monitoring. IMPORTANCE OF STUDY: There is a real need for accurate biomarkers that can measure glioblastoma disease activity and treatment response in a safe and timely manner. This study demonstrates that exosome-associated microRNAs have exceptional utility as blood-based biomarkers in glioma patients. This work also shows the potential for exosomal microRNA profiles to be used for glioma subtyping, grading and determining mutational states. The development of specific, sensitive and non-invasive screening tests would have significant clinical benefit by reducing costs of treatment monitoring, improving accessibility and quality-of-life measures. Moreover, such tests have the potential to provide objectively measured surrogate endpoints to allow clinical trial protocols to be more dynamic and adaptive.

Dataset Information

Quantification of circulating Mycobacterium tuberculosis antigen peptides allows rapid diagnosis of active disease and treatment monitoring.

Publications

Quantification of circulating <i>Mycobacterium tuberculosis</i> antigen peptides allows rapid diagnosis of active disease and treatment monitoring.

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