Novel Biomarkers Distinguishing Active Tuberculosis from Latent Infection Identified by Gene Expression Profile of Peripheral Blood Mononuclear Cells

Abstract

BackgroundHumans infected with Mycobacterium tuberculosis (MTB) can delete the pathogen or otherwise become latent infection or active disease. However, the factors influencing the pathogen clearance and disease progression from latent infection are poorly understood. This study attempted to use a genome-wide transcriptome approach to identify immune factors associated with MTB infection and novel biomarkers that can distinguish active disease from latent infection.Methodology/Principal FindingsUsing microarray analysis, we comprehensively determined the transcriptional difference in purified protein derivative (PPD) stimulated peripheral blood mononuclear cells (PBMCs) in 12 individuals divided into three groups: TB patients (TB), latent TB infection individuals (LTBI) and healthy controls (HC) (n = 4 per group). A transcriptional profiling of 506 differentially expressed genes could correctly group study individuals into three clusters. Moreover, 55- and 229-transcript signatures for tuberculosis infection (TB&LTBI) and active disease (TB) were identified, respectively. The validation study by quantitative real-time PCR (qPCR) performed in 83 individuals confirmed the expression patterns of 81% of the microarray identified genes. Decision tree analysis indicated that three genes of CXCL10, ATP10A and TLR6 could differentiate TB from LTBI subjects. Additional validation was performed to assess the diagnostic ability of the three biomarkers within 36 subjects, which yielded a sensitivity of 71% and specificity of 89%.Conclusions/SignificanceThe transcription profiles of PBMCs induced by PPD identified distinctive gene expression patterns associated with different infectious status and provided new insights into human immune responses to MTB. Furthermore, this study indicated that a combination of CXCL10, ATP10A and TLR6 could be used as novel biomarkers for the discrimination of TB from LTBI.

Beyond the IFN- horizon: biomarkers for immunodiagnosis of infection with Mycobacterium tuberculosis

“…These include measurement of alternative biomarkers in M. tuberculosis-specific antigen-stimulated supernatants [89], the use of ratios of intracellular expression of different cytokines [138], T-cell phenotype as well as cytokine expression profiles of specific T-cells [139][140][141], and transcriptomic approaches to identify genes or gene signatures, which could be characteristic for latent or active disease [142][143][144].…”

IP-10 release assays in the diagnosis of tuberculosis infection: current status and future directions

“…A series of papers have demonstrated that unstimulated IP-10 levels in blood or plasma are increased with infection and disease, such as TB [101][102][103][104], hepatitis C viral infection [105][106][107] and bacteremia [108][109][110]. IP-10 is produced at the site of inflammation and the levels in the blood appear to correlate with the extent of the inflammatory process.…”

New Diagnostics for Childhood Tuberculosis

“…[91][92][93][94][95][96] The sole pediatric study compared host gene expression signatures in blood between children with culture-confirmed TB disease, LTBI, and other diseases with similar presentations. For each of the more than 2000 study participants, the investigators generated a risk score that quantified the degree to which the child's expression signature was consistent with TB disease.…”