title: Circulating biomarkers of pulmonary and extrapulmonary tuberculosis in children.
abstract: Tuberculosis (TB) in children is not only more likely to cause more severe disease than that seen in adults, it is also more likely to be extrapulmonary. Moreover, pediatric TB is very difficult to diagnose and suffers from a lack of understanding of host biomarkers for monitoring the progression of disease. Hence, we sought to identify the expression patterns of a variety of biomarkers in the plasma of children with pulmonary TB (PTB) and extrapulmonary TB (ETB), as well as in healthy control (HC) children. Thus, we examined a variety of circulating markers reflecting tissue inflammation, oxidative stress, innate immune activation, fibrosis, and the cytokine response. Children with active TB, compared to HC children, showed markedly elevated plasma levels of matrix metalloproteinases and their endogenous inhibitors. In addition, children with active TB had significantly elevated levels of C-reactive protein, α-2 macroglobulin, and haptoglobin, as well as hemoxygenase 1. Markers of innate immune activation (lipopolysaccharide [LPS] and lipopolysaccharide-binding protein [LBP]) were significantly lower in ETB than in PTB children. Although there were no significant differences between the two groups in their levels of cytokines (type 1 [gamma interferon (IFN-γ), tumor necrosis factor α (TNF-α), interleukin 2 (IL-2), and IL-12], type 2 [IL-4, IL-5, IL-13, and IL-33], and most type 17 [IL-17A, IL-22, IL-1β, and IL-6] and type 1 interferons [IFN-α and IFN-β]) or most of the cytokines associated with immune modulation (IL-10 and IL-20), pediatric TB was associated with elevated plasma transforming growth factor β (TGF-β), IL-21, and IL-23 levels. Thus, pediatric TB is characterized by elevated levels of a variety of biomarkers at homeostasis, suggesting that these responses may play a crucial role in disease pathogenesis.
authors.affiliation: National Institutes of Health-International Center for Excellence in Research, Chennai, India.
authors.forename: Nathella
authors.initials: N
authors.lastname: Pavan Kumar
authors.forename: R
authors.initials: R
authors.lastname: Anuradha
authors.forename: Bruno B
authors.initials: BB
authors.lastname: Andrade
authors.forename: N
authors.initials: N
authors.lastname: Suresh
authors.forename: R
authors.initials: R
authors.lastname: Ganesh
authors.forename: Janani
authors.initials: J
authors.lastname: Shankar
authors.forename: V
authors.initials: V
authors.lastname: Kumaraswami
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Nutman
authors.forename: Subash
authors.initials: S
authors.lastname: Babu
mesh_terms: D000209:Acute-Phase Proteins; D000293:Adolescent; D015415:Biomarkers / Q000097:blood*; D002097:C-Reactive Protein / Q000032:analysis; D002352:Carrier Proteins / Q000097:blood; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000097:blood; D018450:Disease Progression; D005260:Female; D005355:Fibrosis; D006242:Haptoglobins / Q000032:analysis; D006801:Humans; D007223:Infant; D007249:Inflammation; D008070:Lipopolysaccharides / Q000097:blood; D008297:Male; D061965:Matrix Metalloproteinase Inhibitors / Q000097:blood; D020782:Matrix Metalloproteinases / Q000097:blood; D008562:Membrane Glycoproteins / Q000097:blood; D018384:Oxidative Stress; D019714:Tissue Inhibitor of Metalloproteinases / Q000097:blood; D014376:Tuberculosis / Q000097:blood* / Q000175:diagnosis*; D000511:alpha-Macroglobulins / Q000032:analysis; D000099231:Lipopolysaccharide-Binding Protein
chemical_list: D000209:Acute-Phase Proteins; D015415:Biomarkers; D002097:C-Reactive Protein; D002352:Carrier Proteins; D016207:Cytokines; D006242:Haptoglobins; D008070:Lipopolysaccharides; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases; D008562:Membrane Glycoproteins; D019714:Tissue Inhibitor of Metalloproteinases; D000511:alpha-Macroglobulins; D000099231:Lipopolysaccharide-Binding Protein