IP-10 decreases during antituberculous treatment in children with active tuberculosis

<b>Background:</b> Biomarkers for treatment monitoring in childhood tuberculosis (TB) are needed. Interferon-inducible protein-10 (IP-10) has been shown to decrease upon anti-TB treatment in adults, but not in children. <b>Objective:</b> To investigate changes in IP-10 level during anti-TB treatment in children in a low TB incidence setting and to compare it with IFN-γ. <b>Methods:</b> IP-10 and IFN-γ responses were determined in Quantiferon-TB Gold supernatants in 25 children with active TB, 29 with latent TB infection (LTBI), and 6 TB contacts before and after 2 months of anti-TB treatment. <b>Results:</b> Plasma IP-10 and IFN-γ levels significantly differentiated Mycobacterium tuberculosis-infected children (active TB + LTBI) from uninfected TB contacts at the treatment onset (p=0.003 and p=0.008, respectively), but not active TB from LTBI. A significant decrease in IP-10 but not IFN-γ expression was noticed upon treatment (p=0.0013). Notably, while IP-10 significantly declined in ATB group, no significant decrease was detected in children with LTBI and TB contacts. After 2 months of treatment there was still a significant difference between infected and uninfected children in IP-10 (p=0.008), but not IFN-γ responses. Moreover, on follow-up examination IP-10 differentiated between ATB and LTBI (p=0.015) and between ATB and TB-contacts (p=0.0007). <b>Conclusions:</b> Our results demonstrate that IP-10 declines during anti-TB chemotherapy in childhood active TB and suggest it has the potential to become a biomarker for treatment monitoring in children.