pone-0003901-g003: Stimulation index of IP-10 and IFN-γ in active TB, LTBI and a control group.Horizontal lines indicate medians. Controls are represented by ○, active TB by ▵, and LTBI by □. Open symbols represent IP-10, closed symbols represent IFNγ samples.

Mentions: Figure 3 shows that the stimulation index (SI) of IP-10 in both active (median SI: 9.4, range: 1–125) and latent TB groups (median SI: 8.8, range: 0.32–68.7) are greater than in the control group (median SI: 1.7, range 0–125). This is significant in the active cases (p = 0.04), but not the LTBI cases (p = 0.23). There is only a slight difference in stimulation index between active and latent TB (p = 0.09).

Whittaker E, Gordon A, Kampmann B - PLoS ONE (2008)

Bottom Line: The search for distinguishing biomarkers therefore continues, as the accurate diagnosis of tuberculosis is particularly challenging in children.The baseline levels of IP-10 are increased in active TB and in LTBI, but there is no significant difference of stimulated levels of IP-10 between active TB and LTBI.IP-10 is a biomarker for tuberculosis in children.However like IFNgamma, IP-10 also does not distinguish between active TB and LTBI.

Affiliation: Department of Paediatrics, Imperial College London, London, United Kingdom. e.whittaker@imperial.ac.uk

Abstract: The blood based interferon-gamma release assays (IGRA) for the diagnosis of tuberculosis do not discriminate between active TB disease and latent TB infection (LTBI). The search for distinguishing biomarkers therefore continues, as the accurate diagnosis of tuberculosis is particularly challenging in children. IFN-gamma-inducible protein 10 (IP-10/CXCL10) has recently been evaluated as a marker for active TB in adults with promising results.To investigate this new biomarker for active TB and LTBI in paediatrics.We measured IP-10 levels using ELISA in supernatants of whole blood samples stimulated with TB-specific-antigens and negative control antigen.IP-10 is produced in high levels following mycobacterial antigen stimulation in active TB (n = 17) and LTBI (n = 16) compared to controls (n = 16) and to IFN-gamma. The baseline levels of IP-10 are increased in active TB and in LTBI, but there is no significant difference of stimulated levels of IP-10 between active TB and LTBI.IP-10 is a biomarker for tuberculosis in children. However like IFNgamma, IP-10 also does not distinguish between active TB and LTBI.