IP-10 for the diagnosis and treatment monitoring of tuberculosis in
children.
Abstract
Purpose: To determine the utility of interferon-gamma-inducible
protein 10 (IP-10) for identifying active tuberculosis (TB) and latent
TB infection (LTBI) in children in BCG-vaccinated population, establish
its diagnostic performance characteristics, and evaluate changes in
IP-10 level during anti-TB-chemotherapy. Methods: Concentrations
of IP-10 and IFN-γ were measured in QuantiFERON-TB Gold (QFT)
supernatants in children with suspected TB or due to a recent TB
contact. A total of 225 children were investigated: 33 with active TB,
48 with LTBI, 83 TB contacts, 20 with suspected TB but other final
diagnosis, and 41 controls. In 60 children cytokine responses were
evaluated on follow-up visit after 2 months of anti-TB-treatment.
Results: IP-10 expression was significantly higher in infected
children (active TB and LTBI cases) than in uninfected individuals.
IP-10 proved effective in identifying TB infection at its optimal
cut-off (>1084.5 pg/ml), but was incapable of
differentiating between children with active TB and LTBI. Combining
IP-10 and IFN-γ increased QFT sensitivity. IP-10 but not IFN-γ decreased
significantly during anti-TB-treatment in children with active TB (p =
0.003). Conclusion: IP-10 identifies TB infection and declines
during anti-TB-chemotherapy in children. Incorporating IP-10 into new
immunodiagnostic assays could improve TB diagnosis and allow treatment
monitoring.