Blood and urine inducible protein 10 as potential markers of disease activity.

SETTING: Blood interferon-γ inducible protein 10 (IP-10) has been proposed as a biomarker of disease activity for both tuberculosis (TB) and human immunodeficiency virus (HIV) infection. Urine IP-10 has been detected in adults with active TB, and its level decreases after successful anti-tuberculosis treatment. OBJECTIVE: To evaluate blood and urine IP-10 as biomarker of disease activity. DESIGN: Patients with HIV-TB and active TB were enrolled. Individuals with HIV infection only and healthy donors were included as controls. Blood and urine IP-10 levels were measured using an enzyme-linked immunosorbent assay. RESULTS: Of 39 active TB patients enrolled, 24 were HIV-infected and 15 were HIV-uninfected. Of 87 control subjects without active TB, 54 were HIV-infected and 33 were HIV-uninfected. IP-10 analysis was performed in patients with concomitant blood and urine sample collection. Blood IP-10 was associated with active TB, regardless of HIV infection status; urine IP-10 levels were increased in active TB patients, although the difference was significant in HIV-infected individuals only. Finally, in HIV-infected patients, both blood and urine IP-10 levels were inversely correlated with CD4 T-cell counts. CONCLUSION: These findings suggest that IP-10 could be used as a biomarker for disease activity (inflammation).