IL-5 and IP-10 Detected in Quantiferon Supernatants Distinguish Latent Tuberculosis from Healthy Individuals in Areas with High Burden in Lima, Peru.

BACKGROUND: Peru ranks among the countries with the highest burden of tuberculosis in Latin America. Interferon Gamma Release Assays (IGRAs), such as QuantiFERON-TB (QFT), cannot distinguish latent tuberculosis infection (LTBI) from active tuberculosis (ATB), but they provide a more specific and quantitative assessment of prior exposure to Mycobacterium tuberculosis. METHODS: We enrolled 56 participants and measured 38 cytokines/chemokines from plasma obtained through QFT in patients with active TB (n = 11), LTBI (n = 17), and QFT-negative healthy controls (n = 28) using a Multiplex Bead Assay. RESULTS: Levels of IL-1RA, IL-2, IL-5, IFN-γ, and IP-10 significantly differentiated both ATB and LTBI groups from healthy controls (p < 0.035). Furthermore, IL-5 and IP-10 specifically distinguished LTBI from healthy controls (p < 0.015), while GM-CSF differentiated ATB from controls (p < 0.05). CONCLUSIONS: Beyond IFN-γ as a differential proinflammatory cytokine in TB, cytokines such as IL-5, and IP-10 show potential as biomarkers to discriminate infection status in high-burden TB settings.