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.