Host-derived proteomic biomarkers for discriminating the tuberculosis disease spectrum in a Brazilian cohort.

Despite significant efforts to improve diagnostics, tuberculosis (TB) diagnosis still relies on clinical and laboratory methods limited by cost, expertise, and time. Early diagnosis is essential for effective management of pulmonary TB (PTB), pleural TB (PLTB), and latent TB infection (LTBI), highlighting the urgent need for rapid, accurate, and accessible TB diagnostics based on low-invasive sampling. In this study, a quantitative rapid test, previously evaluated in European and African cohorts, was applied to a Brazilian cohort to measure six host-derived proteins in serum from individuals with PTB, PLTB, other pleural diseases (OPLD), LTBI, and controls. Serum levels of CRP, ferritin, and SAA1/A2 were significantly elevated in PTB and PLTB compared to controls. SAA1/A2 and IP-10 levels were higher in PLTB compared to LTBI. Furthermore, IP-10 serum levels showed diagnostic potential, as they were elevated in PTB compared with both LTBI and controls, and significantly increased in PLTB compared to OPLD. In pleural effusion, IP-10, IL-6, and S100A12 were significantly higher in PLTB than in OPLD, while ferritin levels were higher in OPLD. Our study shows that quantitative detection of host-derived biomarkers identified for active PTB in European and African populations can support clinical decision-making for TB spectrum in a Brazilian setting.