Presepsin and Pentraxin-3 as Diagnostic and Severity Biomarkers in Community-Acquired Pneumonia: A Pilot Study

Background: Biomarkers reflecting innate immune activation may complement clinical severity scores in community-acquired pneumonia (CAP). This study evaluated serum presepsin and pentraxin-3 (PTX3) concentrations in patients with CAP and healthy controls and examined their associations with pneumonia severity. Methods: Ninety participants were analyzed, including 45 patients with CAP and 45 healthy controls. Pneumonia severity was assessed using the Pneumonia Severity Index (PSI) and CURB-65. Group comparisons, Spearman correlation analyses, receiver operating characteristic (ROC) analyses, and an exploratory multivariable logistic regression model were performed. Results: Presepsin concentrations were higher in patients with CAP than in healthy controls (2157 [1824–2524] vs. 1749 [1652–1879] pg/mL; p < 0.001), as were PTX3 concentrations (2.15 [1.76–2.87] vs. 1.67 [1.40–2.11] ng/mL; p < 0.001). For discrimination of CAP from healthy controls, the AUC was 0.822 (95% CI 0.728–0.902) for presepsin and 0.706 (95% CI 0.598–0.810) for PTX3. Among patients with CAP, presepsin correlated with PSI (rho = 0.552, p < 0.001) and CURB-65 (rho = 0.600, p < 0.001), while PTX3 showed stronger correlations with PSI (rho = 0.691, p < 0.001) and CURB-65 (rho = 0.668, p < 0.001). For identifying PSI classes IV–V, the AUC was 0.647 for presepsin and 0.742 for PTX3. Conclusions: Both presepsin and PTX3 were elevated in CAP and were associated with increasing disease severity. Within this pilot sample, presepsin showed a numerically higher AUC for discrimination between CAP and healthy controls, whereas PTX3 showed stronger associations with severity. Larger prospective studies are required to validate these findings.