Utility of plasma osteopontin levels in management of community-acquired pneumonia

Osteopontin (OPN) is an essential cytokine involved in immune cell recruitment and an important regulator of inflammation. The purpose of this study was to examine differences in OPN plasma levels between before and after antibiotic treatment in hospitalized adult patients with community-acquired pneumonia (CAP). OPN levels were measured in 93 patients with CAP and 54 healthy controls using a commercial enzyme-linked immunosorbent assay (ELISA). The CURB-65, Pneumonia Severity Index (PSI), and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores were used to determine the CAP severity in patients upon initial hospitalization. A decline in the number of white blood cells (WBCs) and neutrophils, and decreases in the levels of OPN and C-reactive protein (CRP) were observed after antibiotic treatment. Only the plasma level of OPN, but not CRP, was correlated with the severity of CAP based on the PSI (r = 0.514, p < 0.001), CURB-65 (r = 0.396, p < 0.001), and APACHE II scores (r = 0.473, p < 0.001). The OPN level also showed a significant correlation with the length of hospital stay (r = 0.210, p = 0.044). In conclusion, plasma level of OPN may act as diagnostic adjuvant biomarkers for CAP and further play a role in clinical assessment of the severity of CAP, which could potentially guide the development of treatment strategies.