Hepcidin and Ferritin Predict Microbial Etiology in Community-Acquired Pneumonia

Background. Iron is crucial for survival and growth of microbes. Consequently, limiting iron availability is a human antimicrobial defense mechanism. We explored iron and iron-related proteins as potential biomarkers in community-acquired pneumonia and hypothesized that infection-induced changes in these potential biomarkers differ between groups of pathogens and could predict microbial etiology. Methods. Blood samples from a prospective cohort of 267 patients with community-acquired pneumonia were analyzed for hepcidin, ferritin, iron, transferrin, and soluble transferrin receptor at admission, clinical stabilization, and a 6-week follow-up. A total of 111 patients with an established microbiological diagnosis confined to 1 microbial group (atypical bacterial, typical bacterial, or viral) were included in predictive analyses. Results. High admission levels of ferritin predicted atypical bacterial versus typical bacterial etiology (odds ratio [OR], 2.26; 95% confidence interval [CI], 1.18-4.32; P=.014). Furthermore, hepcidin and ferritin predicted atypical bacterial versus viral etiology (hepcidin: OR = 3.12, 95% CI = 1.34-7.28, P=.008; ferritin: OR = 2.38, 95% CI = 1.28-4.45, P=.006). The findings were independent of C-reactive protein and procalcitonin. Conclusions. Hepcidin and ferritin are potential biomarkers of microbial etiology in community-acquired pneumonia.