IFITM3 Is Elevated in BAL and Plasma Following Infection in ICU Setting

Interferon-induced transmembrane protein 3 (IFITM3) is an antiviral protein with emerging roles in regulating inflammatory pathways. Although much is known about the role of IFITM3 in mediating host antiviral defense, its contribution to systemic immune responses during critical infectious illnesses remains less understood. Here, we provide evidence that IFITM3 levels were significantly higher in cell free BAL fluid in septic patients with pulmonary infections and in circulating plasma extracellular vesicles (EVs) from critically ill septic patients compared to critically ill non-septic patients and healthy individuals. This study provides the first evidence of IFITM3's association with sepsis induced inflammatory responses and bacterial pulmonary infections, raising its potential as an agent of dysregulated immunity during systemic infection.