In the future, we will collect additional samples, including plasma, pleural effusion, and BALF samples, to examine the predictive value of IL-18, the IL-18/IL-38 ratio, and IL-33 for PPE and to determine their potential as biomarkers for the differential diagnosis of PE and the rapid differentiation of pathogens, aiming to uncover more potential clinical applications. The gene discussed is IL18; the disease is Pleural effusion.