[Progress in the application of bronchoalveolar lavage fluid in the diagnosis of infectious lung diseases].

Bronchoalveolar lavage fluid (BALF) contains diverse cellular components and pathogens, directly reflecting the local immune status at sites of pulmonary infection. By detecting pathogens such as bacteria, fungi, and viruses within these samples and analyzing changes in the immune cell composition and cytokine levels, it will help to assess the immune microenvironment of infected lung regions and to predict disease prognosis. In recent years, the application of artificial intelligence in BALF analysis has significantly enhanced the efficiency of cell classification and counting. Combined with molecular diagnostic methods such as metagenomic next-generation sequencing, this approach deeply explores the diagnostic value of immune cells, pathogens, and their molecular characteristics in BALF for infectious lung diseases. It will provide more precise support for early disease identification, personalized treatment, and clinical decision-making.