Considering the heterogeneity of BALF exosomes from the different individuals, the percentage of SCIMP+ particles in CD63+ particles was analyzed; this percentage was significantly higher in the pneumonia cohort than in the pulmonary tumor cohort (Fig. 2e), and the AUC of the ROC curve was 0.84 (Fig. 2f). The gene discussed is CD63; the disease is susceptibility to pneumonia measurement.