IL17A and susceptibility to pneumonia measurement: The prediction capability of IL-4/IL-17A was greater than that of other commonly used indicators, including NLR (AUC = 0.897), oxygenation index (AUC = 0.795), CURB-65 (AUC = 0.795), and pneumonia severity index (PSI) (AUC = 0.786) (as shown in Figure 4 and Table 4).