[The expression and clinical significance of serum soluble programmed cell death ligand-1 in adult patients with community-acquired pneumonia]

To investigate the clinical significance of serum soluble programmed cell death ligand-1 (PD-L1) in adult patients with community-acquired pneumonia (CAP). A total of 44 CAP patients, 54 severe CAP patients and 30 healthy volunteers were recruited in this study. Serum soluble PD-L1 were detected. Univariate and multivariate regression analyses were used to assess the influence of multiple clinical variables on prognosis. Serum soluble PD-L1 level in severe CAP group was 98.20(57.94, 128.90) ng/L, which was significantly higher than that in the CAP group [59.32(33.55, 92.58) ng/L] and healthy controls [20.44(12.15, 36.20) ng/L] (all P<0.001). PD-L1 level was positively correlated with CRUB-65(r=0.481, P<0.001) and the pneumonia severity index (PSI) score (r=0.442, P<0.001). Univariate regression analysis showed that CURB-65 (HR=2.544, 95%CI 1.324-4.889, P=0.005), PSI score (HR=1.036, 95%CI 1.012-1.061, P=0.004), soluble PD-L1(HR=1.013, 95%CI 1.001-1.026, P=0.041) were risk factors of mortality during hospitalization. Multivariate regression analysis suggested that PSI score (HR=1.042, 95%CI 1.012-1.073, P=0.005), soluble PD-L1 (HR=1.011, 95%CI 1.002-1.071, P=0.020) were independent predictors for mortality risk in CAP patients. CAP patients with soluble PD-L1≥98.20 ng/L had a significantly lower survival rate than those with soluble PD-L1<98.20 ng/L (P=0.033). In conclusion, this study indicates that serum soluble PD-L1 level in CAP patients is correlated with the survival prognosis.