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.

Bronchiectasis is a complex and heterogeneous group of diseases with their own characteristics in terms of etiology, symptoms, infections and inflammation, among which infections are both the most common cause of bronchiectasis and the most important factor contributing to the progression of the disease and affecting the prognosis. The current paper will focus on the characterization, diagnosis and treatment of pathogenic bacteria in bronchiectasis.