The Clinical Utility of Serum YKL-40 Levels in Community Acquired Pneumonia

Abstract

Introduction: We aimed to investigate the changes in blood levels of YKL-40 in patients hospitalized with a diagnosis of community acquired pneumonia (CAP) before treatment and on the 7th day of treatment and to determine whether this can be used as a diagnostic and prognostic marker in the disease. Methodology: Sixty-two subjects including 40 with CAP and 22 healthy as a control group were enrolled to the study. Serum YKL-40 levels were measured in patients with CAP before treatment and on the seventh day of the treatment. Degrees of severity of pneumonia were evaluated according to CURB-65 and the Pneumonia Severity Index (PSI). Results: Mean serum YKL-40 levels of 89.24±98.67 ng/ml and 74.37±56.28 ng/ml were measured on the 1st and 7th days, respectively. The difference between two measurements was significant (p=0.003). A significant difference was also determined in serum YKL-40 level between control group and patient with CAP group on 1st and 7th days (p=0.001 and p<0.001, respectively). PSI and CURB-65 scores were not correlated with serum YKL-40 levels in patients with CAP. Conclusion: The results show higher blood YKL-40 levels in patients in the CAP group compared to the controls. Elevated YKL-40 levels in blood specimens at the start of treatment in our pneumonia group, followed by a decrease one week later, may be regarded as evidence that blood YKL-40 levels can be used as an inflammation marker in clinical practice. Keywords: Pneumonia; YKL-40; C-reactive protein