The plasma cathelicidin LL-37 levels in patients with chronic obstructive pulmonary disease

Objective To explore the relationship between cathelicidin LL- 37 levels in plasma and disease severity in chronic obstructive pulmonary disease （COPD） patients. Methods COPI） patients and normal subjects were recruited at Beijing Hospital from October2012 to April 2013 for this study. COPD patients were divided into low risk group and high risk group,depending on disease severity. The LL-37 concentrations in plasma were measured by enzyme linked immunosorbent assay （ELISA） kit. To explore the difference in LL-37 levels between groups and the relationship between LL-37 levels in plasma and disease severity indexes. Results Forty-four COPD patients and 20 normal subjects （control group） were recruited,COPD patients were divided into low risk group （22 cases） and high risk group （22 cases）, depending on disease severity. The plasma LL- 37 levels in control group, low risk group and high risk group were （19.8± 4.8） μ/L, （19.9± 4.3）μg/L and （16.±3.6）μg/L, there was significant difference between groups （ F =5.611, P = 0. 006）. There was no differences between low risk group and control group in the plasma levels of LL- 37 （mean difference -0.08,95% CI -2. 5342.71, P =0. 947）. The plasma levels of LL-37 in high risk group was significantly lower than control group （mean difference -3.69,95% CI -6.31±1.07, P=0. 007） and low risk group （mean difference 3.78, 95% CI-6.33 -1.22, P =0. 004）. The concentrations of LL-37 in plasma were significantly correlated with FEV1 （ r =0.4（50, P =0. 006） ,FEV1%pred （ r =0. 532, P =0. 001） ,FEV1/FVC （ r= 0.515, P =0.012） and modified medical research council score （ r =0.347, P =0.033） in COPD patients. Conclusions The concentrations of LL -37 in plasma was correlated with disease severity, especially with dyspnea severity and airway obstructive severity in COPD patients. Key words: Chronic obstructive pulmonary disease;  Antimicrobial peptides; LL 37