Evaluation of plasma antimicrobial peptide LL-37 and nuclear factor-kappaB levels in stable chronic obstructive pulmonary disease.

Background: Antimicrobial peptides are effectors of host defence against infection and inflammation and can encourage wound repair.

Objectives: The objectives of this study were to investigate the plasma antimicrobial peptide LL-37 and nuclear factor-kappaB (NF-κB) levels in patients with stable COPD compared with a control group and to highlight their importance in immune inflammation.

Methods: One hundred and thirty-eight stable COPD patients and 33 control subjects were enrolled in the study. The COPD patients were classified into four groups based on FEV (groups I-IV) and also divided into "low-risk and high-risk" groups (groups A-B [low risk], C-D [high risk]).

Results: Plasma LL-37 levels were significantly lower while plasma NF-κB levels of the COPD patients were significantly higher than those of the control subjects (<0.001, both). LL-37 levels were significantly lower in group IV than in groups I, II, and III (<0.01, all). NF-κB levels were significantly higher in groups III and IV than in groups I and II (<0.05, both). There was a positive correlation between FEV and FEV/FVC in all COPD patients (=0.742, <0.001) and in group D (=0.741, <0.001). Furthermore, there was an inverse correlation between LL-37 and NF-κB in both the groups C (=-0.566, <0.001) and D (=-0.694, <0.001) and group C+D combined (=-0.593, <0.001). Furthermore, in group C, LL-37 and FEV were positively correlated (=0.633, <0.001).

Conclusion: Our study indicated that plasma LL-37 and NF-κB may play an important role in chronic immune inflammation. Decreased LL-37 levels may be particularly high risk for patients in stage IV disease. The role of LL-37 as a target for treatment of the immune system and COPD must be widely evaluated.