title: Circulating cathelicidin LL-37 in adult patients with pulmonary infectious diseases.
abstract: The antimicrobial peptide cathelicidin LL-37 plays a role in the immune response in the course of lung infections; however, the exact role of LL-37 in defense mechanisms against bacteria within the respiratory tract is has not been precisely described. The aim of our study was to evaluate LL-37 concentrations in the serum of pulmonary tuberculosis (TB) patients, patients with pneumonia caused by Gram-positive and Gram-negative bacteria and to compare them with those of healthy subjects.
  
  
  
  Thirty TB patients, 30 patients with pneumonia caused by Gram-positive bacteria, 30 patients with pneumonia caused by Gram-negative bacteria, and 30 healthy control subjects were enrolled in the study. Serum LL-37 concentration was measured using an enzyme-linked immunosorbent assay (ELISA).
  
  
  
  The mean (± SEM) LL-37 concentration in patients with TB (13.94±5.13 ng/mL) was significantly higher than that in patients with Gram-positive bacteria-induced pneumonia (7.87±4.58 ng/mL, P=0.00077), in patients with Gram-negative bacteria-induced pneumonia (10.27±3.60 ng/mL, P=0.00730), and in control healthy subjects (1.75±0.71 ng/mL, P=0.00004).
  
  
  
  Our data suggest that cathelicidin LL-37 is an important element of host defense in the course of bacterial diseases within the respiratory tract, particularly when the infection is caused by an intracellular pathogen.
authors.affiliation: Department of Experimental Immunology, Medical University of Lodz; Pulmonary Disease Hospital, Lodz . email@email.com.
authors.forename: Karol
authors.initials: K
authors.lastname: Majewski
authors.forename: Paulina
authors.initials: P
authors.lastname: Żelechowska
authors.forename: Ewa
authors.initials: E
authors.lastname: Brzezińska-Błaszczyk
mesh_terms: D000328:Adult; D000368:Aged; D023181:Antimicrobial Cationic Peptides / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018410:Pneumonia, Bacterial / Q000097:blood*; D014397:Tuberculosis, Pulmonary / Q000097:blood*; D054804:Cathelicidins
chemical_list: D023181:Antimicrobial Cationic Peptides; D054804:Cathelicidins