Beta-defensins and LL-37 in bronchoalveolar lavage fluid of patients with cystic fibrosis.
BACKGROUND
The antimicrobial peptides human beta-defensin 1 and 2 (hBD-1 and 2) and the cathelicidin LL-37/hCAP-18 are key factors in innate immune responses of the respiratory tract. The aim of this study was to determine the concentrations of these peptides in airway surface fluid of CF patients with mild lung disease.


METHODS
We measured the concentrations of hBD-1, hBD-2, and LL-37 in bronchoalveolar lavage fluid of 20 patients (5-34 years) participating in the prospective BEAT-study (bronchoalveolar lavage for the evaluation of anti-inflammatory treatment) using an immuno-dot blot-assay.


RESULTS
All three peptides could be detected in lavage fluid of the study population. Increased levels of inflammatory markers in bronchoalveolar lavage fluid were associated with elevated concentrations of LL-37/hCAP-18 (total cell count, P = 0.006; relative neutrophil count, P = 0.002). Deterioration of lung function, measured by MEF25 (maximal flow rate at 25% of residual forced vital capacity), correlated with decreased hBD-2 (P = 0.026), but increased LL-37/hCAP-18 concentrations (P = 0.016).


CONCLUSIONS
The data suggest that concentrations of antimicrobial peptides are correlated with severity of CF lung disease: Levels of LL-37/hCAP-18 are associated with bronchial inflammation and, therefore disease severity, whereas decreased levels of beta-defensins in advanced lung disease likely contribute to a secondary defect of the local host defense.
Department of Pediatric Pneumology and Immunology, Charité, Humboldt-University, Berlin, Germany.
Christiane I-U
CI
Chen
Susanne
S
Schaller-Bals
Karl P
KP
Paul
Ulrich
U
Wahn
Robert
R
Bals
D000293:Adolescent; D000328:Adult; D023181:Antimicrobial Cationic Peptides / Q000032:analysis / Q000378:metabolism*; D015415:Biomarkers / Q000032:analysis; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008297:Male; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D023083:beta-Defensins / Q000032:analysis / Q000378:metabolism*; D054804:Cathelicidins
D023181:Antimicrobial Cationic Peptides; D015415:Biomarkers; C406407:DEFB1 protein, human; C106641:DEFB4A protein, human; D023083:beta-Defensins; D054804:Cathelicidins