Antimicrobial peptide cathelicidin (LL- 37) and human β-defensin 2 in bronchoalveolar lavage fluid of children with pulmonary tuberculosis

BACKGROUND: The antimicrobial peptides cathelicidin LL- 37 /hCAP-18 and human β-defensins (hBD) are the key factors in innate immune responses of the respiratory tract. The aim of this study was to determine the concentrations of LL- 37 and hBD- 2 in BAL fluid of pediatric patients with pulmonary tuberculosis (TB) compared to healthy children. METHODS: We measured the concentrations of these peptides using an immunosorbent assays (ELISAs). RESULTS: Fourty TB patients and 40 healthy control were enrolled to the study. The mean (±SD) BAL LL- 37 level of the TB group was significantly increased than the control group (0.95±1.33 ng/mL and 0.35±0.51 ng/mL, p=0.01, t=2.54)[Figure 1]. The hBD- 2 level was higher in TB group compared with healthy controls but not reached to a statistically significant level (0.30±0.58 ng/mL and 0.14±0.30 ng/mL, p=0.11) [Figure 2]. CONCLUSIONS: Our data suggest that LL- 37 and hBD-2 may play an important role in the pathogenesis of TB in children. To our knowledge, this is the first report showing BAL LL- 37 and hBD-2 concentration in children with pulmonary TB.