title: Pulmonary innate immunity in children with protracted bacterial bronchitis.
abstract: OBJECTIVE
  To determine bronchoalveolar lavage (BAL) levels of 3 innate immunity components (human β-defensin-2 [hBD2], mannose-binding lectin [MBL], and surfactant protein-A [SP-A]), the relationship with airway neutrophilia and infection, and cytokine production of stimulated BAL cells in children with current protracted bacterial bronchitis (PBB), children with resolved PBB (PBB well), and controls.
  
  
  METHODS
  BAL of 102 children (mean age 2.8 years) fulfilling predefined criteria of current PBB (n = 61), PBB well (n = 20), and controls (n = 21) was cultured (quantitative bacteriology) and viruses examined by polymerase chain reaction. hBD2, MBL, and SP-A were measured, and cytokine production by lipopolysaccharide-stimulated BAL cells was determined.
  
  
  RESULTS
  Median hBD2 and MBL levels were significantly higher in the current PBB group (hBD2 = 164.4, IQR 0-435.5 pg/mL; MBL = 1.7, 0.4-4 ng/mL) than in the PBB well group (hBD2 = 0, IQR 0-85.2; MBL = 0.6, IQR 0.03-2.9) and controls (hBD2 = 3.6, IQR 0-126; MBL = 0.4, IQR 0.02-79). hBD2 was significantly higher in children with airway infection (n = 54; median 76.9, IQR 0-397.3) compared with those without (n = 48; 0, IQR 0-236.3), P= .04. SP-A levels and cytokine production of stimulated BAL cells were similar between groups.
  
  
  CONCLUSIONS
  In children's airways, hBD2, but not MBL and SP-A, relates to inflammation and infection. In children with PBB, mechanisms involving airway hBD2 and MBL are augmented. These pulmonary innate immunity components and the ability of BAL cells to respond to stimuli are unlikely to be deficient.
authors.affiliation: Queensland Children's Respiratory Centre, and Queensland Children's Medical Research Institute, Royal Children's Hospital, Brisbane, Australia. annechang@ausdoctors.net
authors.forename: Anne B
authors.initials: AB
authors.lastname: Chang
authors.forename: Stephanie T
authors.initials: ST
authors.lastname: Yerkovich
authors.forename: Peter G
authors.initials: PG
authors.lastname: Gibson
authors.forename: Sophie
authors.initials: S
authors.lastname: Anderson-James
authors.forename: Helen L
authors.initials: HL
authors.lastname: Petsky
authors.forename: Melanie L
authors.initials: ML
authors.lastname: Carroll
authors.forename: I Brent
authors.initials: IB
authors.lastname: Masters
authors.forename: Julie M
authors.initials: JM
authors.lastname: Marchant
authors.forename: Danielle
authors.initials: D
authors.lastname: Wurzel
authors.forename: John W
authors.initials: JW
authors.lastname: Upham
mesh_terms: D029481:Bronchitis, Chronic; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D001999:Bronchoscopy; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007113:Immunity, Innate; D007223:Infant; D008297:Male; D037601:Mannose-Binding Lectin / Q000032:analysis*; D037662:Pulmonary Surfactant-Associated Protein A / Q000032:analysis*; D023083:beta-Defensins / Q000032:analysis*
chemical_list: C106641:DEFB4A protein, human; D037601:Mannose-Binding Lectin; D037662:Pulmonary Surfactant-Associated Protein A; D023083:beta-Defensins