Novel neutrophil-derived proteins in bronchoalveolar lavage fluid indicate an exaggerated inflammatory response in pediatric cystic fibrosis patients.
BACKGROUND
Airway inflammation in cystic fibrosis (CF) is exaggerated and characterized by neutrophil-mediated tissue destruction, but its genesis and mechanisms remain poorly understood. To further define the pulmonary inflammatory response, we conducted a proteome-based screen of bronchoalveolar lavage fluid (BALF) collected from young children with and without CF experiencing endobronchial infection.


METHODS
We collected BALF samples from 45 children younger than 5 years and grouped them according to the presence of respiratory pathogens: > or = 1 x 10(5) colony-forming units (CFU)/mL BALF (18 and 12 samples with and without CF, respectively) and <1 x 10(5) CFU/mL (23 and 15 samples). BALF proteins were analyzed with SELDI-TOF mass spectrometry (MS) and H4 ProteinChips. Proteins were identified and characterized using trypsin digestion, tandem MS, Fourier transform ion cyclotron resonance MS, immunoblotting, and ELISA.


RESULTS
The SELDI-TOF MS BALF profiles contained 53 unique, reliably detected proteins. Peak intensities of 24 proteins differed significantly between the CF and non-CF samples. They included the neutrophil proteins, alpha-defensin 1 and 2, S100A8, S100A9, and S100A12, as well as novel forms of S100A8 and S100A12 with equivalent C-terminal deletions. Peak intensities of these neutrophil proteins and immunoreactive concentrations of selected examples were significantly higher in CF than non-CF samples.


CONCLUSIONS
Small neutrophil-derived BALF proteins, including novel C-terminal truncated forms of S100A proteins, are easily detected with SELDI-TOF MS. Concentrations of these molecules are abnormally high in early CF lung disease. The data provide new insights into CF lung disease and identify novel proteins strongly associated with CF airway inflammation.
McMorran
Brendan J
BJ
Menzies Research Institute, University of Tasmania, Hobart, Australia. brendan.mcmorran@utas.edu.au
Patat
Severine A Ouvry
SA
Carlin
John B
JB
Grimwood
Keith
K
Jones
Alun
A
Armstrong
David S
DS
Galati
John C
JC
Cooper
Peter J
PJ
Byrnes
Catherine A
CA
Francis
Paul W
PW
Robertson
Colin F
CF
Hume
David A
DA
Borchers
Christoph H
CH
Wainwright
Claire E
CE
Wainwright
Brandon J
BJ
D001991:Bronchitis / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry* / Q000166:cytology / Q000382:microbiology; D002675:Child, Preschool; D015169:Colony Count, Microbial; D003550:Cystic Fibrosis / Q000150:complications / Q000276:immunology*; D005260:Female; D006801:Humans; D007223:Infant; D016209:Interleukin-8 / Q000032:analysis; D007958:Leukocyte Count; D008297:Male; D009504:Neutrophils / Q000276:immunology / Q000378:metabolism*; D020543:Proteome / Q000032:analysis*; D009418:S100 Proteins / Q000032:analysis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D016209:Interleukin-8; D020543:Proteome; D009418:S100 Proteins