title: Stability of interleukin 8 and neutrophil elastase in bronchoalveolar lavage fluid following long-term storage.
abstract: BACKGROUND
  Interleukin-8 (IL-8) and neutrophil elastase (NE) are commonly measured markers of inflammation in bronchoalveolar lavage (BAL) fluid from patients with cystic fibrosis. Longitudinal analysis assumes uniform stability during storage, however the effect of extended low-temperature storage on these markers remains unclear.
  
  
  METHODS
  BAL fluid from 104 children with cystic fibrosis was assayed for IL-8 and NE after storage at 4 ° C for 7 days and -80 ° C for up to 6 years and compared with the initial assays performed soon after collection.
  
  
  RESULTS
  IL-8 levels were stable after any measured length of time at -80 ° C or 4 ° C. NE levels were stable for 6 months at -80 ° C but decreased beyond that or after 7 days at 4 ° C.
  
  
  CONCLUSIONS
  Our data support the stability of IL-8 in BAL stored at -80 ° C for prolonged periods. NE in BAL decreases with storage and should be assayed as soon as practical after collection.
authors.affiliation: Division of Clinical Sciences, Telethon Institute for Child Health Research, 100 Roberts Road, Subiaco, WA 6155 Australia and Centre for Child Health Research, University of Western Australia, Perth, Australia.
authors.forename: Luke J
authors.initials: LJ
authors.lastname: Berry
authors.forename: Barbara
authors.initials: B
authors.lastname: Sheil
authors.forename: Luke
authors.initials: L
authors.lastname: Garratt
authors.forename: Peter D
authors.initials: PD
authors.lastname: Sly
mesh_terms: D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry*; D002648:Child; D002675:Child, Preschool; D003550:Cystic Fibrosis / Q000378:metabolism*; D004355:Drug Stability; D004356:Drug Storage; D005260:Female; D006801:Humans; D007223:Infant; D016209:Interleukin-8 / Q000032:analysis*; D019272:Leukocyte Elastase / Q000032:analysis*; D008297:Male; D013696:Temperature; D013997:Time Factors
chemical_list: D016209:Interleukin-8; D019272:Leukocyte Elastase