title: Recovery from workplace-induced airway inflammation 1 year after cessation of exposure.
abstract: BACKGROUND
  Bacterial single-cell protein (BSCP) constitutes of dried bacterial mass which is used as protein enrichment in animal and fish feed. In the production of BSCP, workers are exposed to organic dust containing high levels of endotoxins (arithmetic mean 390 EU/m3 in the moderate exposure and 5800-11,000 EU/m3 in the high exposure groups) and have elevated levels of sputum neutrophils and cytokines associated with exposure.
  
  
  OBJECTIVE
  The aim of the present study was to investigate if airway inflammation among the workers had declined 1 year after cessation of exposure.
  
  
  METHODS
  Twenty-four non-smoking production workers (age 28-52) with a work history of 2-7 years were included in the study.
  
  
  METHODS
  Markers of airways inflammation and innate immune function (using flow cytometry) were assessed in an exposure period and 1 year after cessation of exposure.
  
  
  RESULTS
  Sputum neutrophil proportion and numbers were significantly decreased 1 year after cessation of exposure to BSCP (43% vs. 71%, 186 vs. 598 neutrophils/mg sputum; p<0.001) as were eNO (17 ppb vs. 21 ppb (p=0.01) and interleukin-1β (p<0.05) and interleukin-8 (p<0.05). Neutrophils had enhanced expression of CD11b/CR3 (p<0.01) and CD16/FcγRIII (p<0.001) and macrophages had lower expression of CD86 (p<0.01) 1 year after cessation of exposure.
  
  
  CONCLUSIONS
  One year after closure of the plant airway neutrophils and exhaled NO levels resolved to lower levels and cell surface phenotypes associated with innate immune function recovered to higher levels, indicating that these changes were partly reversible among workers who were no longer exposed to endotoxins in a BSCP plant.
authors: Department of Respiratory Medicine, Oslo University Hospital, Rikshospitalet, University of Oslo, Oslo N-0027, Norway. l.i.b.sikkeland@medisin.uio.no
authors: Liv Ingunn Bjoner
authors: LI
authors: Sikkeland
authors: Wijnand
authors: W
authors: Eduard
authors: Marit
authors: M
authors: Skogstad
authors: Neil E
authors: NE
authors: Alexis
authors: Johny
authors: J
authors: Kongerud
mesh_terms: D000328:Adult; D000395:Air Pollutants, Occupational / Q000009:adverse effects*; D000421:Alcaligenes; D001407:Bacillus; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D005434:Flow Cytometry; D005500:Follow-Up Studies; D006801:Humans; D007113:Immunity, Innate; D007378:Interleukins / Q000378:metabolism; D008070:Lipopolysaccharides / Q000009:adverse effects*; D008297:Male; D020619:Methylococcus capsulatus; D008875:Middle Aged; D009504:Neutrophils / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D009784:Occupational Diseases / Q000139:chemically induced* / Q000276:immunology / Q000378:metabolism; D016273:Occupational Exposure / Q000009:adverse effects* / Q000032:analysis; D011014:Pneumonia / Q000139:chemically induced* / Q000276:immunology / Q000378:metabolism; D013183:Sputum / Q000276:immunology
chemical_list: D000395:Air Pollutants, Occupational; D015415:Biomarkers; D007378:Interleukins; D008070:Lipopolysaccharides; D009569:Nitric Oxide