title: Pneumoproteins in sewage workers exposed to sewage dust.
abstract: OBJECTIVE
  The association between exposure to bacteria and endotoxins in sewage dust and the serum concentrations of pneumoproteins in sewage treatment plant workers were studied.
  
  
  METHODS
  Forty-four workers from eight sewage treatment plants and 38 reference workers participated in the study. Microbial aerosol was collected by personal inhalable samplers. The concentrations of bacteria and endotoxins were determined by fluorescence microscopy and the Limulus assay, respectively. Pneumoproteins (Clara cell protein: CC16, and Surfactant proteins A and D: SP-A, SP-D) were determined by ELISA in blood samples collected post-shift.
  
  
  RESULTS
  The exposure to dust ranged from 0.02 to 9.3 (geometric mean (GM) 0.3 mg/m(3), of bacteria from 0.3 to 4,900 × 10(3) (GM 27 × 10(3)) cells/m(3) and endotoxins from 1 to 3,160 (GM 28) EU/m(3). The exposed workers had lower CC16 [arithmetic mean (AM) 4.9 ng/ml] compared to the referents (AM 6.4 ng/ml, p < 0.01). No significant difference was observed for SP-D and SP-A. Exposure to bacteria was positively associated with CC16 (p < 0.05) and SP-D (p < 0.05), adjusting for possible confounders.
  
  
  CONCLUSIONS
  This study showed that exposed workers had lower serum concentration of CC16 as compared to the referents, which may reflect a long-term effect on secretion of these pneumoproteins. The positive association between exposure to bacteria and the serum concentrations of CC16 and SP-D may be explained by a transient increased permeability of the lung-blood barrier.
authors.affiliation: National Institute of Occupational Health, PO Box 8149 Dep, 0033 Oslo, Norway. kari.heldal@stami.no
authors.forename: Kari Kulvik
authors.initials: KK
authors.lastname: Heldal
authors.forename: Lars
authors.initials: L
authors.lastname: Barregard
authors.forename: Per
authors.initials: P
authors.lastname: Larsson
authors.forename: Dag G
authors.initials: DG
authors.lastname: Ellingsen
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D004391:Dust; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D016273:Occupational Exposure / Q000032:analysis*; D037662:Pulmonary Surfactant-Associated Protein A / Q000097:blood*; D037663:Pulmonary Surfactant-Associated Protein D / Q000097:blood*; D012722:Sewage / Q000382:microbiology; D014598:Uteroglobin / Q000097:blood*
chemical_list: D015415:Biomarkers; D004391:Dust; D037662:Pulmonary Surfactant-Associated Protein A; D037663:Pulmonary Surfactant-Associated Protein D; C556389:SCGB1A1 protein, human; D012722:Sewage; D014598:Uteroglobin