title: Surfactant proteins A, B, C and D in the human nasal airway: associated with mucosal glands and ciliated epithelium but absent in fluid-phase secretions and mucus.
abstract: OBJECTIVE
  To investigate the presence of surfactant protein (SP) A, B, C and D in nasal airways and to determine whether the proteins exert their main functions in nasal secretions or in the deeper layers of the nasal mucosa.
  
  
  METHODS
  Volunteers were recruited from the Department of ENT Head and Neck Surgery, Odense University Hospital, Denmark. The study included 39 subjects. Nasal mucosal biopsies were analyzed by immunohistochemistry, and bronchoalveolar and nasal lavages, nasal brush biopsies and nasal mucus were analyzed for SP-A, -B, -C and -D by SDS-PAGE and Western blotting. The presence of SP-A and SP-D in the first three samplings were also analyzed by enzyme-linked immunosorbent assay.
  
  
  RESULTS
  In nasal mucosal biopsies, SP-A, -B, -C and -D were all demonstrated in the serous acini of the submucosal glands and in the surface epithelium. SP-D was detected in nasal brush biopsies, whereas the other SPs were absent. Moreover, SP-A, -B, -C and -D were absent in nasal lavage and mucus.
  
  
  CONCLUSIONS
  SP-A, -B, -C and -D exert their protective effect in the ductal epithelium of the submucosal glands rather than in nasal secretions and mucus. Further studies are required to clarify the functions of these proteins in nasal secretory pathways for understanding upper airway diseases.
authors.affiliation: Department of ENT Head and Neck Surgery, Odense University Hospital, Odense, Denmark.
authors.forename: Maria Q
authors.initials: MQ
authors.lastname: Gaunsbaek
authors.forename: Anette D
authors.initials: AD
authors.lastname: Kjeldsen
authors.forename: Viggo
authors.initials: V
authors.lastname: Svane-Knudsen
authors.forename: Maiken L
authors.initials: ML
authors.lastname: Henriksen
authors.forename: Soren
authors.initials: S
authors.lastname: Hansen
mesh_terms: D001706:Biopsy; D015153:Blotting, Western; D018893:Bronchoalveolar Lavage; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007124:Immunoenzyme Techniques; D009093:Mucus / Q000737:chemistry; D009297:Nasal Mucosa / Q000378:metabolism*; D037662:Pulmonary Surfactant-Associated Protein A / Q000378:metabolism*; D037701:Pulmonary Surfactant-Associated Protein B / Q000378:metabolism*; D037721:Pulmonary Surfactant-Associated Protein C / Q000378:metabolism*; D037663:Pulmonary Surfactant-Associated Protein D / Q000378:metabolism*; D007507:Therapeutic Irrigation
chemical_list: D037662:Pulmonary Surfactant-Associated Protein A; D037701:Pulmonary Surfactant-Associated Protein B; D037721:Pulmonary Surfactant-Associated Protein C; D037663:Pulmonary Surfactant-Associated Protein D