title: Increased endothelin 1 type B receptors in nasal lesions of patients with granulomatosis with polyangiitis.
abstract: BACKGROUND
  Endothelin 1 (ET-1) is a locally produced vasoactive peptide with proinflammatory capabilities. Systemic levels of ET-1 seem elevated in granulomatosis with polyangiitis (GPA). The aim of this study was to examine the involvement of the endothelin system in patients with GPA using nasal mucosal biopsies.
  
  
  METHODS
  Formalin-fixed and paraffin-embedded nasal mucous membranes from eight patients with GPA and eight controls were analyzed for ET-1 type A receptor (ETAR) and type B receptor (ETBR) expression using immunohistochemistry.
  
  
  RESULTS
  ETAR immunostaining was localized only to a few inflammatory cells and to multinucleate giant cells (MGCs) in the nasal mucosa in GPA subjects. Intense ETBR immunostaining was localized to lymphocytes and MGC in the nasal granulomatous lesions in GPA. CD3(+), CD4(+), CD8(+), and CD68(+) lymphocytes expressed ETBRs in GPA subjects.
  
  
  CONCLUSIONS
  This observation shows that ETBR(+) lymphocyte expression predominates in nasal granulomatous lesions in GPA compared with ETAR. ETBR immunostaining is located to T cells, CD68(+) cells, and MGCs. ETBR may play an active role in the progression of granulomatous lesions in GPA.
authors.affiliation: Department of Medicine, Institute of Clinical Sciences Lund University, Lund, Sweden.
authors.forename: Ivan
authors.initials: I
authors.lastname: Dimitrijevic
authors.forename: Lars
authors.initials: L
authors.lastname: Edvinsson
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D014890:Granulomatosis with Polyangiitis / Q000175:diagnosis / Q000209:etiology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D009297:Nasal Mucosa / Q000737:chemistry*; D044022:Receptor, Endothelin A / Q000032:analysis; D044023:Receptor, Endothelin B / Q000032:analysis* / Q000502:physiology
chemical_list: D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B