title: Mast cells and tryptase in the middle ear of children with otitis media with effusion.
abstract: OBJECTIVE
  This is the first report of the presence of tryptase, a reflection of mast cell activity, in chronic middle ear effusion of patients in whom atopic status was characterized.
  
  
  METHODS
  Mediator activity of mast cells and eosinophils was measured prospectively from effusion of 33 random patients and five controls with chronic otitis media with effusion (OME). Atopy was determined by enzyme-linked immunosorbent assay testing. Middle ear biopsies from a second group of eight OME patients and four controls were fixed in plastic and stained immunohistochemically for mast cells.
  
  
  RESULTS
  Sixty-one percent of patients had extensive activation of mast cells in their middle ears. Among those with elevated tryptase in their effusion, 95.6% were atopic and 94.7% also had elevated effusion eosinophilic cationic protein. Tryptase was elevated only in the effusion of atopic patients as compared with controls (P < 0.01). Mast cells were present in six of eight OME ears and absent in all four normals.
  
  
  CONCLUSIONS
  Mast cells and its mediator tryptase, both indicators of a Th2-driven immune response, are present in the majority of ears which have chronic effusion, suggesting that the inflammation within the middle ear of most OME patients is allergic in nature.
authors.affiliation: Department of Medical Cell Biology, University of Uppsala, Sweden. meear@earthlink.net
authors.forename: D S
authors.initials: DS
authors.lastname: Hurst
authors.forename: K
authors.initials: K
authors.lastname: Amin
authors.forename: L
authors.initials: L
authors.lastname: Sevéus
authors.forename: P
authors.initials: P
authors.lastname: Venge
mesh_terms: D000293:Adolescent; D000328:Adult; D001798:Blood Proteins / Q000032:analysis; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D053818:Chymases; D004432:Ear, Middle / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D047091:Eosinophil Granule Proteins; D006801:Humans; D006969:Hypersensitivity, Immediate / Q000150:complications*; D007150:Immunohistochemistry; D018836:Inflammation Mediators / Q000032:analysis*; D008407:Mast Cells / Q000473:pathology*; D010034:Otitis Media with Effusion / Q000276:immunology* / Q000473:pathology; D011446:Prospective Studies; D012260:Ribonucleases; D012697:Serine Endopeptidases / Q000032:analysis*; D053802:Tryptases
chemical_list: D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D018836:Inflammation Mediators; D012260:Ribonucleases; D012697:Serine Endopeptidases; C083294:chymase 2; D053818:Chymases; D053802:Tryptases