title: Nasal response to a single antigen challenge in patients with allergic rhinitis - inflammatory cell recruitment persists up to 48 hours.
abstract: BACKGROUND
  Allergen challenge in some patients with respiratory allergy is followed by an early and a late reaction.
  
  
  OBJECTIVE
  To evaluate the duration of mediator release and inflammatory cell recruitment during the late antigen-induced nasal response.
  
  
  METHODS
  Eight patients with seasonal allergic rhinitis due to grass pollen underwent local challenge with the relevant allergen, a non-relevant allergen (Parietaria judaica), and nebulized saline solution. Nasal lavages were performed at baseline and 6, 24, 48, 72 h after challenge. Eosinophil cationic protein (ECP), leukotriene C4 (LTC4), leukotriene B4 (LTB4) myeloperoxidase (MPO) and prostaglandin D2 (PGD2) levels were radioimmunoassayed and histamine concentration was measured by an automated fluorometric method.
  
  
  RESULTS
  Nasal challenge with the relevant antigen induced a response 6 h after stimulation, which subsided within 24 h. Eosinophilia, observed in the nasal lavages collected from 6 to 24 h after this challenge, was accompanied by ECP release. Neutrophilia were found in the nasal lavages collected from 6 to 24 h after challenge. The increase in neutrophil number correlated with MPO levels and LTB4 concentrations, but not with the intensity of nasal obstruction. Antigen challenge also induced significant recruitment of mononuclear cells 48 h after provocation. The challenge significantly raised histamine, but not PGD2, levels in the nasal lavages collected 6 h after provocation. A trend towards an increase in LTC4 levels in the nasal lavages collected 6 h after specific antigen challenge was also found. Nasal challenge with a non-relevant allergen or with saline solution did not cause either inflammatory cell recruitment or mediator release.
  
  
  CONCLUSIONS
  Nasal challenge with the relevant antigen can induce a late response characterized by local accumulation of eosinophils, neutrophils and mononuclear cells persisting for 48 h and accompanied by release of ECP, MPO, LTB4 and histamine. These results indicate that a single antigen challenge in patients with allergic rhinitis causes prolonged inflammatory alterations which may contribute to the development of airway hyperreactivity.
authors.affiliation: Respiratory Allergy and Immunology Unit, Third Division of Internal Medicine, IRCCS Ospedale Maggiore Policlinico, Milan, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Miadonna
authors.forename: N
authors.initials: N
authors.lastname: Milazzo
authors.forename: S
authors.initials: S
authors.lastname: Gibelli
authors.forename: C
authors.initials: C
authors.lastname: Salmaso
authors.forename: M
authors.initials: M
authors.lastname: Lorini
authors.forename: A
authors.initials: A
authors.lastname: Tedeschi
mesh_terms: D000293:Adolescent; D000328:Adult; D000941:Antigens / Q000276:immunology*; D001798:Blood Proteins / Q000378:metabolism; D002634:Chemotaxis, Leukocyte; D047091:Eosinophil Granule Proteins; D004804:Eosinophils / Q000276:immunology*; D005260:Female; D006632:Histamine / Q000378:metabolism; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D007975:Leukotriene B4 / Q000378:metabolism; D017997:Leukotriene C4 / Q000378:metabolism; D008297:Male; D017817:Nasal Lavage Fluid / Q000737:chemistry; D009299:Nasal Provocation Tests; D009504:Neutrophils / Q000276:immunology*; D009195:Peroxidase / Q000378:metabolism; D011058:Pollen / Q000276:immunology; D015230:Prostaglandin D2 / Q000378:metabolism; D011863:Radioimmunoassay; D006255:Rhinitis, Allergic, Seasonal / Q000276:immunology*; D012260:Ribonucleases
chemical_list: D000941:Antigens; D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D007975:Leukotriene B4; D017997:Leukotriene C4; D006632:Histamine; D009195:Peroxidase; D012260:Ribonucleases; D015230:Prostaglandin D2