title: Platelet-activating factor nasal challenge induces nasal congestion and reduces nasal volume in both healthy volunteers and allergic rhinitis patients.
abstract: BACKGROUND
  Platelet-activating factor (PAF) is a lipid mediator produced by most inflammatory cells. Clinical and experimental findings suggest that PAF participates in allergic rhinitis (AR) pathogenesis. The aim was to assess the PAF ability to induce clinical response in nasal airway after local stimulation.
  
  
  METHODS
  Ten nonatopic healthy volunteers (HVs) and 10 AR patients out of pollen season were enrolled. PAF increasing concentrations (100, 200, and 400 nM) were instilled into both nasal cavities (0, 30, and 60 minutes, respectively). Nasal symptoms (congestion, rhinorrhea, sneezing, itching, and total 4 symptom score and nasal volume between the 2nd and 5th cm (Vol(2-5)) using acoustic rhinometry (AcR), were assessed at -30, 0, 30, 60, 90, 120, and 240 minutes.
  
  
  RESULTS
  PAF increased individual and total nasal symptom score in both HVs and seasonal AR (SAR) patients from 30 to 120 minutes (maximum score at 120', p < 0.05). Nasal obstruction was the most relevant and lasting nasal symptom. PAF also induced a significant reduction of Vol(2-5) at 90' (27%), 120' (38.7%), and 240' (36.4%). No differences in the response to PAF nasal challenge were observed between HVs and SAR subjects in either clinical symptoms or AcR.
  
  
  CONCLUSIONS
  This is the first description of PAF effects on human nasal mucosa using a cumulative dose schedule and evaluated by both nasal symptoms and AcR. Nasal provocation with PAF showed long-lasting effects on nasal symptoms and nasal obstruction in HVs and in patients with SAR. Nasal challenge may be a useful tool to investigate the role of PAF in AR and the potential role of anti-PAF drugs.
authors.affiliation: Unitat Allèrgia, Pneumologia i Allèrgia Respiratòria Hospital Clínic, Universitat de Barcelona, Barcelona, Spain. rmunoz@clinic.ub.es
authors.forename: Rosa
authors.initials: R
authors.lastname: Muñoz-Cano
authors.forename: Antonio
authors.initials: A
authors.lastname: Valero
authors.forename: Jordi
authors.initials: J
authors.lastname: Roca-Ferrer
authors.forename: Joan
authors.initials: J
authors.lastname: Bartra
authors.forename: Jaime
authors.initials: J
authors.lastname: Sanchez-Lopez
authors.forename: Joaquim
authors.initials: J
authors.lastname: Mullol
authors.forename: Cesar
authors.initials: C
authors.lastname: Picado
mesh_terms: D000281:Administration, Intranasal; D000328:Adult; D000485:Allergens / Q000276:immunology; D052179:Antigens, Plant / Q000276:immunology; D018450:Disease Progression; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007114:Immunization; D008297:Male; D009296:Nasal Cavity / Q000187:drug effects* / Q000473:pathology / Q000601:surgery; D015508:Nasal Obstruction / Q000209:etiology / Q000517:prevention & control; D010972:Platelet Activating Factor / Q000008:administration & dosage* / Q000009:adverse effects; D011058:Pollen / Q000009:adverse effects / Q000276:immunology; D006255:Rhinitis, Allergic, Seasonal / Q000150:complications / Q000175:diagnosis / Q000276:immunology*; D023842:Rhinometry, Acoustic; D016896:Treatment Outcome
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D010972:Platelet Activating Factor