title: An immunodiagnostic assay for quantitation of specific IgE to the major pollen allergen component, Pas n 1, of the subtropical Bahia grass.
abstract: BACKGROUND
  Pollens of the Panicoideae subfamily of grasses including Bahia (Paspalum notatum) are important allergen sources in subtropical regions of the world. An assay for specific IgE to the major molecular allergenic component, Pas n 1, of Bahia grass pollen (BaGP) would have immunodiagnostic utility for patients with pollen allergy in these regions.
  
  
  METHODS
  Biotinylated Pas n 1 purified from BaGP was coated onto streptavidin ImmunoCAPs. Subjects were assessed by clinical history of allergic rhinitis and skin prick test (SPT) to aeroallergens. Serum total, BaGP-specific and Pas n 1-specific IgE were measured.
  
  
  RESULTS
  Pas n 1 IgE concentrations were highly correlated with BaGP SPT (r = 0.795, p < 0.0001) and BaGP IgE (r = 0.915, p < 0.0001). At 0.23 kU/l Pas n 1 IgE, the diagnostic sensitivity (92.4%) and specificity (93.1%) for the detection of BaGP allergy was high (area under receiver operator curve 0.960, p < 0.0001). The median concentrations of Pas n 1 IgE in non-atopic subjects (0.01 kU/l, n = 67) and those with other allergies (0.02 kU/l, n = 59) showed no inter-group difference, whilst grass pollen-allergic patients with allergic rhinitis showed elevated Pas n 1 IgE (6.71 kU/l, n = 182, p < 0.0001). The inter-assay coefficient of variation for the BaGP-allergic serum pool was 6.92%.
  
  
  CONCLUSIONS
  Pas n 1 IgE appears to account for most of the BaGP-specific IgE. This molecular component immunoassay for Pas n 1 IgE has potential utility to improve the sensitivity and accuracy of diagnosis of BaGP allergy for patients in subtropical regions.
authors.affiliation: School of Medicine, University of Queensland, Brisbane, Qld., Australia.
authors.forename: Victoria L
authors.initials: VL
authors.lastname: Timbrell
authors.forename: Lindsay
authors.initials: L
authors.lastname: Riebelt
authors.forename: Claire
authors.initials: C
authors.lastname: Simmonds
authors.forename: Graham
authors.initials: G
authors.lastname: Solley
authors.forename: William B
authors.initials: WB
authors.lastname: Smith
authors.forename: Andrew
authors.initials: A
authors.lastname: Mclean-Tooke
authors.forename: Sheryl
authors.initials: S
authors.lastname: van Nunen
authors.forename: Peter K
authors.initials: PK
authors.lastname: Smith
authors.forename: John W
authors.initials: JW
authors.lastname: Upham
authors.forename: Daman
authors.initials: D
authors.lastname: Langguth
authors.forename: Janet M
authors.initials: JM
authors.lastname: Davies
mesh_terms: D000328:Adult; D019540:Area Under Curve; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D031781:Paspalum / Q000276:immunology*; D011058:Pollen / Q000276:immunology*; D011793:Queensland; D012372:ROC Curve; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000276:immunology*; D012680:Sensitivity and Specificity; D018709:Statistics, Nonparametric
chemical_list: D007073:Immunoglobulin E