title: Hypersensitivity to black locust (Robinia pseudoacacia) pollen: "allergy mirages".
abstract: BACKGROUND
  The allergenicity of the ornamental tree Robinia pseudoacacia, or black locust, is unknown.
  
  
  OBJECTIVE
  To evaluate the prevalence of sensitization to R. pseudoacacia pollen, its possible allergenic cross-reactivity with other common pollens, and the potential implication of pollen panallergens (profilin, polcalcin, and 1,3-beta-glucanase) as a cause of sensitization to R. pseudoacacia pollen.
  
  
  METHODS
  Skin prick testing with R. pseudoacacia pollen was performed in 149 patients with pollinosis. Nasal challenge with R. pseudoacacia pollen was performed in 10 patients. The prevalence of sensitization to the recombinant forms of profilin (rChe a 2), polcalcin (rChe a 3), and the N-terminal of the 1,3-beta-glucanase (rNtD of Ole e 9) was investigated. Immunoblotting, enzyme-linked immunosorbent assay, and competitive inhibition assays were performed with R. pseudoacacia pollen and recombinant pollen allergens.
  
  
  RESULTS
  Sixty-four patients (43%) had positive skin prick test reactions to R. pseudoacacia pollen. Nasal challenge results were positive in 5 sensitized patients and negative in 4 controls and 1 sensitized patient. The allergenic profile of R. pseudoacacia pollen comprises at least the panallergen profilin, a calcium-binding protein, and a 1,3-beta-glucanase. The prevalence of sensitization to rChe a 2, rChe a 3, and rNtD of Ole e 9 was 60%, 33%, and 87%, respectively, among patients sensitized to R. pseudoacacia pollen. Binding of IgE to R. pseudoacacia extract was completely inhibited by Robinia, Chenopodium, Olea, Cupressus, and Lolium extracts.
  
  
  CONCLUSIONS
  The high prevalence of R. pseudoacacia pollen sensitization in patients with pollinosis is likely to be due to cross-sensitization to panallergens (profilin, polcalcin, and 1,3-beta-glucanase) from other common pollens. This phenomenon may lead to a diagnosis of "allergy mirages."
authors: Fundación Jiménez Díaz, Allergy Department, Universidad Autónoma de Madrid, Spain.
authors: Esther
authors: E
authors: Compés
authors: Elena
authors: E
authors: Hernández
authors: Santiago
authors: S
authors: Quirce
authors: Oscar
authors: O
authors: Palomares
authors: Rosalía
authors: R
authors: Rodríguez
authors: Javier
authors: J
authors: Cuesta
authors: Joaquín
authors: J
authors: Sastre
authors: Mayte
authors: M
authors: Villalba