title: Concomitant sensitization to ragweed and mugwort pollen: who is who in clinical allergy?
abstract: BACKGROUND
  In many areas of Europe, double sensitization to ragweed and mugwort is common, and because of the overlapping flowering periods of the 2 plants, it is not possible to diagnose the primary sensitizing allergen source and hence to determine the proper immunotherapy.
  
  
  OBJECTIVE
  To elucidate whether double-sensitized patients are cosensitized or cross-sensitized and, in the latter case, to define the primary sensitizer.
  
  
  METHODS
  Serum samples from 34 patients with late summer respiratory allergy underwent skin prick testing with whole ragweed, and mugwort extracts were analyzed for their reactivity to recombinant Art v 1 and Amb a 1 by ImmunoCAP and then to Amb a 1, Art v 6, and Art v 1 isoforms by a proteomic approach. In double reactors, the primary sensitizing sources were detected by inhibition experiments.
  
  
  RESULTS
  Serum samples from patients monosensitized to ragweed contained IgE to epitopes specific of all Amb a 1 isoforms. In contrast, serum samples from double reactors found to be primarily sensitized to mugwort reacted to Art v 1 and Art v 6 and cross-reacted to a few Amb a 1 isoforms. Finally, serum samples from double reactors found to be primarily sensitized to ragweed contained IgE reacting to all Amb a 1 isoforms, part of which cross-reacted to Art v 6. We did not find cosensitized patients.
  
  
  CONCLUSIONS
  This study found that Art v 6 plays an important role in mugwort allergy and that the cross-reactivity between Art v 6 and Amb a 1 is frequent, bidirectional, and clinically relevant in the area of Milan.
authors: Ambulatorio di Allergologia, Clinica San Carlo, Paderno Dugnano, Milan, Italy.
authors: Riccardo
authors: R
authors: Asero
authors: Dipartimento di Science Ambientali, Università di Milano-Bicocca, Milan, Italy.
authors: Emanuele
authors: E
authors: Bellotto
authors: Dipartimento di Science Ambientali, Università di Milano-Bicocca, Milan, Italy.
authors: Alessandra
authors: A
authors: Ghiani
authors: Dipartimento di Science Ambientali, Università di Milano-Bicocca, Milan, Italy.
authors: Roberta
authors: R
authors: Aina
authors: Allergologia e Immunologia Clinica, Azienda Ospedaliera, S Maria degli Angeli, Pordenone, Italy.
authors: Danilo
authors: D
authors: Villalta
authors: Dipartimento di Science Ambientali, Università di Milano-Bicocca, Milan, Italy. Electronic address: sandra.citterio@unimib.it.
authors: Sandra
authors: S
authors: Citterio
mesh_terms: D000485:Allergens / Q000276:immunology*; D031164:Ambrosia / Q000009:adverse effects*; D052179:Antigens, Plant / Q000276:immunology; D019306:Artemisia / Q000009:adverse effects*; D002352:Carrier Proteins / Q000276:immunology / Q000378:metabolism; D003429:Cross Reactions / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology / Q000378:metabolism; D011058:Pollen / Q000276:immunology*; D011485:Protein Binding; D006255:Rhinitis, Allergic, Seasonal / Q000175:diagnosis / Q000276:immunology* / Q000378:metabolism; D012882:Skin Tests
chemical_list: D000485:Allergens; D052179:Antigens, Plant; D002352:Carrier Proteins; D007073:Immunoglobulin E