Concomitant sensitization to ragweed and mugwort pollen: who is who in clinical allergy?

Ann Allergy Asthma Immunol. 2014 Sep;113(3):307-13. doi: 10.1016/j.anai.2014.06.009. Epub 2014 Jul 19.

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.

Objectives: 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.

Conclusion: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allergens / immunology*
  • Ambrosia / adverse effects*
  • Antigens, Plant / immunology
  • Artemisia / adverse effects*
  • Carrier Proteins / immunology
  • Carrier Proteins / metabolism
  • Cross Reactions / immunology*
  • Humans
  • Immunoglobulin E / blood
  • Immunoglobulin E / immunology
  • Immunoglobulin E / metabolism
  • Pollen / immunology*
  • Protein Binding
  • Rhinitis, Allergic, Seasonal / diagnosis
  • Rhinitis, Allergic, Seasonal / immunology*
  • Rhinitis, Allergic, Seasonal / metabolism
  • Skin Tests

Substances

  • Allergens
  • Antigens, Plant
  • Carrier Proteins
  • Immunoglobulin E