title: T-cell receptor-mediated cross-allergenicity.
abstract: BACKGROUND
  Profilins are conserved and ubiquitous plant and animal proteins. We wanted to discover whether the T-cell response to conserved epitopes on birch and grass profilins could account for cross-allergenicity in subjects allergic to these two pollens.
  
  
  METHODS
  Thirty-one patients allergic to grass and birch were recruited for the study. Grass and birch reactive T lymphocytes were studied by measuring proliferation to birch and grass allergen, respectively, followed by Vbeta T-cell receptor family-specific polymerase chain reaction and heteroduplex analysis. T-cell clones were derived from patients with cross-proliferating T cells.
  
  
  RESULTS
  In 25 of 31 subjects the T-cell response to grass was quite distinct from that to birch. In contrast, in 6 of 31 individuals grass T cells cross-proliferated to birch and this was reproduced in 4 patients by birch profilin. CD4 Th2 cell clones were derived which promiscuously recognized homologously conserved regions on birch and grass profilins.
  
  
  CONCLUSIONS
  We conclude that a functionally relevant T-cell response to conserved regions of panallergens underlie cross-allergenicity in a subset of allergic patients. These results suggest that a reciprocal modulation of the response to one sensitizing allergen can occur following natural exposure to or immunotherapy with another allergen. These results have relevance in the management of patients with multiple allergies.
authors.affiliation: San Raffaele Scientific Institute, Milan, Italy. burastero.samuele@hsr.it
authors.forename: Samuele E
authors.initials: SE
authors.lastname: Burastero
authors.forename: Clara
authors.initials: C
authors.lastname: Paolucci
authors.forename: Daniela
authors.initials: D
authors.lastname: Breda
authors.forename: Renato
authors.initials: R
authors.lastname: Longhi
authors.forename: Michela
authors.initials: M
authors.lastname: Silvestri
authors.forename: Juergen
authors.initials: J
authors.lastname: Hammer
authors.forename: Maria Pia
authors.initials: MP
authors.lastname: Protti
authors.forename: Giovanni A
authors.initials: GA
authors.lastname: Rossi
mesh_terms: D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology*; D000595:Amino Acid Sequence; D029662:Betula / Q000276:immunology; D049109:Cell Proliferation; D003001:Cloning, Molecular; D003429:Cross Reactions / Q000276:immunology*; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D008969:Molecular Sequence Data; D031784:Phleum / Q000276:immunology; D016133:Polymerase Chain Reaction; D011948:Receptors, Antigen, T-Cell / Q000276:immunology*; D016415:Sequence Alignment; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
chemical_list: D000485:Allergens; D018984:Epitopes, T-Lymphocyte; D006684:HLA-DR Antigens; D011948:Receptors, Antigen, T-Cell