Pistachio vicilin, Pis v 3, is immunoglobulin E-reactive and cross-reacts with the homologous cashew allergen, Ana o 1

Clin Exp Allergy. 2008 Jul;38(7):1229-38. doi: 10.1111/j.1365-2222.2008.02998.x. Epub 2008 May 13.


Background: Patients allergic to cashew nuts often report allergy to pistachio, which could be a result of cross-reactivity between the two as both are members of the Anacardiaceae family.

Objective: Because cashew 7S globulin (vicilin, Ana o 1) is a recognized major allergen, we cloned the pistachio homologue and assayed it for IgE reactivity and cross-reactivity with Ana o 1.

Methods: Degenerate primers for 7S globulin were used in PCR to amplify DNA from a pistachio cDNA library. An isolate was sequenced, cloned and expressed in Escherichia coli. Reactivity to the allergen was screened by dot blot using 19 pistachio and/or cashew-allergic patients' sera. Cross-reactivity was investigated by inhibition dot- and Western immunoblot assays using pistachio/cashew-allergic patients' sera, and monoclonal antibodies (MAbs) raised against recombinant Ana o 1 (rAna o 1).

Results: An isolate was found that coded for a 7S vicilin-like protein, designated Pis v 3. IgE reactivity to Pis v 3 was found in the serum of seven of the 19 (37%) patients with histories of allergy to both pistachio and cashew or who were allergic to cashew but had never eaten pistachio. The seven patients with IgE that recognized rPis v 3 also recognized rAna o 1. Six of nine anti-rAna o 1 MAbs also showed reactivity to rPis v 3 on dot blots.

Conclusion: Of the 37% of pistachio/cashew-allergic patients' sera that recognized the pistachio allergen, rPis v 3, all showed complete cross-reactivity with rAna o 1. The data does not identify the primary sensitizing agent but suggests that IgE reactivity to rPis v 3 and rAna o 1 is focused on the most conserved regions of the proteins. Clinical histories suggest that in some cases, cashew was the sensitizing agent. rPis v 3 is a likely contributor to the observed co-sensitivity to pistachio and cashew in some patients.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adult
  • Allergens / chemistry
  • Allergens / genetics
  • Allergens / immunology*
  • Allergens / metabolism
  • Amino Acid Sequence
  • Anacardium / immunology*
  • Antibodies, Monoclonal / immunology
  • Antigens, Plant
  • Base Sequence
  • Cross Reactions
  • Female
  • Humans
  • Immunoglobulin E / blood*
  • Male
  • Middle Aged
  • Molecular Sequence Data
  • Nut Hypersensitivity / immunology*
  • Pistacia / immunology*
  • Plant Proteins / chemistry
  • Plant Proteins / genetics
  • Plant Proteins / immunology*
  • Recombinant Proteins / immunology
  • Seed Storage Proteins
  • Sequence Alignment


  • Allergens
  • Ana o 1 protein, Anacardium occidental
  • Antibodies, Monoclonal
  • Antigens, Plant
  • Plant Proteins
  • Recombinant Proteins
  • Seed Storage Proteins
  • Immunoglobulin E
  • vicilin protein, plant