Rice allergy demonstrated by double-blind placebo-controlled food challenge in peach-allergic patients is related to lipid transfer protein reactivity

Int Arch Allergy Immunol. 2013;161(3):265-73. doi: 10.1159/000345974. Epub 2013 Mar 15.

Abstract

Background: The risk factors for sensitisation to rice and the involved allergens are still partially unknown. In this study we evaluated the clinically relevant aspects of rice allergy in DBPCF-positive patients, the major rice allergens, the severity of peach- and rice-induced symptoms in respect to Pru p 3 sensitisation and the role of anti-rPru p 3 IgE levels as a risk factor for rice allergy.

Methods: In 148 peach-allergic subjects, patients with allergic reactions to rice and rice-positive serum IgE were selected. Symptoms were verified by double-blind placebo-controlled food challenges (DBPCFCs), performed at a maximum dosage of 25 g. Rice allergens, identified by IgE immunoblotting, were characterised by N-terminal amino acid sequencing. The relationship between anti-rPru p 3, 1 and 4 IgE levels and rice symptoms were statistically analysed.

Results: Eight out of 10 recruited rice-allergic patients had positive DBPCFCs, while 2 patients were not challenged due to their previously documented severe reactions. All patients with rice-induced symptoms were Pru p 3 positive and presented with higher anti-rPru p 3 levels than the rice-sensitised but tolerant patients. A 9-kDa lipid transfer protein, which was highly homologous to Pru p 3, was identified as the major rice allergen and elicited a positive response in all of the patients. Five patients reacted to a putative 15- to 17-kDa rice allergenic protein, and 3 patients reacted to an [alpha]-amylase/subtilisin inhibitor that was approximately 20 kDa.

Conclusion: Rarely, allergic reactions to rice can arise in patients with peach allergies who are sensitised to Pru p 3, particularly in patients with high anti-rPru p 3 IgE levels.

MeSH terms

  • Adult
  • Carrier Proteins / chemistry
  • Carrier Proteins / genetics
  • Carrier Proteins / immunology*
  • Chromatography, High Pressure Liquid
  • Double-Blind Method
  • Electrophoresis, Polyacrylamide Gel
  • Female
  • Food Hypersensitivity / immunology*
  • Humans
  • Immunoblotting
  • Immunoglobulin E / blood
  • Male
  • Middle Aged
  • Oryza / immunology*
  • Plant Preparations / immunology*
  • Plant Proteins / immunology
  • Prunus / immunology*
  • Surveys and Questionnaires

Substances

  • Carrier Proteins
  • Plant Preparations
  • Plant Proteins
  • lipid transfer protein
  • Immunoglobulin E