Rice: Another Potential Cause of Food Allergy in Patients Sensitized to Lipid Transfer Protein

Background: Whether the observed clinical pattern of non-specific lipid transfer protein (nsLTP)-mediated food allergies is attributable to a primary sensitization by Pru p 3 from peach and subsequent cross-reactivity with Rosaceae- and non-Rosaceae-derived foods expressing homologous allergens is still unclear. Objective: To investigate the allergenic properties of nsLTPs from Rosaceae and non-Rosaceae foods. Methods: In peach-, cherry- or hazelnut-allergic patients, prevalence of sensitization, IgE-binding capacity, cross-reactivity and allergenic potency of Pru p 3 was compared with Pru av 3 (cherry) and Cor a 8 (hazelnut). Results: Frequency of sensitization to corresponding nsLTPs was 88, 85, and 77% in peach-, hazelnut- and cherry-allergic patients, respectively. Concomitant allergic reactions to cherry and hazelnut were reported in 51 and 44% of peach-allergic patients, respectively. In contrast to cherry allergy, hazelnut allergy was not strictly associated to peach allergy. Sensitization to Cor a 8 or Pru av 3 was strongly correlated with IgE reactivity to Pru p 3, even when subjects tolerated peach. Specific IgE was highest for Rosaceae LTPs, and cross-inhibition experiments confirmed a stronger IgE-binding capacity of Pru p 3 than Cor a 8. The biological potency of Pru p 3 and Pru av 3 was similar but stronger for both nsLTPs than that of Cor a 8. Conclusion: Clinical cross-reactivity of food-allergic patients in the Mediterranean area is likely attributed to a primary sensitization to Pru p 3 and serological cross-reactivity with homologous food nsLTPs. In comparison to Cor a 8, Rosaceae nsLTPs showed a stronger IgE-binding capacity and allergenic potency indicating a different epitope pattern.

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparison of IgE-Binding Capacity, Cross-Reactivity and Biological Potency of Allergenic Non-Specific Lipid Transfer Proteins from Peach, Cherry and Hazelnut

Hartz

Lauer

Moncín

et al. 2010

“…These foods were chosen because they have been reported to cause potentially severe allergic reactions in LTP-hypersensitive subjects [16,17,18,19,20,21]. Reported symptoms were classified as local (oral allergy syndrome, OAS) or systemic (urticaria or anaphylaxis).…”

Section: Methodsmentioning

confidence: 99%

Are IgE Levels to Foods other than Rosaceae Predictive of Allergy in Lipid Transfer Protein-Hypersensitive Patients?

Asero

Arena²,

Cecchi³

et al. 2010

Background: Lipid transfer protein (LTP), the most frequent cause of primary food allergy in Italy, is a cross-reacting plant pan-allergen. Markers able to predict whether a patient sensitized to a certain food but not yet clinically allergic will develop allergy would be extremely helpful. Objective: It was the aim of this study to investigate the relevance of IgE levels to some plant foods other than Rosaceae as predictors of either local or systemic allergic reaction in LTP-allergic subjects. Methods: One hundred (40 males, 60 females , mean age 29 years) peach-allergic patients monosensitized to LTP seen at 14 Italian centres in 2009 were studied. Walnut, hazelnut, peanut, tomato, rice and/or maize allergy was ascertained by interview and confirmed by positive skin prick test. IgE levels to these foods and to rPru p 3 were measured. Results: Higher levels of IgE to Pru p 3 were associated with a higher prevalence of allergy to hazelnut, peanut and walnut. For all study foods, except rice, median IgE levels in allergic subjects significantly exceeded those in tolerant subjects, though within single allergic groups, the differences between patients reporting systemic or local (oral) symptoms were not significant. Ninety-five percent cut-off IgE levels predictive of clinical allergy were established for study foods although the marked overlaps between allergic and tolerant subjects made them of limited usefulness. Conclusion: Specific IgE levels are only partially predictive of clinical allergy. The reasons why some individuals showing low specific IgE levels develop clinical allergy whereas others showing high IgE levels do not, despite similar exposure to the allergen, remain unclear.

“…Other known rice allergens in rice grains include a novel type of plant glycoxalase I of 33 kDa and an α-globulin of 26-28 kDa [14,15,16]. Moreover, two studies identified a lipid transfer protein (LTP) as a potential allergen involved in symptoms induced by ingestion of cooked rice or inhalation of raw rice in patients who are allergic to Prunoideae fruits [7,17]. Trcka et al [18] identified a 56-KDa protein as a relevant allergen in patients with rice-induced anaphylaxis.…”

Section: Introductionmentioning

confidence: 99%

Rice Allergy Demonstrated by Double-Blind Placebo-Controlled Food Challenge in Peach-Allergic Patients Is Related to Lipid Transfer Protein Reactivity

Pastorello

Scibilia

Farioli

et al. 2013

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.