Assessment of the tolerance to lupine-enriched pasta in peanut-allergic children.

BACKGROUND: Reports of allergy to lupine derivatives (as de novo sensitization or cross-reactivity in subjects allergic to peanut) are increasing as their use in food products increases. OBJECTIVES: The aim of this study was to assess: (1) lupine tolerance in a group of children allergic to peanut, using lupine enriched-pasta instead of raw flour as has been done in previous clinical studies; (2) whether technological treatments of lupine modify its cross-reactivity or co-sensitization with peanut; (3) the role of lupine seed proteins in sensitization, and (4) to identify the eliciting doses (EDs) by using double-blind, placebo-controlled food challenges (DBPCFC). METHODS: Twelve patients with a history of clinical allergic reactions to peanut were evaluated by skin prick tests (SPTs), the ImmunoCAP test, immunoblotting, and DBPCFC. The 12 selected subjects were included in a trial where lupine-enriched pasta and placebo pasta were administered in a DBPCFC protocol. RESULTS: Positive clinical reactions were observed in two children, the EDs being 0.2 and 6.4 g of pasta, corresponding to 50 mg and 1.6 g of lupine proteins, respectively. Beta-conglutin was the protein most involved in SPT positivity. CONCLUSION: Lupine-enriched pasta can be tolerated by most subjects suffering from peanut allergy, but a sizeable minority (2/12 of them in this case) can develop potentially dangerous clinical reactions. Information about possible reactions to lupine derivatives by those allergic to peanuts must be included in the labelling of lupine-enriched products to protect consumers at risk.

Assessment of lupin allergenicity in the cholera toxin model: induction of IgE response depends on the intrinsic properties of the conglutins and matrix effects.

BACKGROUND: The well-established murine model of IgE-mediated food allergy, based on oral administration of antigen and cholera toxin (CT), has within the previous years been used to evaluate various food proteins. Nonetheless, little knowledge on the factors that determine the allergenicity of food proteins is available so far. The use of proteins from the legume seed Lupinus albus as food ingredients calls for an evaluation of their allergenic potential, and therefore, we applied the cited model to investigate the putative allergenicity of three lupin protein preparations representing different matrices in which the four types of conglutins are present in varying concentrations. METHODS: Weekly, BALB/c A mice were orally immunized with the three lupin protein products together with CT. Total specific antibodies and IgE were determined by ELISA and Western blotting. RESULTS: A dose-dependent Ig response against the analyzed proteins was observed for all three lupin products, while IgE responses against conglutins beta, gamma and delta, but not against conglutin alpha, were primarily detected after oral administration of lupin flakes. Whereas no differences among the samples for total specific Ig responses were seen, orally administered lupin flake extracts were much more efficient in inducing a conglutin-specific IgE response compared with fractionated lupin protein products. CONCLUSIONS: Although the lupin-specific Ig response induced by coadministration of CT and lupin proteins appears to be dose dependent, the IgE response appears to depend merely on some intrinsic properties of the proteins as well as some factors of the protein matrix.

Assessment of residual immunoreactivity in red or white wines clarified with pea or lupin extracts.

Vegetable proteins could be a suitable alternative to animal proteins in the clarification of wine, but their residues could represent a risk for subjects with food allergy or intolerance. The aim of this study was to investigate the presence of specific immunoreactivity in red and white wines treated, as must or wine, with vegetable proteins in the clarification process. The proteins considered were prepared from lupins and peas, which are not included among the allergens listed in annex Illbis of Directive 2003/89/EC. The presence of residual immunoreactivity to specific rabbit anti-lupin and anti-pea polyclonal antibodies in treated wines was assessed by electrophoresis (SDS-PAGE) and immunoblotting. Residual protein was not detectable in red wines clarified with lupin, pea or a mixture of pea and lupin proteins or in white wines clarified with pea proteins. A small number of musts treated with lupin or pea proteins and white wines treated with lupin proteins yielded equivocal results, probably because of the presence of interfering material (e.g., sugar-rich proteins from grape and yeast). The use of bentonite as a secondary clarifying agent is therefore recommended since its combination with vegetable proteins is particularly effective in removing overall protein immunoreactivity.