Clinical allergy to hazelnut and peanut: identification of T cell cross-reactive allergens.

BACKGROUND: Peanut and tree nut allergies are life-threatening conditions for many affected individuals worldwide. Currently there is no cure. While co-allergy to peanut and tree nuts is a common clinical observation, and IgE cross-reactivity between peanut and tree nuts is reported, T cell cross-reactivity is poorly defined. METHODS: Hazelnut-specific T cell lines were established using peripheral blood mononuclear cells from 5 subjects with co-allergy to hazelnut and peanut. These lines were stimulated with hazelnut and peanut extracts and purified major peanut allergens, Ara h 1 and Ara h 2. Proliferation was determined by (3)H-thymidine incorporation and secretion of key Th1 (IFN-γ) and Th2 (IL-5) cytokines analysed by ELISA. RESULTS: Hazelnut-specific T cell lines from all 5 subjects proliferated upon stimulation with both hazelnut and peanut extracts and for 4 subjects, to Ara h 1 and/or Ara h 2. Proliferating cells were mainly CD4+ T cells and produced both IL-5 and IFN-γ in response to hazelnut and peanut stimulation. Mitogenicity of extracts and allergens was excluded by their lack of stimulation of house dust mite-specific T cells. CONCLUSION: Our finding that hazelnut and peanut co-allergy is associated with cross-reactive T cell responses, driven partly by cross-reactivity to the major peanut allergens Ara h 1 and Ara h 2, points to future development of allergen immunotherapy by targeting cross-reactive T cells.

House dust mite sublingual immunotherapy: the role for transforming growth factor-beta and functional regulatory T cells.

RATIONALE: Sublingual allergen-specific immunotherapy is gaining popularity for treatment of allergic diseases, but underlying immunological mechanisms are unresolved. OBJECTIVES: To perform detailed immunological investigation of sublingual house dust mite (HDM) immunotherapy. METHODS: A 12-month randomized double-blind placebo-controlled study of sublingual HDM immunotherapy in 30 HDM-allergic subjects was performed, with 1-year open extension in 9 patients on active treatment. HDM-stimulated blood mononuclear cells were analyzed for proliferation, cytokines, and regulatory T cells (Tregs) by flow cytometry and ELISA. Effects of blocking transforming growth factor (TGF)-beta and IL-10 on proliferation were determined. Treg suppressor function and allergen-specific antibody levels were measured. Clinical efficacy was assessed by symptom, medication, and Juniper quality-of-life scores. MEASUREMENTS AND MAIN RESULTS: Allergen-induced CD4(+) T-cell division and IL-5 production were significantly decreased after 6- and 12-months' active treatment but not placebo. sTGF-betaRII blocked immunotherapy-induced suppression of allergen-specific T-cell proliferation, maximal at 6 months. Decreased allergen-specific CD4(+) T-cell proliferation and increased IL-10 secretion and serum Der p 2-specific IgG(4) were maximal at 24 months' active treatment. Treg (CD4(+)CD25(+)CD127(lo)/Foxp3(+)) function was demonstrated by suppression of allergen-specific effector T-cell (CD4(+)CD25(-)CD127(hi)) proliferation and cytokine production. Clinical efficacy of immunotherapy was supported by significantly decreased rhinitis symptom score, total asthma score, and Juniper quality-of-life score. CONCLUSIONS: This study establishes the novel finding that TGF-beta mediates the immunological suppression seen early in clinically effective sublingual HDM immunotherapy in addition to an increase in Tregs with suppressor function. Clinical trial registered with www.clinicaltrials.gov (NCT00250263).

Specific and sensitive enzyme-linked immunosorbent assays for analysis of residual allergenic food proteins in commercial bottled wine fined with egg white, milk, and nongrape-derived tannins.

Regulations introduced by the Food Standards Australia New Zealand in December 2002 require all wine and wine product labels in Australia to identify the presence of a processing aid, additive or other ingredient, which is known to be a potential allergen. The objective of this study was to establish sensitive assays to detect and measure allergenic proteins from commonly used processing aids in final bottled wine. Sensitive and specific enzyme-linked immunosorbent assays (ELISA) were developed and established for the proteins casein, ovalbumin, and peanut. Lower limits of detection of these proteins were 8, 1, and 8 ng/mL, respectively. A panel of 153 commercially available bottled Australian wines were tested by these ELISA, and except for two red wines known to contain added whole eggs, residuals of these food allergens were not detected in any wine. These findings are consistent with a lack of residual potentially allergenic egg-, milk-, or nut-derived processing aids in final bottled wine produced in Australia according to good manufacturing practice at a concentration that could cause an adverse reaction in egg, milk, or peanut/tree-nut allergic adult consumers.

The peanut allergy epidemic: allergen molecular characterisation and prospects for specific therapy.

Peanut (Arachis hypogaea) allergy is a major cause of food-induced anaphylaxis, with increasing prevalence worldwide. To date, there is no cure for peanut allergy, and, unlike many other food allergies, it usually persists through to adulthood. Prevention of exposure to peanuts is managed through strict avoidance, which can be compromised by the frequent use of peanuts and peanut products in food preparations. Conventional subcutaneous-injection allergen immunotherapy using crude peanut extract is not a recommended treatment because of the risk of severe side effects, largely as a result of specific IgE antibodies. Consequently, there is an urgent need to develop a suitable peanut allergen preparation that can induce specific clinical and immunological tolerance to peanuts in allergic individuals without adverse side effects. This requires detailed molecular and immunological characterisation of the allergenic components of peanut. This article reviews current knowledge on clinically relevant peanut allergens, in particular Ara h 1, Ara h 2 and Ara h 3, together with options for T-cell-reactive but non-IgE-binding allergen variants for specific immunotherapeutic strategies. These include T-cell-epitope peptide and hypoallergenic mutant vaccines. Alternative routes of administration such as sublingual are also considered, and appropriate adjuvants for delivering effective treatments at these sites examined.

Potential food allergens in wine: double-blind, placebo-controlled trial and basophil activation analysis.

OBJECTIVE: Recent Australian and international legislation requires labeling of wines made by using the potentially allergenic food proteins casein, milk, egg white, or isinglass (fish-derived) where "there is a detectable residual processing aid." We investigated whether wines fined using these proteins or non-grape-derived tannins (tree-nut derived) can provoke significant clinical allergic reactions (anaphylaxis) in patients with confirmed immunoglobulin E-mediated relevant food allergy. METHODS: A double-blind, placebo-controlled trial was performed to determine whether allergic reactions followed consumption of Australian commercial wines fined using one or more of the legislation-targeted food proteins. In addition, allergenicity of a larger panel of these wines was evaluated by blood basophil activation. RESULTS: No anaphylaxis was induced by wine consumption. Three mild clinical reactions to protein-fined wine and two mild reactions to unfined wine occurred, but there was no statistically significant difference in reaction parameters between subject groups or between processing aids. No pattern of basophil activation correlated with wine type, processing aid, or subject group. CONCLUSION: Wines fined with egg white, isinglass, or non-grape-derived tannins present an extremely low risk of anaphylaxis to fish-, egg-, or peanut-allergic consumers. Although consumption of milk protein-fined wine did not induce anaphylaxis, there were insufficient subjects to determine statistically whether wines fined with milk proteins present a risk to the very rare milk-allergic consumers. In summary, the observed lack of anaphylaxis and basophil activation induced by wines made using the legislation-targeted food proteins according to good manufacturing practice suggests negligible residual food allergens in these wines.

Anaphylaxis to lemon soap: citrus seed and peanut allergen cross-reactivity.

BACKGROUND: Many individuals allergic to peanuts have multiple allergen sensitivity. OBJECTIVE: To report the first case, to our knowledge, of a peanut allergic patient who exhibited cosensitivity to citrus seeds and who had experienced anaphylaxis to lemon soap. METHODS: Extracts of peanut and seeds from different varieties of citrus fruit (orange, lemon, and mandarin) were prepared and resolved with 14% sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Direct and inhibition immunoblotting of the patient's serum on the extracts was used to examine the pattern of IgE reactivity and the presence of cross-reactive allergens. RESULTS: Numerous IgE reactive proteins were demonstrated in each citrus seed extract and the peanut extract. Complete IgE cross-reactivity was demonstrated among the different citrus seed extracts. Partial cross-reactivity was demonstrated between the peanut and orange seed extracts. CONCLUSIONS: Citrus seeds contain numerous IgE reactive proteins that are completely cross-reactive among orange, lemon, and mandarin. When peanut allergy coexists with citrus seed allergy, IgE cross-reactivity between peanut and citrus seed proteins can be demonstrated, suggesting a basis to this cosensitivity.