Fruit-pollen-latex cross-reactivity: implication of profilin (Bet v 2).

BACKGROUND: An association between allergy to fruits and latex, and between pollen and plant-derived food has been described. The cross-reactive structures responsible for these associations have not yet been completely elucidated. METHODS: IgE reactivity to the recombinant allergens Bet v 1 and Bet v 2, different pollens, natural latex, papain, and bromelain was investigated in 29 patients with allergy to fruits or vegetables who lived in an area without birch trees. RESULTS: Exactly 79.3% of patients were allergic to grass pollen, and two of them had clinical allergy to latex. Serum IgE reactivity (CAP) to birch pollen was found in 65% of patients, to Bet v 2 in 51.7%, to Bet v 1 in 3.4%, to latex in 58.6%, to bromelain in 51.7%, and to papain in 17.2% of patients. All subjects with positive IgE to Bet v 2 had also reactivity to latex, grass, olive tree, birch, and mugwort pollens. The six patients not allergic to pollen did not show IgE reactivity to latex, Bet v 1, or Bet v 2. A significant correlation was found between CAP to latex with Bet v 2 (r=0.86, P<0.001), with birch (r=0.86, P<0.001), and with ryegrass (r=0.81, P<0.001). Immunoblotting using nine sera with positive CAP to birch pollen showed IgE-binding to a 15-kDa band that was recognized by antiprofilin monoclonal antibody. Bet v 2 CAP could be inhibited up to 52% by ryegrass and up to 23% by mugwort. CAP to latex was almost completely inhibited by ryegrass pollen with sera from five subjects without symptoms due to latex, whereas no inhibition was observed with serum from one patient with allergy to latex. CONCLUSIONS: Patients with allergy to plant-derived food and associated pollinosis showed a high frequency of IgE reactivity to Bet v 2, which may cause positive serum IgE determinations to latex and birch pollen due to the presence of cross-reactive epitopes. IgE reactivity to Bet v 2 may serve as an indicator of broad sensitization.

Asthma caused by Ficus benjamina latex: evidence of cross-reactivity with fig fruit and papain.

BACKGROUND: Ficus benjamina or weeping fig is a plant used increasingly for indoor decoration that can cause allergic rhinitis and asthma. OBJECTIVE: We report a clinical and immunologic study in a patient with perennial asthma caused by F. benjamina latex in whom several episodes of angioedema of the oropharyngeal tract and tongue followed ingestion of figs and kiwi. METHODS: Hypersensitivity to latex from F. benjamina and from Hevea brasiliensis, fig fruit, kiwi, papain, and bromelain was investigated by means of skin prick test, specific IgE determination by CAP, histamine release test, and bronchial provocation test to F. benjamina latex. CAP-inhibition assays were carried out to study possible cross-reactivity among these antigens. RESULTS: Hypersensitivity to F. benjamina latex, fig, kiwi, and proteases was demonstrated by means of skin prick test, determination of specific IgE and histamine release test. Bronchial provocation test with F. benjamina latex resulted in a dual asthmatic reaction, confirming the etiologic role of this plant. A rise of eosinophil cationic protein in patient's serum was observed 21 hours after bronchial challenge, suggesting activation of eosinophils. Inhibition assays showed that F. benjamina latex as liquid-phase inhibited up to 95% the CAP to fig and up to 57% the CAP to papain. Neither sensitization nor cross-allergenicity with H. brasiliensis latex was found. CONCLUSIONS: Hypersensitivity to F. benjamina latex may cause IgE-mediated respiratory allergy. The association with allergy to fig and papain is likely due to the existence of cross-reactive allergen structures.

Green bean hypersensitivity: an occupational allergy in a homemaker.

As a member of the legume family, the green bean is frequently associated with food allergy. However, allergic reactions caused by skin contact or by inhalation of vapors from boiling legumes are rare. This article presents a case of occupational asthma in a homemaker; symptoms occurred during preparation and cooking of raw green beans. Skin prick, rub, and bronchial provocation tests were performed on the patient. In vitro tests were done with the serum samples of the patient and 10 control subjects (5 atopic and 5 nonatopic). Test results indicate that the patient has type I hypersensitivity to raw green bean antigen(s). This case is of interest because it demonstrates that a food allergen, when inhaled, can induce respiratory symptoms in sensitized patients and may even be the source of primary sensitization.

Housewives with raw potato-induced bronchial asthma.

Allergy to white potato has rarely been described. We report two cases of atopic patients, housewives, in whom peeling raw potatoes precipitated rhinoconjunctivitis and asthmatic attacks, and, in one of them, contact urticaria. Type I hypersensitivity to raw potato antigens was demonstrated by means of immediate skin test reactivity, specific IgE determination by RAST, basophil degranulation, histamine release test and an immediate bronchial provocation test response to raw potato extract. The controls did not react to any of these tests. Potato allergenic constituent is currently being investigated but, as far as we know, it is heat-labile and has an MW of more than 10 Kd.