The diagnostic value of crude or boiled extracts to identify tolerant versus nontolerant lentil-sensitive children

OBJECTIVE

The aim of this study was to compare two types of lentil extracts for use in skin prick tests for the diagnosis of lentil clinical allergy.

METHODS

Thirty-six patients with a history of allergic reactions after the ingestion of lentils were skin tested with two types of lentil extracts at 0.05, 0.5, 5, and 10 mg/mL. Both extracts were extracted at 40 degrees C and afterward, one of them was boiled for 15 minutes. Thirty-three of these patients underwent oral challenges with lentils and three had a convincing recent history of lentil anaphylaxis.

RESULTS

Twenty patients had a positive oral challenge; 13 were negative. Skin prick tests performed with the boiled extract at 0.5 and 5 mg/mL were positive in 96% and 100% of patients with positive food challenge, and in 31% and 85% of those with negative food challenge, respectively; positive skin test results were similar in both groups using the crude extract. Mean wheal sizes using the boiled extract at 0.5, 5, and 10 mg/mL were significantly greater in patients with a positive oral challenge than in those with a negative one (4.9, 6.8, and 7.4 mm versus 1.9, 3.5, and 5.1 mm, respectively; P < 0.05) These mean values were not statistically different using the crude extract.

CONCLUSIONS

These data suggest that lentil extracts for the diagnosis of lentil hypersensitivity should be heated, since boiled extracts, used at a concentration of 0.5 or 5 mg/mL, best identify clinically sensitive individuals.

Hypersensitivity to members of the botanical order Fabales (legumes)

Legumes are an important source of proteins and their consumption is very frequent in the Mediterranean region and in some Asian and African countries. In some of these regions, lentils and chickpeas are one of the main food allergens. Legumes are also used as food additives due to their emulsifying properties and can be present in many manufactured foods. These hidden food allergens have the potential of causing adverse reactions in legume-sensitive subjects. The allergenic composition of various legumes has been investigated. They have been found to contain multiple allergens, a few of which have been cloned and sequenced. Legumes contain acid-resistant and thermostable allergens. There is a significant degree of cross-reactivity among legumes, the clinical relevance of which seems to be dependent on the dietary habits in different communities. In Spain, the consumption of several legumes is frequent and, therefore, clinical allergy to more than one species in children is common. Clinical manifestations include cutaneous, digestive and respiratory symptoms. Legumes can cause life-threatening reactions in sensitized individuals. Inhalation of steam, powder or flour from some legumes may cause respiratory diseases such as rhinitis, asthma and hypersensitivity pneumonitis. Soybean allergy is generally transitory, but clinical allergy to peanuts is rarely outgrown. The natural history of other legume allergies is less known and more studies are necessary to reach definite conclusions.

Specific IgE levels to Cicer arietinum (Chick pea) in tolerant and nontolerant children: evaluation of boiled and raw extracts

The chick pea, Cicer arietinum, is a legume commonly consumed in Spain and other Mediterranean countries. The sera of 29 children (mean age: 8.4 years) with a current or past history of allergic reactions after ingestion of chick pea, and positive skin tests to this legume, were used to study the allergenic composition of raw and boiled chick pea extracts. The patient population was divided into 2 groups: group 1 consisted of 19 patients with clinical sensitivity confirmed by either positive oral challenges or a convincing recent history of anaphylaxis after eating chick peas, and group 2 consisted of 10 patients with clinical sensitivity in the past, but tolerant at the time of blood extraction. Six atopic children, not allergic to legumes, were included as controls. Specific IgE to the raw and boiled extracts was measured by ELISA. The allergenic composition of both extracts was analyzed by SDS-PAGE and immunoblots. There were no significant differences between specific IgE levels to the raw and boiled extracts (p = 0.23). The mean levels in group 1 were significantly higher than in group 2 and controls (p = 0.0001). Multiple IgE binding proteins/peptides were detected in both extracts in the molecular weight range of 10-106 kD. Only nontolerant patients recognized a similar number of bands in both extracts. Chick pea extracts contain a majority of heat-stable allergens, which could be responsible for the clinical sensitivity to chick pea. Patients with a current clinical allergy to chick pea have statistically higher specific IgE levels than tolerant patients and controls.

[Sensitization to paprika: anaphylaxis after intake and rhinoconjunctivitis after contact through airways]

naphylaxis after the intake of paprika and with rhinoconjunctivitis symptoms related to her current occupation, as spices-and-condiment seller, induced the patient to attend to a medical consult. The patient tolerated another solanaceous in her diet. The study was based on skin test using own extracts of different solanaceous, both at room temperature and after warming them up. Skin test with prick-by-prick test were also carried out with fresh solanaceous. All skin tests showed a positive result. The study was completed with conjunctival challenge-test using all the different extracts (positive result with paprika) and use-test with fresh solanaceous (positive result with paprika). In laboratory study, specific IgE was detected to all the solanaceous, as well as histamine release-test positive. Crossed-reactivity between the paprika antigenic determinant recognized by the patient and the one presented by the rest of solanaceous could not be detected using RAST-inhibition studies. This results and the good tolerance of other solanaceous in diet could show that the paprika's antigenic determinant, what induced allergic symptoms in the patient, was not present in the rest of solanaceous.

[Detection of IgE specific for egg yolk by enzyme immunoassay. Description of a case]

Food allergy is a common disease in our country, especially affecting atopic children. Egg-white hypersensitivity is frequently found in these patients. However, egg-yolk hypersensitivity is not usually reported in patients with egg allergy. This article describes a young patient with egg-yolk hypersensitivity, a 12 year old female patient with a medical history of contact urticaria, angioedema and severe acute bronchospasm shortly after the intake of small amounts of egg-yolk. All these episodes required treatment in emergency care units because of the severity of the symptoms. The patient did not describe any other food hypersensitivity and remained symptom-free after the intake of boiled or fried egg-white. She had clinical symptoms of grass pollen hypersensitivity and was therefore on specific immunotherapy at the time of the study. The skin prick-tests were positive to grass pollen and egg-yolk and were negative to mites, moulds, animal dander and to the common food tested (milk, fish, peanut, almond and hazel-nut). Total serum IgE was 1.160 UL/ml. The patient had a positive RAST to egg-white (0.0 PRU/ml) as well as to egg-yolk (8.6 PRU/ml). Furthermore, an indirect enzyme immunoassay as well as a reverse enzyme immunoassay also revealed the presence of specific IgE antibodies. The reverse enzyme immunoassay uses microtiter plates as a solid surface. These plates are coated with a monospecific antihuman IgE antibody. Thereafter, the serum samples are incubated overnight in the wells. After several washings, the presence of specific antibodies is revealed by means of a peroxidase conjugated allergen.(ABSTRACT TRUNCATED AT 250 WORDS)