Skin manifestations and immunological parameters in childhood food allergy.

According to Hansen's contact rule, the digestive system should be considered as the main shock organ, yet in food allergy, this is not the case. Very often specific food triggers clinical manifestations not involving the digestive system; that is, reactions are manifested either in the respiratory system, as asthma or rhinitis, or in the skin. In these cases the BALT (broncho-alveolar lymphoid tissue) and GALT (gastrointestinal lymphoid tissue) units play a basic role in the sensitizations. The purpose of this study was to determine the most frequent skin manifestations of food allergy among children, and the most frequently involved foods. We also thought it interesting to evaluate the diagnostic reliability of the different standard immunological parameters utilized by the study team in food allergy. All patients underwent intracutaneous tests with 12 groups of the most frequent food allergens, as well as serum IgE, antigen-specific IgE against foods, and antigen-specific histamine release tests. Antigen-specific IgG4 determination was performed in some cases. The results obtained confirmed previous studies, the most common manifestations being: angioedema (48%), followed by urticaria (31%) and atopic dermatitis (21%). Regarding the frequency of sensitization to different food allergens, in mono- or polisensitization, fish and egg stand out in our environment. Certain food allergens are more frequently responsible for specific skin manifestations. Thus, for fish sensitization, the most frequent skin manifestation is atopic dermatitis (50%); for egg sensitization, angioedema is the most frequent skin manifestation (50%); and for milk, urticaria (50%). Finally, and in agreement with previous works regarding the diagnostic reliability of in vitro techniques, we found that the histamine release test offered the highest percentage of diagnostic reliability. Only for sensitization to milk proteins did antigen-specific IgE demonstrate higher reliability. Once again, we stress that our main problem is the lower reliability of skin tests against food allergens than against inhalant allergens. We emphasize the importance of food as a major factor in the etiopathogenesis of atopic dermatitis, as well as the need to complement the study, when possible, by means of the in vitro techniques described.

Effect of aspirin on beta-receptors in lymphocytes from patients with aspirin-induced asthma.

We studied the effect of aspirin on beta-adrenergic receptors in lymphocytes from three groups of subjects: 5 asthmatic patients presenting sensitivity to aspirin, 10 asthmatic patients with tolerance to aspirin and a control group. Lymphocytes were incubated with aspirin-lysine (36 micrograms/ml). The number of beta-receptors/cell and the dissociation constants (Kd) were assessed by means of [125I]-cyanopindolol (ICYP). There was a decrease in the number of beta-receptors after incubation with aspirin in all asthmatic patients with sensitivity. The differences between mean basal (660 +/- 171 receptors/cell) and postincubation (398 +/- 110 receptors/cell) values were significant (p < 0.05). There were also significant differences (p < 0.01) between basal (23.4 +/- 6 pM) and postincubation (15 +/- 5.1 pM) Kd values, which indicates that the affinity of ICYP increased. In the subjects in the other two groups, aspirin both increased and decreased the number of beta-receptors, but the effects were not significant. It is suggested that in patients with sensitivity, aspirin could induce changes in the plasmatic membrane, thus altering beta-receptors or inducing the release of inflammatory mediators that exert their effect upon these receptors.

Furosemide inhibits in vitro histamine release induced by antigens and anti-IgE.

We used 56 samples of heparinized blood of patients with asthma and/or allergic rhinitis, which were stimulated with Dermatophagoides pteronyssinus or gramineous pollen and anti-IgE in order to study the effect of furosemide on histamine release in basophils. At the same time, blood samples incubated in furosemide in different concentrations (2.5 microM to 1.49 mM) were also subjected to the same stimuli. Results showed a linear and dose-dependent inhibition of histamine release for antigens (r = 0.96; p < 0.01) and anti-IgE (r = 0.95; p < 0.05), reaching 95% at maximum inhibition. These results support the hypothesis that furosemide may act on mastocytes and basophils, thus inhibiting the release of histamine and other mediators.

Variations of intracellular histamine basophil levels after treatment with ketotifen.

As reported in previous studies, ketotifen modifies the number of basophils in peripheral blood, most likely inhibiting their degranulation, which correlates with the lack of exercise-induced respiratory manifestations. In this study, we attempted to measure the approximate amount of intracellular histamine in patients with bronchial asthma sensitized to Dermatophagoides pteronyssinus when they were treated with ketotifen, and compare the values with those of an untreated group and a control group, in order to determine if ketotifen stabilizes the cellular membrane, with the subsequent increase of intracellular mediators. We found that untreated patients had 57% less histamine per basophil than the control group, while treated patients had only 17% less than the controls. This shows that ketotifen acts as a membrane stabilizer, thus inhibiting degranulation and increasing the amount of intracellular mediators.

Food allergy as a cause of rhinitis and/or asthma.

We studied the histories of patients who had visited our Department during the last 5 years, presenting food allergy with exclusively respiratory symptoms (18.5%). We studied the correlation between IgE levels and the histamine release test and the type of food implicated. Seventy-seven percent of patients presented sensitization to one food, and 23% presented polysensitization. We found that foods such as snails and eggs have a strong predilection for the bronchial tree as the shock organ. High total IgE was found in 85.2% of patients. The histamine release test was positive in 66% of cases. We conclude that this is a highly sensitive method for the in vitro diagnosis of food allergy.

In vitro ketotifen protection in bronchial hyperreactivity.

There are drugs, such as ketotifen, that inhibit bronchospasm through different mechanisms. In this study, we looked at the changes in the number of sanguineous cells that ketotifen produces, especially in basophil cells, that could explain its prophylactic effects in bronchial hyperreactivity disclosed by exercise, as well as its relation to the variations in basal and total histamine in blood. 22 patients were selected, with a diagnosis of extrinsic bronchial asthma with sensitization against Dermatophagoides, and were compared to a control group. They all underwent an exercise test. Blood samples were taken before and after exercise in order to measure the number of leukocytes and the changes in basal and total histamine. We found that the number of basophils does not increase after exercise in untreated patients, while it does in the control group and in treated patients. This implies that ketotifen stabilizes the basophil cells, hindering their degranulation and the subsequent liberation of mediators that would produce bronchospasm after exercise.

A sporadic case of Wiskott-Aldrich syndrome.

We present a sporadic case of Wiskott-Aldrich syndrome, with no possibility of complete correction through bone marrow transplant, because no histocompatible donor could be found. The findings obtained in the immunopathological study performed are presented, in the attempt of correlating them with some clinical manifestations and with the aim of starting symptomatic treatment of the same.

Food allergy to Helix terrestre (snail).

Among the rare foods capable of producing food allergies is the snail (Helix terrestre). The snail is a delicacy eaten in Spain, France and Portugal. This study presents the findings of an allergic study of 10 patients with this infrequent food allergy during the past 10 years. The shock organ in the majority (80%) of these patients was the bronchial tree. Six of them did not have any digestive or skin symptoms which are usually seen in cases of food allergy. All patients manifested the symptomatology after ingestion of Helix terrestre. Two also had reactions after eating Patella vulgata (limpet). The snail and the limpet are within the phylogenetic line of molluscs, i.e. of gastropods. All patients tolerated the ingestion of cephalopods and bivalves which belong to two other phylogenetic lines. Skin tests to seafoods (squids, prawns, lobsters and clams) were negative for all patients. This suggests that the sensitizing antigen is probably a protein found only in gastropod molluscs. Skin tests along with the histamine release test were valid diagnostic methods for this food allergy. The limited bibliography on this subject is probably due to the fact that the consumption of snails as well as limpets is limited to specific geographical areas.

A rare case of food allergy: monosensitivity to kiwi (Actinidia chinensis).

We present a case of hypersensitivity to kiwi in a 26 year-old patient with no previous atopic history. The first reaction episode occurred a few minutes after kiwi ingestion, presenting with a localized pruritic reaction. This symptomatology repeated itself a few months later, again immediately after eating kiwi and was accompanied by dysphagia, vomiting and urticaria. In the complementary laboratory analyses a total IgE of 187 IU/ml was appreciated. The skin test to inhalant and food antigens were negative, while the kiwi extract produced a + + + + reaction. The histamine release test was positive (20%). Specific IgE levels (Kallestad) demonstrated results of 0.35 AEU/ml (class I). Specific IgG4 levels were normal and the hemagglutination test was negative. With the above results, we concluded that we were dealing with a case of monosensitivity to kiwi which was probably IgE mediated.