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Notes: Sesame seed and sesame seed oil have been thought of as rare causes of food allergy, representing less than 1% of all food allergy cases. We now report nine cases of IgE-dependent allergy to sesame seed and/or sesame seed oil, six of which were diagnosed in 1995 alone. Our skin test results draw attention to the poor quality of a commercial sesame seed extract and the good sensitivity of skin prick tests made with a freshly prepared sesame seed flour extract. The diagnosis of this food allergy was established by double-blind oral provocation tests, with doses of sesame seed flour ranging from 100 mg to 10 g. Allergy to sesame seed oil was also demonstrated in some cases. The sensitivity of the Pharmacia Phadebas CAP System for the detection of sesame seed-specific IgE was only mediocre. We draw attention to the important use of sesame seed in modern cooking, a fact which may explain the growing frequency of this allergy. We underline the particular risk with sesame seed oil. Sesame seed should also be considered a cause of allergic reactions to drug products and cosmetics.

Notes: The aims of this work were to investigate, in children and adolescents, the clinical aspects of food hypersensitivity and the distribution of allergens, in a prospective and descriptive study. Five hundred and forty-four pediatric cases from a series of 703 patients with food allergies, confirmed by food challenge, were studied. Their clinical characteristics and the distribution according to allergen were investigated. There was a family history of atopic disease in 70.5% of patients. Atopic dermatitis was the main symptom (275/544; 50.5% of patients), followed by urticaria and angio-edema (165/544; 30%). There was asthma in 8.6% of patients (47 children) and anaphylaxis in 4.5% (27 patients). The rarest signs were rhinitis (n=2; 0.3%), oral allergy syndrome (n=8; 1.4%), and gastrointestinal signs (n=11; 2%). Five allergens accounted for 78% of food hypersensitivity. These allergens were: eggs (36%), peanuts (24%), cow’s milk (8%), mustard (6%), and cod (4%). Peanut was the most common allergen for children over the age of 3 yr. In this selected population, sensitivity of individuals to more than three foods was unusual (5%). Atopic dermatitis was the main symptom of food allergy in children. The symptoms changed over time, with respiratory disorders, oral allergy syndrome and ocular problems occuring later. Anaphylaxis also occured mostly in older children. Five allergens were responsible for more than three-quarters of food allergies in children. However, the number of allergens implicated was higher for the group of children over the age of 6 yr than for younger children.

Notes: Background Nasal polyps are characterized by a proliferation of the epithelial layer of the mucosa. cellular infiltrates and other pathological changes; however the mechanisms involved in polyp pathogenesis remain largely unclear.Objectives We have taken two different approaches to study the cellular events involved in nasal polyposis.Methods First, through use of immunohistochemical methods, we have studied the expression of HLA class II antigens in epithelial cells of nasal polyps and the distribution of lymphocytes in the epithelium and in the subepithelial layer in patients with clinical conditions, such as asthma, atopy, aspirin intolerance or cystic fibrosis, and in subjects with an absence of concomitant diseases. Second, in order to investigate whether HLA class II expression is controlled at the pre- or post-transcriptional level, we studied the effect of interferon gamma (INFγ) on epithelial cells in primary culture, which were derived from HLA class II negative and HLA class II positive nasal polyps. Total RNA was extracted from the cells and reverse-transcribed, and the c-DNA corresponding to DR, DP, DQ loci was amplified by PCRResults Expression of HLA class II antigens by the epithelia of nasal polyps was more common in the presence rather than in the absence of concomitant asthma, atopy or cystic fibrosis (59% versus 409%). HLA-DR was the only HLA class II antigen expressed in the seven polyps taken from cystic fibrosis patients. The number of CD8+ cells was significantly higher in polyps associated with known clinical conditions and HLA class II antigen expression than it was in ‘isolated’ polyps and in HLA class II negative polyps. RNA transcripts for at least one or all three HLA-DR, DP and DQ antigens were detected in 10 cultures of the 11 HLA class II positive polyps. Conversely, 8 of 10 cultures derived from HLA class II negative polyps did not express HLA class II transcripts in the absence of INFγ. Adding INFγ (100U/ml) to the latter cell cultures caused expression of transcripts of one or more HLA class II genes.Conclusions We have shown that HLA class II antigens were more frequently detected in polyps of patients with an identified clinical syndrome than in those of asymptomatic subjects. Our results also suggest that IFN γ regulates expression of HLA class II antigens in airway epithelial cells of the nasal polyps at the transcriptional level, and that cultured cells from nasal polyps represent a suitable modei to investigate immune mechanisms involved in diseases such as atopy, asthma and cystic fibrosis.

Notes: Background Hypersensitivity to sesume seeds is becoming increasingly frequent, probably owing to the larger use of this compound in international food.Objectives This study investigated serum responses of 12 sesame sensitized patients (seven with food allergy, five with food sensitization), to a sesame protein extract, and attempted at identifying sesame major antigens.Methods Sesame protein extracts were prepared from black, white and brown sesame seeds. Electrophoretic analysis showed similar protein patterns in the three extracts, and proper preservation of the proteins integrity. The brown sesame extract was used to set-up an ELISA assay and measure serum levels of antisesame IgG, IgA, IgM and IgE in 12 samples from sesame-sensitized individuals and six controls. It also allowed to perform western blot analyses in order to investigate the molecular weight of sesame proteins recognized by IgG, IgA and IgE.Results Nineteen protein bands were observed upon polyacrylamide gel electrophoresis of the sesame protein extracts. Using this whole extract in ELISA, significant antisesame IgG. IgA and IgE-responses were observed in the serum of sensitized individuals, different from the lower signals obtained with control samples. Western blot analysis demonstrated highly polymorphic IgG and IgA responses and a more restricted IgE response pattern, suggesting that two proteins, respectively. 14kDa and 25 kDa are mostly involved in sesame IgE-dependent hypersensitivity, the 25 kDa band presenting several characteristics of a major allergen.Conclusions This study reports novel information on the possible involvement of a 25 kDa sesame protein in IgE-dependent hypersensitivity to sesame seeds.

Notes: An egg protein, lysozyme, is a still unlabeled additive currently used in cheese preparation. Furthermore, the WHO-FAO committee considers it innocuous. However, 31% of children and 8% of adults with food allergies are allergic to eggs. This work aimed to determine the percentage of patients sensitized to lysozyme from a population of egg-allergic patients. Specific IgE was determined with Cap RAST in 52 patients clinically allergic to egg. Thirty-five percent of egg-allergic patients had antilysozyme IgE. Given this high incidence of lysosozyme sensitization, it seems that the presence of lysozyme should be indicated on food labels.

Notes: Histamine in food may be responsible for some cases of food intolerance. We previously demonstrated disturbances in the metabolism of ingested histamine in patients with chronic urticaria (CU) and proposed that this could be related to increased intestinal permeability to histamine. The present study was undertaken to look for ultrastructural changes in the intestinal tract that might explain this abnormality. We examined duodenal biopsies from seven patients with CU before and after intraduodenal administration of histamine (120 mg). Five subjects had clinical symptoms (diarrhea, urticaria, headache, accelerated heart rate. and drop in blood pressure) within 1 h of duodenal histamine challenge (DHC). Ultrastructural changes. including edema of the interstitial tissue, enlargement of the basal intercellular spaces, slight congestion of the endothelial cells, and pericapillary edema, were observed in six subjects 45 min after DHC. In all the biopsies, the epithelium was normal, and the tight junctions were not modified by DHC. This morphologic study demonstrates that histamine can induce edema in the basal intercellular spaces of the duodenal mucosa and in the submucosa without evident change in the integrity of intercellular junctions. The most plausible route for histamine to have taken would appear to be an intracellular one.