Kazue Yamada

Allergenic activity of heated and ovomucoid-depleted egg white.

BACKGROUND No egg white products have been clearly proven to be hypoallergenic. The role of egg white proteins in allergic reactions to eggs is still debatable. OBJECTIVE This study was designed to determine the importance of ovomucoid, an egg white protein, in the development of allergies to egg white. METHODS We performed a double-blind, placebo-controlled food challenge in subjects with high levels of IgE antibodies for egg white to compare the allergenicities of heated and ovomucoid-depleted egg white, freeze-dried egg white, and heated egg white. Levels of IgE antibodies for egg white, ovomucoid, ovalbumin, ovotransferrin, and lysozyme were measured in serum by RAST. RESULTS Twenty-one of 38 subjects with positive challenge responses to freeze-dried egg white had negative challenge responses to heated egg white, whereas 16 of 17 subjects (94.1%) with positive responses to heated egg white did not respond to the heated and ovomucoid-depleted egg white challenge. The subjects with positive challenge responses to freeze-dried egg white tended to have higher IgE antibody values to ovomucoid than those with negative responses. IgE antibody levels to ovomucoid were significantly higher in subjects with positive responses to a challenge with heated egg white than in those with no response. There were no significant differences in the levels of IgE antibodies to the other proteins, except ovomucoid, in the negative-response and positive-response groups in challenge tests with freeze-dried and heated egg white. CONCLUSION The heated and ovomucoid-depleted egg white preparation was less allergenic than heated or freeze-dried preparations. Ovomucoid has a more important role in the pathogenesis of allergic reactions to egg white than other proteins in egg white.

16-Kilodalton Rice Protein Is One of the Major Allergens in Rice Grain Extract and Responsible for Cross-Allergenicity between Cereal Grains in the Poaceae Family

Cross-allergenicity between five cereal grains including rice, wheat, corn, Japanese millet (Panicum crus-galli L. var. frumentaceum Trin.) and Italian millet (Setaria italica Beauv. var. germanica schrad.) was examined by radioallergosorbent test (RAST) and RAST inhibition assay. There were significant close correlations between every combinations of RAST values for the five cereal grain extracts. RAST inhibition assay of each extract against RAST discs coupled with other cereal grain extracts indicated marked cross-reactivity of IgE binding between these cereal grain extracts. Rice protein 16KD (RP16KD) was shown to be one of major allergens in rice grain extracts by immunoblotting analysis, histamine release assay from human leukocytes and RAST inhibition. Next, the involvement of RP16KD in the cross-allergenicity between these cereals was investigated. RAST values for RP16KD significantly correlated with that for Italian millet as well as rice but not with those for corn and wheat. There was a trend of positive correlation between RAST values for RP16KD and Japanese millet. In the RAST inhibition assay using sera with positive RAST for these five cereal grain extracts and RP16KD, RP16KD inhibited IgE binding to these all cereal discs in a dose-dependent manner. Similarly, all of the five cereal grain extracts showed an effective decrease in IgE binding to the RP16KD disc. These results indicated possible participation of IgE binding structure on RP16KD in cross-allergenicity between these cereal grain extracts in the Poaceae family.

Effects of Oral Administration of Lactobacillus acidophilus L-92 on the Symptoms and Serum Markers of Atopic Dermatitis in Children

Background: Few studies have investigated the complementary effects of long-term oral administration of Lactobacillus acidophilus on traditional medical therapy in the treatment of patients with atopic dermatitis (AD). Methods: The Atopic Dermatitis Area and Severity Index was used to evaluate AD severity. Symptom severity was assessed using the symptom score. The effect of medical therapy was evaluated by adding the medication score, calculated as the sum of each product of the amount of steroid ointment used for therapy and its designated strength graded on a 4-point scale, to the symptom score. The complementary effect of long-term oral administration of L. acidophilus strain L-92 (L-92) as a probiotic or biogenic strain in patients with AD was evaluated using the symptom-medication score, which was calculated as the sum of the symptom score and medication score. Both a preliminary casuistic study and a double-blinded, placebo-controlled study were performed to evaluate the effects of L-92 on the symptoms of AD in children. Results: Orally administered L-92 significantly ameliorated the symptoms of AD in Japanese children. L-92 also affected the serum concentrations of thymus and activation-regulated chemokine in a time-dependent manner.Conclusions: The results of the preliminary trial and the double-blinded, placebo-controlled study revealed a complementary effect of oral L-92 on the standard medical therapy (topical application of a steroid ointment) in patients with AD that was mediated, at least in part, by alterations in the Th1/Th2 balance.

Clinical Significance of IgE–Binding Activity to Enzymatic Digests of Ovomucoid in the Diagnosis and the Prediction of the Outgrowing of Egg White Hypersensitivity

Background: We frequently encounter subjects without overt symptoms despite high IgE antibodies to egg white and its components. The measurements of these antibodies are not necessarily efficient for the diagnosis or the prediction of the outcome of egg allergy in children. Methods: Specific IgE antibodies to egg white and its components, including ovomucoid, ovalbumin, ovotransferrin and lysozyme, were measured by direct RAST assays. IgE–binding activity to ovomucoid degraded by pepsin, trypsin and chymotrypsin was examined by RAST inhibition. Thirty subjects were divided into two groups with positive (n=18; mean age ± SD = 42 ±25 months) and negative (n=12; mean age ± SD = 48 ±31 months) oral challenge tests with egg white antigens. The individuals with positive results to the first challenge tests were given the second provocation tests at mean intervals of 32 months. IgE–binding activity of the sera collected on the first challenge to these ovomucoid fragments was compared between subjects with positive and negative reactions to the follow–up challenge tests. Results: There were no significant differences in IgE antibody titers to egg white and its components between the positive and negative groups at the first and the second challenge tests. IgE–binding activity to ovomucoid digests after treatments with pepsin (p = 0.000008) and trypsin (p=0.037), except chymotrypsin (p=0.062), were significantly higher in subjects with positive challenge tests than in those with negative results. The difference was most remarkable in the IgE–binding to pepsin digests; the average concentrations (mean – SD and mean + SD) needed for 50% RAST inhibition in the positive group and in the negative group were 2.6 μg/ml (0.3 and 25) and 94.2 μg/ml (24.7 and 358.7), respectively. A significant difference was still observed in the inhibition tests using filtrates of pepsin digests with a membrane with MW 10,000 (p=0.014) and 3,000 (p=0.042) of cutoff. The concentration (mean= 0.8, mean – SD=0.2, mean + SD=3.4; μg/ml) of pepsin–treated ovomucoid required for 50% RAST inhibition in the subjects with positive second challenge results was significantly (p=0.033) lower than that (mean=6.8, mean–SD=0.6, mean + SD=73.9) of the negative group. Conclusion: IgE–binding activity to pepsin–digested ovomucoid was of diagnostic value to distinguish the challenge–positive subjects from the negative subjects. Subjects with high IgE–binding activity to pepsin–treated ovomucoid are unlikely to outgrow egg white allergy.

A case retaining contact urticaria against egg white after gaining tolerance to ingestion

A girl, 5.7 years old, gained tolerance to egg white ingestion in spite of high immunoglobulin E (IgE) antibody titers to egg white but retained contact urticaria against egg white. She developed atopic dermatitis on her face at 2 months of age and showed high IgE antibody titers to egg white and cows milk. Accidental ingestion of egg products initiated immediate symptoms such as wheezing, urticaria, erythema and edema of the eyelids and conjunctiva three times. These symptoms were confirmed by challenge tests using boiled egg white at 3.9 years of age. She also reacted positively to a 20 min patch test on her volar arm with raw egg white. However, there were no reactions to the oral challenge test by boiled egg and freeze‐dried egg white at 5.1 and 5.7 years of age, respectively. This non‐responsiveness was confirmed by a double‐blind, placebo‐controlled food challenge using freeze‐dried egg white. Nevertheless, she showed positive reactions to a 20 min patch test with freeze‐dried egg white. Her IgE antibody titers to the egg white components including ovomucoid, ovalbumin, ovotransferrin and lysozyme as well as egg white were high from 2.9 to 5.7 years old. Her IgE antibody titers for the ovomucoid fragments digested by pepsin, chymotrypsin and trypsin were not lower than those of positive control subjects. The binding activity of IgE antibody to ovomucoid, however, decreased from 2.9 to 5.6 years as shown by radioallergosorbent test (RAST) inhibition assays. The IgE antibody showed weaker binding activity to pepsin‐ and chymotrypsin‐digested ovomucoid that were filtered through cut‐off 10 000 filter at the age of 2.1 and 5.7 years. We speculated that the maturation of secretion of digestive enzymes was involved in the mechanisms of the acquisition of tolerance to egg white ingestion in spite of the persistence of contact urticaria.