Meeyong Shin

The Influence of the Time and Temperature of Heat Treatment on the Allergenicity of Egg White Proteins

Purpose The present study was performed to determine the factor, either duration or the temperature of heat treatment, exerting maximal and significant influence on the composition and allergenicity of egg white (EW) proteins. Methods Raw EW and 4 kinds of heated EW (fried EW, boiled EW for 10 minutes, boiled EW for 30 minutes, and baked EW for 20 minutes at 170℃) were prepared, and subsequently protein extraction was carried out. The proteins were separated by SDS-PAGE, and then immunoglobulin E (IgE) immunoblots were performed with the sera of 7 egg-allergic patients. Furthermore, the antigenic activities of ovalbumin (OVA), ovomucoid (OM), and ovotransferrin (OT) in different EW samples were measured by inhibition enzyme-linked Immuno-sorbent assay (ELISA). Results In SDS-PAGE analysis, the intensity of the protein band at 45 kD (corresponding to OVA) decreased significantly in boiled EW (30 minutes) and baked EW, but no change was observed in the case of boiled EW for 10 minutes. In IgE immunoblots, the IgE response to 34-50 kD (OM and OVA) in boiled EW for 30 minutes decreased significantly, when compared with raw EW and other heated EWs. In inhibition ELISA, a significant decrease in the OVA antigenic activity was observed in boiled EW for 30 minutes amongst other heated EW samples. However, OM antigenic activity in all kinds of heated EW including boiled EW for 30 minutes did not reduce after heat treatment. The OT antigenic activity nearly disappeared in heated EWs except in the case of boiled EW for 10 minutes. Conclusions Amongst 4 kinds of heated EWs, the boiled EW for 30 minutes showed the most significant changes both in composition and reduction in allergenicity. Our results revealed that the duration of heat treatment had more influence on the composition and allergenicity of EW proteins than the temperature.

The Influence of the Presence of Wheat Flour on the Antigenic Activities of Egg White Proteins

Purpose It is known that ovomucoid, an egg allergen, is heat resistant and remains soluble after heating. However, a recent study showed that the antigenic activity of ovomucoid could be reduced by heating when egg white (EW) was mixed with wheat flour. This study was performed to determine the influence of wheat flour on the antigenic activities of EW proteins when EW is heated, and the influence of the duration of heat treatment. Methods A mixture of EW and wheat flour was kneaded for 10 minutes and then baked at 180℃ for 10 minutes and 30 minutes. The EW without wheat flour was also heated at 180℃ for 10 minutes and 30 minutes. The proteins were separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), and IgE immunoblotting was performed with the pooled sera of 5 egg-allergic patients. The antigenic activities of ovomucoid in different EW samples were measured by inhibition enzyme-linked immunosorbent assay (ELISA). Results 1) SDS-PAGE: the intensity of the 37-50 kD bands (overlapped bands of ovomucoid and ovalbumin) decreased significantly in the mixture of EW and wheat flour baked for 30 minutes, compared with the mixture baked for 10 minutes, heated EW and raw EW. 2) IgE immunoblot: in the mixture of EW and wheat, a remarkable decrease of IgE reactivity to 37-50 kD was observed when baked for 30 minutes. 3) Inhibition ELISA: the antigenic activity of ovomucoid decreased significantly in the mixture of EW and wheat baked for 30 minutes, but not in the heated pure EW. Conclusions This study showed that the antigenic activity of ovomucoid can be reduced by baking EW with wheat flour. The decrease in ovomucoid antigenicity in the baked mixture of EW and wheat flour was dependent on the time of heat treatment, indicating that heating should be prolonged to achieve a reduction in ovomucoid antigenic activity.

Special consideration is required for the component-resolved diagnosis of egg allergy in infants.

BACKGROUND There are few reports regarding differences in reactivity to the major egg allergens according to childrens age, although component-resolved diagnosis is gradually being used. OBJECTIVE To investigate differences in reactivity to major egg allergens among various age groups of children with egg allergy. METHODS Twenty-seven patients diagnosed with egg allergy were included. Egg allergy was defined as a convincing history of reproducible symptoms within 2 hours of egg consumption and an egg white-specific IgE level of at least 0.35 kUA/L. Patients were divided into 3 age groups: younger than 12 months (group A, 7 subjects), 12 to 23 months (group B, 8 subjects), and at least 24 months (group C, 12 subjects). Immunoblotting and enzyme-linked immunosorbent assay investigated IgE reactivity toward ovalbumin, ovomucoid, and ovotransferrin in eggs. RESULTS Immunoblotting analysis showed that all patients in group A reacted to ovalbumin, whereas reactions to other proteins were not detected. All patients in group B displayed a reaction to ovalbumin and ovomucoid. IgE binding to ovotransferrin was shown in 3 patients in group B. All patients in group C displayed reactivity to ovalbumin, 5 patients showed a reaction to ovomucoid, and 8 patients displayed a reaction to ovotransferrin. As a patients age increased, specific IgE binding to ovalbumin and ovotransferrin increased (P = .011 and .004). CONCLUSION IgE reactivity to egg allergens differs according to childrens ages.

Prevalence and Causes of Childhood Urticaria

http://e-aair.org 189 Urticaria is one of the most common skin disease, characterized by the development of wheals (hives), angioedema, or both and it is classified as acute or chronic form based on the duration of illness. Urticaria of longer than 6 weeks duration is classified as chronic urticaria, which is further classified into chronic spontaneous or inducible urticaria. Acute urticaria is more prevalent than chronic urticaria; however, chronic urticaria has a more significant impact on quality of life due to recurrence and unknown etiology. As in adults, the causes are different between acute and chronic urticaria in children, and it is difficult to determine the exact prevalence of childhood urticaria due to lack of papulation-based studies. Common causes or triggers of acute urticaria in children include infections, medications, and foods, while acute spontaneous urticaria is common in young children with atopy. Infection appears to be a more frequent predisposing cause of urticaria in infants and children compared with adults. Infection is the most frequently documented cause (more than 40%) in children with acute urticaria. In a recent systematic review, viral infection was a potential trigger and sometimes the main cause in acute and chronic urticaria. The rate of identification of a specific cause in children with chronic urticaria varies from 20%-50%, but in practice, most patients have no precise causes and are classified as chronic idiopathic urticaria. The underlying causes of chronic spontaneous urticaria do not appear to be different between children and adults; however, their frequencies are different. In recent studies, more than 30% of children with chronic urticaria are classified as chronic autoimmune urticaria. Even though the prevalence is lower in children than in adults, nonsteroidal anti-inflammatory drugs are identified as major aggravating factors of chronic spontaneous urticaria in children. In the very recent studies of adults with chronic urticaria, serum vitamin D levels were likely to be lower and showed significant negative associations with urticaria activity score and duration. Furthermore, several studies have proposed that vitamin D plays a beneficial role in the treatment of adult chronic urticaria; however, the role of vitamin D is still controversial and it is unclear in children with chronic urticaria. Disease activity in spontaneous urticaria usually assessed with the urticaria activity score (UAS) for 7 days , and the recently provided guideline of chronic urticaria recommends use of the UAS for evaluating severity and guiding management. The UAS is based on the assessment of key urticaria symptoms (wheals and pruritus), and it is useful for assessing the urticaria activity by both patients and their physicians. In a previous study, it is estimated that up to 15%-25% of adults experience at least 1 episode of acute urticaria during their life time. A recent population-based questionnaire survey showed that the lifetime prevalence rate of urticaria in adults was 8.8% for all types of urticaria, whereas the prevalence of chronic urticaria in the general population has been estimated to range from 0.5% to 5%. Chronic urticaria in children is expected to be less common than in adults; however, the exact prevalence is unknown because reliable epidemiologic studies are scarce in children with chronic urticaria. In a recent population-based German birth cohort study, the incidence and cumulative prevalence of urticaria in infants and children were reported. The incidence of urticaria was approximately 1% per year of age and the cumulative prevalence of urticaria in children at the age of 10 years was 14.5% for boys and 16.2% for girls, but the prevalence of chronic urticaria was not evaluated separately. In the current issue of the Allergy, Asthma and Immunology Research, Lee et al. reported a valuable study on the prevalence and risk factors of acute and chronic urticaria in Korean children, and it is the first population-based epidemiological study to estimate the prevalence of chronic urticaria in children. This cross-sectional study examined children from the general pediPrevalence and Causes of Childhood Urticaria Meeyong Shin, Sooyoung Lee*

A Case of Hereditary Angioedema in a 7-Year-Old Korean Girl

Hereditary angioedema (HAE) is a rare autosomal dominant disease that usually occurs in adolescence and early adulthood. It is characterized by recurrent non-pitting edema involving the skin and intestinal tract, especially the extremities and face. It is not associated with urticaria and pruritus. The cause is known to be the deficiency of C1 inhibitor. We herein report a 7-year-old girl with HAE who had recurrent episodes of swelling of the extremities and face without urticaria and pruritus. Her great grandmother had suffered from the same symptoms. The level of serum C4 was 8.01 mg/dL (normal: 10-40 mg/dL). The level of C1 inhibitor was 5.0 mg/dL (normal: 18-40 mg/dL). To our knowledge, this is the first pediatric case with typical clinical symptoms of HAE and C1 esterase inhibitor deficiency in Korea.