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High Failure Rate during Oral Food Challenge to Baked Milk in Children with High Serum Cow's Milk (CM)-Specific IgE Antibody Level
Abstracts S247
J ALLERGY CLIN IMMUNOL VOLUME 121, NUMBER 2
Reliability of Food-Specific Serum IgE Values in Determining Negative Outcomes in Oral Food Challenges J. Johnson1, J. Cronin1,2, M. B. Morales1,2, A. D. Hogan2,1; 1Eastern Virginia Medical School, Norfolk, VA, 2Children’s Hospital of the King’s Daughters, Norfolk, VA. RATIONALE: The purpose of this study was to determine whether low Immuno capRAST values can predict negative food challenges. METHODS: A retrospective chart review was conducted for all patients who underwent oral food challenges (OFC) between January 2003 and April 2007. Statistical analyses included descriptive statistics and frequencies and Mann-Whitney U test using SPSS 15.0. RESULTS: 202 patients underwent 268 challenges to multiple foods; 60% were male, 68% Caucasian, and the median age was 3.6 years. Patients demonstrated atopy, including atopic dermatitis (70%), allergic rhinitis (83%), and asthma (49%). 32% (n 5 86) demonstrated significant allergic symptoms, resulting in a positive food challenge. Positive challenges for patients with negative CAP-RAST values, ( 0.35 kilo units of allergen per liter (kUA/L)), were 32% (n 5 6/19) for milk, 23% (n 5 5/22) for egg, and 17% (n 5 5/29) for peanut. For values between 0.35 and 2 kUA/L, positive challenges occurred in 30% for milk (n 5 8/27), 43% for egg (n 5 12/28) and 47% for peanut (n 5 15/32). For CAP-RAST values between 0.35 kUA/L and 5 kUA/L, there were no statistically significant differences in median IgE values for positive and negative challenges for peanut (p 5 0.3) or egg (p 5 0.9). A statistical difference was observed for milk (p < 0.02). In failed challenges for egg, milk, and peanut, urticaria occurred in 86%, respiratory symptoms 15%, gastrointestinal symptoms 17% and cardiovascular symptoms in 1%. CONCLUSIONS: CAP-RAST levels < 0.35 kUA/L for egg, milk, and peanut do not correlate well with food challenge outcomes. Allergenspecific IgE values at low concentrations are not useful predictors of challenge outcomes.
953
High Failure Rate during Oral Food Challenge to Baked Milk in Children with High Serum Cow's Milk (CM)-Specific IgE Antibody Level A. H. Nowak-Wegrzyn, K. A. Bloom, S. H. Sicherer, W. G. Shreffler, H. A. Sampson; Mount Sinai School of Medicine, New York, NY. RATIONALE: We previously reported that the majority of milk-allergic children tolerate baked milk; however children reactive to baked milk may experience severe reactions. We sought to determine whether diagnostic parameters predictive of clinical reactivity to baked milk could be established. METHODS: Milk-allergic children underwent oral food challenges (OFCs) to extensively baked, and if asymptomatic, to regular milk. Serum CM-specific IgE antibody level (kUA/L) and skin prick test (SPT) wheal diameter [mm] to commercial cow’s milk extract were measured and correlated with the outcome of the OFC to baked milk. RESULTS: Ninety-six children, mean age: 8 years; range 3-17 underwent OFC. Sixty-five children (65%) passed only baked, 9 passed baked and regular, and 23 (25%) failed baked milk OFC. Among children with serum CM-IgE level <35 kUA/L, 72/89 (80.9%) passed baked milk, whereas among children with CM-IgE level 35 kUA/L only 1/7 (14.3%) passed baked milk OFC. Among children with SPT <14 mm, 71 of 87 (81.7%) passed baked milk, whereas among children with SPT 14 mm, 2/6 (33.3%) passed baked milk OFC. 9/23 (39.1%) of the reactions to baked milk OFC required treatment with epinephrine, as opposed to the reported rate of 7-11% systemic reactions with clinically indicated standard graded challenges. CONCLUSIONS: High failure rate during OFC to baked milk is associated with high serum CM-specific IgE antibody levels. We no longer offer OFC to baked milk to children with CM-IgE greater than 35 kUA/L. OFC to baked milk should be undertaken with caution in children, especially those with high CM-IgE antibody levels. Funding: NIH NIAID
954
Charasteristics of Sesame Seed Allergy and Sesame-Specific IgE test S. Goto1,2, Y. Takaoka2, M. Futamura2, M. Morishita3, T. Sakamoto1, K. Ito2; 1Nagoya University Graduate School of Medicine, Nagoya, JAPAN, 2Division of Allergology, Aichi Children’s Health and Medical Center, Obu, JAPAN, 3Department of Pediatrics, Tosei General Hospital, Seto, JAPAN. RATIONALE: The aim of this study is to determine the clinical characteristics of sesame allergy in children and the usefulness of the sesame-specific IgE test in diagnosing sesame seed allergy. METHODS: Medical charts of 128 subjects (male: female, 86:42; mean age, 3.47 years) aged 1 year, who had undergone sesame-specific IgE (ImmunoCAPÒ) test and for whom reliable medical records about an allergic reaction associated with sesame uptake were available, were retrospectively analyzed. Diagnosis of sesame allergy was made based on clinically convincing history after consumption of sesame, or a positive sesame challenge test. RESULTS: Sesame challenge test was performed in 22 cases, and failed challenge was observed in 8 cases. An additional 28 cases were diagnosed by convincing history. Skin symptoms were observed in 34 (94.4%) patients. Gastrointestinal (n 5 7), respiratory (n 5 5) and oral mucosal (n 5 3) symptoms were also observed. Based on diagnosis by IgE test, prevalence of allergic symptoms in patients with each IgE Class 2, 3, 4, 5 and 6 was 24.2%, 23.1%, 41.2%, 83.3% and 50.0%, respectively. Convincing allergic history was reported in 2 patients who were negative for sesame-specific IgE detection. In patients with positive sesame-specific IgE ( class 2), mean IgE titer of sesame allergic patients (11.72 kUa/L, n 5 34) was significantly higher than those without sesame allergy (5.60 kUa/L, n 5 78, p < 0.01). CONCLUSIONS: Sesame-specific IgE level was significantly associated with sesame allergy, but diagnostic specificity was not satisfactory, even in cases showing the highest levels of IgE titer. Funding: Ministry of Health, Labor and Welfare, Japan
955
Identification Of A New Brazil Nut Allergen - Ber e 2 K. Beyer1, L. Bardina2, G. Grishina2, A. Ashraf2, S. Teuber3, B. Niggemann1, H. A. Sampson2; 1Charite - Campus Virchow Klinikum, Berlin, GERMANY, 2Mount Sinai School of Medicine, New York, NY, 3 University of California, Davis, CA. RATIONALE: Allergic reactions to Brazil nut have been identified as one of the most common causes of tree nut allergies. Ber e 1 has been identified as the major Brazil nut allergen. The purpose of this study was to determine whether additional proteins in Brazil nut also have allergenic potential. METHODS: Proteins from Brazil nut were extracted and separated by SDS-Page. Immunolabeling was performed with serum from 27 Brazil nutsensitized patients. Proteins of interest were further analyzed by Edman sequencing. RNA isolated from Brazil nut was used to construct a cDNA library. The library was screened using primers designed on the basis of amino acid sequences identified through Edman sequencing. Full-length cDNA clones were isolated, sequenced, expressed and screened with individual patient sera from all patients. RESULTS: An IgE-binding protein that was recognized by 56% of the patients was identified at 29 kD. Analysis by Edman sequencing revealed that this protein was homologue to 11S globulins. Screening the Brazil nut cDNA library the protein was isolated. Using Western blot analysis, 12 out of the 27 Brazil nut-sensitized patients showed IgE-binding to the expressed recombinant protein. Therefore, this 11S globulin was named Ber e 2 by the allergen nomenclature sub-committee. CONCLUSIONS: The present abstract reports a new Brazil nut allergen, Ber e 2, an 11S globulin that belongs to the family of seed storage proteins. The identification of new food allergens is the first step towards the use of these recombinant allergens in future diagnostic and therapeutic approaches. Funding: Food Allergy Initiative
TUESDAY
952
J ALLERGY CLIN IMMUNOL VOLUME 121, NUMBER 2
Reliability of Food-Specific Serum IgE Values in Determining Negative Outcomes in Oral Food Challenges J. Johnson1, J. Cronin1,2, M. B. Morales1,2, A. D. Hogan2,1; 1Eastern Virginia Medical School, Norfolk, VA, 2Children’s Hospital of the King’s Daughters, Norfolk, VA. RATIONALE: The purpose of this study was to determine whether low Immuno capRAST values can predict negative food challenges. METHODS: A retrospective chart review was conducted for all patients who underwent oral food challenges (OFC) between January 2003 and April 2007. Statistical analyses included descriptive statistics and frequencies and Mann-Whitney U test using SPSS 15.0. RESULTS: 202 patients underwent 268 challenges to multiple foods; 60% were male, 68% Caucasian, and the median age was 3.6 years. Patients demonstrated atopy, including atopic dermatitis (70%), allergic rhinitis (83%), and asthma (49%). 32% (n 5 86) demonstrated significant allergic symptoms, resulting in a positive food challenge. Positive challenges for patients with negative CAP-RAST values, ( 0.35 kilo units of allergen per liter (kUA/L)), were 32% (n 5 6/19) for milk, 23% (n 5 5/22) for egg, and 17% (n 5 5/29) for peanut. For values between 0.35 and 2 kUA/L, positive challenges occurred in 30% for milk (n 5 8/27), 43% for egg (n 5 12/28) and 47% for peanut (n 5 15/32). For CAP-RAST values between 0.35 kUA/L and 5 kUA/L, there were no statistically significant differences in median IgE values for positive and negative challenges for peanut (p 5 0.3) or egg (p 5 0.9). A statistical difference was observed for milk (p < 0.02). In failed challenges for egg, milk, and peanut, urticaria occurred in 86%, respiratory symptoms 15%, gastrointestinal symptoms 17% and cardiovascular symptoms in 1%. CONCLUSIONS: CAP-RAST levels < 0.35 kUA/L for egg, milk, and peanut do not correlate well with food challenge outcomes. Allergenspecific IgE values at low concentrations are not useful predictors of challenge outcomes.
953
High Failure Rate during Oral Food Challenge to Baked Milk in Children with High Serum Cow's Milk (CM)-Specific IgE Antibody Level A. H. Nowak-Wegrzyn, K. A. Bloom, S. H. Sicherer, W. G. Shreffler, H. A. Sampson; Mount Sinai School of Medicine, New York, NY. RATIONALE: We previously reported that the majority of milk-allergic children tolerate baked milk; however children reactive to baked milk may experience severe reactions. We sought to determine whether diagnostic parameters predictive of clinical reactivity to baked milk could be established. METHODS: Milk-allergic children underwent oral food challenges (OFCs) to extensively baked, and if asymptomatic, to regular milk. Serum CM-specific IgE antibody level (kUA/L) and skin prick test (SPT) wheal diameter [mm] to commercial cow’s milk extract were measured and correlated with the outcome of the OFC to baked milk. RESULTS: Ninety-six children, mean age: 8 years; range 3-17 underwent OFC. Sixty-five children (65%) passed only baked, 9 passed baked and regular, and 23 (25%) failed baked milk OFC. Among children with serum CM-IgE level <35 kUA/L, 72/89 (80.9%) passed baked milk, whereas among children with CM-IgE level 35 kUA/L only 1/7 (14.3%) passed baked milk OFC. Among children with SPT <14 mm, 71 of 87 (81.7%) passed baked milk, whereas among children with SPT 14 mm, 2/6 (33.3%) passed baked milk OFC. 9/23 (39.1%) of the reactions to baked milk OFC required treatment with epinephrine, as opposed to the reported rate of 7-11% systemic reactions with clinically indicated standard graded challenges. CONCLUSIONS: High failure rate during OFC to baked milk is associated with high serum CM-specific IgE antibody levels. We no longer offer OFC to baked milk to children with CM-IgE greater than 35 kUA/L. OFC to baked milk should be undertaken with caution in children, especially those with high CM-IgE antibody levels. Funding: NIH NIAID
954
Charasteristics of Sesame Seed Allergy and Sesame-Specific IgE test S. Goto1,2, Y. Takaoka2, M. Futamura2, M. Morishita3, T. Sakamoto1, K. Ito2; 1Nagoya University Graduate School of Medicine, Nagoya, JAPAN, 2Division of Allergology, Aichi Children’s Health and Medical Center, Obu, JAPAN, 3Department of Pediatrics, Tosei General Hospital, Seto, JAPAN. RATIONALE: The aim of this study is to determine the clinical characteristics of sesame allergy in children and the usefulness of the sesame-specific IgE test in diagnosing sesame seed allergy. METHODS: Medical charts of 128 subjects (male: female, 86:42; mean age, 3.47 years) aged 1 year, who had undergone sesame-specific IgE (ImmunoCAPÒ) test and for whom reliable medical records about an allergic reaction associated with sesame uptake were available, were retrospectively analyzed. Diagnosis of sesame allergy was made based on clinically convincing history after consumption of sesame, or a positive sesame challenge test. RESULTS: Sesame challenge test was performed in 22 cases, and failed challenge was observed in 8 cases. An additional 28 cases were diagnosed by convincing history. Skin symptoms were observed in 34 (94.4%) patients. Gastrointestinal (n 5 7), respiratory (n 5 5) and oral mucosal (n 5 3) symptoms were also observed. Based on diagnosis by IgE test, prevalence of allergic symptoms in patients with each IgE Class 2, 3, 4, 5 and 6 was 24.2%, 23.1%, 41.2%, 83.3% and 50.0%, respectively. Convincing allergic history was reported in 2 patients who were negative for sesame-specific IgE detection. In patients with positive sesame-specific IgE ( class 2), mean IgE titer of sesame allergic patients (11.72 kUa/L, n 5 34) was significantly higher than those without sesame allergy (5.60 kUa/L, n 5 78, p < 0.01). CONCLUSIONS: Sesame-specific IgE level was significantly associated with sesame allergy, but diagnostic specificity was not satisfactory, even in cases showing the highest levels of IgE titer. Funding: Ministry of Health, Labor and Welfare, Japan
955
Identification Of A New Brazil Nut Allergen - Ber e 2 K. Beyer1, L. Bardina2, G. Grishina2, A. Ashraf2, S. Teuber3, B. Niggemann1, H. A. Sampson2; 1Charite - Campus Virchow Klinikum, Berlin, GERMANY, 2Mount Sinai School of Medicine, New York, NY, 3 University of California, Davis, CA. RATIONALE: Allergic reactions to Brazil nut have been identified as one of the most common causes of tree nut allergies. Ber e 1 has been identified as the major Brazil nut allergen. The purpose of this study was to determine whether additional proteins in Brazil nut also have allergenic potential. METHODS: Proteins from Brazil nut were extracted and separated by SDS-Page. Immunolabeling was performed with serum from 27 Brazil nutsensitized patients. Proteins of interest were further analyzed by Edman sequencing. RNA isolated from Brazil nut was used to construct a cDNA library. The library was screened using primers designed on the basis of amino acid sequences identified through Edman sequencing. Full-length cDNA clones were isolated, sequenced, expressed and screened with individual patient sera from all patients. RESULTS: An IgE-binding protein that was recognized by 56% of the patients was identified at 29 kD. Analysis by Edman sequencing revealed that this protein was homologue to 11S globulins. Screening the Brazil nut cDNA library the protein was isolated. Using Western blot analysis, 12 out of the 27 Brazil nut-sensitized patients showed IgE-binding to the expressed recombinant protein. Therefore, this 11S globulin was named Ber e 2 by the allergen nomenclature sub-committee. CONCLUSIONS: The present abstract reports a new Brazil nut allergen, Ber e 2, an 11S globulin that belongs to the family of seed storage proteins. The identification of new food allergens is the first step towards the use of these recombinant allergens in future diagnostic and therapeutic approaches. Funding: Food Allergy Initiative
TUESDAY
952