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Predictive Measures for Successful Baked Egg Challenges at a Pediatric Tertiary Care Hospital
AB124 Abstracts
388
Predicting Outcomes for Food Challenges to Extensively Heated Milk
SUNDAY
Stephanie Eng, MD1,2, Sharon L. Hwang, MD1,2, Md J. Hossain, PhD1, and Magee L. DeFelice, MD1,2; 1Nemours A.I. duPont Hospital for Children, Wilmington, DE, 2Thomas Jefferson University Hospital, Philadelphia, PA. RATIONALE: Cow’s milk is the most commonly encountered pediatric food allergy. Incorporation of extensively heated milk protein into the diet may be helpful to induce tolerance to native cow’s milk. There are not yet standard guidelines describing predictive measures for successful oral food challenge (OFC) to baked milk. METHODS: Data from OFCs to baked milk in pediatric patients over a four-year period from 2012 to 2016 was aggregated via retrospective chart review. RESULTS: A total of 32 OFCs were performed with baked milk. Twenty-two children (69%) passed and 10 (31%) failed. Three patients developed anaphylaxis, all requiring 2 doses of epinephrine. A statistically significant difference (p50.035) for both cow’s milk-specific IgE and patient age was found between the 2 groups. Passed challenges had a lower cow’s milk-specific IgE (median 1.79kU/L, range 0.37-11kU/L) compared to failed challenges (median 11.59kU/L, range 0.21>100kU/L). Age analysis showed a median age of 3 years for the passed group versus 6 years for the failed group. Skin prick test (SPT) wheal size was not significantly different between the 2 groups, with a median value of 10mm (range 0-24mm) in the passed group and 7mm (range 0-15mm) in the failed group. Male sex and severe initial reactions correlated with higher rates of challenge failure, though not statistically significant. History of atopic dermatitis was not predictive of challenge outcome. CONCLUSIONS: Findings suggest that cow’s milk-specific IgE and patient age may be helpful for risk assessment in children undergoing challenges to baked milk, while SPT may be less diagnostic.
389
Baked Milk Challenges: A 5-Year Clinical Experience from a Large, Paediatric Allergy Specialist Centre in the UK.
Mohammad Awwad Al-Enezi, MD, and Aikaterini Anagnostou, MD, MSc, PhD; St Thomas’ Hospital, London, United Kingdom. RATIONALE: The majority of children with milk allergy can tolerate the baked form of milk; studies have shown that regular consumption of baked milk accelerates the resolution of fresh milk allergy. We performed a review of positive baked milk challenges to assess severity of allergic symptoms and treatment of reactions during the challenge. METHODS: We prospectively assessed children who developed allergic symptoms during challenge to baked milk. Age, history of index reaction, allergic symptoms and medications administered, cumulative dose, milk SPT and specific IgE were recorded. RESULTS: 24 children (mean age 5 years) underwent a baked milk challenge between 2010-2015. The average tolerated amount was 3.75g of skimmed milk powder. Allergic symptoms recorded included skin symptoms (pruritus, erythema, urticaria, angioedema), upper and lower respiratory symptoms (sneezing, rhinorrhea, cough, wheeze, chast tightness), gastrointestinal symptoms (oral itching, nausea, vomiting, abdominal pain), behavioural change and anaphylaxis. The most common symptoms were respiratory (66%). 23/24 (95%) patients received antihistamines, 8/24 (33%) patients needed bronchodilators. Steroids were used in 3/24 (12%). Intramuscular adrenaline was used on three occasions (12%); two children required two doses. The mean SPT result was 6.75 (0 - 20mm), and the mean specific IgE 15 (<0.35 to >100kUA/L). CONCLUSIONS: Most children, who react while undergoing a baked milk challenge, suffer from mild/moderate symptoms. However, anaphylaxis can also occur (8% in our cohort) and requires prompt treatment with intramuscular adrenaline.
J ALLERGY CLIN IMMUNOL FEBRUARY 2017
390
Predictive Measures for Successful Baked Egg Challenges at a Pediatric Tertiary Care Hospital
Sharon L. Hwang, MD1,2, Stephanie Eng, MD1,2, Md J. Hossain, PhD1, and Magee L. DeFelice, MD1,2; 1Nemours A.I. duPont Hospital for Children, Wilmington, DE, 2Thomas Jefferson University Hospital, Philadelphia, PA. RATIONALE: The majority of children with egg allergy may tolerate extensively heated egg, and ingestion has been shown to accelerate tolerance to native protein. Prior studies analyzing predictors of successful oral food challenge (OFC) to baked egg have demonstrated variable results. Additional data is needed to better define the predictive value of in vivo and in vitro testing for tolerance to baked egg. METHODS: A retrospective chart review was conducted of children who underwent OFC to baked egg from 2012-2016. Subjects were included if they had both skin prick testing (SPT) and egg white-specific IgE testing within 6 months of OFC. Testing criteria, age, and severity of initial reaction were analyzed as predictors of OFC outcomes. RESULTS: Sixty baked egg OFCs were performed. Forty-three challenges (71.7%) passed and 17 (28.3%) failed. Two patients developed anaphylaxis. The median SPT wheal sizes for the passed and failed groups were 8mm (range 0-25mm) and 10mm (range 3-19mm) respectively, which was not statistically significant (p5.113). However, the median egg white-specific IgE for the passed and failed groups were 3.63kU/L (range <0.08-29.4kU/L) and 8.03kU/L (range 0.67-39.1kU/L) respectively, which was statistically significant (p5.025). Age and initial reaction analysis demonstrated a trend for higher failure rates as subjects aged or had a severe initial reaction, though not statistically significant. CONCLUSIONS: Findings suggest that egg white-specific IgE may be more predictive than SPT for baked egg OFC outcomes. In vitro testing might be particularly helpful in identifying patients who are good candidates for OFC to extensively heated egg protein.
391
Assessing basophil activation by flow cytometry and mass cytometry in blood stored 24 hours before analysis
Kaori Mukai1, Nicolas Gaudenzio1, Sheena Gupta1, Nora Vivanco1, Sean C. Bendall1, Holden T. Maecker1, R. Sharon Chinthrajah, MD1, Mindy Tsai1, Kari C. Nadeau, MD, PhD, FAAAAI2, and Stephen J. Galli, MD1; 1Stanford University, Stanford, 2Stanford University, Stanford, CA. RATIONALE: Basophil activation tests (BATs) are useful for research and have promise for clinical monitoring of allergic patients, however, BAT protocols vary in blood anticoagulant used and temperature and time of storage before analysis. We aimed to establish a BAT protocol that would permit analysis of blood within 24 hours of obtaining the sample. METHODS: Blood from healthy donors and peanut allergic patients was collected into ethylenediaminetetraacetic acid (EDTA) or heparin tubes, and samples were stored at 48C or room temperature for 4 or 24 hours before analysis. RESULTS: Stimulation with anti-Immunoglobulin E (anti-IgE) or interleukin-3 (IL-3) resulted in strong upregulation of basophil CD203c in samples collected in EDTA or heparin, stored at 48C, and analyzed 24 hours after sample collection. However, N-formylmethionyl-leucylphenylalanine- (fMLP-) induced CD203c upregulation was observed in basophils analyzed in blood anticoagulated with heparin but not in EDTA unless exogenous calcium/magnesium was added. A CD63hi population of basophils was induced by anti-IgE or fMLP stimulation in heparinized blood but not in EDTA-treated samples unless exogenous calcium/magnesium was added at the time of anti-IgE or fMLP stimulation. Heparinized blood stored for 24 hours at 48C also could be used to perform BATs by Cytometry by Time-of-Flight mass spectrometry (CyTOF), with results similar to those obtained by conventional flow cytometry. CONCLUSIONS: BATs to measure the ability of anti-IgE or fMLP to upregulate basophil CD203c and induce a CD63hi basophil population can be conducted using blood obtained in heparin tubes without other additives and stored at 48C for 24 hours.
388
Predicting Outcomes for Food Challenges to Extensively Heated Milk
SUNDAY
Stephanie Eng, MD1,2, Sharon L. Hwang, MD1,2, Md J. Hossain, PhD1, and Magee L. DeFelice, MD1,2; 1Nemours A.I. duPont Hospital for Children, Wilmington, DE, 2Thomas Jefferson University Hospital, Philadelphia, PA. RATIONALE: Cow’s milk is the most commonly encountered pediatric food allergy. Incorporation of extensively heated milk protein into the diet may be helpful to induce tolerance to native cow’s milk. There are not yet standard guidelines describing predictive measures for successful oral food challenge (OFC) to baked milk. METHODS: Data from OFCs to baked milk in pediatric patients over a four-year period from 2012 to 2016 was aggregated via retrospective chart review. RESULTS: A total of 32 OFCs were performed with baked milk. Twenty-two children (69%) passed and 10 (31%) failed. Three patients developed anaphylaxis, all requiring 2 doses of epinephrine. A statistically significant difference (p50.035) for both cow’s milk-specific IgE and patient age was found between the 2 groups. Passed challenges had a lower cow’s milk-specific IgE (median 1.79kU/L, range 0.37-11kU/L) compared to failed challenges (median 11.59kU/L, range 0.21>100kU/L). Age analysis showed a median age of 3 years for the passed group versus 6 years for the failed group. Skin prick test (SPT) wheal size was not significantly different between the 2 groups, with a median value of 10mm (range 0-24mm) in the passed group and 7mm (range 0-15mm) in the failed group. Male sex and severe initial reactions correlated with higher rates of challenge failure, though not statistically significant. History of atopic dermatitis was not predictive of challenge outcome. CONCLUSIONS: Findings suggest that cow’s milk-specific IgE and patient age may be helpful for risk assessment in children undergoing challenges to baked milk, while SPT may be less diagnostic.
389
Baked Milk Challenges: A 5-Year Clinical Experience from a Large, Paediatric Allergy Specialist Centre in the UK.
Mohammad Awwad Al-Enezi, MD, and Aikaterini Anagnostou, MD, MSc, PhD; St Thomas’ Hospital, London, United Kingdom. RATIONALE: The majority of children with milk allergy can tolerate the baked form of milk; studies have shown that regular consumption of baked milk accelerates the resolution of fresh milk allergy. We performed a review of positive baked milk challenges to assess severity of allergic symptoms and treatment of reactions during the challenge. METHODS: We prospectively assessed children who developed allergic symptoms during challenge to baked milk. Age, history of index reaction, allergic symptoms and medications administered, cumulative dose, milk SPT and specific IgE were recorded. RESULTS: 24 children (mean age 5 years) underwent a baked milk challenge between 2010-2015. The average tolerated amount was 3.75g of skimmed milk powder. Allergic symptoms recorded included skin symptoms (pruritus, erythema, urticaria, angioedema), upper and lower respiratory symptoms (sneezing, rhinorrhea, cough, wheeze, chast tightness), gastrointestinal symptoms (oral itching, nausea, vomiting, abdominal pain), behavioural change and anaphylaxis. The most common symptoms were respiratory (66%). 23/24 (95%) patients received antihistamines, 8/24 (33%) patients needed bronchodilators. Steroids were used in 3/24 (12%). Intramuscular adrenaline was used on three occasions (12%); two children required two doses. The mean SPT result was 6.75 (0 - 20mm), and the mean specific IgE 15 (<0.35 to >100kUA/L). CONCLUSIONS: Most children, who react while undergoing a baked milk challenge, suffer from mild/moderate symptoms. However, anaphylaxis can also occur (8% in our cohort) and requires prompt treatment with intramuscular adrenaline.
J ALLERGY CLIN IMMUNOL FEBRUARY 2017
390
Predictive Measures for Successful Baked Egg Challenges at a Pediatric Tertiary Care Hospital
Sharon L. Hwang, MD1,2, Stephanie Eng, MD1,2, Md J. Hossain, PhD1, and Magee L. DeFelice, MD1,2; 1Nemours A.I. duPont Hospital for Children, Wilmington, DE, 2Thomas Jefferson University Hospital, Philadelphia, PA. RATIONALE: The majority of children with egg allergy may tolerate extensively heated egg, and ingestion has been shown to accelerate tolerance to native protein. Prior studies analyzing predictors of successful oral food challenge (OFC) to baked egg have demonstrated variable results. Additional data is needed to better define the predictive value of in vivo and in vitro testing for tolerance to baked egg. METHODS: A retrospective chart review was conducted of children who underwent OFC to baked egg from 2012-2016. Subjects were included if they had both skin prick testing (SPT) and egg white-specific IgE testing within 6 months of OFC. Testing criteria, age, and severity of initial reaction were analyzed as predictors of OFC outcomes. RESULTS: Sixty baked egg OFCs were performed. Forty-three challenges (71.7%) passed and 17 (28.3%) failed. Two patients developed anaphylaxis. The median SPT wheal sizes for the passed and failed groups were 8mm (range 0-25mm) and 10mm (range 3-19mm) respectively, which was not statistically significant (p5.113). However, the median egg white-specific IgE for the passed and failed groups were 3.63kU/L (range <0.08-29.4kU/L) and 8.03kU/L (range 0.67-39.1kU/L) respectively, which was statistically significant (p5.025). Age and initial reaction analysis demonstrated a trend for higher failure rates as subjects aged or had a severe initial reaction, though not statistically significant. CONCLUSIONS: Findings suggest that egg white-specific IgE may be more predictive than SPT for baked egg OFC outcomes. In vitro testing might be particularly helpful in identifying patients who are good candidates for OFC to extensively heated egg protein.
391
Assessing basophil activation by flow cytometry and mass cytometry in blood stored 24 hours before analysis
Kaori Mukai1, Nicolas Gaudenzio1, Sheena Gupta1, Nora Vivanco1, Sean C. Bendall1, Holden T. Maecker1, R. Sharon Chinthrajah, MD1, Mindy Tsai1, Kari C. Nadeau, MD, PhD, FAAAAI2, and Stephen J. Galli, MD1; 1Stanford University, Stanford, 2Stanford University, Stanford, CA. RATIONALE: Basophil activation tests (BATs) are useful for research and have promise for clinical monitoring of allergic patients, however, BAT protocols vary in blood anticoagulant used and temperature and time of storage before analysis. We aimed to establish a BAT protocol that would permit analysis of blood within 24 hours of obtaining the sample. METHODS: Blood from healthy donors and peanut allergic patients was collected into ethylenediaminetetraacetic acid (EDTA) or heparin tubes, and samples were stored at 48C or room temperature for 4 or 24 hours before analysis. RESULTS: Stimulation with anti-Immunoglobulin E (anti-IgE) or interleukin-3 (IL-3) resulted in strong upregulation of basophil CD203c in samples collected in EDTA or heparin, stored at 48C, and analyzed 24 hours after sample collection. However, N-formylmethionyl-leucylphenylalanine- (fMLP-) induced CD203c upregulation was observed in basophils analyzed in blood anticoagulated with heparin but not in EDTA unless exogenous calcium/magnesium was added. A CD63hi population of basophils was induced by anti-IgE or fMLP stimulation in heparinized blood but not in EDTA-treated samples unless exogenous calcium/magnesium was added at the time of anti-IgE or fMLP stimulation. Heparinized blood stored for 24 hours at 48C also could be used to perform BATs by Cytometry by Time-of-Flight mass spectrometry (CyTOF), with results similar to those obtained by conventional flow cytometry. CONCLUSIONS: BATs to measure the ability of anti-IgE or fMLP to upregulate basophil CD203c and induce a CD63hi basophil population can be conducted using blood obtained in heparin tubes without other additives and stored at 48C for 24 hours.