J ALLERGY CLIN IMMUNOL

FEBRUARY 2013

AB84 Abstracts

SUNDAY

303 Basophil Reactivity and Allergen Specific-IgE Levels but NotTotal IgE, Skin Prick Test Size, or Specific IgG4 Are Correlatedwith Severity of Double-Blind, Placebo-Controlled FoodChallenge Reactions

Nicole Leung1, Ying Song, MD1, Julie Wang1, Li Xin Wang1, Jaime

Ross1, Scott H. Sicherer, MD, FAAAAI1, June Straw2, Stacie M.

Jones, MD2, Hugh A. Sampson, MD, FAAAAI1, Xiu-Min Li, MD1;1Mount Sinai School of Medicine, New York, NY, 2University of Arkansas

for Medical Sciences, Little Rock, AR.

RATIONALE: Double-blind, placebo-controlled food challenges

(DBPFCs) remain the gold standard for diagnosing food allergies. Total

IgE (tIgE), allergen-specific IgE (sIgE) and skin prick tests (SPT) are

routinely used in medical practice, but are not sufficient to predict severity

of clinical reactivity. The goal of this study was to determine if basophil

reactivity, sIgE, SPT wheal diameter, tIgE, allergen-specific IgG4 (sIgG4)

and sIgE/sIgG4 ratios correlated with severity of reactions to DBPFCs.

METHODS: 67 subjects (male/female: 38/29; age: 12-43 y/o) underwent

DBPCFCs for peanut, treenut, fish, shellfish and/or sesame as part of

screening for enrollment in a clinical trial. Four subjects underwent two

DBPCFCs after passing the first DBPCFC, totaling 71 challenges.

Basophil activation, SPT, sIgE, tIgE and sIgG4 levels were performed,

and the correlation between these measures and DBPCFC reactivity scores

were analyzed.

RESULTS: Basophil activation was positively correlated with DBPCFC

scores (1-5) at all three concentrations used (200ng/ml: r50.50, p<0.0001;

2ng/ml: r5 0.35, p50.006, and 20pg/ml: r 50.32, p50.011). sIgE was

positively correlated with DBPCFC scores (r5 0.33, p50.005), but tIgE

was not. sIgE/sIgG4 ratios differentiated between positive and negative

challenges but were not correlated with DBPCFC scores. SPTwas weakly

correlated with DBPCFC scores. Receiver Operating Curves (sensitivity

vs. specificity) showed basophil reactivity had the highest area under the

curve at 0.92, sIgE at 0.85, and SPT wheal at 0.84.

CONCLUSIONS: These results support the utility of basophil reactivity

as a biomarker for predicting severity of clinical reactivity in food allergies.

A combination of basophil activation, sIgE and SPT might be more

informative.

304 Oral Immunotherapy At Fixed Low Dose for Mild to ModerateHen's Egg Allergy

Noriyuki Yanagida1,2, Takanori Minoura1, Motohiro Ebisawa, MD, PhD,

FAAAAI2; 1Sendai Medical Center, 2Sagamihara National Hospital.

RATIONALE: Many protocols for oral immunotherapy (OIT) treating

hen’s egg (HE) allergy consists of three phases: an initial dose escalation, a

build-up phase, and a maintenance phase. We hypothesized that effective-

ness and safety of OIT at fixed maintenance low dose without a build-up

phase would be equivalent to OIT with a build-up phase.

METHODS: Under the approval of local ethical committee, we got

informed consent of the OIT from guardians of 50 HE allergy patients aged

3 years and older. Forty-six patients (OIT group; 23 cases, Control group;

23 cases) with positive systemic reactions to heated 1/4-whole egg open

oral food challenge (OFC) were enrolled. Average age of patients was

5.5+/-1.2y. On the initial dose escalation, patients of OIT group were

encouraged to take 1.5-3g scrambled egg twice daily in hospital over 3

days, taking oral anti-histamine drug. After the initial dose escalation, they

had eaten 1.5-3g scrambled egg every morning at home. One year later

after the first OFC prior to OIT, second OFC were performed in the two

groups.

RESULTS: One year later, 15 patients (68%) of 23 in OIT group and 5

patients (22%) of 23 in control group could eat one heated-whole egg

without adverse reactions. Significant difference was seen between two

groups (P value 5 0.006, Fisher’s exact test). No severe systemic

symptoms had been seen in each group.

CONCLUSIONS: Heated-egg OIT by ingestion of fixed maintenance

dose followed by an initial dose-escalation without a build-up phase was

proven to be effective and safe.

305 The Absence of Oil Body Proteins in Allergenic Extract MightBe Involved in False-Negative Diagnosis of Some PeanutAllergic Patients

Marta M. Ferrer, MD, PhD, FAAAAI1, Fernando Pineda, PhD2, Gracia

Javaloyes, MD, PhD3, Miguel Blanca, MD, PhD4, Ana Aranda, PhD5,

Francisca Gomez, MD, PhD6, Gabriel Gastaminza, MD, PhD3, Juliana

de Souza, PhD7, Maria L. Sanz, MD, PhD3, M Jose Goikoetxea, PhD,

MD1; 1Department of Allergy, Clinica Universidad de Navarra, Pamplona,

Spain, 2Diater Laboratorios, Madrid, Spain, 3Department of Allergy,

Clinica Universidad de Navarra, Spain, 4Carlos Haya Hospital, Malaga,

Spain, 5Research Laboratory, Carlos Haya Hospital-FIMABIS, Malaga,

Spain, 6IMABIS Foundation, Malaga, Spain, 7Department of Microbiol-

ogy, Universidad de Navarra, Spain.

RATIONALE: There are patients with clear symptoms after peanut

ingestion although the diagnostic test could be negative.

METHODS: We studied serum from 20 patients with anaphylaxis upon

peanut ingestion. Skin prick test (SPT) with whole peanut extract (WPE)

was positive in 15 patients and negative in 5. We performed to each patient

specific IgE determination against whole peanut extract (WPE), Ara h 1,

Ara h 2, Ara h 3, Ara h 8, and Ara h 9. Basophil activation (CD63

expression) with Ara h 1, Ara h 2, and Ara h 9 was also determined. We

then compared positive and negative skin prick test sera protein recognition

through immunobloting.

RESULTS: Those patients with negative skin prick test and specific IgE to

peanut only recognized the liposoluble extract phase. However, those with

positive skin prick test and specific IgE recognized both hydrophilic and

lipophilic phase. Only one patient from the skin prick negative group had

positive specific IgE against peanut.

CONCLUSIONS: Our data indicate that the liposoluble proteins are re-

quired for theoptimal diagnosis of peanut sensitizedpatients. Peanut allergic

patients could be sensible to lowmolecular weight lipoproteins that could be

overlooked when diagnosed without fraction lipid content. Removing

lipophilic phase from commercial extracts could eliminate an important

allergen fraction. The allergenic properties of proteins involved in oil bodies

have thus far not been characterized in full detail, but their localizationmight

be a reason that they are unrepresented or denatured in most diagnostic

extracts of nuts and seeds that are usually extensively deffated.

306 Patterns of Serum Peanut-Specific IgE in Peanut AllergicChildren Over Time

Lisanne P. Newton, MD1, Alton Lee Melton, Jr, MD2; 1Cleveland Clinic

Foundation, Cleveland, OH, 2Cleveland Clinic.

RATIONALE: Serum peanut-specific IgE (PN-IgE) is used to follow

peanut allergic children to assess risk of reaction. Little is known regarding

distinct patterns of PN-IgE over time or factors associated with a steep rise.

METHODS: This was a retrospective chart review from 2002-2012 of

children with allergic reaction following peanut ingestion and at least 3

serial measurements of PN-IgE (at least 1 value >0.34 kU/L). Patterns of

PN-IgE were divided with 15 kU/L delineating ‘‘low’’ versus ‘‘high’’

values: Group 1 remained low, Group 2 increased (low to high), Group 3

remained high, Group 4 decreased (high to low). Groups were compared

using Chi-square tests and ANOVA.

RESULTS: 102 children met inclusion criteria: 36, 23, 41, 1 in Groups 1,

2, 3, 4, respectively (2 had variable patterns). The majority were boys

(63.7%), Caucasian (83.3%), and averaged 17.6 months of age at initial

reaction. Groups 1 through 3 differed significantly in the rate of multiple

food allergies (58.3%, 69.6%, 87.8% in Groups 1, 2, 3, respectively,

p50.013) and age at initial PN-IgE (33.1, 24.1, 39.2 months, p50.02).

When directly compared, groups 1 and 2 did not differ significantly in age

at initial reaction or initial PN-IgE, reaction severity, prior or accidental

ingestions, multiple food allergies, other atopy, or family history of atopy.

CONCLUSIONS: This review identified a pattern of steep rise in PN-IgE

over time that was not predicted with demographic or clinical variables.

Further investigation is needed to identify predictors of this pattern for

clinical decision making, patient counseling, and possibly future selection

of patients for oral immunotherapy.