DOI: 10.1542/peds.2012-2585; originally published online April 8, 2013;Pediatrics

W. Heymann and Scott P. ComminsLisa Workman, Haley R. James, Anubha Tripathi, Charles J. Lane, Luis Matos, Peter Joshua L. Kennedy, Amy P. Stallings, Thomas A.E. Platts-Mills, Walter M. Oliveira,

in Children-1,3-galactose and Delayed Anaphylaxis, Angioedema, and UrticariaαGalactose-

  

  http://pediatrics.aappublications.org/content/early/2013/04/03/peds.2012-2585

located on the World Wide Web at: The online version of this article, along with updated information and services, is

 

of Pediatrics. All rights reserved. Print ISSN: 0031-4005. Online ISSN: 1098-4275.Boulevard, Elk Grove Village, Illinois, 60007. Copyright © 2013 by the American Academy published, and trademarked by the American Academy of Pediatrics, 141 Northwest Pointpublication, it has been published continuously since 1948. PEDIATRICS is owned, PEDIATRICS is the official journal of the American Academy of Pediatrics. A monthly

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Galactose-a-1,3-galactose and Delayed Anaphylaxis,Angioedema, and Urticaria in Children

WHAT’S KNOWN ON THIS SUBJECT: Delayed anaphylaxis,urticaria, and angioedema to mammalian meat products werefirst described in the adult population in 2009. Patients with thissyndrome who consume mammalian meat typically developsymptoms 4 to 6 hours after ingestion.

WHAT THIS STUDY ADDS: Specific diagnoses for children whodevelop urticaria, angioedema, and idiopathic anaphylaxis arefew and far between. We have now shown delayed anaphylaxis,urticaria, and angioedema due to mammalian meat products inthe pediatric population.

abstractBACKGROUND AND OBJECTIVE: Despite a thorough history and com-prehensive testing, many children who present with recurrent symp-toms consistent with allergic reactions elude diagnosis. Recentresearch has identified a novel cause for “idiopathic” allergic reac-tions; immunoglobulin E (IgE) antibody specific for the carbohydrategalactose-a-1,3-galactose (a-Gal) has been associated with delayedurticaria and anaphylaxis that occurs 3 to 6 hours after eating beef,pork, or lamb. We sought to determine whether IgE antibody to a-Galwas present in sera of pediatric patients who reported idiopathicanaphylaxis or urticaria.

METHODS: Patients aged 4 to 17 were enrolled in an institutional re-view board–approved protocol at the University of Virginia and pri-vate practice allergy offices in Lynchburg, VA. Sera was obtained andanalyzed by ImmunoCAP for total IgE and specific IgE to a-Gal, beef,pork, cat epithelium and dander, Fel d 1, dog dander, and milk.

RESULTS: Forty-five pediatric patients were identified who had bothclinical histories supporting delayed anaphylaxis or urticaria tomammalian meat and IgE antibody specific for a-Gal. In addition,most of these cases had a history of tick bites within the past year,which itched and persisted.

CONCLUSIONS: A novel form of anaphylaxis and urticaria that occurs 3to 6 hours after eating mammalian meat is not uncommon among chil-dren in our area. Identification of these cases may not be straightfor-ward and diagnosis is best confirmed by specific testing, which shouldcertainly be considered for children living in the area where the LoneStar tick is common. Pediatrics 2013;131:1–8

AUTHORS: Joshua L. Kennedy, MD,a Amy P. Stallings, MD,a

Thomas A.E. Platts-Mills, MD, PhD, FRS,a Walter M. Oliveira,BS,b Lisa Workman, BA,a Haley R. James, BS,a Anubha Tripathi,MD,a Charles J. Lane, MD,c Luis Matos, MD,d Peter W. Heymann,MD,e and Scott P. Commins, MD, PhDa,e

aDivision of Allergy and Immunology, Department of InternalMedicine and Departments of bMedical Laboratories andePediatrics, University of Virginia Health System, Charlottesville,Virginia; cAllergy Partners of Lynchburg, Lynchburg, Virginia; anddAsthma and Allergy Center of Lynchburg, Lynchburg, Virginia

KEY WORDSa-Gal, galactose-a-1,3-galactose, delayed anaphylaxis, pediatricurticaria

ABBREVIATIONSa-Gal—galactose-a-1,3-galactoseIg—immunoglobulin

Dr Kennedy performed data analysis and patient enrollment,and drafted the manuscript; Drs Stallings, Lane, and Matos wereinstrumental in patient enrollment; Dr Platts-Millsconceptualized and designed the study, and was involved indrafting the manuscript; Mr Oliveira performed specificimmunoglobulin E (IgE) measurements; Ms Workman collectedand performed all specific IgE measurements; Ms Jamesperformed data analysis and assisted in the specific IgEmeasurements; Dr Tripathi helped with the draft of themanuscript; Dr Heymann was involved in enrolling patients aswell as in drafting the manuscript; Dr Commins conceptualizedand designed the study, and was instrumental in patientenrollment, data analysis, and drafting the manuscript; and allauthors approved the final manuscript as written.

www.pediatrics.org/cgi/doi/10.1542/peds.2012-2585

doi:10.1542/peds.2012-2585

Accepted for publication Jan 18, 2013

Address correspondence to Scott P. Commins, MD, PhD, Divisionof Allergy, Asthma, and Immunology, University of Virginia HealthSystem, PO Box 801355, Charlottesville, VA 22908. E-mail:spc7w@virginia.edu

PEDIATRICS (ISSN Numbers: Print, 0031-4005; Online, 1098-4275).

Copyright © 2013 by the American Academy of Pediatrics

FINANCIAL DISCLOSURE: Dr Platts-Mills is a consultant toViracor/IBT and has a patent on the use of streptavidin solidphase to evaluate immunoglobulin E antibodies to recombinantmolecules; Dr Lane is a consultant for Mylan Specialty, whichmarkets the EpiPen epinephrine autoinjector, used for life-threatening anaphylaxis/food allergy; the other authors haveindicated they have no financial relationships relevant to thisarticle to disclose.

FUNDING: Funded by National Institutes of Health grants AI-20565, U19-AI-070364, R21-AI-087985, and K08-AI-1085190. Fundedby the National Institutes of Health (NIH).

PEDIATRICS Volume 131, Number 5, May 2013 1

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In studies in which the etiology ofanaphylaxis has been established, foodsor venoms cause most reactions,1

and, classically, these immunoglobulinE (IgE)-mediated reactions are thoughtto occur within 5 to 30 minutes afteringestion or injection of an offendingagent.2 Numerous epitopes respon-sible for IgE-mediated food allergy havebeen described and are primarilyprotein-based. Although it is wellknown that the carbohydrate moietiespresent on many plant foods can in-duce antiglycan IgE responses, theclinical significance of these cross-reactive carbohydrate determinantsis unclear.3–5 In contrast, recent workhas shown that IgE antibodies spe-cific for the carbohydrate, galactose-a-1,3-galactose (a-Gal), are capable ofeliciting serious, even fatal, delayedreactions that occur 3 or more hoursafter eating red meat.6,7

An IgG/IgM immune response to a-Galhas been well described, and thismediates hyperacute rejection of pig-to-primate xenotransplantation.8 Workby Chung et al9 demonstrated that inadults, an IgE response to a-Gal wasresponsible for immediate hypersen-sitivity reactions that occurred duringinfusion of the monoclonal antibodycetuximab, an anti–epidermal growthfactor receptor cancer therapeutic.Thea-Gal carbohydrate moiety is knownto be present on multiple tissues (no-tably thyroglobulin) from nonprimatemammals,10,11 and more recently, IgEto a-Gal has been associated withdelayed urticaria and even anaphy-laxis.6,7 The development of IgE anti-body to a-Gal has been linked tobites from ecto-parasitic ticks, espe-cially those of the Lone Star tick,Amblyomma americanum.12 Patientswith IgE antibody to a-Gal report symp-toms of urticaria, angioedema, or evenanaphylaxis starting 3 to 6 hours afterthe ingestion of mammalian meatproducts.7 The symptoms can be severe,

and many patients have required epi-nephrine injections for their reactionsas well as care in emergency depart-ments.7,13 Because the timing of in-gestion occurs much earlier than theactual symptoms, diagnosis and recog-nition of this food allergy has beenchallenging. In fact, we have seen manychildren who had been diagnosedwith idiopathic urticaria/anaphylaxis,or who had been specifically told thatthe reactions were not a result of foodallergy, who had IgE antibodies to a-Galand, in retrospect, a history consistentwith delayed reactions to mammalianmeat (A.P.S., P.W.H., S.P.C., unpublishedobservations). Immediate hypersensi-tivity to meat in children has beenreported by multiple investigators14–18

and the role of beef allergens in chil-dren with atopic dermatitis and milksensitization has also been well estab-lished.19,20

Because a-Gal has been found to be animportant cause of urticaria, angioe-dema, and anaphylaxis in the adultpopulation, we investigated whetherIgE antibodies to a-Gal were present inthe sera of pediatric patients witha clinical history suggestive of delayedurticaria, angioedema, or anaphylaxisto mammalian meat products. Here wereport 45 pediatric patients, aged 4 to17, who were found to have IgE anti-bodies to a-Gal. To our knowledge, thisis the first report of delayed reactionsto mammalian meat in the pediatricpopulation.

METHODS

Patients and Control Subjects

The University of Virginia Human In-vestigation Committee has approvedthese studies. Our patients were en-rolled as subjects from theUniversity ofVirginia Allergy and Immunology Clinic,as well as from private practice allergyclinics in Lynchburg, VA, because eachhad a history suggestive of delayedanaphylaxis, urticaria, or angioedema.

A total of 51subjectswereenrolled fromSeptember 2011 to May 2012 on thebasis of clinical history and answers toquestions regarding tick bites and bitesite characteristics. Specific questionsincluded (1) did episodes occur beforeor after midnight, (2) did episodes fol-low having eaten mammalian meat atthe meal before the reaction (even if 4to 5 hours prior), and (3) was therea history of tick or seed tick bites. Ad-ditional subjects aged 4 to 18 wereenrolled (n = 142) from the Universityof Virginia Hospital where they pre-sented with (or without) wheeze.21

ImmunoCAP IgE Assays

Total and specific IgE antibodies weremeasured by using either commer-cially available ImmunoCAP (Phadia US,Portage, MI) or a modification of theassay with streptavidin on the solidphase (a-Gal, Fel d 1).7,22 The assayswere performed with the ImmunoCAP250 instrument and the resultsexpressed as IU/mL. For specificassays, the cutoff used for a positivereaction was 0.35 IU/mL. The sera weretested with commercially availableassays for IgE antibodies to dust mite(Dermatophagoides pteronyssinus),cat (dander and epithelium in additionto Fel d 1), dog dander, Timothy grass,Alternaria alternata, oak, beef, pork,chicken, codfish, cow’s milk and milkcomponents (Bos d 4, Bos d 5, Bos d 8),boiled milk, goat’s milk, peanut, egg,and total IgE.

Statistical Analysis

We compared the specific IgE antibodyresults between a-Gal, beef, and porkto fish, chicken, peanut, and egg byusing the Mann-Whitney test. We cor-related quantitative measures of IgEantibodies between a-Gal and otherspecific IgE antibodies by using theSpearman rank-order correlation. AP , .05 was considered to indicatestatistical significance. Statistical

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analyses were performed with Graph-Pad Prism 6.0 (GraphPad Software, LaJolla, CA).

RESULTS

Our population included children(n = 51) with a history of recurrenturticaria, idiopathic anaphylaxis, orangioedema suggestive of a delayedresponse to mammalian meat, ofwhich 45 tested positive for IgE anti-body to a-Gal (Table 1). Some patientswere referred as cases of chronic ur-ticaria; however, on careful question-ing, a more appropriate diagnosiswould have been acute, recurrent ur-ticaria. Many of the patients had usedan emergency department for theirsymptoms (5/51 had been to theemergency department $4 times be-fore diagnosis), and they required theuse of epinephrine, antihistamines,and/or injected steroids. There werealso several patients who had requiredadmission to the hospital for observa-tion (Table 1). All of these patients hada clear history of tick exposure beforeour evaluation of IgE to a-Gal, and 39had histories of itching, redness, andswelling for several weeks after thetick bite (Table 1). Of the 51 children, 6subjects were enrolled with similarhistories, yet were found to be negativefor IgE antibody to a-Gal.

As previously reported in adults, ourpediatric subjects had positive immu-noassays to mammalian meat prod-ucts, including beef and pork (Fig 1).The specific IgE levels for these testswere significantly higher than thosefor fish (P , .05), chicken (P , .001),egg (P, .05), and peanut (P, .001) byMann-Whitney analysis. There wasa close correlation (r = 0.99) betweenbeef- and pork-specific IgE, supportingthe view that these assays were mea-suring IgE antibodies to a single com-ponent: a-Gal (Fig 2A). There was alsoa strong correlation between a positiveimmunoassay for a-Gal and a positive

test for beef and pork (r = 0.87 and r =0.89, respectively; Table 2, Fig 2 B andC). The symptoms reported by thesechildren included urticaria, angioe-dema, and anaphylaxis, and in nearly

every case these symptoms weredelayed 3 to 6 hours, much like thoseof their adult counterparts (Table 1).Milk-specific IgE was also elevated inthese patients, as reported in previous

TABLE 1 Patient Demographics

n = 51

Gender, % male 69Mean age at presentation (range) 12 (4–17)Total IgE, geometric mean (95% confidence interval) 147 IU/mL (105–206 IU/mL)No. of subjects testing positive for IgE antibody to a-Gal (%) 45 (88)Symptoms at presentation, %Anaphylaxisa 44Gastrointestinal/Oral 64Urticaria 92Angioedema 31

Average time to symptoms (range) 4.68 h (10 min to 24 h)Tick exposure, % 100Redness and itching at site of tick bite 87Tick-borne illnessb 10

Emergency department visits, % 46c

Medications administered in the emergency department, %Epinephrine 19Antihistamines 35Oral steroids 19Parenteral steroids 17Intravenous fluids 17

Hospital admissions, % 8a Anaphylaxis was defined as hypotension and/or respiratory symptoms including laryngeal edema and wheezing.b All patients with positive answers reported a history of Lyme disease.c Five of the 45 subjects required $4 visits to the emergency department for symptoms.

FIGURE 1Specific IgE antibodybinding to allergens in serumsamples from45patientswith IgE antibodies toa-Gal.The horizontal lines indicate geometric mean values. Numbers below the limit of detection indicate thenumber of negative values for each allergen. * Complete panel of immunoassays was performed forthose sera positive for IgE antibody to a-Gal (n = 45). ** Cat allergen includes epithelium and dander. #The values for chicken, egg, peanut, and fish have significantly lower titers (P , .05) compared witha-Gal, beef, and pork by means of a Mann-Whitney analysis.

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studies.7 However, tests for IgE to milkcomponents, including a-lactalbumin(Bos d 4),b-lactoglobulin (Bos d 5), andcasein (Bos d 8), were negative in mostof the patients who had a positive im-munoassay to milk. Boiled milk immu-noassays were also negative in thissame population (Fig 3). To confirmthat a-Gal–specific IgE antibody wereresponsible for the positive cow’s milkIgE test, absorption studies were car-ried out on 3 sera, which showed thatremoving IgE antibody to a-Gal alsoremoved the positive milk IgE result(Supplemental Table 3).

In keeping with the known distributionof a-Gal, positive immunoassay re-sponses were seen to cat dander andepithelium and dog dander in ourpatients with a-Gal allergy (Fig 1). De-spite a positive test for cat and dog,only 9 of 32 subjects reported rhinitissymptoms on exposure to cat or dog.The immunoassay test for thesemammals is known to contain a-Gal

because of the presence of proteins,such as cat IgA (Fel d 5).23 Sensitizationto dust mite and to the major cat al-lergen (Fel d 1) were similar to thegeneral population (Fig 1) and are notassociated with the a-Gal syndrome.

To further characterize the IgE antibodyto a-Gal response in the pediatricpopulation, an assessment of the prev-alence of this antibody response ina geographically similar but distinctcohort was performed. Sera fromsubjects (n = 142) presenting to theUniversity of Virginia Hospital with andwithout wheeze were assayed for in-door, outdoor, and food-specific IgEantibody responses (Fig 4A). In thisgroup of 142 subjects, the percentageof sera positive for IgE antibody toa-Gal overall was 24%. Because thiscohort was enrolled to investigateasthma, it included patients with andwithout wheezing.21 As might beexpected, patients with wheezing(surrogate for asthma) had higher

overall IgE percent positive for manyallergens but notably percent a-Galsensitization was not significantly dif-ferent between wheezing and non-wheezing subjects (P = .43; Fig 4 A andB). Analysis of the 3 different cohortsshowed that the IgE antibody titer toa-Gal was significantly higher inpatients reporting delayed reactionsafter consuming mammalian meat ascompared with those subjects enrolledwith and without wheeze (P , .001;Fig 4B). A more detailed analysis of theIgE antibody to a-Gal response showsthat among those subjects withwheeze, IgE toa-Gal comprised,1% ofthe total IgE in most cases (Supple-mental Fig 5). On the contrary, thosesubjects enrolled specifically becausethe clinical history supported delayedreactions to mammalian meat had IgEto a-Gal responses that constituted.1% of total IgE, and in many instan-ces .5% of total IgE (SupplementalFig 5).

FIGURE 2Correlations of IgE to a-Gal and specific allergens. A, Correlation of IgE antibody to pork and IgE antibody to beef (r = 0.99), suggesting that these tests areactually measuring the amount of specific IgE to a-Gal in the serum. B, Correlation of IgE antibody to a-Gal and beef (r = 0.89; P, .001) in patients with IgEantibody to a-Gal. C, Correlation of IgE antibody to a-Gal and pork (r = 0.87; P, .001) in patients with IgE antibody to a-Gal. D, Correlation of IgE antibody toa-Gal and total IgE (r = 0.18; P = not significant) in patients with IgE antibody to a-Gal.

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DISCUSSION

The a-Gal syndrome, in children andadults, is unlike any other known IgE-mediated food allergy. Despite hightiters of IgE antibodies to beef andpork, these cases consistently reporta delay of 3 to 6 hours after eatingmammalian meat.7 Furthermore, thesymptoms often become severe, in-cluding significant episodes of hives

and hypotension. In fact, .45% ofthe subjects used an emergency de-partment at least once for their symp-toms and 8% required admission to thehospital for observation (Table 1). Thus,it is our general practice to prescribean epinephrine autoinjector and in-struct patients in its proper use. Notonly the serious nature of the reac-tions but also the rising frequency ofidiopathic angioedema and urticaria

across all age groups24–29 underscorethe importance of identifying a causefor these cases if possible. Our resultsshow clearly that physicians shouldkeep this diagnosis in mind even in thepediatric population, especially if thehistory is consistent with the diseasesyndrome, including delayed symp-toms after ingestion of beef, pork,lamb, or even milk.

It is important to note, however, thatpatients with IgE antibody to a-Gal maynot experience reactions with everyingestion of mammalian meat. Theexplanations for such an observationare several-fold. First, a-Gal is a car-bohydrate and this “inconsistency”may simply be a result of the inherentproperties of digestion, processing,and absorption of glycans. Second, theamount of a-Gal that actually reachesthe bloodstream in an antigenic form(which we believe to be that of a gly-colipid) may be significantly less thanis ingested. Moreover, the food itself(ie, hamburger versus cow’s milk) mayoffer more or less antigen. Fourth, thedose of meat appears to be important,and in some instances children areable to consume a small amount ofmammalian meat or products withoutadverse reactions. Fifth, it may well bethat preparation (mechanical, thermal,or freezing) is a significant factor incontributing to whether foods retainenough of the appropriate antigen tocause a reaction. Finally, it is also im-portant to keep inmind that the naturalhistory of this IgE antibody responseappears to be one that decreases overtime. Thus, as the IgE antibody titerdecreases, children could experiencefewer or inconsistent reactions.

The incidence of food allergy is in-creasing across the population, withalmost 6% of children and 4% of adultsin North America now allergic to 1 ormore foods.30,31 Children who developIgE antibody to a-Gal may have posi-tive skin, intradermal, or immunoassay

TABLE 2 Correlations Between the IgE Specific for a-Gal (IU/mL) and Other Specific Allergens(IU/mL)

Specific IgE Antibody No. of Positives/No. Tested Spearman Correlation (r) With a-Gal P Value

a-Gal 45/45 1Dog dander 33/45 0.71 ,.001Cata 39/45 0.73 ,.001Fel d 1b 9/45 0.07 .66Porkc 39/45 0.87 ,.001Beefc 38/45 0.89 ,.001Milk 34/45 0.79 ,.001Peanut 10/45 20.07 .67Dust mited 13/45 0.25 .1a Cat immunoassay includes epithelium and dander.b Fel d 1 is the major cat allergen.c Pork- and beef-specific IgE antibody were significantly correlated with each other (r = 0.99 and P , .001).d Dust mite = D pteronyssinus immunoassay.

FIGURE 3Component analysis of milk-allergic children with a-Gal. Patients with a-Gal–specific IgE who werepositive for specific IgE to milk (n = 34) were tested for milk components, including a-lactalbumin,b-lactoglobulin, and casein-specific IgE. Interestingly, there does not appear to be any reactivity to themilk components (a-lactalbumin, b-lactoglobulin, and casein), suggesting that there is no a-Gal inthese immunoassays. Similar results are present for boiled milk and goat’s milk.

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testing to milk, beef, pork, cat, or dog.32

It is important to understand thatmanychildren suffer from milk allergy, butIgE to a-Gal is distinct from the moretraditional, protein-based cow’s milkallergy. a-Gal–related reactions pres-ent in older children, many of whomhave no previous history of either foodallergy or any allergic disease.7 Clini-cians should recognize that the car-bohydrate moiety a-Gal is found inmammalian milk, as evidenced bythe positive immunoassay results tocow’s milk and goat’s milk. Therefore,in a patient older than 5 who has anapparent new-onset milk allergy, IgEantibody toa-Gal should be consideredas an alternative diagnosis to a protein-based milk allergy, a cross-reactivitybetween beef allergy and cow’s milk,19

or even a distinct mammalian proteincross-reactivity.18

Interestingly, we were unable to showpositive tests fora-Gal on the individualcomponents of milk as tested in thisstudy. Children with IgE antibody to

a-Gal (and, therefore, “milk allergic”)had negative immunoassays toa-lactalbumin, b-lactoglobulin, and ca-sein in 32, 31, and 33 of 34 instances,respectively, leading us to surmise thatthese milk protein antigens are notsignificant sites of a-Gal–based glyco-sylation. Similarly, onemight anticipatethat the allergens bovine immuno-globulin (Bos d 7) or bovine serumalbumin (Bos d 6) could contain gly-cosylation with a-Gal, but the pub-lished evidence that has assessed thispossibility for Bos d 6 suggestsa-Gal isnot present, and our unpublished datahave also been in keeping with a lack ofa-Gal on bovine serum albumin.11 Thenegative results for milk allergenscould also be explained by the pro-cessing of these components for theimmunoassay, which might change thestructure or alter the galactose link-ages. The latter theory is supported byour finding that the boiled milk immu-noassay was negative in most of thepatients with a positive a-Gal–specific

IgE, whereas another mammalian milk(goat) was positive in those sera thathad the highest titer of IgE antibody tocow’s milk. Taken together, the datasuggest that the goat’s milk Immu-noCAP has fewer a-Gal epitopes thandoes the cow’s milk assay, not thata-Gal is absent from goat’s milk orthat goat’s milk may be a safe alter-native for these children. In fact, wehave not a priori recommended re-moval of milk or dairy products fromthe diet of adults with this syndromeif they have previously toleratedthese products. We have continueda similar approach in the pediatricpopulation, unless the allergic epi-sodes persist, at which time wewould suggest performing an oralmilk challenge.

Skin testing for beef, pork, or lamb(mammalian meat) in both adult andpediatric patients has been challeng-ing. Many patients have only smallreactions (2–5 mm) to these allergensby skin-prick testing, and intradermal

FIGURE 4A, Percentage of children (aged 4–18) positive for specific IgE antibodies in wheezing (n = 61; red) and nonwheezing (n = 81; blue) control groups. There weresignificant differences between the wheezing and control population with regard to aeroallergen sensitization (**P, .001; *P = .001), whereas there were nodifferences in sensitization patterns to a-Gal, beef, or milk (P = .43, P = .15, and P = .21, respectively). B, Comparison of positive tests for a-Gal among an age-matched pediatric cohort with symptoms of delayed mammalian meat allergy (n = 45) and a cohort of wheezing (n = 17) and nonwheezing (n = 16) controlsubjects in the hospital. The pediatric cohort with symptoms of delayed mammalian meat allergy has significantly higher levels of specific IgE to a-Gal (P,.001). NS, not significant.

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tests have been used in adults to clarifythe intermediate results.7 We have, onoccasion, also performed intradermaltesting in older teenagers, and theseresults mirrored those seen in adults.Overall, we are less likely to performintradermal testing in children and,therefore, recommend use of in vitroassays. Although we have performedmammalian meat challenges in adultsubjects to document the delayed ap-pearance of clinical symptoms, thesefood challenges have produced sig-nificant symptoms beyond what thesubject had reported after natural ex-posure. In protein-based food allergiesin which symptoms arise in 5 to 30minutes, food challenges use smallamounts of allergen and proceed in-crementally, such that the procedureis stopped when patients begin toreact. Because of the time course tosymptoms, incremental dosing is notpossible in the case of delayed reac-tions to mammalian meat and theentire dose must be given at the startof the challenge. Because of the (sig-nificant) reactions observed duringmammalian meat challenges withadult subjects and the inability to in-crementally dose, we do not plan toperform food challenges in pediatricsubjects and acknowledge the lack offood challenges as a limitation in ourstudy.

The pediatric population seems to fol-low the trend seen in adult subjectswith regard to the geographic dis-tribution of this disease. Screening se-rum samples from multiple geographic

locales reveals a distinct regional pat-tern of disease in the southeasternUnited States, a pattern that roughlycorrelates with the higher incidence ofcetuximab hypersensitivity in adults.33 Infact, we have been made aware of chil-dren presenting with IgE antibody toa-Gal in numerous centers throughoutthe eastern and now central UnitedStates. Colleagues at Duke University(Dr Michael Land and Dr Moira Breslin),Kansas City Children’s (Dr Paul Dowlingand Dr Tara Federly), and in EastHampton, NY (Dr Erin McGintee) havediagnosed pediatric patients with IgEantibody to a-Gal and the character-istic delayed reactions to mammalianmeat. Based on our assessment ofsera from children enrolled in studiesin central Virginia, the prevalence ofspecific IgE (sIgE) antibody to a-Gal canbe as high as 15% in some areas. In-terestingly, this area overlaps with theknown distribution of the Lone Startick, A americanum.34 As suggested inour recent publication, we believe thatthere is a causal relationship betweentick bites and sensitization toa-Gal.12 Inthe current study, .90% of patientswith this syndrome reported tick bitesin the previous year. For patients withIgE antibody to a-Gal, tick bites causesignificantly pruritic reactions at the siteof the bite(s) which often persist. Thus, 2clinically relevant questions that canassist in formulating a diagnosis are toinquire about a history of tick or seedtick bites, and further, whether the site(s) of a bite(s) had persistent (ie, 2–3weeks) itching, erythema, or swelling.12

Of note, in our experience, if patientsare able to avoid subsequent tick bites,the level of a-Gal–specific IgE tends todecrease over time. In fact, some adultpatients with this form of allergy havebeen able to tolerate mammalian meatagain after avoiding additional tickbites for 1 to 2 years (S.P.C., T.A.E.P-M.,and J.L.K., unpublished data, 2010–2013).

Although there are multiple potentialcauses for both acute and chronic ur-ticaria, as well as angioedema and id-iopathic anaphylaxis, we report here 45pediatric patients who fit the syndromeof delayed reactions to red meat. Thisstudy not only further broadens thedifferential for evaluating “idiopathic”allergic reactions but informs of anexpanded population at risk for de-veloping this unique allergy. In keepingwith the known distribution of a-Gal,we have found that restriction ofmammalian meat can lead to completeremission of previous symptoms. Mostchildren and adults are able to con-tinue to drink milk products, althougha few patients may have symptomswith dairy ingestion. Importantly, webelieve that this research providesclear evidence that thea-Gal syndromeis important in the pediatric pop-ulation, and it should be diagnosticallyconsidered in children with a historysuggestive of delayed responses tored meat and acute, recurrent urti-caria, angioedema, or idiopathic ana-phylaxis, particularly in those patientsliving in areas where the Lone Startick is common.

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8 KENNEDY et al at Univ Of Virginia on April 12, 2013pediatrics.aappublications.orgDownloaded from

DOI: 10.1542/peds.2012-2585; originally published online April 8, 2013;Pediatrics

W. Heymann and Scott P. ComminsLisa Workman, Haley R. James, Anubha Tripathi, Charles J. Lane, Luis Matos, Peter Joshua L. Kennedy, Amy P. Stallings, Thomas A.E. Platts-Mills, Walter M. Oliveira,

in Children-1,3-galactose and Delayed Anaphylaxis, Angioedema, and UrticariaαGalactose-

  

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Supplemental Information

METHODS FOR SUPPLEMENTALTABLE 3

Absorption assays were carried outwith a-Gal bound to sepharose beads.Gala1-3Galb-OCH2CH2CH2NH-sepharosewas purchased from Glycotech (Gai-thersburg, MD). Beadswere stored as a

slurry at a 1:10 bead/phosphate-buffered saline ratio at 4°C. Mock-coupled beads were created concur-rently for control absorption studies.Absorption experiments were per-formed by incubating 500 mL of serumand 50 mL of bead slurry rotating

overnight at 4°C. Sera were spun toremove beads and assayed for re-maining specific IgE levels. Percent in-hibition was calculated as the fractionof postabsorption-specific IgE valueremaining from the preabsorptionvalue (IU/mL).

SUPPLEMENTAL FIGURE 5Comparison of specific IgE to a-Gal and total IgE among an age-matched pediatric cohort withsymptoms of delayed mammalian meat allergy (n5 45; red boxes) and a cohort of wheezing (n5 17;black circles) and nonwheezing (n5 16; blue circles) control subjects in the hospital. Subjects in thepediatric cohort with delayed reactions to mammalian meat had increased percentages of specific IgEto total IgE as compared with the control cohorts (wheezing and nonwheezing hospitalized patients).

SUPPLEMENTAL TABLE 3 Absorption of a-Gal and Cow’s Milk-specific IgE by Using Solid-Phasea-Gal in Subjects With IgE Antibody to a-Gal

Subject Specific IgE (IU/mL) Sepharose Beads Used forAbsorption

Percent InhibitionWith a-Galb

Controla a-Galb

E509 Cow’s milk 6.72 ,0.35 100a-Gal 21.5 2.08 90

T908 Cow’s milk 6.55 0.44 93a-Gal 75.2 4.94 93

CR1 Cow’s milk 5.75 ,0.35 100a-Gal 52.7 2.17 96

a Absorption with control beads reduced a-Gal or cow’s milk IgE binding by ,1%.b Galactose-a-1,3-galactose-b-1,4-GlcNAc.

PEDIATRICS Volume 131, Number 5, May 2013 SI1

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