Anaphylactic and urticarial reactions in patients with IgE antibodies specific for the xenoantigen a

1
Anaphylactic and urticarial reactions in patients
with IgE antibodies specific for the xenoantigen
alpha 1-3 galactose

• Scott Commins
• University of Virginia
• Estes Park, 2007

2
Case Report

• 24 yo man presented to ED with abrupt onset of
  urticaria, pruritus, and wheezing roughly 5-6
  hours after eating dinner.
• PMH
• Single HSR/anaphylactoid reaction 1 year prior -
  attributed to beef
• History of childhood asthma

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Physical Exam

• VS 361, 89, 145/95, 18, 96
• Pruritic rash over abdomen, face, ears
• Urticaria over arms, shoulders, abdomen, and
  thighs
• Expiratory wheezes bilaterally
• No angioedema

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ED Course

• Treated with
• 50mg IV Benadryl
• 20mg IV Pepcid
• 125 mg IV Solumedrol
• Observed x4 hours and discharged to home
• Referred to allergy clinic

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Allergy Follow-up

• Total IgE 188 IU/mL
• Skin prick and ID positive to beef, lamb, pork
• Skin prick and ID negative to codfish, oyster,
  shrimp, cashew, peanut, wheat, chicken meant,
  turkey, corn, soybean, egg
• Skin prick and ID positive to cat, dog, yeast
• ImmunoCAP positive to beef, lamb, pork

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IgE?

• While pondering
• This appears to be IgE-mediated, so why the time
  delay
• We were finding
• Increasing evidence of cross-reactivity bewteen
  IgE to a chimeric monclonal antibody, C225, and
  beef.

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C225 and Beef

• Cetuximab

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IgE to Alpha 1-3 Galactose

• Cross-inhibition between cetuximab, a-gal, beef
  and cat (not Fel d 1)
• Lack of IgE response when cetuximab is expressed
  in CHO cell line, which does not add
  glycosylation sites

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Anaphylaxis and Urticaria Study

• Enrolled patients (n10) with recurrent
  anaphylaxis or chronic idiopathic urticaria
• - Patients who improved on avoidance diets
• - Patients with clear symptoms to beef

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IgE Abs (IU/mL) to Cetuximab F(ab)2 fragment
Depletion with anti-IgE
Patients enrolled
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Skin testing

• Currently accumulating this data will be ready
  by presentation date

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Specificity of IgE Abs (IU/mL) binding to
Cetuximab
Patients enrolled
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Contributors

• Dr. Thomas Platts-Mills
• Jacob Hosen
• Shama Satinover
• Lucy Goddard