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Food Allergy
A Practice
Parameter
Update 2014
Part II
Suda Sibunruang, M.D.
Commins S. and Platts-Mills T. J Allergy Clin Immunol 2009;124:652-7Tripathi A. et.al. J Allergy Clin Immunol Pract 2014;2:259-65
α-gal oligosaccharide • Major blood group substance of non-primate mammals• Present on glycolipids and glycoproteins in meat
and organs of a wide range of mammals• Target of IgG antibodies, which are present in the serum
of all immunocompetent individuals
Commins S. and Platts-Mills T. J Allergy Clin Immunol 2009;124:652-7
N-acetylglucosamine GalactoseFucose
Comparison of mammalian blood group-related oligosaccharides
O’Neil B.et.al. J Clin Oncol 2007;25:3644-8
Picture from www.ephotopix.comAccess December 16, 2014
Chung C. et.al. N Engl J Med 2008;358:1109-17
Chung C. et.al. N Engl J Med 2008;358:1109-17
Chung C. et.al. N Engl J Med 2008;358:1109-17
In most subjects who had a hypersensitivity reaction to cetuximab, IgE antibodies against cetuximab were present in serum before therapy.
The antibodies were specific for galactose-α-1,3-galactose
Tripathi A. et al. J Allergy Clin Immunol Pract 2014;2:259-65
Whether there were allergic diseases associated with IgE antibodies to alpha-gal ?
Identified a group of patients who had episodes of generalized urticaria, angioedema, or
recurrent anaphylaxis
Several patients had delayed anaphylaxis to red meat
Picture from www.washingtonpost.comAccess December 16, 2014
Delay anaphylaxis to red meat
• Delay symptoms for at least 2 hours
(most cases, 3 – 5 hours)
• All patients reported meat consumption before the onset of syndrome
• Many patients > 60 years old
(reported cases in children 5 years old)
Tripathi A. et al. J Allergy Clin Immunol Pract 2014;2:259-65
Differential diagnosis
Tripathi A. et al. J Allergy Clin Immunol Pract 2014;2:259-65
Cat- pork syndrome
Commins S. and Platts-Mills T. Curr Allergy Asthma Rep 2013;13:72–7
Differential diagnosis
• Reactions are rapid
(occur within 1 hr)
• Only after ingestion of pork
Tripathi A. et al. J Allergy Clin Immunol Pract 2014;2:259-65
Cat- pork syndrome
Investigations
• Specific IgE to -gal, beef, pork, lamb and milk
(lack of IgE to chicken, turkey, and fish)
• Skin tests
Tripathi A. et al. J Allergy Clin Immunol Pract 2014;2:259-65
Kennedy J. et.al. Pediatrics 2013;131:1545–52
Correlations of IgE to a-Gal and specific allergens
Commins S. et.al. J Allergy Clin Immunol 2009;123:426-33
SPT and ID test in patients with IgE antibodies to α-gal
SPT- commercially reagents1:20 wt/vol
ID - commercially reagents1:100 dilution (ie, 1:2000 wt/vol)
Commins S. et.al. J Allergy Clin Immunol 2009;123:426-33
SPTs with commercially available reagents (Lt) and fresh meat extract (Rt)
Picture from www.healthunit.orgAccess December 16, 2014
Relevance of tick bites
Commins S. et.al. J Allergy Clin Immunol 2011;127:1286-93
States where anaphylactic reactions to cetuximab were reported in 2006
Commins S. et.al. J Allergy Clin Immunol 2011;127:1286-93
Reported prevalence of Rocky Mountain spotted fever
Tripathi A. et al. J Allergy Clin Immunol Pract 2014;2:259-65Data are from the Centers for Disease Control and PreventionWeb site (http://www.cdc.gov/
ticks/geographic_distribution.html#lone-star)
Commins S. et.al. J Allergy Clin Immunol 2011;127:1286-93
Patients with delayed anaphylaxis to red meat whose serum contained IgE antibodies to alpha-gal
Access from www.jamestownri.govDecember 16, 2014
These bites characteristically itch for 10 days or more !
Wolver S. et.al. J Gen Intern Med 2012;28:322–5
Commins S. and Platts-Mills T. Curr Opin Allergy Clin Immunol 2013;13:354–9
Why is there delay in response ?
• The only coherent explanation is that the oligosaccharide is absorbed in some form that enters the circulation slowly
Tripathi A. et al. J Allergy Clin Immunol Pract 2014;2:259-65
Management
• Avoidance of “red meat”
• Avoiding tick bites
• Management of episodes
Tripathi A. et al. J Allergy Clin Immunol Pract 2014;2:259-65
Avoidance of “red meat”
• Avoiding not only beef, pork, and lamb but also horse, goat, rabbit, and squirrel,includes organs from mammalian sources such as liver, intestine, heart, and kidney
• In addition, other mammalian products include lard, suet, gelatin, pork rinds, and dairy products
Tripathi A. et al. J Allergy Clin Immunol Pract 2014;2:259-65
Management
• Avoidance of “red meat”
• Avoiding tick bites
• Management of episodes
Tripathi A. et al. J Allergy Clin Immunol Pract 2014;2:259-65
Unknown aspects
• Why the tick bites induce such high levels of IgE antibody and why the response is specific for this oligosaccharide
• The basis for the delay in symptoms is not clear
Tripathi A. et al. J Allergy Clin Immunol Pract 2014;2:259-65
Summary Statement 5
• Test for IgE antibodies specific for the immunogenic oligosaccharide galactose-alpha-1, 3-galactose (alpha-gal) in patients who report a delayed systemic reaction to red meat or unexplained anaphylaxis, particularly if they have a history of previous tick bites[Moderate; C Evidence]
Summary Statement 6
• Avoid all mammalian meats in patients with alpha-gal allergy because this oligosaccharide antigen is widely expressed in mammalian tissues[Moderate; C Evidence]
Thank you for your attention
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