Drug allergens and food--the cetuximab and galactose-α-1,3-galactose story

Abstract

Objective: A novel form of food allergy has been described that initially became apparent from IgE reactivity with the drug cetuximab. Ongoing work regarding the etiology, distribution, clinical management, and cellular mechanisms of the IgE response to the oligosaccharide galactose-α-1,3-galactose (α-gal) is reviewed.

Data sources: Brief review of the relevant literature in peer-reviewed journals.

Study selection: Studies on the clinical and immunologic features, pathogenesis, epidemiology, laboratory evaluation, and management of IgE to α-gal are included in this review.

Results: Recent work has identified a novel IgE antibody response to the mammalian oligosaccharide epitope, α-gal, that has been associated with 2 distinct forms of anaphylaxis: (1) immediate-onset anaphylaxis during first exposure to intravenous cetuximab and (2) delayed-onset anaphylaxis 3 to 6 hours after ingestion of mammalian food products (eg, beef and pork). Study results have suggested that tick bites are a cause of IgE antibody responses to α-gal in the United States. Patients with IgE antibody to α-gal continue to emerge, and, increasingly, these cases involve children. Nevertheless, this IgE antibody response does not appear to pose a risk for asthma but may impair diagnostic testing in some situations.

Conclusion: The practicing physician should understand the symptoms, evaluation, and management when diagnosing delayed allergic reactions to mammalian meat from IgE to α-gal or when initiating treatment with cetuximab in patients who have developed an IgE antibody response to α-gal.

Figure 1

The known distribution of the tick Amblyomma americanum is shown. Data are from the Centers for Disease Control and Prevention Web site (http://www.cdc.gov/ticks/geographic_distribution.html#lone-star), revised August 2011.

Figure 2

(A) Patient with initial flushing and erythema of the back 345 minutes (5 hours 45 minutes) after a 150-g mammalian meat challenge. (B) His symptoms progressed to systemic urticaria before resolving with antihistamine.

Figure 3

(A) Patient with systemic urticaria that appeared 225 minutes (3 hours 45 minutes) after consuming 150 g of pork sausage. Enlarged photographs of the (B) right and (C) left arms show the coalesced discrete urticaria.