Alpha-gal syndrome is an allergic condition resulting from the bite of the Lonestar tick in the southeastern US that leads to sensitization to mammalian products containing the oligosaccharide galactose-alpha-1,3-galactose (alpha-gal). Cetuximab is a chimeric monoclonal antibody that contains alpha-gal and can lead to allergic reactions in individuals with alpha-gal syndrome. A 66-year-old with metastatic squamous cell carcinoma of the right tonsil with involvement of the lung and liver was planned to receive palliative therapy with cetuximab. He was screened for alpha-gal sensitization and found to have elevated specific IgE to alpha-gal but had not had adverse reactions to mammalian products previously. He was referred to our allergy clinic for further recommendations to minimize the risk of a hypersensitivity reaction. He received his first dose as a graded challenge with cetuximab. Shortly after increasing the rate of his infusion to the second step of his challenge, the patient developed flushing, disseminated urticaria, and labored breathing. The remainder of his first dose and subsequent treatments were administered via a one-bag desensitization protocol. This case suggests caution with the use of cetuximab in those with asymptomatic alpha-gal sensitization, along with the potential utility of graded challenge in a closely monitored setting, such as the ICU, to diagnose and desensitize to manage such patients in the future.
Emerson et al. (Thu,) studied this question.