001971 - Omalizumab‑Assisted Accelerated Oral Immunotherapy In Alpha‑Gal Syndrome: A Case Report

Background:

Alpha-gal syndrome (AGS) is characterized by delayed-type IgE-mediated reactions to galactose-α-1,3-galactose found in mammalian meat. Elimination therapy is often insufficient due to both the prevalence of mammalian-derived products and patients´ difficulty in adhering to the diet. Omalizumab is used to raise the reaction threshold in food allergies, either alone or in combination with oral immunotherapy (OIT); however, the literature on omalizumab-assisted OIT in AGS is extremely limited, and no standard protocol has been defined. Although red meat desensitization has been reported in current publications, to our knowledge, no controlled AGS OIT cases with omalizumab have been published.

Case presentation:

A 54-year-old male AGS patient with high alpha-gal-specific IgE levels (12.9 IU/mL), a history of recurrent severe anaphylaxis, and difficulty adhering to the diet underwent red meat desensitization with omalizumab support due to a significant deterioration in quality of life. Following an eight-week pretreatment with 300 mg every 4 weeks omalizumab, a 21-day accelerated OIT regimen was implemented by modifying protocols found in the literature. All dose increases were performed in a clinical setting, and by the end of the protocol, the patient was able to tolerate 200 g of red meat and 100 mL of kelle-paca soup (a collagen-rich bone broth made from sheep’s head and trotters) without reaction. During the maintenance period, regular consumption of 100 g of red meat twice a week continued without any problems; omalizumab treatment was safely discontinued. At month 4, the alpha-gal IgE level decreased to 0.51 IU/mL, and no new anaphylactic reactions were observed during follow-up.

Conclusion:

To our knowledge, this case presents the first example in the literature demonstrating successful management of AGS with controlled and short-term red meat desensitization administered under omalizumab treatment. Despite high IgE levels and a history of severe reactions, the achievement of safe desensitization suggests that omalizumab may be a viable adjuvant for OIT in selected AGS cases. However, since there is no evidence-based standard approach for omalizumab-assisted OIT in AGS, extensive case series and advanced controlled studies are needed to generalize this method.