The Angiotensinogen AGT p.M235T Gene Polymorphism May Be Responsible for the Development of Severe Anaphylactic Reactions to Insect Venom Allergens

Background: Insect venom allergy (IVA) is present in 1-3% of the population. A group of patients with high specific IgE do not react to stings. In contrast, a proportion of patients with IVA have low specific IgE levels. These findings indicate that factors other than specific IgE may also be involved in IVA. Dysfunction of the renin-angiotensin system (RAS) has been described as a potential factor in IVA. The objective of this study was to determine the prevalence of angiotensin AGT p.M235T and angiotensin-converting enzyme ACE I/D, I/I, D/D gene polymorphisms in patients with IVA and to relate the presence of these gene variants to the course of IVA and the safety of treatment. Methods: A total of 107 patients with IVA and 113 controls were studied. AGT p.M235T and ACE (ID, I/I, D/D) gene polymorphisms were examined, and angiotensin I levels were measured by immunoassay. Results: The frequency of the AGT MM M235T variant was significantly higher in IVA patients (29.9%) than in controls (17%, p = 0.02). The presence of the MM M235T genotype increased the risk of grade IV reactions (odds ratio = 2.5 and 95% confidence interval 1.04-6.08). There were no differences in the prevalence of the ACE I/D polymorphism and angiotensin I levels between control groups and patients with different grades of anaphylactic reactions or patients with side effects of venom immunotherapy. Conclusion: The AGT M235T MM variant may be responsible for severe anaphylactic reactions to insect venom allergens in some patients. Copyright (C) 2010 S. Karger AG, Basel