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.