Serum allergen-specific IgE, allergic rhinitis severity, and age

Background: Allergic rhinitis (AR) is characterized by an IgE-mediated reaction. Aging usually induces a progressive decline of immune system function. There is common belief that both allergic symptoms severity and serum IgE production decline during aging. Objective:This study aimed to evaluate the possible impact of age on: i) serum allergen-specific IgE levels in a large sample of subjects, and ii) AR symptom severity in a group of mono-allergic patients. Methods: Serum allergen-specific IgE to birch, Bet v 1, Parietaria, and Dermatophagoides pteronyssinus were measured by immunofluorometric assay (IFMA) in a sample of 8098 subjects. AR symptom severity was assessed by visual analogue scale (VAS) in a sub-group of 531 mono-allergic patients. Results: The analysis of variance showed that IgE to Bet v 1, birch, and Dermatophagoides pteronyssinus significantly decreased considering the age, whereas IgE to Parietaria did not significantly decline in respect of the age. Considering the global sample of mono-allergic patients, elderly subjects (>65 years old) tended to have lower IgE levels, but had significantly lower VAS rating, and significantly less sensitizations than adult subjects (18-65 years old). In both adult and elderly patients VAS strongly correlated with IgE values. Conclusions: Allergen-specific IgE levels tend to reduce with aging, but with differences between types of allergy. The IgE decrease is usually associated with reduced AR symptom severity. Elderly AR patients seem to have a different phenotype/endotype in comparison with adult AR ones, characterized by milder symptoms, lower IgE production, and less sensitizations. However, a close positive relationship between IgE values and VAS scores is shared by both adult and elderly AR patients, confirming the close link between allergy and symptoms that persists also in the elderly.