Serum transforming growth factor-beta levels depend on allergen exposure in allergic rhinitis

Allergic rhinitis (AR) is characterized by inflammation sustained by dysregulated immune response. T-regulatory cells are involved in AR pathogenesis, mainly producing IL-10 and transforming growth factor (TGF)-beta. Indeed, there is a functional and allergen-specific defect of T-regulatory cells in AR. However, there are no data about the influence of allergen exposure on TGF-beta serum levels. Therefore, the aim of this preliminary study was to evaluate TGF-beta serum levels in patients with seasonal AR. Patients were evaluated either outside the pollen season and after 1 preseasonal sublingual immunotherapy (SLIT) course (38 subjects) or during the pollen season (57 subjects).

All patients were allergic to Parietaria and/or grasses alone. TGF-beta was measured by a commercially available kit. Symptoms, drug use and eosinophils were evaluated.Serum allergen-specific IgG and IgA levels were also measured by the ELISA method.

TGF-beta serum levels were significantly lower in patients evaluated outside the pollen season in comparison with the other 2 situations. SLIT induced the significantly highest TGF-beta serum levels. There was a significant negative relationship between TGF-beta and eosinophils in patients after SLIT. IgG and IgA levels were higher in SLIT-treated patients.

This preliminary study provides evidence that TGF-beta serum levels are significantly dependent on allergen exposure.