Carry-over effect on IFN-gamma production induced by allergen-specific immunotherapy

Allergic rhinitis is characterized by Th2 polarization and defective IFN-gamma production. Specific immunotherapy determines an allergen-specific clinical improvement.

It was to evaluate whether a course of pre-seasonal SLIT with pollen allergen extract might affect the in vitro IFN-gamma production using Dermatophagoides farinae (Df) allergen as stimulus, in patients presenting with rhinitis due to pollen allergy.

Thirty-nine AR patients with pollen allergy were included in the study. They assumed pre-seasonal SLIT for 3 months. IFN-gamma-specific producing cells were assessed by cytokine ELISPOT before and 3 months after the SLIT course end.

SLIT provided a significant increase of both pollen-induced and Df-induced IFN-gamma production (p<0.001).

The present study provides evidence that though the defective IFN-gamma production is allergen-specific in allergic subjects, the SLIT increasing effects on IFN-gamma may be non-specific.