Nasal obstruction is a leading symptom in patients with allergic rhinitis and depends on inflammation characterized by Th2 polarization. Thus, IFN-gamma is typically deficient in allergic patients. It has been previously reported that ebastine is able to reduce Th2-dependent cytokines. The aim of this study is to preliminarily evaluate IFN-gamma production by peripheral blood mononuclear cells (PBMNC) and clinical changes after a treatment with lyophilized ebastine in patients with persistent allergic rhinitis (PER). Ten patients with PER were evaluated, 7 males and 3 females (mean age 32.4 +/- 6.2 years), all of whom received lyophilized ebastine (20 mg/daily) for 3 weeks. Total nasal symptom score (TSS), subjective evaluation score by visual analogue scale (VAS), and rhinomanometry were evaluated in all subjects before and after treatment. IFN-gamma production by peripheral blood mononuclear cells (PBMNC) was evaluated using different stimuli, in un-treated and ebastine-treated allergic patients by ELISPOT. Ebastine treatment induced significant increase of IFN-gamma production stimulated by grasses (p<0.0001) and Dermatophagoides farinae (p=0.0015). This effect was significantly related with TSS and VAS improvement after treatment (p=0.0038 and 0.004 respectively). In conclusion, this preliminary study demonstrates the effectiveness of ebastine treatment in increasing IFN-gamma production. The clinical relevance of this study is that the clinical improvement is related to the immunologic activity.