Objective The study was designed to analyze the efficacy of standardized house dust mite allergen vaccine to allergic rhinitis by subcutaneous injection and investigate the possible mechanism of specific immunotherapy(SIT).Methods From January 2011 to December 2011 a prospective study was performed in the Department of Otorhinolaryngology Head and Neck Surgery,the Affiliated Hospital of Nantong University,involving 90 patients with perennial AR,of whom 60 patients received Der p-SIT +pharmacotherapy after their approval and 30 received only pharmacotherapy.All patients were allergic to house dust mites.Symptom and medication scores were recorded three times:before the treatment,at the middle of treatment and at the end of treatment.Over a period of 1 yr.prior to and at the end of treatment,CD4 + CD25 + Foxp3 + Treg cells and Th17 cells were measured by flow cytometry.SPSS 21.0 software was used to analyze the data.Results The symptom scores using VAS and medication scores in AR patients treated with SIT and medication were reduced,the differences were significant (14.25 ± 6.40,1.00 ± 0.84 vs.32.18 ± 7.78,3.12 ± 1.54,t value was 19.65,10.71,both P ＜ 0.05).The symptom of VAS score in medication group was reduced after treatment (30.30 ±5.97 vs.20.30 ±5.79,t =10.09,P ＜0.05),but the medication score had not significant difference (P ＞ 0.05).The frequency of Thl7 cells in peripheral blood mononuclear cells were decreased in patients treated with SIT,whereas the frequency of Treg cells were increased (x2 value was 2.81,2.80,both P ＜ 0.05),but not in medication group.Conclusions Both SIT and pharmacotherapy can improve symptoms of allergic rhinitis,but SIT can also reduce medication use.The effect of immunotherapy is better than drug treatment alone.The frequency of blood Th17 cells in peripheral blood mononuclear cells were decreased in patients treated with SIT,whereas the frequency of Treg cells were increased.