[A long-term follow-up study after discontinuation of immunotherapy for Japanese cedar pollinosis].

BACKGROUND: To elucidate how long the effect of immunotherapy (IT) persist after discontinuation in patients with Japanese cedar pollinosis (JCP). METHODS: After discontinuation of IT 485 patients with JCP who completed one course of IT for 3.6 years in average were followed repeatedly up by means of author's original evaluation system of symptom-medication system from 1996 to 2005 using the method of questionnaire. Since the variations of terms after discontinuation and times of examination existed, the outcomes were averaged in every one year and follow-up seasons after discontinuation. Comparison of score and type in the year of discontinuation (base-line level) with those of follow-up was made for evaluation of outcomes. In addition, of these, 100 JCP patients, who had both intervals of 3 years or more from the discontinuation and examination times of 3 or more during the follow-up period, were examined as the evidence of reliability. RESULTS: Although the scores and types in each year were affected slightly by yearly changes in air borne pollen count, the effect persisted for 10 years with a slight change, keeping score 3 to 4. Forty two% of patients had no symptom and medication even in 2005, a year of large pollen count. Conclusively effect of the JCP IT persists satisfactorily for at least 10 years. This is the first study of long term follow-up in JCP against cross sectional study.