Rationale: Asthma inception occurs only in susceptible individuals, and is often triggered by specific environmental factors, such as respiratory viruses and aeroallergens. Although asthma is generally viewed as a chronic persistent disease, remission of asthma is possible in a subset of patients. This is highly relevant, since understanding mechanisms that contribute to asthma inception and remission may teach us how asthma can be stopped and thus may provide novel avenues for the treatment of asthma. In adulthood, average remission rates of asthma are approximate 2% per year 1. We observed that remission in adulthood is more likely with earlier onset of asthma, less airway obstruction, more severe bronchial hyperresponsiveness, and smoking cessation. A proper definition of remission is very important; we therefore introduced the terms 'clinical remission' and 'complete remission' 2. Clinical remission was defined as the absence of asthma symptoms and no use of asthma medication, complete remission as the absence of asthma symptoms, no use of asthma medication, normal lung function and no bronchial hyperresponsiveness. In a longitudinal study of 119 allergic asthmatic children followed-up for 30 years, our group found that clinical remission occurred in 30% and complete remission in 22% of all cases.