Bronchial thermoplasty is a new therapeutic tool for severe and uncontrolled asthma patients. Clinical trials have demonstrated clinical benefits regarding quality of life and exacerbations. Animal models suggested the reduction of bronchial smooth muscle as the principal responsible for the clinical benefits observed in asthma patients treated in the clinical trials, although there is little information about its mechanism of action, and limited to a very small number of case reports. Given that the mechanism of action of bronchial thermoplasty is still not well understood, we proposed a biological study in asthma patients treated with bronchial thermoplasty with the purpose to analyze changes in inflammatory markers and histological samples, as well as its correlation with clinical outcomes in real practice.