The Use of FKBP51 in the Identification of Non-adherence to Inhaled Corticosteroids in Difficult Asthma

Approximately 5-10% of people with asthma do not respond to to standard therapy and are referred to as having difficult asthma. Evidence shows that this poor response is not always related to asthma severity and non-adherence to treatment is recognized as a common underlying problem, in 35% of these patients. Recognising non-adherence in the clinic is problematic as there is no straightforward objective test to identify it. Previous studies have demonstrated up-regulation of FKBP51 gene expression following treatment with steroids, making it a potential biomarker of steroid exposure. It is therefore also a potential biomarker of non-adherence to inhaled corticosteroid therapy. The investigators plan to assess the feasibility of distinguishing non-adherent subjects who are by omission steroid naïve from adherent subjects, steroid exposed subjects using FKBP51 gene expression in sputum and throat swabs. To do this the investigators will obtain throat swab and sputum samples from healthy volunteers, steroid naïve asthmatics and adherent asthmatics on high dose ICS to assess if FKBP51 gene expression is comparable in each group. The investigators will then compare the FKBP51 gene expression response to directly observed inhaled steroid therapy in steroid naïve, non-adherent and adherent asthmatics. This will identify if the response in gene expression distinguishes steroid exposed (adherent) from steroid naïve (non-adherent) patients. Identifying non-adherence will benefit patients by enabling appropriate tailored management for non-adherence to enhance treatment effectiveness. It will also identify patients with therapy resistant asthma who have an unmet need and may benefit from expensive novel therapies such as Omalizumab.