Mucins and Toll-like Receptors in Asthma

Asthma with bronchial hypersecretion is a type of asthma poorly studied. Its pathogenesis is not well understood but probably is related to the innate impaired immunity, particularly with "toll-like receptors" (TLR) and secretory mucin (MUC).

Objectives 1) Define the clinical and inflammatory phenotype of asthma with bronchial hypersecretion of mucus. 2) Compare the type of mucin present in induced sputum (IS) of patients with and without bronchial hypersecretion. 3) Determine the expression of TLRs in the IS and in the peripheral blood of asthmatics with and without bronchial hypersecretion.

Method: Cross-sectional study which included 43 asthmatic patients, 19 with and 24 without bronchial hypersecretion. All patients underwent the following: IS, spirometry, fractional exhaled nitric oxide (FeNO), prick test, total IgE and blood albumin. Analysis of mucins (MUC2, MUC5AC, MUC5B and MUC1) was determined by ELISA and expression of TLR2 and TLR4 by flow cytometry. The level of asthma control was determined by the asthma control test questionnaire (ACT) and quality of life was assessed by the MiniAQLQ questionnaire.

Inclusion criteria

• Non-smokers, asthma diagnosed as per the Global INitiative for Asthma (GINA) criteria on maintenance treatment for asthma, aged 18 to 80 years.

Exclusion criteria

• Patients were excluded from the study if they had a respiratory tract infection and/or required the use of oral corticosteroids within 30 days prior to inclusion; if they had a concomitant disease (sarcoidosis, lung cancer, pulmonary tuberculosis, bronchiectasis, nephropathy, rheumatic or liver disease); significant comorbidity that could affect the study results in the physician's judgment; or a cognitive impairment that could limit their comprehension of the subject under study or their ability to participate