Increased frequency of cystic fibrosis Delta F508 mutation in bronchiectasis associated with rheumatoid arthritis

This study investigated the clinical characteristics and the possible invol vement of the cystic fibrosis transmembrane conductance regulator (CFTR) ge ne in patients with symptomatic diffuse bronchiectasis (DB) associated with rheumatoid arthritis (RA). Twenty-six patients with both RA and DB (group RA+DB) and control groups of 29 consecutive patients,vith RA but no bronchiectasis (group RA) and 29 pa tients with symptomatic DB of unknown origin (group DB) were prospectively studied, Among the patients of the RA+DB group, four (15.4%) were heterozygous for t he CFTR gene Delta F508 mutation, whereas no Delta F508 mutation was found in patients of the RA and the DB groups (both, p<0.05). This frequency of D elta F508 mutation was also higher than the expected frequency (2.8%) in th e general European population (p<0.04), Sweat chloride values and nasal pot ential differences were normal in three out of four patients carrying the D elta F508 mutation, In the RA+DB group, those,vith Delta F508 mutation had more frequent chronic sinusitis (p<0.05), a trend toward a more severe pulm onary involvement, and a lower value of nasal potential differences (p<0.01 ) whereas their rheumatic features had no particularity, In the RA+DB group , patients with adult-onset bronchiectasis (including two with Delta F508 m utation) had a greater reduction in total lung capacity (p<0.05) and lower nasal potential differences (p<0.005) than those with childhood-onset bronc hiectasis. This study suggests a possible deleterious effect of the cystic fibrosis tr ansmembrane conductance regulator mutated protein in the airways which may predispose to the development and severity of bronchlectasis in patients su ffering from rheumatoid arthritis.