[Mucoviscidosis: what is the cause of bronchitis?]

To this day, there is no explanation as to why chronic airway obstruction develops in cystic fibrosis (CF). Even if the mucous secretions are considered abnormal, these abnormalities resemble those observed in patients without CF. There is no primary alteration of the ciliated cells and the presence of a CF ciliary inhibitory factor has not yet been established. However, the electrolyte (chloride and sodium) transport abnormalities in airway epithelia can induce a dehydration of bronchial secretions and a slowdown of mucociliary transport in peripheral airways. But this does not explain the specific lung infection and the role of Pseudomonas aeruginosa. No specific biochemical or structural abnormality of the CF-specific bronchial secretions and/or cell membranes has yet been identified. The question therefore remains open: are we dealing with a deficient respiratory tract immunity? The CF coding gene has been localized: could the discovery of a "basic defect", a direct expression of the abnormal gene, explain the electrolyte transport abnormalities, the specific lung infection and other CF manifestations?