 Defective mucociliary clearance characterizing CF is associated with local immunological disorders.In addition, the prolonged therapy with antibiotics and the use of corticosteroid treatments may also facilitate fungal growth.Although the clinical relevance of the fungal airway colonization is still a matter of debate, filamentous fungi may contribute to the local inflammatory response and therefore to the progressive deterioration of the lung function, as often happens with allergic bronchopulmonary aspergillosis – the most common fungal disease in the context of CF, involving a Th2-driven immune response to "Aspergillus" species.