Progress and challenges in fungal lung disease in cystic fibrosis

Purpose of review This review is an overview of the recent progress made for the diagnosis and understanding of fungal lung disease in people with cystic fibrosis (CF), with a focus on Aspergillus fumigatus, the most common filamentous fungus in the CF airway. Currently, the longstanding question of the clinical significance of Aspergillus fumigatus and other fungi in CF respiratory cultures, in the absence of allergy, remains. Clinical criteria and biomarkers are needed to classify fungal lung disease and determine who may warrant therapy. Recent findings Several retrospective and prospective studies have described the prevalence of A. fumigatus and other fungi in the CF lung and factors contributing to the changes in fungal epidemiology. Selective fungus culture testing for the detection of fungi in CF sputa has been well studied, yet a standardized fungus culture protocol has yet to be defined. Culture-independent molecular studies and other fungal diagnostic testing have been conducted in the CF population, leading to efforts to better understand the clinical role of these tests. Recent works have aimed to determine whether chronic A. fumigatus colonization is associated with lung disease progression measured by FEV1 percentage predicted, structural lung disease, lung clearance index and respiratory quality-of-life. However, the existing knowledge gaps remain: definition of a fungal respiratory infection, the association between fungal infection and clinical outcomes, and indications for antifungal therapy. Summary Significant progress has been made for the detection and diagnosis of fungal lung disease. Yet, the role and impact of A. fumigatus and other fungal infections on respiratory health in people with CF remains to be determined.