Charcot-Leyden crystals and their constituent protein galectin-10 as a biomarker for allergic bronchopulmonary aspergillosis

Résumé fourni par la source

Allergic bronchopulmonary aspergillosis (ABPA) is driven by a hypersensitivity reaction to Aspergillus spp. and characterized by predominant type 2 inflammation. While Charcot-Leyden crystals (CLCs) have been sporadically described in ABPA mucus, a systematic evaluation is lacking. Given that CLCs are composed of galectin-10 (Gal-10), systemic Gal-10 levels might reflect airway pathophysiological processes, positioning it as a putative biomarker for ABPA. This monocentric prospective cohort study was conducted between December 2021 and January 2025 at the Cystic Fibrosis (CF) Reference Centre, Ghent University Hospital, Belgium. CLCs were screened for on airway sample cytospins using light microscopy, and plasma Gal-10 was quantified via an in-house ELISA. A total of 168 study participants was included, of whom 121 with CF, 23 with asthma and 24 healthy volunteers. In all 21/168 subjects diagnosed with acute ABPA, CLCs were observed in airway samples (sensitivity: 100[93–100]%), whereas CLCs were infrequently detected in the CF and asthma control population (specificity: 59[41–75]%). Notably, specificity for ABPA improved as the CLC count increased. Plasma Gal-10 levels were significantly elevated in individuals with airway CLCs (p=0.01), and to discriminate acute ABPA from CF and asthma controls, the mean AUROCC for plasma Gal-10 was 0.70. In conclusion, the absence of airway CLCs has clear potential as a rule-out test for acute ABPA. The presence of airway CLCs correlates with elevated plasma Gal-10 levels, which might be a promising systemic biomarker for acute ABPA. Further research is warranted to establish its position among existing diagnostic criteria.

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