IL-6 and TIMP-1 correlated to airway pathogen colonization and predict disease severity in patients with non-cystic fibrosis bronchiectasis

<bold>Background:</bold> Non-cystic fibrosis bronchiectasis is associated with airway pathogen colonization. We planned to investigate the inflammatory markers in patients with different airway pathogens and their correlation with outcomes. <bold>Methods:</bold> We enrolled patients aged between 20 and 75 from October 2021 to August 2022. All patients had sputum evaluation for bacterial and fungal cultures before enrollment, and were classified into 4 groups according to the culture results. <bold>Results:</bold> Forty-four patients with non-CF bronchiectasis and 6 controls were enrolled and categorized as follows: Group 1, no pathogens identified in sputum cultures (n = 14); Group 2, positive fungal culture results (n = 18); Group 3, positive P. aeruginosa culture results (n = 7); and Group 4, positive culture results for both fungi and P. aeruginosa (n = 5). Group 4 had significantly higher serum defensin α1, IL-6 and tissue inhibitors of MMP (TIMP)-1 levels than group 1 patients. Serum levels of IL-6 and TIMP-1 were positively correlated with the FACED score and negatively correlated with distance-saturation product. <bold>Conclusions:</bold> Significantly higher levels of serum IL-6 and TIMP-1 were found in the patients who had concomitant fungal and P. aeruginosa colonization, and were closely related to clinical severity and may have important roles in disease monitoring.