The association of TH2 inflammation and alarmins with disease severity in patients with non-cystic fibrosis bronchiectasis

Bronchiectasis is a progressive lung disease characterized by recurrent infections, inflammation, and irreversible bronchial wall dilation. Approximately one-third of patients with bronchiectasis exhibit eosinophilic inflammation. In a disease like bronchiectasis, where treatment options are limited, this study aimed to evaluate the relationship between potential treatment pathways and disease severity. The study included 79 patients diagnosed with non-cystic fibrosis bronchiectasis who presented to the Chest Diseases outpatient clinic at Çukurova University Balcalı Hospital between October 2024 and October 2025. Blood samples were collected from these patients for ELISA analysis to measure the levels of IL-25, IL-33, TSLP, IL-4, IL-5, IL-13, and IL-17A. The mean age of the patients was 50.19 years (range: 19-80). Etiological analysis revealed that 40.5% of cases were post-infectious, 22.8% were related to COPD, and 34.2% were associated with asthma. Pulmonary function tests showed obstructive patterns in 38% of patients, while 32.9% had normal findings.Evaluation using the BSI score revealed a statistically significant correlation between increased disease severity and higher neutrophil counts, CRP, and CD8+ T cells. Similarly, the FACED score showed a significant relationship between disease severity and body mass index, neutrophil count, and CRP. When the relationship between the FACED score and interleukins was examined, a significant increase in IL-25 and IL-5 levels was observed with rising disease severity. Furthermore, a positive correlation was found between the BSI score and IL-13 levels. When the relationship between the FACED score and interleukins was evaluated, a positive correlation was observed with IL-25, IL-5, and IL-13 levels. Both scoring systems indicated that an increase in IL-25 levels raised the risk of exacerbations. In conclusion, the BSI and FACED scores should be used to determine the risk of mortality and exacerbation in all patients. Close monitoring is necessary for patients with a history of frequent exacerbations and hospitalizations in the last year, as well as elevated IL-25 and IL-5 levels, as they have a higher risk of mortality. The data from this study, when considered alongside the pathogenesis of bronchiectasis, highlights the need to elucidate a potential treatment pathway. Further multi-center studies are required to develop new biological agents targeting these pathways and to evaluate the effectiveness of existing agents for bronchiectasis, a disease open to advancements in treatment.