Tehran University of Medical Sciences Iranian Journal of Allergy, Asthma and Immunology 1735-1502 25 4 2026 06 03 502 516 Shuke Rao Department of Pulmonary and Critical Care Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China AND Dongguan Key Laboratory of Precision Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China Jiashun Xu Department of Pulmonary and Critical Care Medicine, Qingxi Hospital of Dongguan, Dongguan, Guangdong, China Weixia Xu Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital, Jinan University, Guangzhou, China Yingjie Chang Department of Pulmonary and Critical Care Medicine, The First Affiliated Hospital, Jinan University, Guangzhou, China Lichong Chen Department of Pulmonary and Critical Care Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China Weiliang Yuan Department of Pulmonary and Critical Care Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China Jiamin Xie Department of Pulmonary and Critical Care Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China Huafeng Li Department of Pulmonary and Critical Care Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China Jinjian Zhang Department of Pulmonary and Critical Care Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China Ying Xie Department of Pulmonary and Critical Care Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China Guihua Xu Department of Pulmonary and Critical Care Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China AND Dongguan Key Laboratory of Precision Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China Chenli Xie Department of Pulmonary and Critical Care Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China AND Dongguan Key Laboratory of Precision Medicine, Binhaiwan Central Hospital of Dongguan, Dongguan, Guangdong, China 2025 09 16 2025 11 14 We aimed to determine the impact of combined bacterial lysates (BLs) and bronchoalveolar lavage (BAL) therapy on specific immune biomarkers (interleukin [IL]-6, IL-17, CD4+, CD8+), lung function (forced expiratory volume in 1 second [FEV1], forced vital capacity [FVC], maximal expiratory flow at 25% of FVC [MEF25]), and clinical symptoms in bronchiectasis patients with chronic P aeruginosa colonization. Sixty-five stable bronchiectasis patients were randomized to receive BAL plus oral BLs (treatment group) or BAL alone (control group). After 3 months, IL-6 and IL-17 levels in BAL fluid and serum, peripheral blood T-lymphocyte subsets, lung function indices, clinical symptom scores (CSS), and reinfection rates were assessed. Compared with BAL alone, the combination therapy significantly reduced IL-6 and IL-17 concentrations in both BAL fluid and serum. CD4+ and CD8+ T-cell counts increased markedly in the treatment group, correlating positively with improved lung function metrics (FEV1, MEF75%, MEF50%, MEF25%, diffusion capacity). Elevated IL-6 and IL 17 were inversely correlated with pulmonary function and positively associated with symptom severity and reinfection risk. Clinically, the treatment group demonstrated improved CSS, enhanced lung function, and reduced reinfections. BLs combined with BAL exert potent immunomodulatory effects by enhancing T-cell responses and downregulating pro-inflammatory cytokines, thereby improving both immune regulation and clinical outcomes in P aeruginosa-colonized bronchiectasis. These findings suggest BLs represent a promising adjunctive immunotherapy in chronic airway infections. https://ijaai.tums.ac.ir/index.php/ijaai/article/view/4590 https://ijaai.tums.ac.ir/index.php/ijaai/article/download/4590/2303