Lung Function Changes in Response to Antibiotic Therapy for Pulmonary Exacerbations in Primary Ciliary Dyskinesia

Background: Primary ciliary dyskinesia (PCD) is a rare disease caused by mutations in genes important for ciliary function and assembly. Ciliary dysfunction leads to an impaired mucociliary clearance, resulting in chronic progressive muco-obstructive lung disease. First causative treatments are underway, but clinical outcome parameters are not well defined. Thus, we aimed to detect changes in lung function to systemic antibiotic therapy in patients with PCD with a pulmonary exacerbation (PEx). Methods: PCD patients with a PEx which required systemic antibiotic treatment were included in our prospective observational study. Spirometry and multiple-breath washout (MBW) were measured within 72h at start of PEx and 2 to 4 weeks after the end of antibiotic treatment (FU) and lung clearance index (LCI), percent predicted forced expiratory volume in one second (ppFEV1), sputum and clinical data were collected. Pre-PEx values were retrospectively obtained from routine visits within 3 months prior to PEx in stable condition. Results: 23 PCD patients (71% female) with 29 PEx were included. Median age at PEx was 29.2 (IQR, 16.6 to 35.9) years. 7 (29%) participants were minors. Median ppFEV1 at pre-PEx was 70.5 (IQR, 50.3 to 83.5), 63.5 (IQR, 48.8 to 75.5) at PEx and 69.5 (IQR, 61.0 to 84.8) at FU. ppFEV1 was significantly lower at PEx (–3.6%; IQR,−9.5 to 1; p= 0.0057 ) compared to pre-PEx and significantly improved at FU compared to PEx (6.6%; IQR, 1 to 10, p= 0.0003 ). There was no significant change in LCI with a median LCI at pre-PEx of 10.5 (IQR, 9.3 to 12.5), at PEx of 10.2 (IQR, 8.7 to 11.9) and at FU of 10.5 (IQR, 9.3 to 12.5). Conclusions: Our results indicate that ppFEV1 is more sensitive than LCI to detect lung function changes at PEx and after antibiotic treatment in PCD patients. Publication History Article published online: 26 February 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany