Nasal nitric oxide combined with clinical features for preliminary screening of primary ciliary dyskinesia in bronchiectasis.

RATIONALE: Primary ciliary dyskinesia (PCD), an underdiagnosed genetic disorder characterised by dysfunctional cilia, is a known cause of bronchiectasis.

OBJECTIVES

To prospectively identify PCD among patients with bronchiectasis using nasal nitric oxide (nNO) and clinical features, and to characterize genetic features.

METHODS

This cross-sectional study enrolled adolescent and adult patients with bronchiectasis from the BE-China registry at Shanghai Pulmonary Hospital. Individuals with either strong clinical suspicion or nNO ≤77 nl·min-1 received a structured diagnostic work-up, including transmission electron microscopy and whole exome sequencing. Diagnoses followed the 2025 ERS/ATS PCD diagnostic guidelines.

RESULTS

Among 373 patients with bronchiectasis, 27 (7.4%) were in the PCD group (14 "Confirmed PCD" and 13 "PCD Highly Likely"). nNO showed high screening accuracy (sensitivity 84.8%, specificity 97.1%). Patients with PCD were younger and had earlier bronchiectasis onset. Age-adjusted regression analysis showed independent associations between PCD and lower BMI (regression coefficient [RC] -1.5; 95% CI -2.9 to -0.1), FEV1 % predicted (RC -18.4; 95% CI -28.3 to -8.6), FVC % predicted (RC -11.3; 95% CI -19.5 to -3.0), and FEV1/FVC (RC -10.3; 95% CI -16.9 to -3.8). Strong associations were observed with rhinosinusitis (OR 25.3; 95% CI 8.8 to 92.1) and P.aeruginosa infection (OR 8.5; 95% CI 3.2 to 25.7). Situs inversus occurred in 25.9% of patients with PCD. DNAH11 was the most common pathogenic gene.

CONCLUSIONS

Patients with PCD had more severe disease, reinforcing the need for structured screening in patients with bronchiectasis. nNO combined with clinical features is an effective and reliable screening strategy for PCD in bronchiectasis.