Ciliary dyskinesia might be reduced in cystic fibrosis patients diagnosed by newborn screening - 20/03/24

Mucociliary clearance (MCC) results from an effective interaction between the mucus layer and the normal coordinated ciliary beating. Ciliary dyskinesia, or an abnormal ciliary beating, is defined as an abnormal ciliary beat frequency (CBF) and/or ciliary beat pattern (CBP), and can be primary, or secondary to chronic infection or inflammation. In cystic fibrosis (CF), MCC is impaired due to dehydrated mucus, but recent data suggested that a ciliary dyskinesia may contribute to poor MCC in CF patients. Newborn screening (NBS) for CF was implemented in Belgium in 2019. The impact of NBS on pulmonary outcomes is quite unclear, but some data have suggested that lung deterioration would be slowed, likely due to reduced respiratory infections. However, to our knowledge, it is unknown if this has an impact on MCC impairment in CF. The aim of this study was to compare ciliary beating between CF patients diagnosed after a positive NBS (newborn-screened) and CF patients referred for a CF diagnosis due to suggestive clinical manifestations (clinically diagnosed).

Ciliated epithelial samples were obtained by nasal brushing from 25 newborn-screened CF patients, and from 24 clinically diagnosed CF patients. Beating cilia were recorded using digital high-speed videomicroscopy at 37°C. Ciliary functional analysis was assessed by CBF and by the percentage of abnormal CBP.

Our results showed that ciliary dyskinesia is increased in clinically diagnosed CF patients. Indeed, compared with newborn-screened CF patients, in clinically diagnosed CF patients, CBF is decreased (14.0 [13.0–16.0] Hz vs. 12.5 [10.8–14.6] Hz, P=0.017), and the percentage of abnormal CBP is increased (22.7 [14.1–29.8] % vs. 29.4 [25.3–43.2] %, P=0.034).

Our pilot study showed that ciliary dyskinesia is increased in clinically diagnosed CF patients compared with newborn-screened CF patients. This might be explained by a reduced infection and inflammation, as an appropriate CF treatment is proposed from birth in newborn-screened patients.