Ciliated epithelial cell nipples are a common feature of primary ciliary dyskinesia (PCD)

Background: Laboratory based PCD diagnosis relies on a battery of complex tests. Common epithelial features of PCD include abnormal ciliary beat pattern after high speed video analysis and, in most cases, abnormalities of the ciliary axoneme seen after transmission electron microscopy (TEM). Phenotyping of PCD could be further enhanced by discovery of common features of the epithelium specific to PCD. We noted ciliated cells in PCD biopsies that project from the epithelium and these are referred to as ciliated epithelial cell nipples. Aims: To test the hypothesis that ciliated epithelial cell nipples are a common feature of PCD. Methods: Nasal brush biopsies were taken from 40 PCD and 18 non-PCD patients. The strips of ciliated epithelium were visualised by a light microscope and a high speed video recording made. The epithelium was fixed for TEM analysis. Re-growth of cilia from the biopsy was performed using cultures at an air-liquid interface. Light microscopy and TEM analysis was repeated on the cultured cilia. Results: Ciliated epithelial cell nipples were found in 72.5% of the PCD positive samples tested. There were no nipples present in non PCD biopsies. After re-growth of the PCD cilia in culture the nipples were present in 15% of the cultures. Data to show PCD phenotype breakdown of this feature and ciliary functional analysis data will be presented. Conclusion: Ciliated epithelial cell nipples are a common feature of PCD. The physiological significance of the ciliated nipples in PCD remains to be determined.