Introduction: Primary ciliary dyskinesia (PCD) is an autosomal recessive rare disease caused by an alteration of ciliary structure. As there is not a unique gold standard diagnostic test, the European Respiratory Society and the American Thoracic Society have recently proposed the use of different diagnostic techniques to improve the accuracy and diagnosis rate of PCD. In this study, we examined our patients' immunofluorescence (IF) staining results with clinical findings suggestive of PCD with genetically inconclusive outcomes at the University of Münster.

Material-Method: Respiratory epithelial cells were obtained by transnasal brush biopsy and suspended in cell culture. Cells were treated with 4% paraformaldehyde, 0.2% Triton X-100, and 0.5% skim milk before incubation with primary antibody and secondary antibody at room temperature. The subcellular localization of DNAH5 and GAS8 in human respiratory epithelial cells of patients with PCD and control subjects were determined by using specific antibodies on IF imaging. All patients' nasal nitric oxide measurements, high-speed video microscopy analysis and genetic analyses were done.

Results: Nineteen patients were evaluated for tested antibodies. The median age (25-75p) was 15 years (10-20 years). Twelve (63.2%) patients were male. Three cases (15.7%) presented an absence of DNAH5, and one (5.3%) had a proximal distribution of DNAH5 in the ciliary axoneme. One patient (5.3 %) had cells without cilia. All patients with abnormal IF analysis had a PICADAR score of 6 and above.

Conclusion: Although IF analysis can not be used as a standalone test, it is a guiding diagnostic test for PCD in the absence of transmission electron microscopy.