Ciliary videomicroscopy at room temperature might lack sensitivity for primary ciliary dyskinesia diagnosis

Background: Primary ciliary dyskinesia(PCD) is an heterogenic inherited ciliopathy in which respiratory cilia are stationary or dyskinetic. Digital high-speed videomicroscopy(DHSV) is highly sensitive and specific for PCD diagnosis but lacks of standardization. Various laboratories perform DHSV using different temperature, which may influence ciliary functional analysis(CFA). Recent data suggest that ciliary beat frequency(CBF) increases with temperature, but the relationship between ciliary beat pattern(CBP) and temperature has not been extensively studied. However, CBP evaluation is more sensitive and specific for PCD diagnosis. Aims: To study the effect of temperature during DHSV on CFA. Methods: Ciliated epithelial samples were obtained by nasal brushing from 5 confirmed PCD patients. Beating cilia were recorded using DHSV at 37°C and at room temperature(25°C). CFA was assessed by CBF and the percentage of dyskinesia(%DK). Results: Patients 1 to 4 had abnormal ciliary function at 25°C and at 37°C, as measured by CBF and the %DK. In contrast, while at 37°C patient 5 presents with %DK=93% (normal value:17%±8) and with CBF=9.4Hz ±13.3 (normal value:14.8Hz±2.2), CFA performed at 25°C would miss a PCD diagnosis. Conclusion: In this pilot study, as suggested previously, some PCD variants present a temperature sensitive ciliary function and the diagnosis may be missed if DHSV is performed under 37°C. Due to the heterogeneity of PCD, this result has to be confirmed in a higher number of patients.