Long-term follow-up of the clinical relevance of short outer dynein arms in human nasal cilia

Clinical significance of short outer dynein arms was examined in a long-ter m follow-up study of 76 patients with various respiratory symptoms. Clinica l evaluations, nasal mucociliary transport rate (NMTR) measurement and tran smission electron microscopy were performed. Follow-up examinations took pl ace 5-11 years later. In the initial examination four patients and on follo w-up seven patients were found to have short outer dynein arms in their nas al mucosal biopsies. Short dynein arms were associated with a slow NMTR, po orly coordinated ciliary beat direction, and clinical symptoms of perennial rhinitis and recurrent sinusitis. Short dynein arms were found to be a sig nificant histologic finding and probably represent a variant of primary cil iary dyskinesia. In some cases short outer dynein arms may be a reversible finding with improving clinical symptoms. It is obvious that at least part of dynein defects are acquired.