Pathophysiology of the ciliated epithelium of the respiratory mucosa in humans. Disorders of ciliogenesis.

If we want to interpret morphological alterations of the ciliated epithelium of the respiratory tract, we have to consider the physiological differentiation of ciliated cells and cilia. For this, we suggest a system in which disorders are distinguished at three distinct arrest levels of the ciliary development: (1) Disorders in the production of procentrioles (secondary centrioles) lead to partial or total aplasia of the ciliary apparatus. (2) Disorders in the development of kinetosomes from secondary centrioles result in a reduced number of cilia and malformations of ciliary components. (3) Disorders in the outgrowth of cilia result in morphological abnormalities of the peripheral ciliary shaft (i.e., immotile cilia syndrome). We suppose that at all three arrest levels hereditary factors may be important, whereas at levels 2 and 3 exogenous influences may cause these alterations too. Correlation between morphology and clinical status is made difficult by conditions of auxiliary mechanisms, like cough, which compensate the mucociliary dysfunctions. For the purpose of morphometric evaluation of the biopsies we established a method of light microscopical semiquantitative analysis of brush biopsies. The regenerative power of the ciliary apparatus with respect to these frequently observed abnormalities is discussed.