RESUMO
OBJECTIVE: To validate the authenticity of the cases diagnosed as pulmonary Lophomonas blattarum infection in literatures and Lophomonas blattarum as a kind of pathogen resulting in pulmonary infection. METHODS: From June 2012 to May 2013, mobile cells with cilia at the anterior end of the cells were observed in BALF from 6 patients with pulmonary disease in our hospital. Morphological feature and ultrastructure of the cells were further investigated by optical microscope and electron microscope to determine the type of the cells referring to literature-published photos of Lophomonas blattarum. Literatures about Lophomonas blattarum infection were searched with keyword Lophomonas blattarum from Wanfang Data, China National Knowledge Infrastructure (CNKI) and PubMed. Diagnostic methods and figures provided by the literature were carefully reviewed, and the accuracy of diagnosis of pulmonary Lophomonas blattarum was identified. RESULTS: Mobile cells found in BALF from the 6 patients in our hospital had the morphological features of bronchial ciliate epithelial cells. A nucleus far from the cilia was observed in the middle or at the bottom of the cytoplasm, and these cells did not display the characteristic cytological structures of Lophomonas blattarum: calyx, perinuclear tubules and axial filament. Diagnosis of pulmonary Lophomonas blattarum reported in literatures so far were all based on the morphological features of mobile cells with a cluster of flagellate at anterior end of the cell by optical microscopy. None of the authors did further exploration on the ultrastructure of such a kind of cells and compared with features of Lophomonas blattarum described in the literature. All the active cells reported in literatures had the identical morphological features to those found in our investigation. CONCLUSION: In the past 20 years, all the diagnosed cases as pulmonary Lophomonas blattarum infection reported in our country were misdiagnosed. Currently, there is no evidence to show Lophomonas blattarum as a pathogen resulting in pulmonary infection.