We have read in detail the letter published by Martínez-Girón et al. entitled “Lophomonas or ciliated epithelial cells?”1, in which they question the evidence of the findings of flagellated parasites in patient samples from bronchoscopy samples.1

It is true that it is unusual to find this type of protozoan in bronchial lavage samples and it is also true to say that they may go unnoticed due to the lack of expertise of the microscopist, as they can be easily confused with ciliated cells originating in the bronchial tree. No specific culture media have been identified to date, but molecular techniques for confirming lophomoniasis were published by Fakhar et al. in 20192.

We reported the presence of Lophomona sp. in patient specimens using the wet-mount technique with 400× magnification post-centrifugation and subsequent Giemsa staining. This was used to distinguish between ciliated respiratory cells and the protozoan and also to analyze various morphological characteristics of the parasite, including its rounded or ovoid form (20-60 mm long × 12-20 mm wide); the double strand of flagellae at the anterior end; the absence of a terminal bar; and a certain cytoplasmic plasticity. It also helped detect the presence of thick granules and some vacuoles along with a difficult-to-visualize nucleus and the main characteristic of these protozoa, namely, asynchronous movements that generate vibratory, rotational and revolving movements in the protozoan cytoplasm (Fig. 1).

Fig. 1.

400× magnification of slide-mounted bronchial brushing sample.

(0.24MB).

These characteristics distinguish them from ciliated cells originating in the tracheobronchial tree, which are characterized by a basophilic cytoplasm, a basal end with a sharp conical insertion, and an apical end with a reinforced edge corresponding to the terminal bar from which the cilia arise. The nucleus is central, round, or oval with fine chromatin and a discrete nucleolus can be seen3,4.

Martínez-Girón et al. also mention that the protozoa were perhaps confused with the phenomenon called ciliocytophthoria, which is defined as a degenerative process of the ciliated cells as a consequence of viral infections and characterized by typical morphological changes. As we stated in our article, our lophomoniasis cases did not present any viral process at the time of diagnosis nor did we detect any evidence of carcinoma, another typical cause of these phenomena5.

It is true that the species of Lophomonas sp. cannot be distinguished in fresh mounts, but they can be distinguished from ciliated cells using stains such as Giemsa and by observing the internal characteristics of the protozoan.