1220 Arch Pathol Lab Med—Vol 124, August 2000 Ciliocytophthoria in Clinical Virology—Hadziyannis et al Ciliocytophthoria in Clinical Virology Emilio Hadziyannis, MD; BelindaYen-Lieberman, PhD; Gerri Hall, PhD; Gary W. Procop, MD ● Direct immunofluorescence assays (DFAs) are used in the clinical virology laboratory for the rapid detection of viruses. An assessment of the cellularity of specimens sub- mitted for DFA is necessary for the most effective use of this assay. This assessment ensures that an adequate num- ber of the appropriate cells are present for examination. During this assessment, clinical virologists may encounter unfamiliar cellular elements or cellular fragments. One of these elements, ciliocytophthoria, has been misinterpreted as a parasite in specimens submitted for cytologic testing. We describe a similar case in which a technologist thought that ciliocytophthoria possibly represented a ciliated par- asite in a nasopharyngeal specimen sent for respiratory syncytial virus DFA. After a thorough morphologic exami- nation, the staff dismissed the possibility of a ciliated par- asite. We confirmed this entity as ciliocytophthoria using morphologic criteria and the Diff-Quik stain. This near mis- identification of ciliocytophthoria as a ciliated parasite af- fords us the opportunity to raise the awareness of clinical virologists about ciliocytophthoria. Additionally, we briefly review useful features for differentiating ciliocytophthoria from the only ciliate parasitic for humans, Balantidium coli. Finally, we present the utility of a commonly used cytologic stain, the Diff-Quik stain, for the confirmation of ciliocytophthoria. (Arch Pathol Lab Med. 2000;124:1220–1223) D irect immunofluorescence assays (DFAs) are common- ly used in the clinical virology laboratory for the rapid detection of a wide variety of viral pathogens. These rapid and highly specific assays consist essentially of staining an air-dried portion of a patient specimen with a fluorescein-labeled antibody that is directed toward a spe- cific viral pathogen. After removing unbound stain by washing, the specimen is examined using fluorescence mi- croscopy for the presence of virally infected cells. To en- sure that adequate and appropriate cells are present for staining, the cellularity of specimens submitted for DFA should be assessed. During this assessment, clinical virol- ogists may encounter unfamiliar cellular elements or cel- lular fragments. Ciliocytophthoria have been misinterpreted as ciliated microorganisms. 1–4 Hilding first noted these anucleate, apical remnants of ciliated epithelial cells in 1930. 5 In 1956, Accepted for publication December 6, 1999. From the Section of Clinical Microbiology, Department of Clinical Pathology, Division of Pathology and Laboratory Medicine, Cleveland Clinic Foundation, Cleveland, Ohio. Reprints: Gary W. Procop, MD, Clinical Microbiology/L40, The Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195. Papanicolaou used the term ciliocytophthoria to describe these degenerative cellular fragments. 6 Ciliocytophthoria are now well described by cytologists and cytopatholo- gists and are most often seen in fixed, stained cytologic preparations. 1,3–11 Motile forms have also been observed in fresh nasopharyngeal and peritoneal specimens. 2,4 We describe both motile and nonmotile ciliocytophthor- ia in a fresh specimen, which originally raised concerns of a parasitic infection. We discuss means to differentiate this entity from the pathogenic-ciliated protozoa Balanti- dium coli. It is important that clinical virologists, who now examine the cytologic contents of some specimens, are fa- miliar with ciliocytophthoria and are able to avoid this potential diagnostic pitfall. REPORT OF A CASE A 7-month-old male infant, who was born premature at 30 weeks’ gestation, presented to a local pediatrician with wheezing. A viral origin was suspected, and a nasopharyngeal swab was submitted in M4 media to the microbiology laboratory. A DFA for respiratory syncytial virus was requested. The medical technologist prepared a wet mount of the speci- men to determine if an adequate number of columnar epithelial cells were present. The examination of the wet mount, however, revealed a round-to-oval, rapidly moving, but dyssynchronous, ciliated form that was thought to represent a ciliated microor- ganism (Figure 1). Numerous morphologically similar but non- motile forms were also noted. The specimen was then examined by parasitologists and pathologists, who determined the forms to represent ciliocytophthoria and not a ciliated protozoan. A Diff-Quik stain confirmed the identification of ciliocytophthoria (Figure 2). Both respiratory syncytial virus DFA and additional viral cultures for other respiratory pathogens were negative. The patient was seen in a follow-up visit 5 days later, and he ap- peared healthy. COMMENT The enumeration and differentiation of cells present in clinical specimens submitted for microbiologic studies have already proven cost-effective and medically rele- vant. 12 For instance, it is now standard of practice to de- termine the number of squamous epithelial cells in spec- imens submitted for bacterial sputum culture and to reject specimens contaminated with oropharyngeal flora. 13 In clinical virology, it is important to assess a specimen sub- mitted for DFA to determine the presence and number of columnar epithelial cells. Specimens with few columnar epithelial cells may be suboptimal for DFA, since poten- tially infected cells either are not present or may be pres- ent in low numbers. 14 In our laboratory, if fewer than 25 ciliated respiratory epithelial cells are present, the speci- men is processed, but the clinician is notified that the