Flow cytometry of non-hematopoietic cells in canine effusions

Our plain-English summary of Flow cytometry of non-hematopoietic cells in canine effusions, by F. Sini, M. Melega, F.T. Cannizzo, et al (Frontiers in Veterinary Science, 2024).

The study

• Authors: F. Sini, M. Melega, F.T. Cannizzo, B. Miniscalco, P. Valenti, F. Riondato
• Journal: Frontiers in Veterinary Science
• Published: 2024;11:1414271
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The identification of non-hematopoietic cells in effusions is a diagnostic challenge in cytology. Biopsies from mesothelium or primary lesions are infrequently performed in clinical settings and immunochemistry on smears or immunohistochemistry on cell blocks are the most common ancillary test to refine the cytological diagnosis. Cavitary effusions are an ideal matrix for flow cytometry and the availability of a cytometric panel to describe non-hematopoietic cells would represent a useful tool. Here we present the results of the flow cytometric and immunohistochemical determination of cytokeratin (CK), vimentin (VIM) and desmin (DES) in 36 canine effusions. The concordance between the two methods was perfect for CK (100%), substantial for VIM (77.8%), and almost perfect for DES (97.2%). The panel was interpreted to define the epithelial (CK+VIM-DES-), mesothelial (CK+VIM+DES+), or mesenchymal (CK-VIM+DES-) origin of the cells. Unexpected profiles were considered doubtful and observed patterns were individually discussed. The concordance of the panel interpretation between two methods was 75%. The evaluation of discordant and doubtful cases suggests a lower sensitivity of flow cytometry in detecting VIM expression and revealed a high frequency of VIM+ epithelial cells, variable expression of VIM in mesothelial cells, and an important role of DES in excluding an epithelial origin when positive. Multicentric studies based on histopathological diagnoses are necessary to confirm these findings and evaluate the diagnostic utility of the panel to refine cytological diagnosis. Our results show that flow cytometry can be a timesaving alternative to IHC on cell blocks in clinical settings to detect CK, VIM and DES expression. The interpretation of the panel is similar in most cases; however, occasional discordant results, particularly for VIM, may occur.

Copyright © 2024 Sini, Melega, Cannizzo, Miniscalco, Valenti and Riondato.

In plain English

This study compared two laboratory methods for identifying the kinds of cells found in fluid that had built up in the chest, abdomen or around the heart of dogs. The samples were received at the University of Turin veterinary teaching hospital in Italy. The study did not examine asbestos or any other exposure. The authors tested 36 fluid samples from 36 dogs for three cell proteins (cytokeratin, vimentin and desmin). Each sample was tested by flow cytometry and by immunohistochemistry on cell blocks. The two methods agreed in 100% of samples for cytokeratin, 97.2% for desmin and 77.8% for vimentin. In all 8 vimentin disagreements, flow cytometry was negative and immunohistochemistry was positive. The three markers were then combined to classify cells as epithelial, mesothelial, mesenchymal or doubtful, and the two methods agreed on this classification in 27 of 36 cases (75%). The authors concluded that flow cytometry can be a timesaving alternative to immunohistochemistry on cell blocks, but that discordant results, particularly for vimentin, may occur. They stated that the main limitation was the lack of a definitive histopathologic diagnosis.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Laboratory method-comparison study in dogs: flow cytometry compared with immunohistochemistry on cell blocks from the same fluid samples
• Who was studied: 36 fluid samples from 36 privately owned dogs: 19 pleural, 11 peritoneal and 6 pericardial. There were 17 females and 19 males, with a mean age of 9.7 years. Samples were received at the Laboratory for Clinical Analyses of the Veterinary Teaching Hospital of the University of Turin, Italy. Study dates are not given.
• Exposure: No asbestos or fiber exposure was studied. The study measured the cell proteins cytokeratin (CK), vimentin (VIM) and desmin (DES) by two laboratory methods.
• Main results:
  • Cytokeratin: flow cytometry and immunohistochemistry agreed in all 36 samples (35 positive, 1 negative), which is 100% agreement.
  • Vimentin: the two methods agreed in 28 samples (18 positive, 10 negative) and disagreed in 8, which is 77.8% agreement.
  • In all 8 vimentin disagreements, flow cytometry was negative and immunohistochemistry was positive.
  • Desmin: the two methods agreed in 35 samples (15 positive, 20 negative) and disagreed in 1, which is 97.2% agreement.
  • Combined panel interpretation: the two methods agreed in 27 of 36 cases (11 mesothelial, 9 epithelial, 1 mesenchymal, 6 doubtful), which is 75% agreement.
  • Of the 9 panel disagreements, 8 were caused by vimentin being positive by immunohistochemistry and negative by flow cytometry.
  • Taking immunohistochemistry as the reference, the authors interpreted the discrepancies as suggesting that flow cytometry is less reliable for detecting vimentin.
• The authors' conclusion: The authors concluded that flow cytometry can be a timesaving and multiparametric alternative to immunohistochemistry on cell blocks in clinical settings. They added that histopathology and immunohistochemistry should still be the main tools for a definitive diagnosis, and that discordant results, particularly for vimentin, may occur.
• Limitations the authors state:
  • There was no definitive histopathologic diagnosis, so the diagnostic value of the panel could not be assessed.
  • The small number of cases and the lack of definitive diagnoses prevented any solid association between desmin-negative results and cancer.

Topics

Medical terms in this study, explained in our Lexicon: Cytology, Mesothelium, Immunohistochemistry, Cell Block, Desmin, Mesothelial Cells.

Related studies

• Diagnostic DNA-flow- vs. -image-cytometry in effusion cytology — H. Motherby, N. Pomjanski, et al. (2002)
• DNA analysis by flow cytometry in malignant pleural mesothelioma: relationship to histology and survival — H. Dazzi, N. Thatcher, et al. (1990)
• A predictive assay for human tumor cellular response to hyperthermia using dansyl lysine staining and flow cytometry — S.Y. Woo, G.C. Rice, et al. (1988)
• Rapid screening of possible cytotoxic effects of particulate air pollutants by measurement of changes in cytoplasmic free calcium, cytosolic pH, and plasma membrane potential in alveolar macrophages by flow cytometry — A. Tárnok, M. Dörger, et al. (2001)
• Flow cytometry in the exploration of the physiopathology of occupational lung disease — A.D. Curran (1999)
• Immunocytochemistry and DNA-image cytometry in diagnostic effusion cytology I. Prevalence of markers in tumour cell positive and negative smears — H. Motherby, M. Kube, et al. (1999)

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