Pathological investigations on lung lesions in natural infectious peritonitis infection in cats

The aim of this study is to examine the lung lesions in infectious peritonitis infection of cats in detail and to evaluate the cellular response types and cytokine effects in the region during inflammation comparatively. The material of this study was composed of paraffin blocks belonging to the tissues of 25 cats, 20 of which were diagnosed with FIP, and 5 of which were in the control group (no pathology was found in the lung) in the archive of Burdur Mehmet Akif Ersoy University, Faculty of Veterinary Medicine, Department of Pathology. Paraffin blocks were cut at a thickness of 4 µm and placed on normal and poly-l-lysine slides. Sections taken on normal slides were stained with Hematoxylin-Eosin and microscopic lesions of the disease were determined. Tissues taken on slides with poly-1-lysine were separately Anti-Mause Anti-Feline Coronavirus Monoclonal Antibody, Anti-TNFα Antibody, Anti-IL-1-β Antibody, IL6 Antibody, Anti-CD3 Antibody and Anti-CD20 Antibody streptavidin- Biotin peroxidase method and immunohistochemical method were applied using standard commercial kit (Ultravision Detection System Anti-Polyvalent, HRP). The stained sections were examined under a light microscope, and microphotographs of the lesioned areas were taken and recorded. Photographs of the cases were examined one by one, scoring was done and tabulated. A different table was created for each cytokine and comparisons were made. As a result, in severe cases, it was determined that T lymphocytes (CD3) with high IL-1 IL-6 TNFα oscillations decreased in number, whereas B lymphocytes (CD20) increased in number. Accordingly, it was observed that the virus inhibited T lymphocyte defense by destroying T lymphocytes, and the virus replicating in macrophages increased B lymphocyte proliferation with repeated attacks. However, it was determined that the damage was related to excessive cytokine releases against antigen-antibody complexes as a result of B lymphocyte-mediated immune response rather than the direct effect of the virus. With this feature, it is thought that there are similarities to the Covid-19 disease seen in humans and that it can be a role model in the formation mechanism, diagnosis and treatment of Covid-19 and FIP.