P‐9 CD8 and CD4 lymphocyte populations in blood from healthy dogs and dogs naturally infected with Ehrlichia canis

Abstract

The purpose of this study was to assess the presence of an immune dysregulation in dogs naturally infected with Ehrlichia canis. We compared CD4 and CD8 lymphocyte populations in a group of dogs with ehrlichiosis and a group of healthy dogs. Thirty‐seven dogs with natural canine ehrlichiosis (Group A) and 15 unaffected dogs (Group B) were included in the study. The study of lymphocyte populations was made by flow cytometry. Monoclonal antibodies against CD3, CD4 and CD8 were used. Results obtained in this study show an inversion in the CD4:CD8 ratio in the blood of dogs with ehrlichiosis when compared with the CD4:CD8 ratio in blood from control dogs. In healthy dogs, the number of CD4 T lymphocytes was greater than CD8 T lymphocytes. However, in dogs with ehrlichiosis, the number of CD8 T lymphocytes was greater than CD4 T lymphocytes. The percentage of CD4 T lymphocytes was lower in dogs with ehrlichiosis than in healthy dogs, but significant differences were not found between both groups. However, mean value of the percentage of CD8 T lymphocytes (with respect to lymphocyte population) in dogs with ehrlichiosis (45.81 ± 20.90%) was significantly higher (P = 0.001) than in healthy dogs (25.41 ± 13.63%). These results confirm the presence of an alteration in the T lymphocyte subpopulations of dogs with ehrlichiosis, suggesting the presence of an immune dysregulation. Funding: Self‐funded.