CD4+ and CD8+ T lymphocyte counts and ratio in cats with chronic gingivostomatitis and naturally infected with feline immunodeficiency virus: a preliminary study

This study aimed to evaluate the CD4+ and CD8+ T lymphocytes counts and CD4+: CD8+ ratio in a colony of cats with chronic gingivostomatitis (CGS). We used forty domestic short-haired cats inhabiting the same colony. Ten cats with CGS were immunodeficiency virus-positive (group IV), and ten with CGS were immunodeficiency virus-negative (group III). As a control, twenty cats without CGS were used: ten cats were immunodeficiency virus-positive (group II) and ten cats were immunodeficiency virus-negative (group I). We employed flow cytometry to count CD4+ and CD8+ T lymphocytes. In cats infected with the immunodeficiency virus, the presence of CD4+ lymphocytes were lower both for animals with and without CGS. Conversely, not immunodeficiency virus-infected cats with CGS had a higher amount of CD4+ when compared to seronegative animals without CGS. The counts of CD8+ T lymphocytes showed no significant difference among cats with CGS, whether infected with immunodeficiency virus or not. The CD4+: CD8+ ratio was only different for group III, which was higher than any other group. No difference was observed for total lymphocyte number and CD8+ among groups. By contrast, mean CD4+ levels were different, with cats from groups III and IV showing higher levels than those from groups I and II. The flow cytometry could be a useful tool for the diagnosis and prognosis of cats with CGS infected by the immunodeficiency virus.