Investigations into the lymphocyte phenotypes and the presence of rheumatoid factor and antinuclear antibody in the peripheral blood of 515 dogs

The levels of rheumatoid factor (RF), antinuclear antibody (ANA), and composition of peripheral lymphocyte subsets in 515 dogs were examined. Of these sample cases, 33 cases were diagnosed as immune-mediated fever that presented with high C-reactive protein (CRP), 31 cases were diagnosed with Hansen’s Type 1 disc herniation and the remaining 415 cases were clinically healthy dogs, and served as controls. In the cases diagnosed with immune-mediated fever, 84% of the dogs tested positive to either RF or ANA (RF positive 60.6%; ANA positive 24.2%). By contrast, 16.2% of the healthy dogs were positive for either RF or ANA (RF positive 14.9%; ANA 1.3%). The CD4/CD8 ratio for peripheral lymphocyte was high for all analysed cases diagnosed with immune-mediated fever, and was significantly higher than those of healthy controls. These results indicate that the abnormal levels of lymphocytes may be an effective indicator for immune-mediated disease coupled to immune-mediated fever.