High mobility group box 1 (HMGB1) protein is present in the cerebrospinal fluid of dogs with encephalitis.

Many cases of encephalitic disease with unknown etiologies have been reported in specific breeds of small dogs. High mobility group box 1 (HMGB1) in neuronal cells was recently found to be a novel cytokine-like mediator that is a marker of neuronal necrosis and inflammation. The aim of this study was to determine whether HMGB1 levels are elevated in the cerebrospinal fluid (CSF) of dogs suspected of having encephalitis. CSF was obtained from 31 dogs that were diagnosed with an encephalitic disease by clinical examinations and magnetic resonance image (MRI) scanning. The CSF samples were analyzed via western blotting (WB) and an enzyme-linked immunosorbent assay (ELISA) with a polyclonal antibody against HMGB1. The mean HMGB1 concentration was significantly higher in the encephalitic dogs than that in the healthy controls. The concentrations of HMGB1 were correlated with the cell counts and total protein concentrations, which are known CSF indicators of the neuronal inflammation associated with encephalitis. These results suggest that HMGB1 protein in CSF confirms the presence of necrosis and inflammation in most cases of canine encephalitis and that HMGB1 will be a new indicator of encephalitis.