Tauopathies are a heterogeneous mixture of neurodegenerative disorders, including Alzheimer's disease and frontotemporal dementia (FTD), characterised by the accumulation of tau filaments in brain tissue. Tau protein aggregation is inhibited by hydromethylthionine (HMT), an effect that appeared to be prevented in clinical trials for subjects already receiving acetylcholinesterase inhibitors or memantine. Since neuroinflammatory responses are associated with tauopathies, we investigated the effect of HMT on the brain immune response and inflammatory status in line 66 (L66) mice, an FTD-like model overexpressing human tau, in the presence of memantine. We determined whether HMT (5 and 15 mg·kg