The correlations between cerebrospinal fluid tau protein levels, immunological parameters of cerebrospinal fluid, and the findings on magnetic resonance imaging in patients with multiple sclerosis in a bout

Objective and HypothesisAxonal degeneration is an important feature of multiple sclerosis and occursearly in the disease course. Axonal degeneration is the cause of irreversibleneurologic deficit. To date, there is no biological marker of axonal damage in multiplesclerosis. In this study, we aimed to elucidate whether the cerebrospinal fluid taupotein could be a marker of axonal degeneration. We also aimed to assess thecorrelations between cerebrospinal fluid tau protein levels, demographic features,other parameters of the cerebrospinal fluid, and magnetic resonance imagingfeatures.Material and MethodsWe included 41 patients with multiple sclerosis that were diagnosed accordingto McDonald criteria. We also included 12 patients with the first attack of ademyelinating disease suggesting multiple sclerosis. The control groups were consistof 8 patients with with neurological diseases other than multiple sclerosis (controlgroup 1) and 18 patients without neurological symptoms or signs (control group 2).Cerebrospinal fluid tau protein was measured using the ELISA method based on thesandwich method with Innogenetics Innotest h tau antigen kit. Magntic resonanceimaging scans were performed with Philips Interna (1,5 Tesla) according to a fixedprotocol for patients with multiple sclerosis.ResultsThe mean tau levels of the patients with multiple sclerosis, control group 1, andcontrol group 2 were 189.15 pg/ml, 228.27 pg/ml, and 170.21 pg/ml respectively. Nosignifcant differences between patients with mutiple sclerosis, and control groupswere detected, but in the subgroup of RRMS patients it was significantly higher thanthe mean tau level of control group 2 (202.45 pg/ml, 170.21 pg/ml respectively). Inthe subgroup of SPMS patients, the mean CSF tau level was significantly lower thanthe mean CSF tau level of the control group 2. The mean tau level of multiplesclerosis patients with 10?14 black holes on T1 weighted magnetic resonanceimages were statistically higher than the mean tau level of patients with less than 5black holes on T1 weighted images. Tau levels tend to decrease in patietns withmore than 14 black holes, but this was not significant. There was no correlationbetween the CSF tau levels and the IgG index and the number of white cells in theCSF which are the markers of inflammation. The CSF tau level and the number ofenhancing lesions on MRI were not correlated, too.ConclusionOur study showed similar tau concentrations in multiple sclerosis patients in anattack and in the control groups. The tau levels of the patients with multple sclerosisand the control groups change in a wide range, and the distance of MS plaques tothe ventricles or the spinal canal may effect the level of the tau protein in the CSF. Allthese factors suggest that tau protein is not a useful biological marker of axonaldegeneration in multiple sclerosis. In spite of these factors, the decrease of tau levelsafter an increment may suggest an increase in neurodegeneration.Key WordsMultiple sclerosis, cerebrospinal fluid, tau protein, axonal degeneration