Total-tau in cerebrospinal fluid of patients with multiple sclerosis decreases in secondary progressive stage of disease and reflects degree of brain atrophy

INTRODUCTION Tau protein is a potential marker of neuronal damage. The aim of the study is to investigate its potential role as a marker of brain atrophy in multiple sclerosis (MS). MATERIALS AND METHODS Cerebrospinal fluid (CSF) and blood samples were collected from 48 patients with multiple sclerosis. Total-tau (t-tau) and phospho(181Thr)-tau (p-tau) concentrations were assayed with commercially available INNOTEST® hTAU Ag and INNOTEST® phospho181Thr-tau((181P)) and correlated with indices of brain atrophy in magnetic resonance imaging (MRI) and clinical characteristics of the study population. RESULTS T-tau concentration in CSF was significantly higher in relapsing-remitting (RR) compared to secondary progressive (SP) MS patients (P = 0.01). Brain parenchymal fraction (BPF) was significantly decreased in SP patients (P = 0.002). BPF in the whole study population correlated inversely with Expanded Disability Status Scale (EDSS) (r = -0.51, P = 0.0002) and Multiple Sclerosis Severity Score (MSSS) (r = -0.42, P = 0.002). T-tau in CSF in the whole patient group correlated inversely with EDSS (r = -0.58, P = 0.0006). CONCLUSIONS The results of our study suggest that total-tau concentration in CSF in a MS population decreases in the course of disease and reflects degree of parenchymal brain loss.