Neurofilament (NF) is one of the major cytoskeleton proteins of neurons and sTNFR1 is thought to reflect the true biological activity of TNF-alpha. To evaluate the levels of the heavy subunit of neurofilament (NF-H) and soluble TNF receptor 1 (sTNFR1) in cerebrospinal fluid (CSF) as biomarkers of clinical severity of subacute sclerosing panencephalitis (SSPE), concentrations of NF-H and sTNFR1 in CSF of 34 patients with SSPE and in control subjects were measured by ELISA. The CSF NF-H levels were significantly higher in patients with SSPE than in controls (p<0.0001), and those in patients in Jabbour stage III were significantly higher than in patients in stage II (p=0.015). The CSF sTNFR1 levels in SSPE patients were significantly higher than those in controls (1)=0.004), but there were no significant differences in CSF sTNFR1 levels between patients in Jabbour stages II and III. There was a significant correlation between CSF NF-H and sTNFR1 levels in patients with SSPE (p=0.011). We suggest that CSF NF-H levels can be used as a marker of development of neuronal degeneration in SSPE, and that TNF-alpha modifies the neurodestructive pathogenesis in SSPE. (C) 2008 Elsevier B.V. All rights reserved.