In vivo relationship of tumor necrosis factor-α to blood-brain barrier damage in patients with active multiple sclerosis

Tumor necrosis factor-alpha (TNF-alpha) has well recognized effects on cerebral endothelial cells and, therefore, may mediate disruption of blood-brain barrier in patients with multiple sclerosis (MS). To evaluate the in vivo relationship of TNF-alpha to blood-brain barrier impairment in MS, levels of this cytokine in cerebrospinal fluid (CSF) and serum samples from 38 patients with active MS and 48 controls were correlated with CSF to serum albumin ratios. TNF-alpha was detected in the serum of 74% and the CSF of 66% of patients with active MS. CSF levels of TNF-alpha were significantly higher in active MS compared to stable MS or other controls, and were significantly higher than corresponding serum levels. In patients with active MS, only those with detectable TNF-alpha showed signs of blood-brain barrier damage. Moreover, intrathecal levels of TNF-alpha in active MS correlated with albumin ratios and with the degree of barrier damage. Our findings are important in understanding some of the pathological changes in active multiple sclerosis.