ELEVATED LEVELS OF INTERLEUKIN-6 IN SERUM AND CEREBROSPINAL-FLUID OF HTLV-I-ASSOCIATED MYELOPATHY TROPICAL SPASTIC PARAPARESIS

A significant elevation of interleukin-6 (IL-6) level was observed both in serum (mean 0.455 ± 0.251) and in cerebrospinal fluid (CSF) (mean 0.043 ± 0.016) obtained from 13 patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP) when compared to that of either asymptomatic carriers (mean 0.181 ± 0.074 and 0.021 ± 0.015, respectively) or controls (mean 0.208 ± 0.119 and 0.021 ± 0.015, respectively). The differences were statistically significant between HAM/TSP and asymptomatic carrier for serum (P < 0.05) or CSF (P < 0.01). The correlation indexes between serum IL-6 and anti-HTLV-I antibody titers in serum and CSF were 0.61 (P < 0.06) and 0.67 (P < 0.05), respectively. Both the cell count and protein level in CSF correlated with CSF IL-6 activity at 0.68 (P < 0.01) and 0.56 (P < 0.05), respectively. The results demonstrate that IL-6 may contribute to the production of anti-HTLV-I antibody, and signs of slight inflammation are present in the central nervous system in HAM/TSP. © 1990.