[Clinical and immunological findings of hepatitis B virus associated spastic paraparesis--a comparison with HAM].

We investigated clinical features and immunological parameters in 40 patients with slowly progressive spastic paraparesis including 13 cases (4 men and 9 women, aged 43 to 71, mean 61 years) with positive antibody to hepatitis B virus (HBV), 13 (6 men and 7 women, aged 39 to 75, mean 63 years) with positive antibody to HBV and HTLV-I, and 14 (3 men and 11 women, aged 33 to 71, mean 55 years) with positive antibody to HTLV-I (HAM). None showed obviously organic changes of the spine on magnetic resonance image. Patients with positive antibody to HBV (hepatitis B virus associated myelopathy, HBM) were significantly lower in disability grade and had a fewer incidence of micturition than in the HAM. Furthermore, natural killer (NK) activities were in normal range and peripheral blood lymphocytes did not show autologous proliferation response (APR). Patients with positive antibody to both HBV and HTLV-I showed APR similar to HAM, but in most patients NK activities were within normal range. These results suggest that the mechanism of myelopathy in HBM may be different from that in HAM, and HBV infection may play a role as a cofactor in HAM.