HTLV‐I‐associated myelopathy, tropical spastic paraparesis and Borrelia burgdorferi

Abstract

Involvement of the nervous system by the human T-lymphotropic virus type I (HTLV-I) was demonstrated in the tropics and Japan in two chronic neurological disorders, tropical spastic paraparesis (TSP) {l] and HTLV-I-associated myelopathy (HAM) {2]. HAM and HTLV-I-positive TSP are recognized as clinically and pathologically identical diseases [3], and the name HAWTSP is now used for this disorder {3a].In previous reports, treponemal infections have been suggested as a suspected cause of TSP by serological and pathological studies {4]. In subsequent investigations to evaluate this hypothesis, Rodgers-Johnson and colleagues { 57 noted that Treponemu pertenue and Treponemu pallidum were unlikely to be etiological candidates for TSP. Samples were also tested for the presence of antibody to Bowelia burgdorferi, a causative agent of Lyme disease, which was recognized as a multisystem disease involving neurological complication [67. Rodgers-Johnson and colleagues [5] were able to demonstrate that 25% of Jamaican patients with TSP had antibodies to B. burgdofleri. In Japan, some cases of Lyme disease have been reported since 1987 [7].We recently examined 2 patients who had facial diplegia and elevated serum antibodies to B. burgdorferi in the Kagoshima prefecture, one of the areas in Japan in which HAWTSP is most prevalent {8]. Neuroborreliosis apparently exists in this area, and consequently, it would be important to know whether B. burgdorferi might play a role in the development of HAWTSP in Japan.Serum samples were obtained from 20 patients with HAWTSP (15 women and 5 men) from the Kagoshima prefecture. Their ages ranged from 23 to 76 years (mean, 52). The two groups of control subjects consisted of 20 healthy carriers of HTLV-I (15 women and 5 men; age range, 21 to 75, mean, 52) and 20 seronegative healthy individuals (1 5 women and 5 men; age range, 2 1 to 76, mean, 52). The serum samples from these groups were tested by immunofluorescence assay using B. burgdorferi (IFA-Bb) from Ixodes ricinus as the antigen. Positive samples in IFA-Bb were examined by the Treponema pallidum hemagglutination test (TPHA) to exclude syphilis or other treponemal infections.Only one of the HAWTSP patients was positive by IFABb. However, this patient was also positive by TPHA, indicating a previous syphilis infection. All samples from the control groups consisting of healthy carriers and healthy individuals were negative when tested by IFA-Bb and TPHA.The present results clearly demonstrate that there is not a causal relationship between B. burgdorferi and HAWTSP in Japan. However, since some differences of clinical features are known to exist between HAWTSP in Japan and in the Caribbean basin 131, the possibility remains that these differences may be influenced by infection with B. burgdofleri, which may act as a cofactor.