Is myelopathy of unknown origin related with tropical spastic paraparesis and myelopathy associated with human T cell lymphotropic virus type I?

Paired cerebrospinal fluid (CSF) and serum samples from 52 Italian patients affected by myelopathy of unknown origin (MUO) were tested for the presence of antibodies to human T cell lymphotrophic virus type I (HTLV-I) by an enzyme-linked immunosorbent assay, in an attempt to demonstrate a common retroviral origin of MUO, tropical spastic paraparesis (TSP) and HTLV-I-associated myelopathy (HAM). All the patients complained of weakness to the legs, while weakness to the arms, mild sensory disturbances, impaired bladder and bowel functions, and impotence were present in different percentages. All CSF and serum samples were devoid of HTLV-I antibodies. The possible relations between MUO, TSP and HAM are discussed.