Analysis of human T-lymphotrophic virus sequences in multiple sclerosis tissue

Several observations suggest that retroviral infection is involved in the pathogenesis of the human demyelinating disease multiple sclerosis (MS). First, lymphadenopathy-associated virus/human T-lymphotropic virus type III (LAV/HTLV-III), the agent of acquired immune deficiency syndrome (AIDS), has been shown to be neurotropic in man. Second, the genetic organization of the lentivirus visna, which causes a chronic demyelinating disease of sheep, closely resembles that of LAV/HTLV-III. Recently, Koprowski and colleagues reported that MS is associated both with raised levels of circulating antibodies to HTLV-I and with the presence of HTLV-I-specific RNA within cell lines derived from the cerebrospinal fluid (CSF). Here we report that no HTLV-I-like or LAV/HTLV-III-like sequences can be detected, by in situ hybridization, in central nervous system (CNS) tissues from MS patients, and that nonspecific HTLV-I-like signal in peripheral blood mononuclear cells or in CSF cell lines is characteristic of MS. Furthermore, enzyme-linked immunosorbent assay (ELISA) analysis of circulating and CSF antibodies for HTLV-I reactivity fails to distinguish between MS and control groups.