Search for retroviral sequences in peripheral blood mononuclear cells and brain tissue of multiple sclerosis patients.

DNAs from peripheral blood mononuclear cells (PBMCs) of 21 patients with multiple sclerosis (MS), 1 patient with tropical spastic paraparesis (TSP) as well as DNAs from brain and spinal cord of 5 MS cases and 3 controls were examined for human T-cell lymphotropic virus (HTLV)-related sequences by polymerase chain reaction. The primers used were derived from the HTLV-I gag, env and tax genes. Amplified products were separated on agarose gels, blotted onto nylon membranes and hybridized to specific radiolabelled oligonucleotides. The sensitivity of amplification and hybridization was one copy of target DNA in 10(5) cellular genomes. None of the specimens was positive for HTLV-I sequences except the TSP probe. These negative data are all the more significant because brain material from MS patients was used in these studies. Our studies thus fail to support speculations that HTLV-I is involved in the aetiology of multiple sclerosis.