HTLV-I sequences are not detected in peripheral blood genomic DNA or in brain cDNA of multiple sclerosis patients.

Human T-cell lymphotropic virus (HTLV-I) was recently reported to be etiologically associated with multiple sclerosis (MS). Genomic DNA from peripheral blood lymphocytes and brain plaques of patients with MS was analyzed for the presence of sequences homologous to the HTLV-I pol gene using the polymerase chain reaction and dot blot techniques. Comparison of DNA amplification patterns between patients with MS, and with control subjects who have other autoimmune conditions, with those in healthy control subjects and with an HTLV-I-infected cell line indicates that HTLV-I pol sequence is not present in the peripheral blood of patients with MS, and that the virus is not active in MS brain plaques.