- Common human T cell leukemia virus type 1 (HTLV-1) integration sites in cerebrospinal fluid and blood lymphocytes of patients with HTLV-1-associated myelopathy/tropical spastic paraparesis indicate that HTLV-1 crosses the blood-brain barrier via clonal HTLV-1-infected cells. Cavrois, M., Gessain, A., Gout, O., Wain-Hobson, S., Wattel, E. J. Infect. Dis. (2000)