Amplification of HTLV‐1‐related Sequences among Patients with Neurological Disorders in Highly Endemic Nagasaki: Lack of Evidence for Association of HTLV‐1 with Multiple Sclerosis

We studied DNA sequences homologous to HTLV‐1 in peripheral blood mononuclear cells (PBMC) of 30 patients with neurological disorders in Kyushu, where HTLV‐1 is highly endemic. The regions of HTLV‐1 amplified by means of polymerase chain reaction (PCR) included U3, U5, gag, pol, env and pX. Our system specifically detected HTLV‐1 sequences only from HTLV‐1‐positive cells and was sufficiently sensitive to detect one proviral copy per 10(3) PBMC. All PCR‐positive cases were seropositive, including 4 cases of tropical spastic paraparesis/HTLV‐1‐associated myelopathy (TSP/HAM) (4/4), and one case each of myasthenia gravis (1/7) and multiple sclerosis (1/8). The PCR‐positive rate of patients, excluding 4 TSP/HAM cases, was 8% (2/26), which is similar to the seroprevalence of the adult population in the area. The data suggest that multiple sclerosis is not associated with prototype HTLV‐1.