Prevalence of HTLV-1 antibodies in hemodialysis patients in Japan.

The southwestern region of Japan is known as a very high endemic area of human T-cell lymphotropic virus type 1 (HTLV-1), the etiologic agent for adult T-cell leukemia (ATL) and probable causative agent for tropical spastic paraparesis and its Japanese version, HTLV-1-associated myelopathy (HAM). Hemodialysis (HD) patients seem to be at high risk for HTLV-1 infection even in other regions of Japan because they sometimes receive multiple blood transfusions. We examined antibody against ATL-associated antigen (ATLA-Ab) in 1,132 HD patients, including 1,066 patients in nonendemic areas (Chubu and Tokyo) and 66 in a highly endemic area (Okinawa). The HD patients in Okinawa showed the highest prevalence, 21.2% (14/66), while those in the Chubu area showed the lowest, 1.1% (10/846), and those in the Tokyo area an intermediate value, 2.7% (6/220). The prevalence of HD patients in each area was significantly higher than that of local blood donors, reflecting an increased prevalence roughly corresponding to the respective endemic rate. The average prevalence of ATLA-Ab among the HD patients was 2.7% (30/1,132), which was similar to that of HBs antigen (3.2%). In the nonendemic areas, 15 of 16 patients with ATLA-Ab had a history of blood transfusions, showing a significant correlation to the presence of ATLA-Ab (P less than 0.01), although four had family histories related to the endemic area. The relative risk of the presence of ATLA-Ab for HD patients with a history of blood transfusions was calculated as 10.3. In the endemic area of Okinawa, the relationship to blood transfusion was not so close, probably masked by the high background prevalence.