[High prevalence of adult T-cell leukemia virus infection in family members of adult T-cell leukemia patients in non-endemic Hokkaido District].

Family members of non-endemic Hokkaido patients with adult T-cell leukemia (ATL) were assessed for the prevalence of ATL virus (ATLV) infection. Immunofluorescence test showed that 53 (39.8%) of 133 healthy family members of 23 ATL patients were positive for antibodies of ATLV-associated antigen (ATLA). When seropositive T-cell malignancies other than ATL and healthy controls in Hokkaido were examined, 10 of 33 family members (30.3%) of 9 patients and 3 of 18 family members (16.7%) of 5 donors had ATLA antibodies, respectively. In sharp contrast, the overall seropositivity in this northern part of Japan was 0.73%. None were seropositive (0%), when 26 family members of 6 patients with acute myeloid leukemia sero-converted by blood transfusion during the course of the disease.