For this reason, using an enzyme-linked immunosorbent assay, we first examined the humoral response against different HERVs Env in the sera of patients with acute adult T-cell leukemia/lymphoma (ATLL) compared to HTLV-1 asymptomatic carriers (ACs) and a non-infected control (NI). This evidence concerns the gene ERVW-1 and adult T-cell leukemia/lymphoma.