How does HTLV-1 induce ATL?

Human T-cell leukemia virus type 1 (HTLV-1) spreads through cell-to-cell transmission in vivo. HTLV-1 mainly infects CD4+ T cells in vivo. Viral genes enable infected cells to proliferate and escape detection by the host immune system. HTLV-1 infected cells tend to infiltrate tissues, and enter breast milk and semen, thereby infecting a new host. HTLV-1 bZIP factor (HBZ) causes overproduction of interferon gamma, which is associated with inflammation and lymphomagenesis. Thus, the strategies by which HTLV-1 proliferates and survives in infected cells are promoted, which is thought to induce ATL and inflammatory diseases in infected individuals.